Cotton

Cotton consists of practically pure cellulose and may be chemically described as poly (1, 4-B-D- anhydroglucopyranose).

The helical reversal structure of natural cellulose shows the constantly recurring cellobiose unit, consisting of two glucose units each with six carbon atoms. The length of unit cell along the fibre axis is 10.4A calculated for the cellobiose unit. In natural cellulosic fibres there are 3000 - 5000 C6 or glucose units joined together. This corresponds to a molecular weight of the order of 300,000 -500,000.

Proteins

Nitrogenous compounds:

•  Present in primary cell wall and lumen.
•  Yellow colour of cotton is due to presence of proteins and some colouring matter.

Some amino acids: 

• Leucine
• Valine  
• Proline 
• Alanin

Fats and waxes

The wax present in the primary cell wall of cotton protects the fibre from environmental agencies Responsible for the smooth handle and is a source of hydrophobicity. In the presence of wax, cotton has poor wettability. The wax consists of long chains of fatty alcohols, fatty acids, their esters, cholesterin & hydrocarbons.

Pectins 

Derivatives of pectic acid Found in the cover of citrus fruits Polymer of high molecular weight Pectin is a polysaccharide that acts as a cementing material in the cell walls of all plant tissues. It is a polymer of α-Galacturonic acid with a variable number of methyl ester groups. Some COOH groups are present as Ca and Mg salts.