Thermoplastic: These polymer gets soften on heating and can be converted into any shape that they can retain on cooling. Such polymers that soften on heating and stiffen on cooling are termed as "Thermoplastic".

For examples: Polythene, PVC, nylon, and sealing wax.

Thermosetting: They are like the yolk of egg, which on heating sets into a mass, and once set, cannot be reshaped. Such polymers, which become infusible and insoluble mass on heating, are called "Thermosetting" polymers. E.g. Bakelite.