What is the reason of crystalline structure of nylon?

Explanation

Nylons are polyamides as they consist of amide groups `(-NHCO-)` in their backbone chains. As amide groups are highly polar , their presence in polymeric chains lead to the formation of intermolecular hydrogen bonds between adjacent chains, thereby holding the chains together tightly. The polymeric chains of nylons are usually linear and symmetrical . Because of the strong forces of attraction due to hydrogen bonding between the symmetrical chains of nylons, they are aligned in a regular and ordered arrangement. This makes nylons crystalline in nature .