Effect of the Addition of Silicone Graft Copolymers on Toughness of Cured Epoxy Resin Modifiedwith RTV-Silicone

Abstract

An attempt was made to disperse stably RTV-silicone as fine particles in bisphenil-A type epoxy resin by the addition of silicone-methyl methacrylate graft copolymer. The size of the silicone phase decreased to lower than 1μm with the addition of the graft copolymer. The toughness of the modified resin increased with a decrease in the diameter of silicone phase. In the region where the diameter of the dispersed phase was less than 1μm, the fracture toughness of the modified system became higher than that of the unmodified system. It is suggested that the toughening of the modified system is mainly caused by the cavitation of the fine rubber phases.