The cotton fiber comes from the fruit of the cotton plant. Cotton is the white, downy fibrous substance covering the seed of the cotton plants. The seeds with this covering are encased in pods which grow on the cotton plant and burst open when ripe, disclosing the white, downy covering of the seed subsequently grown into cotton fibers. The manufacturing process of cotton are opening, picking, carding, combing, drawing, roving and spinning.
The cotton fiber is the shortest of all the textile fibers. Its length varies from 8-10th of an inch to 2 inches. It absorbs moisture quickly and dries quickly. It is fairly cheap, and comfortable both in warm and cool weather. It can stand frequent laundering. Cotton is known as the ‘King of Fibers” and are mostly grown in tropical climate. India is the birth place of cotton. Other principal cotton producing countries are Egypt, South United States, Brazil and East Indies.
The cotton fiber, when it is raw, has a tube-like structure containing sap. After ripening of the sap inside the fiber dries up so that the fiber flattens and twists like ribbon.
These twists are called ‘convolutions’. Long length and many convolutions contribute to the spin ability of the fibers.
The cotton fiber contains about 90 percent cellulose and about 6 per cent moisture; the remaining consists of natural impurities.
Cotton fiber is relatively strong due to its natural twisted nature, as it helps to keep the yarn firm and strong. It also makes easier to spin it into long threads.
Cotton fiber has very little natural Microscopic elasticity.
The tendency of cotton fabrics is to wrinkle easily and offset by finishing processes that give a wrinkle-resistant quality.
5. Heat conductivity:
Cotton is a better conductor of heat than silk and wool. Hence, it can make excellent summer clothing.
6. Effect of heat:
Cotton can withstand moderate heat. It is not harmful unless scorching takes place.
Cotton fiber is composed primarily of cellulose, which is very absorbent, hence, it holds moisture. Thus, cotton garments absorbs perspiration readily and soon gives a sense of chill.
8. Effect of moisture and friction:
It is not affected by moisture or friction and is stronger when moisture content increases. Therefore, it lends itself to the washing process.
The fiber itself does not shrink but the fabrics made with it, which have been stretched in the finishing processes (such as stiffened with starch), do so. But it is usually lost in washing.
10. Effect of light:
Cotton fiber oxidizes, turning yellow and losing strength from exposure to sunlight over a protracted period of time.
11. Reaction to Alkalis:
Cotton is not harmed by alkalis.
12. Reaction to Acids:
Cotton is not damaged by volatile organic acids as acetic acid (Vinegar). However, concentrated, cold or diluted hot mineral acids, such as sulphuric acid will destroy cotton.
13. Affinity for Dyes:
Cotton has a good affinity for dyes. It is dyed best with vat dyes, such as provide good colour fastness.
14. Resistance to Perspiration:
Acid perspiration has a slightly deteriorating effect on cotton.
15. Effect of Bleaching:
Cotton may be safely bleached with ordinary household bleaches.