Studies on cure kinetics and rheological properties of difunctional epoxy/polysulfone blend system

In this work, the cure kinetics and Theological properties of difunctional epoxy (diglycidylether of bisphenol A, DGEBA)/polysulfone (PSF) blends were investigated using differential scanning calorimeter and rheometer. From the DSC results of the blends, the temperature of the exothermic peak and cure activation energy (E_a) using a half-width method were increased with increasing the PSF content to neat epoxy resin up to 30 wt%. However, a marginal decrease in the blend system was shown in E_a. The conversion (a) and conversion rate (dα/dt) were decreased as the content of PSF increases. Rheological properties of the blend system were investigated under isothermal condition using a rheometer. Cross-linking activation energy (E_c) was determined from the Arrhenius equation based on gel time and curing temperature. As a result, the E_c showed a similar behavior with E_a, which could be resulted from high viscosity of PSF and the phase separation between DGEBA and PSF.