Cure kinetics of cycloaliphatic/DGEBA epoxy blend system initiated by thermal latent catalyst

For the cycloaliphatic epoxy (CAE)/DGEBA epoxy blends containing 1 mol% of benzylpyrazinium hexafluoroantimonate (BPH) as a thermal latent initiator, the effects of blend composition and cure temperature on the cure kinetics was investigated by isothermal and dynamic DSC measurements. The composition of CAE/DGEBA blend was varied within 100:0, 80:20, 60:40, 40:60. 20:80 and 0:100(mol%). Dynamic DSC thermograms revealed that the weak peaks of CAE/DGEBA blend occurred by the complex formation of the hydroxyl functional group and BPH and of the epoxide group and BPH were firstly shown in low temperature ranges. And the strong peaks considered as an exothermic reaction by the formation of three-dimensional network were consecutively shown in high temperature ranges. Isothermal DSC thermograms indicated that the cure reaction rate strongly depended on the cure temperature and the composition of CAE. The activation energies obtained from KamalSourour equation were increased with the content of DGEBA, which could be resulted from the autocatalytic reaction accelerated by the hydroxyl group produced through the reaction between the epoxy and BPH. The cure kinetics were discussed in terms of the curing reaction orders, reaction constants and frequency factors determined from the Kamal-Sourour equation.