Novel effect of barbituric acid on glass transition temperature of bismaleimide–epoxy resin systems

Abstract
Barbituric acid (BTA) has a novel influence on glass transition temperature (Tg) of bismaleimide (BMI)–epoxy resin systems. It causes the Tg of a BMI–epoxy resin system to rise significantly. The BTA's influence on Tg was investigated by changing the molar ratio of the reactants. In addition, the influence of benzoperoxide (BPO) on Tg was compared with that of BTA. The reaction selectivity of BTA and diamino‐diphenyl sulfone (DDS) toward BMI and epoxy individually in the BMI–epoxy blended systems were studied using the DSC and GPC. By controlling the amount of DDS and BTA, epoxy and BMI could form intercrosslinking networks.