Toughening and enhancing mechanical and thermal properties of adhesives and glass-fiber reinforced epoxy composites by brominated epoxy

Abstract Blends of brominated epoxy (BE) and conventional epoxy resins (ER) were studied as adhesives and matrices of glass fiber (GF) reinforced composites following curing by medium and high temperature hardeners. The addition of BE resulted in an increased Tg in both hardener systems. The addition of BE resulted in a simultaneous increase in Tg (glass transition temperature), toughness, strength, and elongation, which is unusual with conventional tougheners. Failure analysis by electron microscopy, indicated that the increase in toughness and mechanical properties could be attributed to the development of unique energy dissipating mechanisms, manifested by rough fracture surfaces, river lines morphology, matrix deformation, shear bands and good interfacial bonding between the matrix-fiber interface.