Epoxies have excellent electrical, thermal, and chemical resistance. Their strength can be further increased with fibrous reinforcement or mineral fillers. The variety of combinations of epoxy resins and reinforcements provides a wide latitude in properties obtainable in molded parts. Molded epoxy parts are hard, rigid, relatively brittle, and have excellent dimensional stability over a broad temperature range. Their excellent electrical properties, in combination with high mechanical strength, qualify them for electrostructural applications.
Resins based on bisphenol-A are adequate for most services.
However, cycloaliphatics are recommended for parts subjected to arcing conditions or those requiring outdoor weatherability. Excellent adhesion in structural applications is another outstanding property of epoxy systems. Epoxy adhesives for bonding many dissimilar materials can be supplied either as one or two-part systems. Epoxy laminates are important because of their excellent electrical properties over a wide temperature range, as well as their dimensional stability and chemical resistance. The amine-based resins are used in conjunction with graphite fiber to make structural composites for commercial and military aircraft and components for space equipment.