Thermoset, or thermosetting, plastics are synthetic materials that strengthen during being heated, but cannot be successfully remouldedor reheated after their initial heat-forming. This contrasts withthermoplastics, which soften when heated and harden and strengthen after cooling. Thermoplastics can be heated, shaped and cooled as often as necessary without causing a chemical change, while thermosetting plastics will burn when heated after the initial moulding.
