thermosetting polymer

Prepolymer in a soft solid or viscous state that changes irreversibly into an infusible, insoluble polymer network by curing.
Notes:
  1. Curing can be induced by the action of heat or suitable radiation, or both.
  2. A cured thermosetting polymer is called a thermoset.
Source:
PAC, 2004, 76, 889 (Definitions of terms relating to reactions of polymers and to functional polymeric materials (IUPAC Recommendations 2003)) on page 898