Synthetic fibers are man-made polymers created by linking small chemical units called monomers into long chains called polymers. Common synthetic fibers include nylon, polyester, acrylic, acetate, spandex, aramid, and olefin. They are produced through processes like melt spinning, wet spinning, and dry spinning. Synthetic fibers have properties like high chemical resistance, strength, and availability but are flammable and do not absorb moisture well. They are widely used to make clothing, home textiles, and industrial materials due to their low cost and unique properties compared to natural fibers.

1. 1. Md Shafiul Alam Shawon
2. Md Tasdid Alam
3. Pallab Karmokar
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3. Synthetic Fibres
• A synthetic fibre is a chain of small chemical units joined
together.
• Each small unit is called a monomer.
• Large chain formed by many monomers is called a Polymer.
• The process of combining small monomers to form a large
polymer is called Polymerisation.

4. Properties of Synthetic fibres
> Man- made fibers from petrochemical and textile
industries.
> Cheap, abundantly available.
> High chemical resistance.
> High melting point.
> Low modulus of elasticity.
> It's types are acrylic, aramid, carbon, nylon,
polyester, polyethylene, polypropylene, etc.
> Applications in cladding panels and shotcrete.

5. Uses of Synthetic Fibre

7. Spinning Process of Different Synthetic
Fibers:
Melt spinning:
In melt spinning, the fiber-forming substance is melted for
extrusion through the spinneret and then rapid cooling of
liquids. Nylon, olefin, polyester, saran and sulfar are
produced in this manner.
Melt spun fibers can be extruded from the spinneret in
different cross-sectional shapes (round, trilobal,
pentagonal, octagonal, and others). Trilobal-shaped fibers
reflect more light and give an attractive sparkle to textiles.

9. Wet spinning:
Wet spinning is the oldest process. It is used for polymers that
need to be dissolved in a solvent frist. The spinnerets are
submerged in a chemical bath and as the filaments emerge
they precipitate from solution and solidify.
Because the solution is extruded directly into the precipitating
liquid, this process for making fibers is called wet spinning.
Acrylic, rayon, aramid, modacrylic and spandex can be
produced by this process.
Dry spinning:
In dry spinning the polymer is dissolved in its solvent and then
extruded, as the fibres emerge through the spinneret the
solvent is evaporated off with hot air, in most cases this is
then collected and re-used. Dry spinning is also used for fiber-
forming substances in solution.
This process may be used for the production of acetate,
triacetate, acrylic, modacrylic, PBI, spandex, and vinyon.

10. Different types of synthetic fibres
• Nylon
• Rayon
• Polyester
• Acrylic
• Acetate
• Spandes (Lycra)
• Aramid (Kevlar, Nomex)
• Olefin
• Triacetate
• Modacrylic

11. Nylon
Nylon is a generic designation for a family of synthetic
polymers, based on aliphatic or semi-aromatic polyamides.
Nylon is a thermoplastic silky material that can be melt-
processed into fibers, films, or shapes. It is made of
repeating units linked by amide links similar to the peptide
bonds in proteins.
Properties of Nylon
> Polymer of Adipic Acid and Hexamethylene diamine
> Lustrous, dull, white or coloured
> Bead formed when heated
> Soluble in 5M HCI
> Insoluble in 90% Formic Acid, 90% Phenol
> Filter cloths, seives and non absorbable sutures
PH103.81 24

12. Uses of Nylon
> It is used for making fishing nets, parachutes and cords.
> Nylon is widely used as plastic for making machine parts.
> Apparel: Blouses, dresses, foundation garments, hoisery,
underwear, raincoats, ski apparel, windbreakers,
swimwear, and cycle wear.

13. Rayon
Rayon is a regenerated cellulose fiber that is made from
natural sources of cellulose, such as wood and related
agricultural products. It has the same molecular structure
as cellulose.
Properties of Rayon
> It is the first man made fibre.
> It has a serrated round shape with smooth surface.
> It loses 30-50% of its strength when it is wet.
> Rayon is produced from naturally occurring polymers and
therefore it is not as cellulosic fiber.
> The fiber is sold as artificial silk.
> There are two principal varieties of rayon namely viscose
and cupra ammonium rayon.

14. Uses of Rayon
> Used in textile industry to make textile.
> Making tyre cords.
> Making carpets & surgical dressings.
> Used to make bedspreads, curtains, blankets etc.
> Used for sportswear, slacks, suits etc.

15. Polyester
Polyester is a synthetic polymer made of purified terephthalic
acid (PTA) or its dimethyl ester dimethyl terephthalate (DMT)
and monoethylene glycol (MEG). With 18% market share of
all plastic materials produced, it ranges third after
polyethylene (33.5%) and polypropylene (19.5%).
Properties of Polyester
• Very low absorbency.
• Heat conductivity better than acrylic.
• Melts nd flamable by effect of heat.
• Good resistance when exposed to light.
• Good resistance to bleaches.
• Fair resistant to alkalis at room temperature.
• Good resisitance to acids.
• Resistant to insects.

16. USES OF POLYESTER
> Polyester is the most used synthetic fiber.
> Polyester is a tough fabric used in clothing.
> Polyester is used in the manufacturing of all kinds of
clothes and home furnishings like bedspreads, sheets,
pillows, furniture, carpets and even curtains.
> Woven and Knitted Fabrics, especially blends.
> For paper making machine Insulating tapes Hose pipe
with rubber or PVC.
> Ropes, fish netting and sail cloth.

17. Acrylic
Acrylic fibers are synthetic fibers made from a polymer
(polyacrylonitrile) with an average molecular weight of ~100,000,
about 1900 monomer units. To be called acrylic in the U.S, the
polymer must contain at least 85% acrylonitrile monomer.
Properties of Acrylic Fibre
> Acrylic has a warm and dry hand like wool. It is about 30%
bulkier than wool.It has about 20% greater insulating power
than wool.
> Breaking elongationis 15% ( both states).
> It has a elastic recovery of 85% after 4% extension when the
load is released immediately.
> It has a good thermal stability..
> It has a good resistance to mineral acids.
> The resistance to weak alkalies is fairly good.
> Easy to wash and wear.

18. Uses of Acrylic
> Make woollen clothes like hats, scarves, gloves, sweaters,
blankets, and other home- furnishing fabrics.
> Make fake fur used for making toys and fur accessories.
> Make garments for babies (as the fabric is machine-washable).

19. Man made Synthetic Fibres
> Polyamides-Nylon 66, Nylon 610, Nylon 6 etc
> Polyester-Terylene, Terene, Dacron etc.
> Polyvinyl deri vatives
> Polyvinylchloride
> Polyvinylchloride acetate
> Polyvinylchloride -Acrylonitrile
> Polyacrilonitrile
> Polyvinyl alcohol
> Polystyrene and Copolymers
> Polyvinylide Chloride and Copolymers
> Polyolefins
> Polyethylene
> Polypropylene

20. Advantages of Synthetics
• Synthetic fibers do not depend either on an
agricultural crop or on animal farming.
• They are generally cheaper than natural fibre.
• Synthetic fibers possess unique characteristics
which make them popular dress material.
• They dry up quickly. are durable, readily
available and easy to maintain.
• Synthetic fibres are generally soft so they are
used in clothing materials.
• Clothes made by synthetic fibres are generally
cheaper than those made by natural fibres.

21. Disadvantages of Synthetics
• Synthetic fibers melt before burning
• Some electrical charge accumulates on the
synthetie fibers. The electrical charge causes
irritation of the skin.
• Can make you cold when wet
• Does not absorb moistures
• It is dangerous to wear near fire, as they catch
fire easily.
• They cannot be easily ironed as they melt very
easily.

22. Thank You