Write short notes-polyester and polyamide.

(i) Polyester- Polyester have innumerable ester functional group containing repeating units. It is formed by combination of two hydroxyl and two carboxylic groups containing substances.

Polyester fibres are mixed with cotton fibres and used in textile industry.

(ii) Polyamide- Polyamide is a polymer which containing amide group. It can be prepared by condensation of diamine and carboxylic acid and it is known as nylon.