EFFECTS OF DIFFUSION ON THE KINETIC-STUDY AND TTT CURE DIAGRAM FOR ANEPOXY DIAMINE SYSTEM/

The curing reactions of an epoxy system consisting of a diglycidyl eth er of bisphenol A (BADGE n = 0) and 1,2-diamine cyclohexane (DCH) were studied to determine a time-temperature-transformation (TTT) isotherm al cure diagram for this system. Differential scanning calorimetry (DS C), dynamic mechanical analysis (DMA), and a solubility test were used to obtain the different experimental data reported. Two models, one b ased solely on chemical kinetics and the other accounting for diffusio n, were used and compared to the experimental data. The inclusion of a diffusion factor in the second model allowed for the cure kinetics to be predicted over the whole range of conversion covering both pre- an d post-vitrification stages. The investigation was made in the tempera ture range 60-100 degrees C, which is considered optimum for the isoth ermal curing of the epoxy system studied. (C) 1998 John Wiley & Sons, Inc.