Different Properties and Uses of Cotton Fibre:
Effect of Heat:
Cotton has an excellent resistance to degradation by heat. It begins to turn yellow after several hours at 120 degree Celsius and decomposes markedly at 150 degree Celsius. As a result of oxidation, cotton is severely damaged after a few minutes at 240 degree Celsius. Cotton burns readily in air.
Effect of Age:
Cotton shows only a small loss of strength when stored carefully. It can be kept in the warehouse for long periods without showing any significant deterioration. After fifty years of storage, cotton may differ only slightly from fiber a year or two old. Ancient samples of cotton fabric taken from tombs more than 500 years old had four-fifths of the strength of new material.
Effect of Sunlight:
There is a gradual loss of strength when cotton is exposed to sunlight and the fiber turns yellow. The degradation of cotton by oxidization when heated is promoted and encouraged by sunlight. It is particularly severe at high temperatures and in the presence of moisture. Much of the damage is caused by ultra violet light and by the shorter waves of visible light. Under certain conditions, the effects of weathering in direct sunlight can be serious. The cotton can be protected to some degree by using suitable dyes.
Uses of Cotton Fiber:
In cotton, nature has given us an all-round utility fiber that is second to none. Cotton fabrics combine remarkably durability with attractive wearing qualities. Cotton fabrics have a pleasant feel or handle. They are cool in hot weather.
Cotton is inherently strong and it is stronger when wet than it is when dry. This property, allied with cottons stability in water and alkaline solutions, endows cotton garments with a long useful life. Cotton can withstand repeated washings and is therefore ideal for household goods and garments that can be laundered time and time again. Heavily soiled garments can be rubbed vigorously without being damaged.
The cotton fiber itself is dimensionally stable. A made up cotton garment may shrink to some extent due to the tensions introduced by spinning and weaving but the fiber itself does not contribute significantly to any shrinkage.
This so-called “relaxation shrinkage”, caused by the easing of strains set up during spinning and weaving, can be overcome by a treatment called compression shrinkage. Rigmel and Sanforized shrunk cotton fabrics are compression shrunk in this way; they are dimensionally stable and will neither stretch nor shrink more than 1 per cent in either direction.