This document provides information on various regenerated cellulose fibers including acetate rayon, viscose rayon, and their properties. It discusses that acetate rayon is manufactured from cellulose through a process involving cellulose dissolution and dry spinning. The document also summarizes the properties, manufacturing process, and uses of heat-resistant fibers Kevlar and Nomex. Kevlar is very strong and resistant to heat while Nomex is resistant to flame and maintains its properties even at high temperatures. Both fibers are used in protective clothing and applications requiring high durability.

1. DR.B.M.N College of Home
Science (Autonomous)
Matunga,Mumbai-19

2. Presented by
SYBSc - TSAD
Sonal Gaikwad
Pooja jakhar
Kalyani Kadam
Khadija Khan
Rutuja Kadam

4. • Acetate Rayon is a manufactured regenerated cellulose fiber.
• Purified cellulose , primarily from wood pulp.
• Converted into a soluble compound.
• Dissolved and forced through a spinneret.
• To produce filaments.
• Chemically solidified, resulting in synthetic fiber, pure
cellulose.
• Rayon is manufactured from naturally occurring polymer.
• It is considered a semi-synthetic fiber.

5. • Acetate rayon a synthetic filament, yarn, or fabric
composed of a derivative of the acetic ester of cellulose.
• Differing from viscose rayon in having greater strength
when wet and greater sensitivity to high temperatures.
High quality Acetate
fabric

6. • Origin :
• Acetate, which is properly called as cellulose acetate, was
first made by Paul Schützen berger, in 1869.

7. • The basic raw material for rayon is cellulose.
• Natural cellulose are – wood pulp, spruce, hemlock tree
and cotton linters.
• Cotton linters are residue fibers .
• Acetate Rayon is a manufactured fiber composed of
regenerated cellulose.
• It is a manufactured fiber in which substitutes have not
replaced more than 15 percent of the hydrogens.

11. • The manufacturing acetate include cellulose, acetate
anhydride, plus sulphuric acid as a catalyst.
• Primarily from wood pulp, purified, bleached and shredded.
• The shredded is fed into pre-treatment tanks, mixed with
glacial acetic acid and held for a specified length of time.
• To kneading machines called acetylates and acetic
anhydride is added.
• Dissolved and becomes cellulose acetate. Clear liquid called
acid dope.
• The dope is aged, in special storage tanks ; water is added
as needed reduce the acid concentration.
• Hydrolysis occurs during the ripening; formation of
acetate.
• Secondary acetate solution in mixed with water.
• Precipitate out in the form of small flakes.
• The flakes are washed and dried

12. • Dissolved in acetone to form a spinning dope.
• This spinning solution is forced through filters to remove any
undissolved acetate and impurities and then through the
spinnerette into a warm air chamber.
• The acetone evaporates and the acetate coagulates as it falls
through the chamber.
• The filaments travelling downward are twisted together to form
yarn.
• Fiber manufacture is called dry spinning.

14. FIBRE PROPERTIES

15. • Manufactures can produce a wide variety of fiber shapes
and confirmations.
• Acetate Rayon has low strength and requires careful
handling.
• But the desirable properties of hand, drape, and
appearance make the fabrics manufactured from these
fibres results in fabrics that become easily wrinkled and
permanently deformed.
• Moisture regain is slightly less than cottonattractive to
designers and consumers.
• The low elastic recovery of acetate, with its low resiliency,.

16. • Dilute alkalis have little effect on acetate.
• Concentrated acids weaken the fibres drastically and in
most instances cause complete disintegration.
• Dilute hot acids may cause, a loss of strength.
• Cold dilute acids weaken the fibre if exposure is prolonged.
• Petroleum solvents used in dry cleaning do not damage
acetate, phenol and chloroform will destroy the fibres.
• Storage may result in weaker acetate fibres.
• All acetate develops static charges, especially when dry,
because they are poor conductors of electricity.

17. • Fungi such as mildew and bacteria may discolour acetate
fibres.
• Moths and other households pests do not damage acetate.
• However, silverfish may attack heavily sized fibers in order
to eat the starch sizing.

18. • Acetate rayon is a thermoplastic fibre.
• Melt and burn, forming a hard, black bead ash.
• Odour is similar to that of hot vinegar.

20. • A manufactured fiber in which the fibre-forming substance
is a long-chain synthetic polyamide, in which at least 85%
of the amide linkages are attached directly to two aromatic
rings.

22. • Kevlar is a heat-resistant and strong synthetic fiber, related
to other aramids such as Nomex and Tecnora.
• Developed by Stephaine Kwolek at Dupont in 1965.
• First commercially in the early 1970s as a replacement for
steel in racing tires.
• Typically it is spun into ropes as an ingredient in composite
material components.

23. • Properties
• It is resistant to alkalis at room temperature.
• Kevlar is spun the resulting fiber has a tensile strength
about 3,620 Mpa and a relative density of 1.44.
• The polymer owns its high strength to the many inter chain
bounds .
• Hydrogen bounds form between the carbonyl group and NH
centres.
• Additions strength is derived from aromatic stacking
interaction between adjacent strands.

24. • Uses
• Bullet/stab proof vest or jackets.
• Diving gloves, walking boots, military helmet, cut resistant
gloves.
• Bicycle tyres cars tyres and fire proof clothing.

26. • Nomex is a brand of lightweight, heat resistant aramid fiber
used in clothing especially for fire fighter and protective
fabrics.

27. • Properties
• Inherent dielectric strength
• Mechanical toughness
• Thermal stability
• Chemical compatibility
• Radiation resistance
• Flame resistance
• Moisture insensitivity
• Cryogenic capabilities.
• Inherent Dielectric Strength
• Nomex® products withstand short-term electrical stresses
of 18 kV/mm to 34 kV/mm (460 V/mil to 870 V/mil),
depending on product type and thickness.
• Mechanical Toughness
• Nomex® products are strong, resilient and (in the thinner
grades) flexible, with good resistance to tearing and
abrasion.

28. • Thermal Stability
• Temperatures up to 200°C have little or no effect on the
electrical and mechanical properties of Nomex® products.
• At temperature 370c (700f) Nomex degrades.
• Nomex® products are essentially unaffected by most
solvents and are unusually resistant to attacks by acids and
alkalis at room temperature.
• They are not attacked by insects, fungi or mold.
• Prolonged exposure to sodium hydroxide in concentration
greater than 50% at elevated temperature degrades nomex.

29. • Radiation Resistance
• Nomex® is essentially unaffected by 800 me garads (8
Mgy) of ionizing radiation and still retains useful
mechanical and electrical properties after eight times this
exposure.
• Flame Resistance
• Nomex® products do not produce known toxic reactions in
humans
• Nomex® products do not melt and, with a limiting oxygen
index (LOI) at 220°C above 20.8—the critical value for
combustion in air—they do not support combustion.
• Cryogenic Capabilities
• Nomex® products have found acceptance in a variety of
cryogenic applications due to their unique polymer
structure.

30. • Uses
• Gloves , nomex hood, Divers protection, Driving shoes ,
protective socks , firefighter protection, filtering material

32. • Title : Essential of Textiles. Publisher: Holt, Rinehart and
Winston, INC. Year : Oct 1987.
Web Refernces:
• https://en.wikipedia.org/wiki/Rayon
• https://www.dupont.com/products/nomex-fibers.html
• https://www.dupont.com/what-is-kevlar.html