Question

Which of the following can be repeatedly softened on heating? (i) Polystyrene (ii) Melamine (iii) Polyesters (iv) Polyethylene (v) Neoprene

• A. (i) and (iii)
• B. (i) and (iv)
• C. (iii), (iv) and (v)
• D. (ii) and (iv)

Hint:

Thermoplastics soften on heating and harden on cooling repeatedly.

Answer 1

The Correct Option is B

Step 1: Thermoplastics soften repeatedly on heating. Step 2: \beginitemize • Polystyrene – thermoplastic • Polyethylene – thermoplastic • Melamine – thermosetting plastic • Neoprene – elastomer \enditemize Step 3: Hence, materials that can be repeatedly softened are polystyrene and polyethylene.