8th august rayin nylon

8/4/2019 8th August Rayin Nylon

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Textile Science Presentation


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Rayon


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What is Rayon fiber? A manufactured fibre composed of regenerated

cellulose, in which substituents have replaced not

more than 15% of the hydrogen of the hydroxyl

groups. (Federal Trade Commission Definition forRayon Fibre)

It is neither an artificial fibre nor a natural fabric.

Rayon is usually classified as a manufactured

fibre and considered to be regenerated

cellulose. In the production of rayon, purified cellulose is

chemically converted into a soluble compound. A

solution of this compound is passed through the

spinneret to form soft filaments that are then

converted or regenerated into almost pure

cellulose. Because of the reconversion of the

soluble compound to cellulose, rayon is referred

to as a regenerated cellulose fiber.

Rayon is one of the most peculiar fabrics in

commercial use today.


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Molecular structure of Rayon


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Process of manufacturing rayon

Cellulose

Immersion: (C6H10O5)n+ nNaOH (C6H9O4ONa)n + nH2O

Pressing

White Crumb

Aging

Xanthation (C6H9O4ONa)n + nCS2 (C6H9O4O-SC-SNa)n Yellow Crumb

Viscose

Ripening: (C6H9O4O-SC-SNa)n + nH2O (C6H10O5)n + nCS2 + nNaOH

Filtering

Degassing Extruding

Acid Bath: (C6H9O4O-SC-SNa)n + nH2SO4 (C6H10O5)n + nCS2 + nNa2SO4

Drawing

Washing

Cutting


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Nylon


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NYLON A manufactured fiber in

which the fiber formingsubstance is a long-chainsynthetic polyamide inwhich less than 85% of theamide-linkages are attacheddirectly (-CO-NH-) to twoaliphatic groups. (FederalTrade CommissionDefinition for Nylon Fiber)

Nylon is a genericdesignation for a family ofsynthetic polymers knowngenerically as polyamides


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Facts about nylon The term nylon is derived from the New

York and London

It was developed in the 1930s as an

alternative to silk, although it quickly

became unavailable to civilian consumers,

because nylon was used extensively during

the war.

It was developed by Wallace Carothers at

the Dupont Chemical company, which

continues to manufacture it today.

the very first nylon product was a

toothbrush with nylon bristles.

Nylon's first real success came with it's use

in women's stockings, in about 1940.

When the United States entered World

War II, nylon was needed to make war

materials, like parachutes and ropes


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Methods of making Nylon

There are two common methods of making nylon for fiberapplications: In one approach, molecules with an acid (COOH) group on each

end are reacted with molecules containing amine (NH2) groups oneach end. The resulting nylon is named on the basis of the

number of carbon atoms separating the two acid groups and thetwo amines. Thus nylon 6,6 which is widely used for fibers ismade from adipic acid and hexamethylene diamine. The twocompounds form a salt, known as nylon salt, an exact 1:1 ratio ofacid to base. This salt is then dried and heated under vacuum toeliminate water and form the polymer.

In another approach, a compound containing an amine at oneend and an acid at the other is polymerized to form a chain withrepeating units of (-NH-[CH2]n-CO-)x. If n=5, the nylon is referredto as nylon 6, another common form of this polymer. Thecommercial production of nylon 6 begins with caprolactam uses aring-opening polymerization.


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Properties of Nylon

Density 1.15 g/cm3

Electrical

conductivity ()

1012 S/m

Thermal

conductivity0.25 W/(mK)

Melting point

463624 K

190350 C

374663 F


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Exceptionally strong

Elastic

Abrasion resistant

Lustrous Easy to wash Resistant to damage

from oil and manychemicals

Can be precolored ordyed in wide range ofcolors

Resilient Low in moisture

absorbency Filament yarns provide

smooth, soft, long-lasting fabrics

Spun yarns lend fabrics

light weight and warmth


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Manufacturing Nylon 6,6

In a nylon plant, nylon is usually made by reacting

adipic acid with hexamethylenediamine.


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Manufacturing Nylon 6

It's made by a ring opening polymerization form the

monomer caprolactam.


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History of rayon The Swiss chemist, Georges Audemars invented the first crude

artificial silk around 1855, by dipping a needle into liquid mulberry

bark pulp and gummy rubber to make threads. The method was too

slow to be practical.

In 1884, a French chemist, Hilaire de Charbonnet, Comte de

Chardonnay, patented an artificial silk that was a cellulose-based

fabric known as Chardonnay silk." Pretty but very flammable, it was

removed from the market.

In 1894, British inventors, Charles Cross, Edward Bevan, and Clayton

Beadle, patented a safe a practical method of making artificial silkthat came to be known as viscose rayon. Avtex Fibers Incorporated

first commercially produced artificial silk or rayon in 1910 in the

United States.

The term "rayon" was first used in 1924.


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Physical Properties of Rayon

drapes well easy to dye

highly absorbent

tends to age poorly

yellows with age

pills or forms small balls

and areas of roughness

where the fabric is mostheavily worn

may have problems with

shrinking

has few static problems


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Some facts about rayon Trade Names: Viscose rayon, artificial silk/art silk,

Bemberg, Modal and Tencel appears in both woven and knitted forms

oldest manufactured fiber

excellent, nicely draping alternative to silk

Facing stiff competition from manmade fibers like nylon

Grasim of India is the largest producer of rayon in the

world

Types of rayon:High wet modulus rayon (HWM)

High-tenacity rayon

Cupramonium rayon

8th august rayin nylon

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