Microdielectric analysis and curing kinetics of an epoxy resin system

Microdielectric analysis (DEA) was carried out to investigate the cure behavior of a bisphenol F epoxy/aromatic amine resin system using an online dielectric cure monitoring technique. Ionic conductivity measured by a microdielectric sensor under isothermal conditions was correlated to the degree of cure and glass-transition temperature, which are determined by differential scanning calorimetry (DSC). Results obtained by isothermal DSC measurement were used to establish a cure kinetic model for the epoxy resin. Experimental results show that the ratio of the ion conductivity to the initial ion conductivity, Log sigma/Log sigma(o), has a linear relation with the glass-transition temperature. Furthermore, correlations between ion conductivity and degree of cure and cure rate are established using the best fit of the measured data. Cure behavior of the epoxy resin obtained by DEA is compared with that predicted by the cure kinetics model. Good agreement was observed.