Which of the following polymers are thermoplastic?
(i) Teflon
(ii) Natural rubber
(iii) Neoprene
(iv) Polystyrene
The answer is the option (i, iv) Thermoplastic polymers can be repeatedly softened on heating and hardened on cooling. Thus, they can be remoulded again and again. Teflon and polystyrene are common examples of thermoplastics.