MANMADE FIBERS

RAW MATERIALS

Classification Of man-made fibers.

MANMADE FIBERS

FROM NATURALPOLYMERS

PLANT DERIVEDCELLULOSIC FIBERS

Cupramonium rayon.Viscose rayon.ModalPaper.Acetate and triacetates.

ALGINIC MAN MA

DE FIBERS

ELASTOMERS (RU

BBERS)

ANIMAL DERIVED

REGENERATED PROTEIN

FIBERS

From

plant

protein

s

zein

From animal protein

s

casein

FROM SYNTHETIC POLYMERS

POLYMERIDE

FIBERS

Polyethylene

.Polypropylene.polychloride.

Fluoric

fibers.Modacrylic.Vinyl

fibers.Tr-

vinylElastomers.

POLYCONDENSA

TION FIBERSPolyamide.Polyes

ter.polycarbami

de

POLYADDITION

FIBERS

Polyurethan

eElasthane.

FROM INORGANIC MATERIALS

Glass fibersMetal fibers

carbon fibers.

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

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.

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.

 

Properties of rayon

easily dyed and woven into cloth

drapes well

lustrous in appearance

good absorbent of

sweat

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

Other Regenerated FibersAlginate 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.

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

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.

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.

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.

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.

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