Thermoset

Q. Why can't thermosetting polymers be reused after getting moulded?

1. They become soft at high temperatures and melt.
2. They form crosslinks at high temperatures which make them hard and strong
3. They become brittle at high temperatures
4. They cannot be heated as they are very good conductors of heat.

Q. _____ undergoes permanent deformation on heating.

1. Polythene
2. PVC
3. Teflon
4. Bakelite