3. Copolymerization

3.1 Principle

This copolymerization (also known as cross-linking) leads to the hardening of polyester resins by a radical mechanism analogous to that of vinyl polymerization.

This phenomenon may occur spontaneously during storage, in which case it is slow, irregular and incomplete. To prevent this uncontrolled gelling, stabilizers such as diphenols, quinones or alkali or alkaline-earth salts are added to the polyester solution.

This copolymerization can be controlled and carried out under precise conditions by the use of suitably selected catalyst...