Which statement best describes thermoplastics?

• A. They can be reshaped with heat multiple times
• B. They harden permanently after curing
• C. They cannot be melted
• D. They are metals

Answer: (A)

Thermoplastics are polymers that soften when heated and can be remolded and reshaped multiple times. This happens because they don’t form a permanently crosslinked network during processing, so heat loosens the intermolecular forces enough for the material to flow and then, upon cooling, solidifies again. That reversible heating-and-cooling behavior is what lets thermoplastics be reshaped repeatedly.

In contrast, thermosetting plastics undergo a curing process that creates a rigid, crosslinked structure. Once cured, they cannot be melted and reshaped, which is why statements about permanent hardening after curing describe thermosets, not thermoplastics. Saying thermoplastics cannot be melted is also inaccurate, since they do melt (or soften) with heat. And labeling them as metals is incorrect because they are polymers, not metallic materials.