Effect of substituted benzene group on thermal and mechanical properties of epoxy resins initiated by cationic latent catalysts

Epoxy resins (DGEBA) were cured by cationic latent thermal catalysts i.e., N-benzylpyrazinium hexafluoroantimonate (BPH) and N-benzylquinoxalinium hexafluoroantimonate (BQH) to investigate the effect of substituted benzene group on thermal and mechanical properties of epoxy system. Differential scanning calorimetry (DSC) was undertaken for activation energy of the epoxy system. It was also characterized in terms of Izod impact strengths for the mechanical tests. As a result, the cure reaction of both epoxy systems resulted in an autocatalytic kinetic mechanism accelerated by hydroxyl groups. And, the conversion and cure activation energy of DGEBA/BQH system were higher than those of DGEBA/BPH system. The impact strength of DGEBA/BQH system was also superior to that of DGEBA/BPH system, as well as the morphology. This was probably due to the consequence of the effect of substituted benzene group of BQH catalyst, resulting in increasing the cross-link density and structural stability in the epoxy system studied.