Polyepoxide

Polyepoxide is a class of polymers that contain one or more oxirane (epoxide) rings in their structure. These rings may be part of repeating units in the polymer backbone (pendant glycidyl groups) or form the repeating units themselves, enabling crosslinking when the material is cured. The most commercially important polyepoxides are epoxy resins derived from glycidyl ethers of polyols, typically produced by reacting epichlorohydrin with bisphenol A derivatives and then polymerizing to form prepolymers with terminal epoxide groups.

The most common example is diglycidyl ether of bisphenol A (DGEBA). Higher-functionality glycidyl ethers, such as those based on novolac resins, provide increased crosslink density and heat resistance. Polyepoxides are typically cured (crosslinked) with hardeners such as amines, acid anhydrides, or phenolic compounds. The cure involves ring-opening of the epoxide groups and formation of covalent bonds, resulting in a thermoset network whose properties depend on crosslink density, resin type, and curing agent.

Key properties of polyepoxides include strong adhesion, good chemical and recognizably high mechanical performance, and excellent electrical insulation. Their versatility allows tuning of viscosity, flexibility, and thermal stability for specific applications. Common uses include protective coatings, structural and decorative paints, high-performance adhesives, composite matrix resins for aerospace and automotive parts, and electronic encapsulation or potting compounds.

Safety and handling considerations center on the reactive epoxy groups, which can cause irritation and require proper storage and curing practices to prevent premature polymerization.