glassepoxy

Glassepoxy, often written glass-epoxy, refers to a composite material made by embedding glass fibers in a cured epoxy resin. It is widely used in electrical and structural applications due to its combination of stiffness, electrical insulation, and chemical resistance.

The reinforcement is typically E-glass or S-glass fabric or mat, embedded in a cured epoxy matrix. The material is produced as prepregs (pre-impregnated fiber sheets) or as laminated plates through laminating processes. Standard variants include glass-epoxy laminates such as G10 or FR-4 used in electronics.

Key properties include high dielectric strength, good thermal stability with a glass transition temperature commonly around 120–140°C for standard epoxy systems, and low moisture absorption when properly sealed. It offers good mechanical strength and stiffness but tends to be brittle, with a relatively low impact resistance.

Manufacturing involves lay-up of prepregs or fabric layers, followed by curing under heat and pressure in an autoclave or press to form rigid panels. The material can be machined with standard tools, though fiber reinforcement can cause rapid wear. Bonding to other parts is typically done with epoxy adhesives.

Applications include printed circuit board substrates, electrical insulation for devices and transformers, and lightweight structural components in aerospace, automotive, and consumer electronics. Limitations include moisture sensitivity, environmental aging, and brittleness compared with metals or composites with tougher matrices; cost and recycling considerations also influence use.