Study on the Epoxy Resin Heat Resistance Modified by Polyamide Acid

The epoxy resin heat resistance was prepared with epoxy modified with PAA,and DDS as curing after the pre-reacting and curing.The effects of the amount of PAA,the amount of curing agent,curing condition,reaction time on the heat resistance of epoxy resin were studied.A better formula and appropriate conditions for curing were chosen.The heat resistance of modified epoxy resin was measured with TG in different proportions,pre-reaction time and different curing conditions.Then,the surface morphology and the fracture morphology of the curing epoxy modified were analyzed with SEM.The result has shown that better curing process conditions of modified epoxy resin are as follows: 120 ℃,1 h→150 ℃,1 h→170 ℃,2 h→200 ℃,2 h→250 ℃,2 h,the proportion of modified epoxy resin is mEP∶mPAA∶mDDS=1∶0.75∶0.08,the pre-reaction time is 3h.The decomposition temperature of modified epoxy resin is 411 ℃ after the pre-reacting and curing,which is increased by 80 ℃,compared with the decomposition temperature of non-modified epoxy resin.There is no distinct two-phase structure in EP/PAA/DDS system after the pre-reacting and curing,which indicates that the resin has a good compatibility.