Kinetic study of the effect of poly(phenyl sulfone) on the curing of an epoxy/amine resin by conventional and by temperature- modulated differential scanning calorimetry

Kinetic studies of the curing reaction of semi-interpenetrating polymer networks (semi-IPNs) based on diglycidyl ether of bisphenol-A (DGEBA) and 4,4′-diaminodiphenylmethane (DDM), containing poly(phenyl sulfone) (PPSU), were carried out using differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC), under both isothermal and dynamic conditions. The curing kinetics is discussed in the framework of three kinetic models: the Kissinger and the Flynn–Wall–Ozawa models, and the autocatalytic model developed by Kamal. To describe the cured reaction in its latter stage, we used the semi-empirical relationship proposed by Chern and Poehlein to consider the influence of diffusion on reaction rate. The cure mechanism for the system studied remained broadly autocatalytic regardless of PPSU content, and it became far more diffusion controlled at higher PPSU content and lower cure temperatures. The vitrification time of the resins was obtained with TMDSC by following the changes on the complex modulus of heat capacity, , and exhibited a strong dependence on the PPSU content in the semi-IPN systems. Copyright © 2005 Society of Chemical Industry