Optimization of thermal remendability of epoxy via blending

To prepare epoxy materials with improved thermal remendability, two types of epoxy resins (N,N-diglycidyl-furfurylamine (DGFA) and furfuryl glycidyl ether (FGE)), which were synthesized in the authorsʹ lab and contained different proportions of furan and epoxide groups, were blended and cured by anhydride and maleimide. Like the cured version of either DGFA or FGE alone, the cured blends of DGFA and FGE have also acquired thermal reversibility due to the Diels–Alder (DA) bonds from the reaction between furan and maleimide groups. The addition of FGE into the blends increased the DA bonds density as a result of the higher furan concentration in FGE. Accordingly, remendability originating from successive retro-DA and DA reactions was obviously improved. On the other hand, the crosslinked epoxy networks generated by the reaction between epoxide and anhydride groups were strong enough to provide the blends with acceptable mechanical performance.