COTTON FIBER

Cultivation

Harvesting
Ginning
Commercial varieties

                        - Sea Island

                        - Egyptian

                        - Upland

                        - Indian

                        - China 

                                                              

Cotton Grading

Color: 

•  Extra White 
  
• White 
• Spotted 
• Tinged 
• Yellow Stained

Grading of Upland Cotton

No.1 Middling Fair

No.2 Strict Good Middling

No.3 Good Middling

No.4 Strict Middling

No.5 Middling

No.6 Strict Low Middling

No.7 Low Middling

No.8 Strict Good Ordinary

No. 9 Good Ordinary

Chemical Composition

Cellulose ------------------------------------- 85.5%

Proteins and coloring matters ----------- 4.5%

Oil & wax ------------------------------------ 0.5%

Mineral Matters ---------------------------- 1%

Moisture -------------------------------------- 8.5%

Physical Properties 

• Tensile strength 
• Tenacity   26.5 – 44.1  CN/Tex 
• 3 – 5 gm/den ( affected by moisture, long sea island fibers produce strongest yarn ) 
•  Specific gravity – 1.51-1.54 
•  Elongation at break – 5- 10% 
•  Elastic behavior – At 2% extensors it has elastic recovery 74% at 5% it is 45% 
•  Moisture regain -  8.5% 
•  Length width ratio - 6000:1 to 350:1 
•  Resiliency - low 
•  Abrasion resistance  - Medium 
•  Dimensional stability – Medium 
•  Effect of age : Little loss of strength when stored carefully. After 50 years slight loss of strength and after 500 years it loose 1/5th of strength.
• Action of water as cotton – It has good water absorbency and swell during wet condition. Also increase strength. Due to penetration of water molecule move more freely relation to are another

Chemical Properties 

•         Effect of acid – Cotton is attacked by hot diluted acid or cold concentrated acids. It is not affected by cold weak acids, but long time treatment weakens hydrolysis and destroyed.

•         Effect of bleaches – Excellent resistance to alkalies, swells in caustic alkalies.

•         Effect of bleaches: The most common bleaches used on cotton textile material are sodium hypocrite and sodium perforate. They bleach most effectively in alkaline conditions to which cotton textile materials are resistant. Oxidizing bleaches also can be used.

•         Effect of organic solvents - High resistant to normal organic solvents, so dry wash is possible. Very few solvents can dissolve cotton completely.

•         Effect of insects - Moth can’t attack cotton.

•         Effect of micro–organism  -  Bacteria, fungus, mildew attack cotton. They feed as cotton fabric, rotting and weaken the material.

•         Dye ability – Cotton fiber can be dyed by various dye like – reactive, direct, vat, sup her, alienate, azoic, mordant, indigo and other natural dyes.

•         Effect of heat – Excellent resistant to degradation by heat. After several hours at 1200 c it becomes yellow. Decompose at 1500 due to oxidation. Severely damage at 2400 ignites at 390º c Burn in the air.

•         Effect of sunlight - Gradual loss of strength when exposed to sunlight end fiber turns yellow. Much damage caused by ultra-violet ray.

•         Effect of atmosphere – Acidic polluted air may rapidly accelerate fiber break dam throw acid hydrolysis.

•         Color fast mess – less color fastness for direct dye. Reactive has moderate and good for vat dye.

Use

•         Cotton fiber has remarkable durability with attractive wearing qualities and pleasant feel or handle. Cotton can be spun into fine yarns and made into light woven fabric like poplin, voile, flannel etc. Heavier fabric also can be produced by cotton. Though we use cotton fabric for summer reason but it is possible to wear cotton fabric is winter for warn feeling.

•         Use of cotton is very wide like deference types of household textile, rain wear fabrics, chemical proof fabric and flame retardant fabric. It goes into boot and shoes, carpet, and curtain, clothing and hats. Heavy cotton yarn and materials are used for tire cords and marquees, tarpaulins and industrial fabric of all descriptions. There is a huge use of cotton in medical textile and also for geotextile.

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