Polymers which have amide linkages are called polyamides. These are prepared by the condensation polymerization of dibasic acids with diamines or their equivalents.
a) Nylon 6, 6
(Here, 6, 6 indicates the no. of carbon atoms in diamide and dibasic acid, respectively)
b) Nylon 6, 10
(6, 10 is number of ‘C’ in diamine & diacid, respectively)
c) Nylon 6