3. Classification Of man-made fibers.
MANMADE FIBERS
FROM
NATURALPOLYMERS
PLANT
DERIVED
CELLULOSIC
FIBERS
Cupramonium rayon.
Viscose rayon.
Modal
Paper.
Acetate and triacetates.
ALGINIC MAN
MADE FIBERS
ELASTOMERS
(RUBBERS)
ANIMAL
DERIVED
REGENERATED
PROTEIN FIBERS
From plant proteins
zein
From animal proteins
casein
FROM
SYNTHETIC
POLYMERS
POLYMERI
DE FIBERS
Polyethylene.
Polypropylene
.polychloride.
Fluoric fibers.
Modacrylic.
Vinyl fibers.
Tr-vinyl
Elastomers.
POLYCONDENSA
TION FIBERS
Polyamide.
Polyester.
polycarbamide
POLYADDITION
FIBERS
Polyurethane
Elasthane.
FROM INORGANIC
MATERIALS
Glass fibers
Metal fibers
carbon fibers.
4. Cellulosic Regenerated fibers
Manufactured regenerated fibers:
From naturally occurring polymers; regenerated fibers – cannot be used in their natural state,
but are chemically processed into a solution that is then extruded through a spinneret
Cellulosic: Rayon, lyocell
Protein: Azlon – soy silk, silk latte
Derivative cellulosic Fibers:
chemically changed derivative of cellulose known as esters
Acetate, triacetate
5. Rayon
Rayons:
These are the most widely used semisynthetic fibres. They are derived from cellulose and are available in
three different varieties— viscose, cuprammonium (or cupro) and acetate rayons.
Viscose Rayon:
Cellulose (say, cotton) is dissolved in a mixture of sodium hydroxide (NaOH) and carbon disulphide (CS2, a
solvent). A viscous liquid (i.e., a liquid which cannot flow freely) called viscose is obtained. The viscose is then
forced through spinnerets (which have small holes) into an acid bath, and filaments of viscose rayon are
obtained.
Cuprammonium Rayon (or cupro):
A copper sulphate solution (blue), on treatment with an excess of an ammonia solution, gives a deep blue
solution of a compound, cuprammonium hydroxide. Cellulose is dissolved in this solution. The resulting
solution is forced through spinnerets into an acid bath to give the filaments of cuprammonium rayon.
Acetate rayon:
In this case, cellulose is dissolved in a mixture of acetic acid, sulphuric acid and some other chemicals. The
solution is forced through spinnerets to obtain filaments of acetate rayon.
6. Advantage of rayon :
it is cheaper to produce as compared to cotton itself since waste
cotton and paper is used for making rayon.
Secondly, rayon can be blended with other fibers like wool and silk.
8. Uses
of
rayon
Mixed with
fibre glass for
making
helmets
Reinforcing
nylon tyres
Upholstery for
luxury cars
and officeand
home
furnishings
Curtains
because it
drapes well
Dress material
because it is
soft, silky and
moisture
absorbent
9. Other Regenerated Fibers
Alginate fiber: Polysaccharides
processed from brown seaweed; used for
wound dressings.
Regenerated protein fibers
Soysilk®: from soybean waste; durable, good
drape, good comfort; apparel
Silk Latte®: from milk protein; soft hand,
dyeable; apparel
Bamboo: Soft, silky hand; similar to high
quality ramie.
10. Synthetic fibers
Polyesters:
The first synthetic fibre obtained was of this class. Polymers obtained by the reaction between
certain sets of organic (carbon-containing) compounds form a melt which can be spun into
filaments. The special property of these filaments is that they can be stretched several times their
original length. Terylene and Dacron belong to this class of synthetic fibres. Terylene is used to
make clothes. In general, polyesters are used to make textiles, bottles and insulating tapes.
Polyamides (nylons):
Nylon 6 and nylon 6, 6 are the most important fibres of this class. Nylon 6 is made of an organic
compound which contains six carbon atoms. Nylon 6, 6 is made of a more complicated monomer.
Nylon was first made in 1935.
It was intended to be a substitute for silk and was used in place of silk in parachutes in 1941, when
the USA entered World War II. Nylon is very suitable for women’s wear. Having a high tensile
strength, nylon is also used for making ropes.
Acrylics:
Acrylic fibres are a substitute for natural wool. These polymers decompose without melting. So,
they are dissolved in a suitable solvent and the solution is forced through spinnerets to obtain
filaments. The filaments can be cut into staples and the staples spun into yarns.
Acrylic fibres are crimpy (i.e., wavy) and not straight like polyester or nylon fibres. So acrylic yarns
appear to be bulky and compete with wool. They are generally used to make knitwear, upholstery
and artificial furs.
Acrylic fibres are not easily acted upon by moisture, chemicals or bacteria
11. Advantages of synthetic fibers:
Synthetic fibers have many advantages over natural fibers:
1. Synthetic fibers do not depend either on an agricultural crop as cotton,
flax and jute do, or on animal farming as silk and wool do.
2. The fabrics made of synthetic fibers like polyester and nylon are easily
heat-set, i.e., they retain the fold or pleat made on them by ironing even
after washing. Thus it is easier to maintain clothes made of synthetic fibers
than those made of natural fibers.
3. Synthetic fibers are much stronger, and hence more durable than natural
fibers. They dry easily and have faster colors.
4. Synthetic fibers are not easily acted upon by moisture, chemicals or
bacteria.
5. They are generally cheaper than natural fibers.
12. Disadvantages of synthetic fibers:
Synthetic fibres suffer from the following disadvantages:
1. Clothes made of pure synthetic fibres are garishly lustrous.
2. Synthetic fibres melt before burning. So clothes made of such fibres stick to the
skin when in contact with a flame, causing burns. Therefore, they should not be
worn in the kitchen or while setting off fireworks.
3. Synthetic fibres are generally hydrophobic, i.e., they repel moisture (e.g.,
sweat) and do not absorb it. They do not allow enough circulation of air either. So
clothes made of synthetic fibres are not comfortable to wear as they do not allow
sweat to evaporate easily. Natural fibres are hydrophilic, i.e., they absorb
moisture. They also allow the circulation of air. Therefore, clothes made of
natural fibres are comfortable to wear as they allow sweat to evaporate.
4. Some electrical charge accumulates on synthetic fibres due to which they cling
together as well as to the skin. The electrical charge irritates the skin.
13. Inorganic fibers
Inorganic fibers are the fibers made from inorganic materials and are classified into
the following categories: glass fiber, amorphous fiber like rock wool, carbon fiber,
polycrystal fiber like alumina fiber, and monocrystal fiber like wollastonite and
potassium titanate fiber.
Glass fiber
A glass thread less than a thousandth of an inch (25 micrometers) thick, used loosely
or in woven form as an acoustic, electrical, or thermal insulating material and as a
reinforcing material in laminated plastics. Also known as fiber glass.
Uses: Available in a broad range of particle retention sizes and thicknesses, they can
be used in a variety of sample preparation, prefiltration, diagnostic, and analytical
testing applications ,insulation , heat proofing.
14. Metallic fibers
Metallic fibers are manufactured fibers composed of metal, plastic-coated
metal, metal-coated plastic, or a core completely covered by
metal[1]. Gold and silverhave been used since ancient times as yarns for fabric
decoration. More recently,aluminum yarns, aluminized plastic yarns, and
aluminized nylon yarns have replaced gold and silver. Metallic filaments can
be coated with transparent films to minimize tarnishing. A common film is
Lurex polyester
Coated metallic filaments help to minimize tarnishing. When suitable
adhesives and films are used, they are not affected by salt water, chlorinated
water in swimming pools or climatic conditions.[7] If possible anything made
with metallic fibers should be dry-cleaned, if there is no care label. Ironing
can be problematic because the heat from the iron, especially at high
temperatures, can melt the fibers.
15. Carbon fiber
is a material consisting of fibers about 5–10 micrometres in diameter and
composed mostly of carbon atoms.
To produce carbon fiber, the carbon atoms are bonded together in crystals
that are more or less aligned parallel to the long axis of the fiber as the
crystal alignment gives the fiber high strength-to-volume ratio (making it
strong for its size). Several thousand carbon fibers are bundled together to
form a tow, which may be used by itself or woven into a fabric.
The properties of carbon fibers, such as high stiffness, high tensile strength,
low weight, high chemical resistance, high temperature tolerance and low
thermal expansion, make them very popular in aerospace, civil engineering,
military, and motorsports, along with other competition sports. However, they
are relatively expensive when compared to similar fibers, such as glass
fibers or plastic fibers
