COTTON FIBRE: PART 2

COTTON FIBRE: PART 2

COTTON FIBRE

CHEMICAL COMPOSITION OF COTTON:

Types of soil, plant and climate effect on the chemical composition of cotton fibre and the quantity of the constituent in the cotton.

CHEMICAL STRUCTURE OF COTTON

Cellulose is the main component of cotton and it consist of 94% of 100. Cotton is produced on various contries of the world. All of the cotton have not same chemical properties it depends on the geographical condition.

CONSTITUENT IN COTTON	TYPICAL (%)
CELLULOSE	95
PROTIENS	1-1.5
PECTIC SUBTANCES	0.9
WAXES	0.5
ASH	1.2
TOTAL SUGAR	0.3
ORGANIC ACIDS	0.8
OTHERS	1.4

CHARACTERISTICS OF COTTON FIBRE: -

-Cotton is comfirtable to wear.

-It is natural cellulosic fibre.
-Made from the cotton ball.
-Cotton absorbs water.
-It is slowly dry.
-Resists static electricity.
-Wrinkles easily.
-It can withstand heat, detergent and bleach.
-In wet condition, it is 20% more stronger than dry.
-Damaged by mildew.
-Damage when prolonged to direct sunlight.
-Long staple fibre can be woven into smooth fabric

PHYSICAL PROPERTIES OF COTTON:

Cotton is a natural cellulosic fibre and it has some chemical properties. Chemical properties of the cotton fibre are given below:

1. Effect of acids:
 Cotton is attacked by hot dilute acids or cold concentrated acids which it disintegrates. It is not affected by acids.

2. Effects of Alkaline:
 Cotton has an excellent resistance to alkalis. It swells in caustic alkalis( NaOH) but it does not damaged. It can be washed repeatedly in soap solution without any problem.

3. Effect of organic Solvent:
 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.

4. Effect of insects: 
Cotton is not attacked by moth-grubs or beetles.

5. Effect of Micro Organism:
 Cotton is attacked by fungi and bacteria. Mildews.will feed on cotton fabric, rotting and weakline the materials. Mildews and bacteria will flourish on cotton under hot and humidification. They can be protected by impregnation with certain types of chemicals. Copper Nepthenate  is one of the chemical.

6. Action with  bleaching:
 No damaging event is occurred here. Cotton is converted into oxi-cellulose in strong oxidising bleaching. The most common bleaches used on cotton textile materials are sodium hypochlorite and sodium perborate. They are: oxidizing bleaches and bleach because of the oxygen liberated from them.

7. Sunlight prevention power:
 Ultraviolet ray converts the cotton into oxi-cellulose.

8. Mildew preventive power: 
Untreated not easy. There is possibility to be affected.

9. Dye ability: 
Affinity to colour is good. Direct, reactive, sulphur and vat dyes are used.

10. Insects preventive power: 
Not affected by moth.Sliver fish will eat cotton cellulose especially if heavily starched.


11. Heat:
 Conductive Ironing temperature is 150oC where decomposes is 2400oC and ignition temperature is 390oC.

12. Action of water:
 Water, which is very strong polar in nature, easily attacked by the polar -OH group of the cotton fibre. So that water is able to penetrates into the cellulose network of the cotton fibre. This water absorption causes swelling of the fibre.

13. Effect of temperature:
 Cotton fibre shows an excellent resistance to thermal decomposition. Prolonged heating at  100oC shows the cotton no visible change heat at 120oC for several hours shows the cotton little or no change in strength. But begin to turn yellow gradually. Cotton decomposes markedly at 150oC. 

14. Effect of Sunlight and weather:
 The ultra-violet rays of sunlight provide photo chemical energy whilst the infra-red rays provide heat energy essential to degrade the cotton polymers in the pressure of atmospheric oxygen, moisture and air pollutants. The breakdown of polymers takes place through diverse hydrolysis reactions. The beginning degradation Is noticed as a slight fibre discolouring. Fading of coloured cotton textile is partially because the breakdown of the dye molecules in the fibre’s polymer system.

15. Colour Fastness: 
Cotton is easy to dye and print. The classes of dye which may be used to colour cotton are azoic, direct, reactive, sulphur and vat dyes. The polar polymer system easily attracts any polar dye molecules into the polar system. Therefore, dye molecules which can be dispersed in water will be absorbed by the polymer system of cotton. However, the dye molecules can enter solely the amorphous regions of the polymer system of cotton. The small inter polymer spaces in he crystalline regions of the polymer system prohibit the entry of the crystalline molecules.

16. Mildew:
 Cotton is damaged by fungi. Heat and dampness support the growth of mildew. The fungi produce a chemical compound which has the power of changing cellulose to glucose. The fungi feed on the molecules of sugar: cotton treated with acrylo nitrite is resistant to mildew.

USES OF COTTON FIBRE:

DENIMS
SHIRTING
SUITINGS
TOWELS
DHOTIS
BED SHITS
CURTAINS

• Published By:

Anjali Sanjaykumar Bachhav
Dept. Of Textile Technlogy,
DKTE Textile and Engineering Institute.
bachhavanjali2@gmail.com