COMPOSITE POLYESTER

Polymer engineering

APRIL 14, 2018

YASSER ASHOUR 127978
The British university in Egypt
Abstract
the aim of this experiment is to obtain the characterization of composite polyester. Firstly, solution of
unsaturated polymer is added to a graduated beaker then the fillers are prepared to be added
corresponding to their concentrations and another sample without added fillers. After that, leave the
mix for 5 hours to get completely hardening and the way of measuring can be produced after that
using the needed test (Hardness, Compression and pressure). To conclude, the carbon Nano tube
failure rate were found to be lower than magnesium carbonate and polyester without filler addition.

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Table of Contents
Abstract ................................................................................................................................................... 0

Introduction ............................................................................................................................................ 5

Polystyrene ......................................................................................................................................... 5

Properties of polystyrene ................................................................................................................... 6

COMMERCIAL POLYSTYRENES ............................................................................................................ 8

The three most important grades are: ........................................................................................... 8

Forms produced .................................................................................................................................. 9

Sheet or moulded polystyrene........................................................................................................ 9

Copolymers ................................................................................................................................... 10

Oriented polystyrene .................................................................................................................... 11

Procedures ............................................................................................................................................ 12

Results ................................................................................................................................................... 13

Hardness test .................................................................................................................................... 13

Tensile dog bone shape test ............................................................................................................. 14

Pure sample .................................................................................................................................. 14

Magnesium carbonate filler .......................................................................................................... 15

Carbon Nano tube filer ................................................................................................................. 16

Compression test .............................................................................................................................. 17

Pure sample .................................................................................................................................. 17

Magnesium carbonate filler .......................................................................................................... 18

Carbon Nano tube filler................................................................................................................. 19

Discussion.............................................................................................................................................. 20

Conclusion ............................................................................................................................................. 20

References ............................................................................................................................................ 20

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list of figures
Figure 1 structure of polystyrene ........................................................................................................... 5

Figure 2 ................................................................................................................................................... 9

Figure 3 ................................................................................................................................................. 10

Figure 4 pure sample tensile test.......................................................................................................... 14

Figure 5 polyester sample with magnesium carbonate filler tensile test............................................. 15

Figure 6 polyester with carbon Nano tube filler tensile test ................................................................ 16

Figure 7 pure polyester compression test ............................................................................................ 17

Figure 8 polyester with magnesium carbonate filler compression test ............................................... 18

Figure 9 polyester with carbon Nano tube filler compression test ...................................................... 19

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List of tables
Table 1 properties of polystyrene ........................................................................................................... 7

Table 2 results of hardness test ............................................................................................................ 13

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Introduction
A composite material is a material made from two or more constituent materials with significantly
different physical or chemical properties that, when combined, produce a material with characteristics
different from the individual components. The individual components remain separate and distinct
within the finished structure, differentiating composites from mixtures and solid solutions. Composite
materials are generally used for buildings, bridges, and structures such as boat hulls, swimming pool
panels, racing car bodies, shower stalls, bathtubs, storage tanks, imitation granite and cultured marble
sinks and countertops.

(jackoub, 1998)

Polystyrene
Is a hard, stiff, brilliantly transparent synthetic resin produced by the polymerization of styrene. It is
widely employed in the food-service industry as rigid trays and containers, disposable eating utensils,
and foamed cups, plates, and bowls. Polystyrene is also copolymerized, or blended with other
polymers, lending hardness and rigidity to several important plastic and rubber products. Styrene is
obtained by reacting ethylene with benzene in the presence of aluminium chloride to yield
ethylbenzene. The benzene group in this compound is then dehydrogenated to yield phenyl ethylene,
or styrene, a clear liquid hydrocarbon with the chemical structure CH2=CHC6H5. Styrene is
polymerized by using free-radical initiators primarily in bulk and suspension processes, although
solution and emulsion methods are also employed. The structure of the polymer repeating unit can
be represented as:

Figure 1 structure of polystyrene

The presence of the pendant phenyl (C6H5) groups is key to the properties of polystyrene. Solid
polystyrene is transparent, owing to these large, ring-shaped molecular groups, which prevent the
polymer chains from packing into close, crystalline arrangements. In addition, the phenyl rings restrict

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rotation of the chains around the carbon-carbon bonds, lending the polymer its noted rigidity. The
polymerization of styrene has been known since 1839, when German pharmacist Eduard Simon
reported its conversion into a solid later named metastyrol. As late as 1930 little commercial use had
been found for the polymer because of brittleness and crazing (minute cracking), which were caused
by impurities that brought about the cross-linking of the polymer chains. By 1937 American chemist
Robert Dreisbach and others at the Dow Chemical Company’s physics laboratory had obtained purified
styrene monomer through the dehydrogenation of ethylbenzene and developed a pilot
polymerization process. By 1938 polystyrene was being produced commercially. It quickly became one
of the most important modern plastics, owing to the low cost of producing large volumes of styrene
monomer, the ease of shaping the melted polymer in injection-molding operations, and the optical
and physical properties of the material. Polystyrene foam was formerly made with the aid of
chlorofluorocarbon blowing agents—a class of compounds that has been banned for environmental
reasons. Now foamed by pentane or carbon dioxide gas, polystyrene is made into insulation and
packaging materials as well as food containers such as beverage cups, egg cartons, and disposable
plates and trays. Solid polystyrene products include injection-molded eating utensils, videocassettes
and audiocassettes, and cases for audiocassettes and compact discs. Many fresh foods are packaged
in clear vacuum-formed polystyrene trays, owing to the high gas permeability and good water-vapour
transmission of the material. The clear windows in many postage envelopes are made of polystyrene
film.

(kilnare, 2001)

Properties of polystyrene
Polystyrene (PS) is a clear, amorphous, nonpolar commodity thermoplastic that is easy to process and
that can be easily converted into a large number of semi-finished products like foams, films, and
sheets. It is one of the largest volume commodity plastic, comprising approximately seven percent of
the total thermoplastic market. PS is a very good electrical insulator, has excellent optical clarity due
to the lack of crystallinity, and has good chemical resistance to diluted acids and bases. It is also easy
to fabricate into many finished goods since it is a viscous liquid above its glass transition temperature
(Tg) that can be easily moulded. However, polystyrene has several limitations. It is attacked by
hydrocarbon solvents, has poor oxygen and UV resistance, and is rather brittle as it has poor impact
strength due to the stiffness of the polymer backbone. Furthermore, its upper temperature limit for
continual use is rather low due to the lack of crystallinity and its low glass transition temperature of
about Tg = 373 K (100°C). Below its Tg, it has medium to high tensile strength (35 - 55 MPa) but low

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impact strength (15 - 20 J/m). Despite all these weaknesses, styrene polymers are very attractive large-
volume commodity plastics. Some of its weaknesses can be overcome by copolymerization with other
monomers. For example, polystyrene can be copolymerized with methyl methacrylate. The copolymer
poly (styrene-co-methyl methacrylate) (PSMMA) has higher clarity and improved chemical and UV
stability. One of the most important styrene copolymers is poly(styrene-co-acrylonitrile) (PSAN). It has
much improved chemical resistance, better heat stability, and improved mechanical properties.
However, these copolymers often yield yellow products. Probably of equal importance are
poly(styrene-co-butadiene) (SBR, SBS) and poly(styrene-co-acrylonitrile-co-butadiene) (ABS). Both
copolymers have very high stress and impact resistance and ABS has higher tensile strength than pure
PS. To increase the heat resistance, styrene is sometimes copolymerized with small amounts of maleic
anhydride or it is copolymerized with this monomer to an alternating structure. The copolymer poly
(styrene-co-maleic anhydride) (PSMA) has a higher Tg than pure polystyrene (400 - 430 K), improved
heat resistance and high dimensional stability. Many styrene derivatives have been synthesized on a
laboratory scale and some have been extensively investigated. However, no other styrene polymer
has become a large-volume commodity thermoplastic. Among those that are commercially produced
are α-methyl styrene, o-, m-, and p-methyl styrene, methoxy styrene, chlorostyrene, divinylbenzene
and p-divinylbenzene. The latter is used as a cross-linking agent in many different polymer materials.
Polystyrene is a not biodegradable plastic and resistant to photolysis. It is a major contributor to the
debris in the ocean. Although recyclable, polystyrene is not recycled in many parts of the world. The
biggest problem is expandable polystyrene (EPS); due to its low density, it takes up a relative large
amount of space in landfills. In recent years, the (food) packaging industry has developed alternative
insulating plastics for thermal applications, like Versatile which is an expanded polypropylene (PP) that
can be recycled right along with other PP products in the general recycle stream. We expect other
lower-cost and lower-density resins to gain market share in traditional large volume applications of
expandable polystyrene.

Table 1 properties of polystyrene

Properties

Density of EPS 16–640 kg/m3[24]

Young's modulus (E) 3000–3600 MPa

Tensile strength (st) 46–60 MPa

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 Elongation at break 3–4%

Charpy impact test 2–5 kJ/m2

Glass transition temperature 100 °C[25]

Vicat softening point 90 °C[26]

Coefficient of thermal expansion 8×10−5 /K

Specific heat capacity (c) 1.3 kJ/(kg·K)

Water absorption (ASTM) 0.03–0.1

Decomposition X years, still decaying

(rodanina, 1992)

COMMERCIAL POLYSTYRENES
Polystyrene is one of the most important commodity plastics. The production volume of polystyrene
and styrene copolymers is several million tons per year. It is sold under various trade names, including:
Styrofoam, Styropor, Styron, Carinex, Styro-Flex, Cellofoam, Depron XPS, Fostarene, Styraclear,
Lustrex, SABIC PS, and INEOS Styrenics.

The three most important grades are:

GPPS: General purpose polystyrene, also known as crystal-clear polystyrene, is a fully transparent,
rigid and rather brittle low-cost thermoplastic made from styrene monomer. GPPS is a solid product
manufactured in the form of 2-5 mm pellets.

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HIPS: High impact polystyrene contains usually 5 to 10% rubber (butadiene) and is used for parts which
require high(er) impact resistance. HIPS is a graft copolymer having polystyrene sidearms. The grafting
occurs when some of the radicals react with the double bonds of the polybutadiene.

EPS: Expandable polystyrene consists of micro-pellets or beads containing a blowing agent (usually
pentane). The expanded or foamed polystyrene is thermally insulating, has high impact resistance and
good processability.

(smith, 2002)

Forms produced
Polystyrene is commonly injection molded, vacuum formed, or extruded, while expanded
polystyrene is either extruded or molded in a special process. Polystyrene copolymers are also
produced; these contain one or more other monomers in addition to styrene. In recent years the
expanded polystyrene composites with cellulose[27][28] and starch[29] have also been produced.
Polystyrene is used in some polymer-bonded explosives (PBX).

Sheet or moulded polystyrene

Figure 2

CD case made from general purpose polystyrene (GPPS) and high impact polystyrene (HIPS)

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Figure 3

Disposable polystyrene razor

Polystyrene (PS) is used for producing disposable plastic cutlery and dinnerware, CD "jewel"
cases, smoke detector housings, license plate frames, plastic model assembly kits, and many other
objects where a rigid, economical plastic is desired Production methods
include thermoforming (vacuum forming) and injection moulding. Polystyrene Petri dishes and
other laboratory containers such as test tubes and microplates play an important role in biomedical
research and science. For these uses, articles are almost always made by injection moulding, and often
sterilised post-moulding, either by irradiation or by treatment with ethylene oxide. Post-mold surface
modification, usually with oxygen-rich plasmas, is often done to introduce polar groups. Much of
modern biomedical research relies on the use of such products; they therefore play a critical role in
pharmaceutical research.

(stephane, 1991)

Copolymers
Pure polystyrene is brittle, but hard enough that a fairly high-performance product can be made by
giving it some of the properties of a stretchier material, such as polybutadiene rubber. The two
such materials can never normally be mixed because of the small mixing entropy of polymers, but
if polybutadiene is added during polymerisation it can become chemically bonded to the
polystyrene, forming a graft copolymer, which helps to incorporate normal polybutadiene into the
final mix, resulting in high-impact polystyrene or HIPS, often called "high-impact plastic" in
advertisements. One commercial name for HIPS is Bextrene. Common applications of HIPS
include toys and product casings. HIPS is usually injection molded in
production. Autoclaving polystyrene can compress and harden the material.Several other
copolymers are also used with styrene. Acrylonitrile butadiene styrene or ABS plastic is similar to
HIPS: a copolymer of acrylonitrile and styrene, toughened with polybutadiene. Most electronics

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cases are made of this form of polystyrene, as are many sewer pipes. SAN is a copolymer of
styrene with acrylonitrile, and SMAone with maleic anhydride. Styrene can be copolymerized with
other monomers; for example, divinylbenzenecan be used for cross-linking the polystyrene chains
to give the polymer used in Solid phase peptide synthesis.

(smith, 2002)

Oriented polystyrene

Oriented polystyrene (OPS) is produced by stretching extruded PS film, improving visibility through
the material by reducing haziness and increasing stiffness. This is often used in packaging where the
manufacturer would like the consumer to see the enclosed product. Some benefits to OPS are that it
is less expensive to produce than other clear plastics such as polypropylene (PP), polyethylene
terephthalate (PET), and high-impact polystyrene (HIPS), and it is less hazy than HIPS or PP. The main
disadvantage to OPS is that it is brittle and will crack or tear easily.

(stephane, 1991)

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Procedures and material used
 Commercial linear unsaturated polyester
 Benzoyl Peroxide initiator
 Cobalt octuate activator readily dissolve in the polyester.
 Carbon Nano tubes filler
 Magnesium Carbonate filler
 3 Beaker 250 ml
 3 Test tubes
 2 Petri dish
 Glass rod for stirring
 Weighing bottles
 Analytical balance

Firstly, 50g of linear unsaturated polyester are added to 250 ml beaker followed by the addition of
the required mass of the filler based on the type of the filler. After that, 1 gm of Benzoyl peroxide is
added and stirred precisely for 5 min. moreover, the mixture is poured in 2 test tubes and one 1 Petri
dish. Finally, the prepared composite polyester has to be lift for 1-5 hours for the purpose of complete
curing and hardening then required tests which are tensile, hardness and compression tests have to
be done.

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Results
Hardness test
Table 2 results of hardness test

Sample Hardness in Pascale

Pure polyester sample 78

Composite polyester sample with carbon 75

nanotube
Composite polyester sample with ---
magnesium carbonate

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Tensile dog bone shape test
Pure sample

Figure 4 pure sample tensile test

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Magnesium carbonate filler

Figure 5 polyester sample with magnesium carbonate filler tensile test

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Carbon Nano tube filer

Figure 6 polyester with carbon Nano tube filler tensile test

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Compression test
Pure sample

Figure 7 pure polyester compression test

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Magnesium carbonate filler

Figure 8 polyester with magnesium carbonate filler compression test

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Carbon Nano tube filler

Figure 9 polyester with carbon Nano tube filler compression test

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Discussion
As shown in the above results, in compression test it was shown that in the magnesium carbonate
sample the highest stress was about (75 MPA) and the strain about (15 MPA). While, in carbon Nano-
tube the highest stress was (38 MPA) and the strain was (12.2 MPA). While, in the pure polyester the
highest stress was (38 MPA) and the strain was (8.2 MPA). In the tension test from the resulted graphs
the magnesium carbonates its highest stress strain was 25 MPA While, the carbon Nano-tube its
highest stress and the strain was 19 MPA and the pure polyester its highest stress and the strain was
20 MPA.so from these previous tests we concluded that the magnesium carbonate is having the best
results among the three samples but actually in reality carbon nanotube was supposed to be the best
filler but according to the errors which have been made such as poor stirring that effect the
composition of the sample as some air bubbles may enter the sample.

Conclusion
By the end of this experiment, the preparation of composite polyester with different fillers to study
the characteristic of each filler such as hardness, tensile and compression was achieved and the
polyester with carbon Nano tube filler was discovered to have much more better characteristics than
the polyester with magnesium carbonation filler or pure commercial polyester. Tensile, compression
and hardness Tests were performed on three samples such as polyester with carbon nanotube,
polyester with magnesium carbonate and pure polyester to discover the characteristics of each
composite polyester.

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References
jackoub. (1998, july). Retrieved from www.rsc.org.

kilnare. (2001). Retrieved from www.rsc.org.

rodanina. (1992). Retrieved from www.rsc.org.

smith. (2002). Retrieved from www.rsc.org.

stephane. (1991). Retrieved from www.rsc.org.

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