Identify thermosetting polymer from following.

Thermosetting polymers are cross-linked or heavily branched molecules, which on heating undergo extensive cross-linking in moulds and become infusible. These cannot be reused.

Examples of thermosetting polymers include Bakelite, urea-formaldehyde resins, and melamine-formaldehyde resins.

Polystyrene is a thermoplastic polymer.

Buna-S is an elastomer.

Terylene is a fibre.

Answer: Ureaformaldehyde resin