It's a presentation on viscose rayon which is mainly a man made or synthetic fiber.

1. Presented By
Md. Mohebullah Sarker Maruf & Jony Roy
Dept. Applied Chemistry & Chemical Engineerning
Noakhali Science & Technology Univerisity
Viscose Rayon
Presentation on

2. TABLE OF
CONTENTS
Intruduction 01
03
02 05
06
07
Properties of Viscose
Rayon Fiber
Some Pictures of
Rayon Fiber & Fabric
Manufacturing
Process
Applications
Uses
04
Steps involved in
Manufacturing of
Viscose Rayon
08
Advantages &
Disadvantages

3. Intruduction
Viscose Rayon is
 Oldest commercial man-made fiber
 Naturally regenerated cellulosic fiber
 Due to fine silk-like properties, it is
also known as "Artificial Silk"
 Made from naturally occurring
cellulosic based material (such as
cotton linters, wood pulp, seed hair, leaf,
grasses and bamboo etc.)
3
Figure: Cellulosic materials
Chemical Structure
of viscose is same as that of cotton i.e.
Cellulose, But the polymer chains are much
shorter . The degree of polymerization value
of rayon is 400-700 while that of cotton is
5000.
Figure: Chemical Structure of viscose Rayon

4. Properties of Viscose Rayon Fiber 4
Properties
Physical Chemical
 Color: White
 Ability to protect friction:
Less
 Tensile strength : 1.5-2.4 gpd
in dry and 0.7 -1.2 gpd in wet
state or high.
 Elasticity : good
 Elongation at break : 13%
 Moister absorption: 11-13%
 Action of heat: lose strength
when it heated above 1500C
 Action of light: UV ray damage
the fiber
 Insulating: Do not have good
insulator
 Action of acid: damaged by
strong acids
 Action of base: Good resistance
to weak alkalis but strong alkali
is harmful.
 Action of bleaching: Strong
oxidizing agents damage it.
 Action organic solvent: ability
to protest the action of organic
solvents.
 Action of soaps : no direct effect
 Action of insects : not affected
 Action of microorganisms:
affect the color, strength,
dyeing properties and luster of
rayon.
Some Pictures of
Rayon Fiber & Fabric

5. Steps involved in Manufacturing of Viscose Rayon
5
Steeping Spinning
Shredding Filtration
Ripening
Ageing
Preparation of
spinning
solution
Xanthation

6. Manufacturing Process
1. Steeping
● Pulp is treated for
mercerization in presence of
NaOH at the mercerizing
strength.
● The pulp sheets are immersed
in 17-20% NaOH. Alkali
cellulose is generated as
product during the reaction.
6
2. Shredding
● The pressed alkali cellulose is
shredded mechanically
● Yield: finely divided fluffy
particles called "crumbs“
● Increased surface area of the
alkali cellulose
● Increasing its ability to react
in the steps that follow.
3. Ageing
● Crumbs transferred to a steel container.
● Stored under specific temperature (18-300C) for
3 to 72 hours
● Depolymerize the cellulose to the desired
degree of polymerization.
● Average molecular weight of the original pulp
is reduced by a factor of two to three
● Get a viscose solution of right viscosity and
cellulose concentration
4. Xanthation
● Aged alkali cellulose crumbs are placed in
vats
● Allowed to react with carbon disulphide
under controlled temperature 20-300C
● Forms cellulose xanthate.

7. Manufacturing Process
5. Ripening
● The viscose is allowed to ripen for a stipulated period of
time.
● Two major processes takes place firstly, the xanthate
groups are redistributed and then lost.
● The viscosity of the solution first decreases and then rises
to its original value.
7
6. Preparation of spinning solution
Water-69%
ZnSO4 - 1%
Na2SO4 - 18%
Glucose - 2%
H2SO4 - 10%
● The Na2SO4 precipitates the dissolved sodium cellulose
xanthate.
● The H2SO4 converts xanthate into cellulose, carbon
disulphide and sodium sulphate.
● The glucose provides softness and pliability to the
filaments whereas ZnSO4 helps in adding strength.
7. Filtration
● The viscose is filtered to remove undissolved materials
● Which disrupt the spinning process or cause defect in the
rayon filament.
8. Wet Spinning
The ripened viscose solution passes through a centrifugal pump
by the compressed air. Then viscose solution is forced through a
spinneret. It has many fine holes with diameters ranging from
(0.05-0.1)mm. The viscose solution is metered through a
spinneret into a spin bath. Containing H2SO4, Na2SO4 and ZnSO4
The dilute H2SO4 decomposes the xanthate and regenerates
cellulose by the process of wet spinning. The outer portion of the
xanthate is decomposed in the acid bath, forming a cellulose skin
on the fiber. Na and ZnSO4 control the rate of decomposition (of
cellulose xanthate to cellulose) and fiber formation.
Once the cellulose xanthate is neutralized and acidified,
rapid coagulation of the rayon filaments occurs which is
followed by simultaneous stretching and decomposition of
cellulose xanthate to regenerated cellulose.

8. Applications
● With polyester, nylon
and acrylic:
Rayon contributes
absorbency, comfort
and softness when
blended with them.
● With cotton:
It alters appearance to
create soft luster.
● With wool:
It will decrease the
cost.
● With flax and
ramie:
It can help produce
appearance that are
typically associated
with linen like
fabrics.
 Blends
Regular rayon blend with many fibers like polyester, acrylic, nylon, acetate, cotton, flax, wool and ramie.
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9. 9
 Fabrics
gabardine, suiting, lace, outerwear fabrics and
lining for fur coats & outerwear
 Apparel
dresses, saris, jackets, lingerie, linings, milinerey
(hats), slacks, sport shirts, sportswear, ties, work
clothes
 Domestic Textiles
blankets, curtains, draperies, sheets, slip covers,
tablecloths, upholstery, bedcover
 Industrial Textiles
high tenacity rayon is used as reinforcement to
mechanical rubber goods (tires, conveyor belts,
hoses), applications within the aerospace,
agricultural and textile industries, braided cord,
tape
Uses
linings
sportswear slacks
blankets upholstery draperies
Reinforcement fabric
suiting gabardine
jackets saris
braided cord
lining for fur coats

10. Advantages
1. Lightweight - Viscose fabric is lightweight and
drapes over the body nicely, making it great for
clothing.
2. Soft - Viscose fabric is made to look like silk.
However, it feels more like cotton on the skin rather
than silk.
3. Breathable - It easy to breathe in and suitable for
warm weather or climates.
4. Highly absorbent - Rather than trap heat, viscose
fabric absorbs water and sweat effectively. Hence,
making it a great material for sportswear as well.
5. Easy to dye - Viscose fabric is easy to dye, and its
color does not fade even after multiple washes and
years of use.
Disadvantages
1. Non-elastic - Maintains its shape and is non-elastic.
2. Shrinks and wrinkles easily - Unfortunately, after
several washes, products made with viscose fabric
eventually shrink. It also wrinkles easily if not carefully
used and maintained.
3. Deteriorates under the heat of the sun - The
quality of viscose fabric also deters after long exposures
to sunlight. Hence, it is best to be used in close off areas
away from the sun.
4. Dissolves with dry cleaning fluid - Cannot use
dry cleaning fluid with viscose fabric. Otherwise, it will
end up completely destroying the fabric.
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11. Thanks to All

12. Any Question ??