Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus Gossypium in the mallow family Malvaceae. The fiber is almost pure cellulose. Under natural conditions, the cotton bolls will increase the dispersal of the seeds.

1. C O T T O N
Anchal Kumari
FD3
Fabric Fundamentals

2. Cotton is a soft, fluffy staple fiber that grows in
a boll, or protective case, around the seeds of
the cotton plants of the genus Gossypium in
the mallow family Malvaceae. The fiber is
almost pure cellulose. Under natural
conditions, the cotton bolls will increase the
dispersal of the seeds.
The plant is a shrub native to tropical and subtropical
regions around the world, including the Americas,
Africa, and India. The greatest diversity of wild cotton
species is found in Mexico, followed by Australia and
Africa. Cotton was independently domesticated in the
Old and New Worlds.

3. Growth Cycle
The growth cycle of the various cotton species vary in length, but the sequence of fruit
production remain the same. Weather, insects and moisture can adversely affect optimum
conditions for plant growth and it is the farmer's responsibility to adjust to these conditions
to optimize yield.

5. History
The oldest cotton fibers and boll fragments, dated from around
5000 B.C., were discovered in Mexico. In 5 B.C., the Greek
historian Herodotus reported of a plant that “bore fleece.” Cotton
has been worn in India and Egypt for over 5,000 years. Cotton
was grown by Native Americans as early as 1500. In England in
the 1700s, it was against the law to import or manufacture fabric
made of cotton since it was a threat to the sheep and wool
industry.
American colonists were able to grow lots of cottons, but
processing was difficult. It was not until the 1700s that the cotton
industry flourished in the United States. It was then that Samuel
Slater, an Englishman, built the first American cotton mill. These
mills converted cotton fibers into yarn and cloth.
In 1793, Eli Whitney developed the cotton gin, which
mechanically separates the seed from the lint fiber. Whitney
named his machine a “gin,” short for the word “engine.”
Technology has improved over the past centuries making cotton
growth and production much more efficient.

6. Textile classification-
• As it is obtained from a plant it is classified as a natural, cellulose,
seed, mono-cellular, staple fiber.
Fiber Morphology
The macro structure of cotton
• Under a microscope, a cotton fiber appears as a very fine, regular
fiber. • It ranges in length ½” to 2 ¾ “, depending upon the quality
of the fiber.
• It is the finest in common use, ranges 11µm to 22µm . Fiber
morphology
• The fiber length to breadth ratio of cotton ranges from about
6000:1 for the longest and best types, to about 350:1 for the
shortest coarsest cotton type. the greater the ratio, the more
readily can the cotton fibers be spun into yarn.
• The color of cotton fibers depends on its type, environment, soil
and climatic conditions under which it is grown.

7. The microscopic appearance of cotton-
Under the microscope, the cotton fiber looks like a twisted ribbon or a collapsed and twisted
tube. These twists or convolutions identify the cotton fiber under the microscope.
• The seed end of the fiber is quite irregular, having been torn, during ginning, from the
epidermis or skin of the cotton seed.

8. • The main part of the fiber, about 3/4th to 5/6th of its length, is regular, with a
thick fiber wall, a canal along the center of the fiber called the lumen, and
about 16 convolutions/cm.
• Fiber tip is less than 1/4th of the fiber length.
• At this end, the fiber tapers to a cylindrical, pointed tip, and has no
convolutions.
• The convolutions are formed after the cotton boll bursts open, the limp, sap-
filled cotton seed hairs begin to dry out, their cell walls collapse inward,
decreasing the size of the lumen. When the cotton seed hairs cease shrinking,
twisting and collapsing inward, they become the valuable, convoluted cotton
fiber.

9. The micro-structure of cotton fiber
Its cross-section is oval, compared with the normal
hexagonal plant cell. However, like all plant cells, cotton
has a distinct cuticle, well developed primary and
secondary walls, and a lumen.
Macro Structure of a Cotton Fiber :
Length : 1 cm to 6.5 cm
Diameter: 11 um to 22 um
Convolutions : Sixty per centimeter. (Creamy or brown.)
Color : Generally White, may be Creamy or Brown.
Length:Width: 6000:1
Light reflection: Low lusture, dull.
Micro Structure or Morphological
Structure of Cotton Fiber

10. • The cuticle is the’ very-outside’ or ‘skin’ of the cotton fiber. It is composed of a waxy layer
(pectin) only a few molecules thick. The waxy nature of the cuticle enables it to adhere
tenaciously to the primary wall of the fiber.
• The primary cell wall, which is immediately underneath the cuticle, is about 200nm thick.
It is composed of very fine threads of cellulose, called fibrils.
• These fibrils are about 20nm thick, but length is not known. The fibrils spiral at about 70° to
the fiber axis. This spiraling imparts strength to the primary cell wall and hence, to the
Secondary cell wall, which forms the bulk of the fiber. Concentric layers of spiraling,
cellulosic fibrils, not unlike the growth rings of trees, make up the secondary wall.
• The hollow canal, running the length of the fiber, Is called the lumen.
• The lumen was once the central vacuole of the growing cotton fiber. It was full of cell sap,
which was composed of a dilute, aqueous solution of proteins, sugars, minerals and
cellwaste products.
• When the sap evaporated, its constituents remained behind to contribute to the color of the
cotton fiber. • This caused the fiber to collapse inward resulting in the characteristics
kidney-shaped crosssection of the cotton fiber.

11. The polymer system
The cotton polymer-
• The cotton polymer is a linear, cellulose polymer. The repeating unit in the cotton
polymer is cellobiose which consists of two glucose units.
• The cotton polymer consists of about 5000 cellubiose units, i.e. degree of
polymerization. • The most important chemical groupings on the cotton polymer
are hydroxyl groups(OH) and methylol groups(CH2OH).

12. • The polymer system of cotton-Cotton is a crystalline fiber. Its polymer
system is about 65-70% crystalline and, correspondingly, about 35- 30%
amorphous.
• cotton polymers are, in the main, well oriented and probably no further apart
then 0.5nm , in the crystalline regions. This is maximum distance across
which hydrogen bonds can form between polymers.
• Hydrogen bonds are the most dominant and most important forces of
attraction present in the polymer system of cotton. For this reason, Van der
Waal’s forces which are also present have little relevance.

13. Physical properties
• Structure: The cotton fibre is short (1/2 inch -2 long inch) and cylindrical or
tubular as it grows. The cotton fibre is essentially cellulose consisting of carbon,
hydrogen and oxygen. Bleached cotton is almost pure cellulose raw cotton
contains about 5% of impurities.
• Strength: Cotton fibre is relatively strong which is due to the intricate structure
and 70% crystalline.
• Elasticity: Cotton is relatively inelastic because of its crystalline polymer system
and for this reason cotton textile wrinkle and crease readily.
• Hygroscopic moisture: Cotton does not hold moisture so well as wool or silk but
absorbs it and so feels damp much more quickly. It also rapidly spreads
throughout the material.
• Electrical property: The hygroscopic nature ordinarily prevents cotton textile
materials from developing static electricity.
• Absorbency: As cotton has cellulose it is a good absorbent of fibre.

14. • Thermal properties Cotton fibres have the ability to conduct heat energy, minimizing any
destructive heat accumulation thus they can withstand hot ironing temperature.
• Drape ability: Cotton does not have good body to drape well in shape. The type of
construction of the fabric may improve this property.
• Resilience: Cotton wrinkles easily some wrinkle resistant finishes may reduce this
property.
• Cleanliness and wash ability: Though cotton absorbs dust due to its rough nature. It can
be washed easily in the hot water and strong soaps without damaging the fibre.
• Luster: The natural cotton has no pronounced lustre. This can be improved by the
mercerization finish of the cotton(that is sodium hydroxide treatment).
• Shrinkage: The fibre itself does not shrink but cotton fibre which has been stretched in the
finishing process tends to relax back creating shrinkage.
• Heat conductivity: Cotton is the better conductor of heat than wool or silk but not as good
as rayon.

15. Chemical properties
• Action of acids and alkalis Strong acids will destroy the fibres immediately. Dilute inorganic
acids will weaken the fibre and if left dry will rot it. Therefore after treatment with acidic
solutions cotton articles should be thoroughly rinsed in water. They are affected very little by
organic acids. They are also quite resistant to alkalis even to strong caustic alkalies at high
temperature and pressure. In 8% NaOH cotton fibres swells, spirals, twisted uncoil and
shrinks and become thicker. The resultant fibre is smoother, lustrous, and stronger and has
increased water and dye absorption.
• Effect of bleaching: These have no effects until used in uncontrolled conditions and with
heat.
• Effect of sunlight and weather: Ultraviolet rays of sunlight affect the strength of fibre and
change the colour to yellow when exposed to prolonged period. Pollution also effect
fibre.Concentrated and diluted mineral acids like sulphuric acids will discolor fibre .
• Affinity to dyes: Cotton takes in dyes better than linen but not as readily as silk and wool. If
a mordant is used cotton is easy enough to dye mordant colours, direct or substantive dyes
should be applied to the cotton.

16. Properties of cotton fibre
The chemical
composition of cotton is:
Cellulose – 91.00%
Water – 7.85%
Protoplasm, Pectins – 0.55%
Waxes, Fatty Substances –
0.40%
Mineral Salts – 0.20%

17. Properties of cotton fiber
• Comfortable & soft feel.
• Highly absorbent.
• Color retention.
• Gets Printed well.
• Washable.
• Can be Dry cleaned.
• Good strength.(cotton get strength in wet condition)
• Poor drapability.
• Easy to handle and sew.
• Very little natural elasticity.
• Low resilience, wrinkles easily.
• Shape is Fairly uniform in width, 12–20 micrometers; length varies from 1
cm to 6 cm (½ to 2½ inches); typical length is 2.2 cm to 3.3 cm (⅞ to 1¼
inches).

18. • Contains moister content 8.5%
• Dimensional stability is good
• Acids damage, weaken fibers
• Resistant to alkalis
• No harmful effects
• High resistant to most organic solvent
• Bacteria in soil can also degrade cotton
• Long expodure to light turns fiber yellow and loses its strength
• Fungus can grow on cotton
• Withstand moderate heat
• Acid perspiration has a slightly deteriotating effect

19. Manufacturing of cotton-
Introduction-
cotton is grown in different parts of world, where the climate is mild. The most
favorable conditions for cotton belt are North America, Egypt. The largest cotton
growing areas are India, China, United States, Egypt etc.
1. Growing and harvesting- cotton grows on bushes 3-4 feet height, the blossoms
or flowers appears, falls off and the ball begins its growth, inside the ball are the
seeds from which the cotton fibers grow.
This is also called seed hair. When ball is ripe, it splits open and the fluffy white
cotton stands out from the ball.
The cotton is picked up with the help of machine or by hand. Cotton gets discolored
and dirty if it is kept on plant for longer duration.

20. 3. Bailing- cotton is compressed or pressed into bales. These are wrapped with jute
cocking and cotton is then supplied to mills in bales.
Ginning
2. Ginning- in this process seeds are removed and fibers are pressed into bales. This
process is carried out by a machine. Seeds are used for the production of oil, soaps
and cosmetics. The fiber at this stage is called LINT.

21. 4.Opening and picking-opening refers to opening of the bale and loosening and
fluffing of the fiber which have been tightly packed into bales.
Layers of fibers from several bales are fed into an opener. The fibers emerge from
the opener like a fluffy mass, i.e. 10-15 times as bulky as compared to the bale.
The picking machine continues the loosening and cleaning of the fibers and a thick
white sheet is formed which is called LAP.
5.Carding-In this process the lap passes between two cylinders covered with
clothing, which is a heavy fabric with many specialty bent wires. Individual fibers are
straightened and made somewhat parallel.
In this machine cotton is thoroughly cleaned off all embedded dirt and foreign matter.
There is no sorting of long and short fibers. The fibers emerges from the carding rolls
as a thin sheet

22. 6.Combing-It removes the short fibers and keeps rest of the fibers nearly
parallel. As much as ¼ of the fiber may be combed out as waste which are
used for other purposes.
The fibers that remain here are long staple, good quality fibers. These are
used for manufacturing cotton. Combed fibers are fine, uniform, strong and
smooth.
7.Slivering-The thin sheet of fibers laid parallel to each other after combing.
These are given a slight pull and then twisted into one inch thick, long sliver.
The slivers are collected in a dram.

23. 8.Drawing-The slivers are fed into the drawing rolls at the same time. This is a
continuation of the blending which started in the opening process.
The drawing frame consists of four sets of cells, each of which travels at a
faster speed then the previous set. The difference in the speed causes
elongation of the sliver and reduction in the diameter.
Drawing

24. 9. Roving- This is similar to drawing but the
diameter of the sliver reduces further and slight
twist is given. Then it is wound on the bobbin.
10.Spinning & weaving- In factories cotton is
spun into yarns on large spinning machines.
Afterwards it is fed to the spools which are sent
for weaving to the weaving mills.
11.Dyeing & finishing- The woven fabric is dyed
with different colors and then finishing is given to
the fabric t improve its appearance and to remove
certain drawbacks or limitations.The bobbins are
place in the spinning frame, where these are
passed through several sets of rollers running at
successively more speed and finally drawn out to
yarn of the desired size.
Spinning & weaving

25. cultivation
• Successful cultivation of cotton requires a long frost-free period, plenty of
sunshine, and a moderate rainfall, usually from 600 to 1200 mm (24 to 48 inches).
Soils usually need to be fairly heavy, although the level of nutrients does not need
to be exceptional. In general, these conditions are met within the seasonally dry
tropics and subtropics in the Northern and Southern hemispheres, . but a large
proportion of the cotton grown today is cultivated in areas with less rainfall that
obtain the water from irrigation. Cotton grows in any part of the world where the
growing season is long and the climate temperate to hot with adequate rainfall or
irrigation Cotton grows best in best climate.
cultivation

26. End uses of cotton fiber
• Cotton is used to make a number of textile products.These include terrycloth
for highly absorbent bath towels and robes.
• Socks, underwear, and most T-shirts are made from cotton.
• Bed sheets often are made from cotton.Cotton also is used to make yarn used
in crochet and knitting.Fabric also can be made from recycled or recovered
cotton that otherwise would be thrown away during the spinning,weaving, or
cutting process.
• While many fabrics are made completely of cotton, some materials blend
cotton with other fibers, including rayon and synthetic fibers such as
polyester.It can either be used in knitted or woven fabrics, as it can be
blended with elastine to make a stretcher thread for knitted fabrics, and
apparel such as stretch jeans.

27. • Cotton is used in fishing nets, coffee filters, tents, explosives manufacture,
cotton paper, and in bookbinding.
• Cotton is a food and a fiber crop.
• Cotton seed is fed to cattle and crushed to make oil.This cottonseed oil is
used for cooking and in products like soap, margarine, emulsifiers,
cosmetics, pharmaceuticals, rubber and plastics.
• Linters are the very short fibers that remain on the cottonseed after ginning.
They are used to produce goods such as bandages, swabs, bank notes,
cotton buds and x- rays.

28. Thank You