Influence of catalyst content on the thermal and mechanical properties of epoxy resins initiated by a cationic latent thermal catalyst at elevated temperatures

The effect of catalyst content on the thermal and mechanical properties of diglycidyl ethers of bisphenol A (DGEBA)/BPH system was investigated at elevated temperatures. The contents of the catalyst, N-benzylpyrazinium hexafluoroantimonate (BPH), examined were 0.5, 1, and 3 wt.-% and the elapsed heating time was varied from 0 to 1024 h. As a result, the thermal-oxidative resistance and mechanical properties, including flexural strength, elastic modulus in flexure, and impact strength showed a maximum value at 1 wt.-% BPH. By increasing the elasped time to 4 h, the thermal and mechanical properties of the specimens were also improved. These results showed that the internal structure of the epoxy system was stabilized and post-cured as the elapsed time increased, resulting in an improvement of the thermal and mechanical properties of the specimens.