Studies on epoxy resins cured by cationic latent thermal catalyst at elevated temperature

In this work, the effect of the catalyst content was investigated in terms of the thermal and mechanical properties of epoxy resins at elevated temperature. A synthesized cationic latent thermal catalyst, N-benzylpyrazinium hexafluoroantimonate (BPH), was used to cure epoxy resins. The content of catalyst added was 0.5, 1, 2, 3 and 5 wt% and the heating time was varied from 0 to 1024 h. As a result, the mechanical properties, including flexural strength, elastic modulus in flexure and impact strength, as well as thermal-oxidative resistance, showed a maximum value in the presence of 1 wt% BPH. With increasing elapsed time, up to 4 h, the thermal and mechanical properties of the specimens were improved. These results show that the internal structure of the epoxy system was stabilized, and post-curing for a longer period of time, resulted in improved thermal and mechanical behaviour of the cast specimens.