Which of the following polymer is NOT a thermoplastic?

1. A

   Teflon

   (a) Teflon. PTFE is a thermoplastic fluoropolymer; it softens on heating and is processed as a thermoplastic.

2. B

   Neoprene

   (b) Neoprene. Neoprene (polychloroprene) is a synthetic rubber—an elastomer, not a thermoplastic. That exclusion is the official key.

3. C

   Polystyrene

   (c) Polystyrene. A standard thermoplastic (styrofoam, CD cases).

4. D

   Polythene

   (d) Polythene. Polyethylene is the most common thermoplastic.

Summary. Official key is (b). Neoprene is an elastomer, not a thermoplastic. Teflon, polystyrene and polythene are thermoplastics.