Characteristics of cotton

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Characteristics of Cotton

Cotton is a natural fibre of vegetable origin like linen, jute or hemp. Cotton is the fruit of a shrubby plant commonly referred to as the "cotton plant". Cotton fiber has natural twists along the entire length of the fiber called convolutions. The convolutions help the fibers interlock when it is spun into yarn. Long fibers have about 300 convolutions per inch and short fibers have 200 or less. Sea Island cotton has highest number of convolutions per inch than the others:

Sea Island cotton --> 300

Egyptian cotton --> 230

American cotton --> 210

Indian cotton --> 150

Long fibre is required to produce higher and fine count. For long staple cotton fibre the ratio of length and thickness is 6000:1 where in short fibre the ratio is 3500:1. When the ratio is high than it is suitable and more easy to spun yarn.   

Cotton has a diameter of 16 to 22 micron. But surface of cotton fibre is not regular. Its middle portion is thick and tip is thin and there is no convolution at tip region. Therefore, cotton consists of a irregular surface that increases the friction between the fibres during spinning  and yarn becomes strong.

Cotton is not circular in cross-section. It looks like kidney in cross-sectional view under microscope. Due to its convolution and kidney like cross-section air, can pass through the cotton fabric and we feel comfort.

Color of cotton is ranges from white to grey. The color of the fibers is affected by climatic conditions, impact of insects and fungi, type of soil, storage conditions etc. There are five recognized groups of color: white, gray, spotted, tinged, and yellow stained. As the color of cotton deteriorates, the process ability of the fibers decreases.

Cotton has about 55% -70% crystalline region and 30%-35% amorphous region. That’s why the molecules of cotton polymer are arranged in a specific sequence and probably no part is 0.5nm far from the crystalline part. 0.5nm is the maximum distance to form Hydrogen bond in a polymer. These Hydrogen bonds among the polymers make the fibre strong. When cotton is wetted some molecules of amorphous region arranged in a balance way. As a result, 5% Hydrogen bond increases and that’s why wet cotton has greater strength than dried cotton.

Due to higher crystalline region cotton has less elasticity and its tendency of creasing is higher than any other natural fibre.

Cotton fabric becomes dirty easily because of its uneven surface but can be removed quite easily as it has good resistance to bleaching agent and not damaged into hot water.