Abstract
Diallyl phthalate resin was modified with an epoxy resin in order to improve adhesive property, using an allylester derivative having an allyl group and carboxyl group (DAPY) as a coupling agent. Lap shear strength of the cured system was markedly improved compared with that of the diallyl phthalate resin system. By adding 10wt% of the epoxy resin, the lap shear strength was improved by four times. This can be explained by the generation of hydroxyl groups, resulting from the reaction of epoxide and carboxyl; that is, introducing hydroxyl groups caused an increase in the adhesion force between the cured resin and a steel surface. Glass transition temperature (Tg) of the modified resin was about the same as that of the diallyl phthalate resin, while thermal decomposition temperature (Td) was decreased with increasing of epoxy resin concentration. By this modification, electrical and mechanical properties were maintained at the level of the diallyl phthalate resin, though its anti-water property was decreased. Fracture toughness (KIC), especially, was highly improved by the modification.
