Thermal characteristics of thermo-latent initiator/epoxy cure systems in oxidation conditions

The thermal characteristics of epoxy resin (diglycidyl ether of bisphenol A, DGEBA, YD-128) containing 1, 2, 3wt% of thermo-latent initiator, N-benzylpyrazinium hexafluoroantimonate (BPH), were investigated. The specimens were stored at 300 °C in oxidation conditions for 0, 2, 4, and 8 hours. The flexural properties and fracture surface of the DGEBA/BPH system showed an optimum value at about 2∼3 wt% of BPH. The result of activation energy for thermal degradation in oxidation conditions showed that internal structure of DGEBA/BPH systems was stabilized as the retention time was increased. The similar result was also shown in flexural behavior. These results could be explained by the post-reaction of unreacted functional groups in the cured specimens by post-curing.