A Study on the Properties of Epoxy Resin Toughened by a Liquid Crystal-Type Oligomer

摘要

A series of novel reactive toughening agents (LCEU_ppg) containing both a flexible spacer and rigid liquid crystalline unit were synthesized to modify the bisphe-nol epoxy resin/dicyandiamide curing system.The curing reactivity,apparent activa-tion energy,curing mechanism,dynamic mechanical behavior,and impact strength of the modified system were systematically studied.Compared with the unmodified sys-tem,the results indicate that LCEU_ppg have greatly accelerated the curing reaction between epoxy resin and dicyandiamide,reduced the apparent activation energy of the curing reaction,enhanced the impact strength 3-7 times,and maintained high dynamic modulus and good thermal properties.In addition,SEM observation of the fracture surfaces showed a two-phase microstructure in the modified systems.