Synthesis, curing behavior and properties of siloxane and imide-containing tetrafunctional epoxy

A novel tetrafunctional epoxy resin containing siloxane and imide groups, i.e., N,N,N′,N′-tetraglycidyl-bis(4-aminophenyl)-5,5′ (1,1,3,3-tetramethyl-1,1,3,3-disiloxane-bisnorbornane-2,3-dicaroximide, was synthesized and characterized. The curing behavior of this resin and the properties of its cocured material with commercial tetraglycidyl meta-xylene (GA-240) was studied. Functional group changes during cocuring reactions were investigated with FTIR. Kinetic parameters were analyzed with dynamic DSC. Thermal properties were measured with TGA, TMA and DMA. Curing kinetics revealed that this novel tetrafuctinal epoxy indicated a lower activation energy and lower curing temperature than GA-240. The cocured materials, due to the presence of siloxane and imide groups in the polymer matrix, show higher glass transition temperature, better dimensional stability and toughness, and also enhanced properties than pure GA-240.