Cotton Fibre | Physical Properties and Chemical Properties of Cotton

Cotton is a cellulosic fibre. Cotton is used as a fibre because it has a large amorphous portion which makes the fabric comfortable. It is also soft when properly ginned and has a high absorbency power hence making it easy to use for dyeing. It is also said to have good strength and good drape ability.

Characteristics of Cotton

• Comfortable Soft hand
• Good absorbency
• Color retention
• Prints well
• Dry-cleanable
• Good strength
• Drapes well
• Easy to handle and sew

Physical Properties of Cotton

• Color: The color of cotton fibre could be white, creamy white, bluish white, yellowish white or grey.
• Tensile Strength: Cotton is moderately strong fibre; tenacity is 26.5-44.1 cN/tex and tensile strength 2800-8400 Kg/cm^2. The strength is greatly affected by moisture, the wet strength of cotton is 20%, which is higher than dry strength.
• Elongation at break: Cotton does not stress easily. It has an elongation break of 5-1%.
• Elastic Recovery: Cotton is inelastic and rigid fibre. at 2% extension it has an elastic recovery of 74% and at 5% extension the elastic recovery is 45%.
• Specific Gravity: Specific gravity is 1.54
• Moisture Regain: Standard moisture regain is 8.5%.
• Effect of heat: Cotton has an excellent resistant to degradation by heat. It begins to turn yellow after several hours at 120°C and decomposes marked by at 150°C. As a result of oxidation, cotton is severally damaged after few minutes at 240°C. Cotton burns in air.
• Effects of Age: Cotton shows a small loss of strenth when stored carefully. After 50 years of storage cotton may differ only slightly from the new fibres.
• Effect of Sun Light: There is gradual loss of strength when cotton is exposed to sun light and the fibre turn yellow. The degradation of cotton by oxidation is done when heat is promoted and encouraged. By sun light much of the damage is caused by UV-light and by the shorten weaves of visible light.

Chemical Properties of Cotton

• Effects of Acids: Cotton is attacked by hot dilute acids or cold concentrated acids which it disintegrates. It is not affected by cold weak acids.
• Effects of Alkalis: Cotton has an excellent resistance to alkali. It swells in caustic alkalis but does not damaged. It can be washed in soap solution without any problem.
• Effects of Organic Solvents: Cotton has high resistance to normal cleaning solvents. Cotton is dissolved by the copper complexes, such as cuprammonium hydroxide, cupriethylene diamine and concentrated 70% H2SO4.
• Effects of Insects: Cotton is attacked by moth-grubs or beetles.
• Effects of micro Organism: Cototn is attacked by fungi and bacteria. Mildew will feed on cotton fabric, rotting and weakling the materials. mildews and bacteria will flourish on cotton under hot and humid condition. They can be protected by impregnation with certain types of chemicals. Copper Nepthenate is one of the chemicals.