Effect of modified rubber compound on the cure kinetics of DGEBA/MDA system by Kissinger and isoconversional methods

The cure kinetics of diglycidyl ether of bisphenol A (DGEBA)/4,4′-methylene dianiline (MDA) system with various contents of MDA-endcapped carboxyl-terminated butadiene acrylonitrile (CTBN) were studied by Kissinger and isoconversional methods. With increasing MDA-endcapped CTBN content, the exothermic heat decreased due to the diffusion control induced by rubber domain produced in the epoxy matrix, which disturbed the diffusion of functional groups, and the maximum exothermic peak value and the activation energy by Kissinger equation decreased due to the increasing content of amine group in rubber compound, which reacted with epoxy group and formed a hydroxyl group acted as a catalyst. In the isoconversional method, the activation energy decreased until minimum value in the initial stage and increased after that value. The decreasing in the initial stage was due to the autocatalytic cure reaction and the increasing after the minimum value was due to the increasing crosslink density and rubber domain.