Chemical composition and properties of cotton

 Chemical composition of cotton:

Cellulose ---------------------------------------------- 85.5%
Oil and wax -------------------------------------------- 0.5%
Proteins, Pectoses andColoring matters------------------- 5%
Mineral matters------------------------------------------ 1%
Moisture------------------------------------------------ 8.5%


Cotton is a crystalline fibre. Its polmer system is about 65 to70 percent crystalline and correspondingly about 35-30 percet amorphous. The cotton fibre is made up of a cuticle, primary wall, secondary wall and lumen.

Physical properties of cotton:

a.    Specific gravity—1.5-1.55
b.    Strength-Dry- 3.5 gm/den wet-Dry*1.11
c.    Elasticity- Low
d.    Breaking extension – 5-7%
e.    Stiffness – 57-60 gm/den
f.    Resilency – Low
g.    Abrasion resistance –Medium.

Chemical properties of cotton:

a.    Inorganic acids have no effect on cotton but organic acids can decompose or hydrolyze cotton.
b.    Cotton has a lot resistance to alkali. Cotton treated with alkali become oval form kidney shape and         more lustrous.
c.    Cotton can be bleached with all types of bleaching agents. Among them per hydroxide is less harmful.
d.    It has resistance to organic solvent.
e.    It has good heat conductivity.   
f.    It can be dyed by Azoic. Direct, Reactive, Sulphur and Vat dyes.