Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.
Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable.

It was molded into thousands of forms,
such as cases for radios, telephones and
clocks, and billiard balls. Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.
The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

v Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.

Plastic
Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic

solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as
cases for radios, telephones and clocks, and billiard balls.
 Plastic

Household items made of various kinds of plastic.

A plastic material is any of a wide range of synthetic or semi-synthetic organic
solids[citation needed] used in the manufacture of industrial products. Plastics are typically
polymers of high molecular mass, and may contain other substances to improve
performance and/or reduce costs. Monomers of plastic are either natural or synthetic
organic compounds.

The word plastic is derived from the Greek πλαστικός (plastikos) meaning capable of
being shaped or molded, from πλαστός (plastos) meaning molded.[1][2] It refers to their
malleability, or plasticity during manufacture, that allows them to be cast, pressed, or
extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and
much more.

The common word plastic should not be confused with the technical adjective plastic,
which is applied to any material which undergoes a permanent change of shape (plastic
deformation) when strained beyond a certain point. Aluminum which is stamped or
forged, for instance, exhibits plasticity in this sense, but is not plastic in the common
sense; in contrast, in their finished forms, some plastics will break before deforming and
therefore are not plastic in the technical sense.

There are two types of plastics: thermoplastics and thermosetting polymers.

Thermoplastics are the plastics that don't undergo chemical change in their composition
when heated and can be moulded again and again; examples are polyethylene,
polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE).[3] Thermosets can
melt and take shape once; after they have solidified, they stay solid.

The raw materials needed to make most plastics come from petroleum and natural gas.[4]

Overview
Plastics can be classified by chemical structure, namely the molecular units that make up
the polymer's backbone and side chains. Some important groups in these classifications
are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics
can also be classified by the chemical process used in their synthesis, such as
condensation, polyaddition, and cross-linking.[5]

Other classifications are based on qualities that are relevant for manufacturing or product
design. Examples of such classes are the thermoplastic and thermoset, elastomer,
structural, biodegradable, and electrically conductive. Plastics can also be classified by
various physical properties, such as density, tensile strength, glass transition temperature,
and resistance to various chemical products.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to
water, plastics are used in an enormous and expanding range of products, from paper
clips to spaceships. They have already displaced many traditional materials, such as
wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their
former uses.

The use of plastics is constrained chiefly by their organic chemistry, which seriously
limits their hardness, density, and their ability to resist heat, organic solvents, oxidation,
and ionizing radiation. In particular, most plastics will melt or decompose when heated to
a few hundred degrees celsius.[6] While plastics can be made electrically conductive, with
the conductivity of up to 80 kS/cm in stretch-oriented polyacetylene,[7][8][9][10] they are still
no match for most metals like copper which have conductivities of several hundreds
kS/cm. Plastics are still too expensive to replace wood, concrete and ceramic in bulky
items like ordinary buildings, bridges, dams, pavement, and railroad ties.[citation needed]

Chemical structure
Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are
assumed to have infinite molecular weight. These chains are made up of many repeating
molecular units, known as repeat units, derived from monomers; each polymer chain will
have several thousand repeating units. The vast majority of plastics are composed of
polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the
backbone. (Some of commercial interests are silicon based.) The backbone is that part of
the chain on the main "path" linking a large number of repeat units together. To
customize the properties of a plastic, different molecular groups "hang" from the
backbone (usually they are "hung" as part of the monomers before linking monomers
together to form the polymer chain). This fine tuning of the properties of the polymer by
repeating unit's molecular structure has allowed plastics to become such an indispensable
part of twenty first-century world.

Some plastics are partially crystalline and partially amorphous in molecular structure,
giving them both a melting point (the temperature at which the attractive intermolecular
forces are overcome) and one or more glass transitions (temperatures above which the
extent of localized molecular flexibility is substantially increased). The so-called semi-
crystalline plastics include polyethylene, polypropylene, poly (vinyl chloride),
polyamides (nylons), polyesters and some polyurethanes. Many plastics are completely
amorphous, such as polystyrene and its copolymers, poly (methyl methacrylate), and all
thermosets.

Molded plastic food replicas on display outside a restaurant in Japan.

History
This section requires expansion.

The first human-made plastic was invented by Alexander Parkes in 1855;[11] he called this
plastic Parkesine (later called celluloid). It was unveiled at the 1862 Great International
Exhibition in London. The development of plastics has come from the use of natural
plastic materials (e.g., chewing gum, shellac) to the use of chemically modified natural
materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely
synthetic molecules (e.g., bakelite, epoxy, polyvinyl chloride, polyethylene).

Parkesine is the trademark for the first man-made plastic. It was invented by Alexander
Parkes in 1862.[12] In 1866 Parkes formed the Parkesine Company to mass produce the
material. The company, however, failed due to poor product quality as Parkes tried to
reduce costs. Parkesine's successors were Xylonite, produced by Daniel Spill (an
associate of Parkes), and Celluloid from John Wesley Hyatt. Parkesine was made from
cellulose treated with nitric acid and a solvent. The generic name of Parkesine is
pyroxylin, or Celluloid. Parkesine is often synthetic ivory. The Parkesine company
ceased trading in 1868. Pictures of Parkesine are held by the Plastics Historical Society of
London. There is a plaque on the wall of the site of the Parkesine Works.[13]

Types

Cellulose-based plastics

In 1855, an Englishman from Birmingham named Alexander Parkes developed a

synthetic replacement for ivory which he marketed under the trade name Parkesine, and
which won a bronze medal at the 1862 World's fair in London. Parkesine was made from
cellulose (the major component of plant cell walls) treated with nitric acid and a solvent.
The output of the process (commonly known as cellulose nitrate or pyroxilin) could be
dissolved in alcohol and hardened into a transparent and elastic material that could be
molded when heated.[14] By incorporating pigments into the product, it could be made to
resemble ivory.

Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by
Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg
or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which
gives a black or brown resin. The mixture is dried and ground into a fine powder. The
powder is placed in a steel mold and compressed in a powerful hydraulic press whilst
being heated by steam. The final product has a highly polished finish imparted by the
surface of the steel mold.

Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and
formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo
Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was
searching for an insulating shellac to coat wires in electric motors and generators. He
found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky
mass when mixed together and heated, and the mass became extremely hard if allowed to
cool. He continued his investigations and found that the material could be mixed with
wood flour, asbestos, or slate dust to create "composite" materials with different
properties. Most of these compositions were strong and fire resistant. The only problem
was that the material tended to foam during synthesis, and the resulting product was of
unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform
product. He publicly announced his discovery in 1912, naming it bakelite. It was
originally used for electrical and mechanical parts, finally coming into widespread use in
consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin
Corporation acquired the patent and began manufacturing Catalin plastic using a different
process that allowed a wider range of coloring.

Bakelite was the first true plastic. It was a purely synthetic material, not based on any
material or even molecule found in nature. It was also the first thermosetting plastic.
Conventional thermoplastics can be molded and then melted again, but thermoset plastics
form bonds between polymers strands when cured, creating a tangled matrix that cannot
be undone without destroying the plastic. Thermoset plastics are tough and temperature
resistant.

Bakelite was
cheap, strong, and
durable. It was
molded into
thousands of
forms, such as cases
for radios,
telephones and
clocks, and billiard
balls.
v