Silk, cotton and wool

1. MEANING OF NATURAL
POLYMER
•Polymer can be found easily in the nature
and these, of course, are called “ natual
polymers”

2. SILK, COTTON AND WOOL

3. TYPES OF NATURAL POLYMER
TO BE DISCUSS
NATURAL
POLYMER
SILK COTTON WOOL

4. SILK
•Silk is a protein, a natural biopolymer,
produced by silkworms and spiders that is
formed into fibers with remarkable
mechanical properties. Silk has
similarities to synthetic polymers

5. COMPOSITION OF SILK

6. PROCESSING OF SILK

7. PROPERTIES OF SILK

8. COTTON
•Cotton is a soft fiber that grows around the seeds of the
cotton plant (Gossypium sp.), a shrub native to tropical
and subtropical regions around the world, including the
Americas, India, and Africa. However, virtually all of the
commercial cotton grown today worldwide is grown from
varieties of the native American species Gossypium
hirsutum and Gossypium barbadense. The fiber is most
often spun into yarn or thread and used to make a soft,
breathable textile, which is the most widely used natural-
fiber cloth in clothing today. The English name derives
from the Arabic (al) qutn ن,طْن, قُ, meaning "cotton". (The
Spanish word algodón has the same etymology.)
•Cotton fiber, once it has been processed to remove
seeds and traces of wax, protein, etc., consists of nearly
pure cellulose, a natural polymer. Cotton production is
very efficient, in the sense that ten percent or less of the
weight is lost in subsequent processing to convert the
raw cotton bolls (seed cases) into pure fiber. The
cellulose is arranged in a way that gives cotton fibers a
high degree of strength, durability, and absorbency.
Each fiber is made up of twenty to thirty layers of
cellulose coiled in a neat series of natural springs.
When the cotton boll is opened, the fibers dry into flat,
twisted, ribbon-like shapes and become kinked together
and interlocked. This interlocked form is ideal for
spinning into a fine yarn.
•

9. COMPOSITION OF COTTON

10. PROCESSING OF COTTON

11. PROPERTIES OF COTTON

12. WOOL
•Wool is the fiber derived
from the fur of animals of
the Caprinae family,
principally sheep, but the
hair of certain species of
other mammals such as
goats and rabbits may also
be called wool.

13. COMPOSITION OF WOOL

14. PROCESSING OF WOOL
• Wool straight off a sheep contains a high level of grease which contains
valuable lanolin, as well as dirt, dead skin, sweat residue, and
vegetable matter. This state is known as "grease wool" or "wool in the
grease". Before the wool can be used for commercial purposes it must
be scoured, or cleaned. Scouring may be as simple as a bath in warm
water, or a complicated industrial process using detergent and alkali. [1]
In commercial wool, vegetable matter is often removed by the chemical
process of chemical carbonization[2]. In less processed wools,
vegetable matter may be removed by hand, and some of the lanolin left
intact through use of gentler detergents. This semi-grease wool can be
worked into yarn and knitted into particularly water-resistant mittens or
sweaters, such as those of the Aran Island fishermen. Lanolin removed
from wool is widely used in the cosmetics industry.
• After shearing, the wool is separated into five main categories: fleece
(which makes up the vast bulk), pieces, bellies, crutchings and locks.
The latter four are packaged and sold separately. The quality of fleece
is determined by a technique known as wool classing, whereby a
qualified woolclasser tries to group wools of similar gradings together to
maximise the return for the farmer or sheep owner. Wool straight off a
sheep contains a high level of grease which contains valuable lanolin,
as well as dirt, dead skin, sweat residue, and vegetable matter. This
state is known as "grease wool" or "wool in the grease". Before the wool
can be used for commercial purposes it must be scoured, or cleaned.
Scouring may be as simple as a bath in warm water, or a complicated
industrial process using detergent and alkali. [1] In commercial wool,
vegetable matter is often removed by the chemical process of chemical
carbonization[2]. In less processed wools, vegetable matter may be
removed by hand, and some of the lanolin left intact through use of
gentler detergents. This semi-grease wool can be worked into yarn and
knitted into particularly water-resistant mittens or sweaters, such as
those of the Aran Island fishermen. Lanolin removed from wool is widely
used in the cosmetics industry.
• After shearing, the wool is separated into five main categories: fleece
(which makes up the vast bulk), pieces, bellies, crutchings and locks.
The latter four are packaged and sold separately. The quality of fleece
is determined by a technique known as wool classing, whereby a
qualified woolclasser tries to group wools of similar gradings together to
maximise the return for the farmer or sheep owner.

15. PROPERTIES OF WOOL
•Wool's scaling and crimp make it easier to spin and felt the fleece. They
help the individual fibers attach to each other so that they stay together.
Because of the crimp, wool fabrics have a greater bulk than other textiles
and retain air, which causes the product to retain heat. Insulation also works
both ways; bedouins and tuaregs use wool clothes to keep the heat out.
•The amount of crimp corresponds to the thickness of the wool fibers. A fine
wool like merino may have up to a hundred crimps per inch, while the
coarser wools like karakul may have as few as one to two crimps per inch.
•Hair, by contrast, has little if any scale and no crimp and little ability to bind
into yarn. On sheep, the hair part of the fleece is called kemp. The relative
amounts of kemp to wool vary from breed to breed, and make some fleeces
more desirable for spinning, felting or carding into batts for quilts or other
insulating products.
•Wool is generally a creamy white color, although some breeds of sheep
produce natural colors such as black, brown, silver and random mixes.

16. USES OF WOOL
•In addition to clothing, wool has been used
for carpeting, felt, wool insulation (also see
links) and upholstery. Wool felt covers
piano hammers and it is used to absorb
odors and noise in heavy machinery and
stereo speakers.

17. USES OF NATURAL POLYMER