thermosetting

adjective

1. pertaining to a type of plastic, as the urea resins, that sets when heated and cannot be remolded.

adjective

1. (of a material, esp a synthetic plastic or resin) hardening permanently after one application of heat and pressure. Thermosetting plastics, such as phenol-formaldehyde, cannot be remouldedCompare thermoplastic

1. Relating to a compound that softens when initially heated, but hardens permanently once it has cooled. Thermosetting materials are made of long-chain polymers that cross-link with each other after they have been heated, rendering the substance permanently hard. Compare thermoplastic.