Introduction to Man-Made Fibre

Fibre:
Fibre is a raw material used in textile manufacturing. Fibres are pliable, hair like substance that is
very small in diameter in relation to their length (usually at least 100 times longer than its
diameter). They are the fundamental units used in the making of textile yarn and fabrics.
Most apparel fibres are about 15 to 150 mm long and 10 to 50 µm (µm= 0.001 mm) thick but the
length of filament fibre may be several kilometres.

Man-made fibre:
Man-made fibres or chemical fibres are those fibres whose chemical composition, structure, and
properties are significantly modified during the manufacturing process. The chemical compounds
from which man-made fibres are produced are known as polymers, a class of compounds
characterized by long, chainlike molecules of great size and molecular weight.
Man-made fibres consist of regenerated fibres and synthetic fibres.

Regenerated fibres:

The fibers regenerated from nature cellulose sources like wood pulp or cotton linters are referred
to as regenerated fibers. They are the earliest synthetic fibers based on biopolymers. The raw
materials are deconstructed into fluffy white cellulose and then turned into a viscous resin, which
is squeezed through spinnerets and hardened as a manufactured fiber form natural plants. By the
regeneration process, the chemical constitution of the original polymers is not altered. However a
certain variation in degree of polymerization occurs resulting in some modified physical properties
of the regenerated fibers that essentially differ from the original one. Viscose rayon, polymeric,
cupro, lyocell etc. belong to this category.

Synthetic fibres:

Synthetic fibres are derived from substances that are not present in nature, but instead created
through chemical reactions (synthesis) from petrochemical products.
True synthetic fibers are non-cellulosic. Examples are polyamide (nylon), polyester, acrylic,
modacrylic, polyurethane (spandex), polyethylene, polypropylene etc. true synthetic polymer
fibers are products of the polymerization of smaller chemical units into long- chain molecular
polymers. Fibers are formed by forcing a viscous fluid or solution of the polymer through the small
orifices of as spinneret and immediately solidifying or precipitation and the result is filamentsor
can be cut at predefined lengths.

Inorganic fibres:

Inorganic fibers, both metal and non metal ones, are more rigid, have a higher melting point and
are more heat resistant than traditional fibers. They are also totally inflammable, but except for the
metal ones, they are fragile. Their textile importance is also limited, whereas they are widely used
as reinforcement in composite materials. They are usually excellent in high temperatures and in a
corrosive surrounding.

A Short History of Manufactured Fibres

For thousands of years, the use of fibre was limited due to dependency on natural source. At first
in 1664 English naturalist Robert Hooke suggested the possibility of producing a fibre that would
be “if not fully as good, nay better” than silk. His goal remained unachieved for more than two
centuries.

Prof.Schonben of Basle University was experimenting in his kitchen one day, using a mixture of
nitric acid and sulphuric acids. Accidentally the flask broke and he mopped the corrosive liquor
by a cotton fabric. This caused the treated fabric to ignite and char. Finally in 1846 he successfully
produced cellulose nitrate, a highly flammable material.

A patent for “artificial silk” was granted in England in 1855 by a Swiss chemist “Audemars”. He
dissolved the fibrous inner bark of a mulberry tree, chemically modifying it to produce cellulose.
He formed threads by dipping needles into this solution and drawing them out. Extreme
flammability made them unacceptable for textile use.

In 1870 Jhon Easley Hyatt introduced cellulose nitrate film which is also known as celluloid. At
first it was used in Kodak company. In 1875 Alfred Nobel stabilised nitroglycerine with cellulose
nitrate (guncotton).In the early 1880's, Sir Joseph W. Swan, an English chemist and electrician
introduced spinneret by coagulating fromcollodion. But on that time his target was to produce
illuminate. In 1885 by using Audemars solution, he draws the filament through spinneret.Thus
artificial silk was produced.
In 1989, the first commercial scale production of Chardonnet silk was achieved by French chemist.
Count Hilaire de Chardonnet became the first to exploit the textile aspect commercially. He
partially hydrolysed cellulose nitrate after extrusion to make it less flammable.
In 1905 Courtaulds acquired the Cross and Bevan patents to the viscose process for manufacturing
artificial silk or rayon from dissolving pulp.The first commercial textile uses for acetate in fibre
form were developed by British Celanese Company in 1924.

During the 1920s, most organic chemists (Staudinger and others) believed that polymeric
substances were aggregates of relatively small molecules bound together as colloids by physical
forces of cohesion.

In 1931, American chemist Wallace Carothers reported on research carried out in the laboratories
of the DuPont Company and invented nylon. Invention of nylon is a revolution in the fibre industry.
Rayon and acetate had been derived from plant cellulose, but nylon was synthesized completely
from petrochemicals. DuPont began commercial production of nylon from 1939. In that same
period (1939), a new polyamide fibre was produced under the name perlon by Mr.Schlack.

In 1941 J. T. Dickson and J. R. Whinfield produced a polyester fibre by condensation

polymerization of ethylene glycol with terephthalic acid. In 1953 DuPont starts its commercial
production. By the 1950's DuPont began production of this wool-like product acrylic.

In 1959 Dupont was start the production of spandex (lycra) which was discovered by Guilio Natta
an Italian researcher in 1954. It is an elastomeric manmade fibre.In 1965 Dupont invented bullet-
stopping Kevlar; aramid fibre.In1981 Courtaulds discovered lyocell and went commercial
production in 1992. In 1998 Toyobo (Japan) started PBO (poly paraphenylenebenzobisoxazole)
production at commercial scale.

Forms of Man- Made Fibres:

Man-made fibres are produced in three forms-

1. Filament
2. Staple
3. Filament tow

Staple fibers:
A staple fiber is a fiber of relatively short length, as is the case with most natural fibers, which
range from a fewmillimeters (e.g. the shortest cotton fibers, known as linters) to around a meter
(e.g. fibers from bast plants). Staple fibers aretypicallybetween 3 to 20 cm in length.
In case of man-made fibre around half of the fibres have been chopped up into short lengths of few
inches. In this way they have become more like cotton, which has a fibre length of about 1"-1.5",
or wool, which is usually within the range of 3"-6" fibre length. All man-made fibres are spun
continuously, but more than half of their weight is chopped up into short length, usually of form
1"-6". Often this cutting is done continuously as the filaments are made, the chopping up is the
part of the process. The chopped fibre is called staple fibre and is used for spinning on the cotton
and worsted systems, being very largely used for blending.

Filaments:
A filament is a fiber of indefinite length. Silk is the only natural filament fibers. Most regenerated
andsynthetic fibers are produced as filaments form. These can be used in single or multifilament.
In multifilament the final filament is made of more than one filament.One familiar application of
mono filament is bristle (nylon bristle in tooth-brush).

Filaments tow:

Tow is fibre that is spun with tens or hundreds or thousands of filaments bundled together into a
loose rope and wound up onto some sort of spool or package.

Classification of man-made fibres:

Provide individual file.

Advantages and Disadvantages of Natural fibre

Advantages:
 They are abundantly available in nature.
 They readily absorb moisture and perspiration, provide great body comfort.
 It did not generate no static charge during processing and wearing.
 It has no adverse effect on human skin.
 It is very easy to sew and the seam holds tightly.
Disadvantages:

 Strength of natural fibres are low.

 Natural fibre do not possess high degree of resiliency as compared to man made fibre.
 Production of natural fibre can not be comparatively controlled by man, so the quality and
quantity may vary.
 Variation in length, fineness etc. of natural fibre cause less regular and uniform yarn that
obtained form man made fibre.

Advantages and Disadvantages of MMF

Advantages:

 Manmade fibres are produced in factories so specific qualities of the fibre can be produced
deliberately and quickly according to the demand.
 The filaments can be produced as fine or as thick as required, staple length can be cut
exactly to order.
 Fibres can be produced with high degree of luster or with reduced or completely dull luster
 Unlike natural fibres, the final product of manmade fibres does not require cleaning.
 Most of the fibres are pure white or colorless when produced, but if necessary, color can
be used during production of the fibre.
 The utility and growth of manmade fibres is influenced by its positive qualities – wrinkle
resistance, crease recovery, easy care properties etc.
 Most of the synthetic fibres have high resistance to moth, mildew, insects, moulds, which
simplifies storage problems.
 Permanent pleats could be introduced to most of the manmade fabrics because of their
unique heat setting properties.

Disadvantages:
 Fabrics made from 100% manmade fibres are costlier than 100% natural fibres. This is
because of the high cost of raw materials, chemicals and intermediates etc.
 Some individuals are often prone to skin allergy
 In general manmade fibres are hydrophobic in nature. These fabrics fail to absorb
perspiration, thus the wearer feels discomfort in hot climate.
  Manmade fabrics are a little difficult to sew. Seams do not hold tight as in natural fibre
fabrics so stitching charge is higher.
 Most of the manmade fibres fabrics fail to provide warmth to the wearer.

Sequence of producing manmade fibres

Manufacture of fibre forming polymer

Spinning the fibre from polymer

Spin finish application

Stretching or Drawing

Heat setting (made dimensionally stable)

Texturing or crimping

Interlacing or intermingling (applied instead of twisting)

Cutting (staple fibre production)