Copolymers of phenolphthalein-aniline-based benzoxazine and biphenyl epoxy: curing behavior and thermal and mechanical properties

In this work, the crosslink density and mechanical properties of phenolphthalein-aniline-based benzoxazine (BP-a) were enhanced through blending with biphenyl epoxy. The curing behavior of the blends was explored, and the thermal and mechanical properties of the corresponding copolymers were investigated in detail. The results showed that these copolymers possessed higher initial decomposition temperatures and better mechanical properties but slightly lower glass transition temperatures and coefficients of thermal expansion than those of BP-a.