A plastic material softens upon heating and regains its hardness on cooling without undergoing any chemical change. How is this polymer classified?
Q1. A plastic material softens upon heating and regains its hardness on cooling without undergoing any chemical change. How is this polymer classified?
Answer: Thermoplastic polymer
Explanation: Thermoplastics soften repeatedly with heat; thermosetting polymers are tempting but they harden permanently due to cross-linking when heated the first time.