Consider the following statements in connection with thermoplastics:
(i) They are long-chain molecules held together by van der Waals‟ forces.
(ii) They cannot be resoftened once they have set and hardened.
(iii) They are highly plastic and are easy for shaping.
(iv) Some commercial thermoplastics are polyethylene, polystyrene and PVC.
Which of the above statements are correct?
(a) 1, 2 and 3 only (b) 1, 3 and 4 only
(c) 2, 3 and 4 only (d) 1, 2, 3 and 4