A study on properties of epoxy resin toughened by functionalized polymer containing rigid, rod-like moiety

A series of novel reactive toughening agents defined as LCEUPEG containing both flexible chain and rigid, rod-like moiety were synthesized and used to modify the epoxy resin (E-51)/dicyandiamide (dicy) curing system. The curing reactivity, apparent activation energy Ea, curing mechanism, dynamic mechanical behavior, impact strength of E-51/LCEUPEG/dicy systems was studied. The results show that the addition of LCEUPEG to epoxy resin and dicy curing system has apparently accelerated the curing reaction, reduced the apparent activation energy Ea of the curing reaction by about 60 kJ/mol, and decreased the curing temperature by about 50°C. In addition, the high modulus and good thermal properties are maintained, and the impact strength is enhanced by three to seven times compared with that of the unmodified sample.