Thermosetting Plastic
A polymer that solidifies on heating and cannot be remelted.
The setting action results from crosslinking of the polymer chains at high temperature, a process that is not reversed by cooling and reheating.
A-stage
An early stage of polymerization of thermosetting resins in which the material is still soluble in certain liquids and is fusible.
B-stage
Intermediate stage in the polymerization reaction of thermosets, following which material will soften with heat and is plastic and fusible. Also called resistal. The resin of an uncured prepreg or premix is usually in B-stage.
C-Stage
The final step in the cure of a thermoset resin; results in essentially irreversible hardening and insolubility.
See also: Pot Life, Thermoplastic.
