Question

Define thermoplastic and thermosetting polymers. Give one example of each.

Answer 1

Thermoplastic polymers : In these polymers, the intermolecular forces of attraction are between those of elastomers and fibres. They are hard at room temperature, become soft and viscous on heating and again rigid on cooling.
e.g., Polythene, PVC, etc.
Thermosetting polymers : These are semifluid substances with low molecular masses which when heated in a mould undergo a permanent change in composition to give a hard, infusible and insoluble mass. They cannot be remelted and reworked. e.g., Bakelite.