Define thermoplastics and thermosetting polymers with two examples of each.

Explanation

Thermoplastics are linear polymers which can be repeatedly softened on heating and hardened on cooling and hence can be used again and again without any change in their chemical composition and mechanical strength. For example , Polythene, Polypropene, etc.
Thermosetting polymers , on the other hand , are permanently setting polymers. On heating in a mould, they get hardened and set and cannot be softened again. This hardeing on heating is due to cross linking between different polymer chains to give a three -dimensional network solid. For examplel. bakelite , melamine -formaldehyde polymer, etc.