Thermoplastics polymers are linear (slightly branched) long chain polymers, which can be repeatedly softened and hardened on heating. Hence, they can be modified again and again. Examples include polyethylene, polystyrene.
Thermosetting polymers are cross-linked or heavily branded polymers which get hardened during moulding process. These plastics cannot be softened again on heating. Examples of thermosetting plastics include bakelite, urea-formaldehyde resins.
