Study of cure kinetics of epoxy/DDS/nanosized (SiO2/TiO2) system by dynamic differential scanning calorimetry

In this study the curing kinetics of epoxy based on the diglycidyl ether of bisphenol A (DGEBA), 4,4'-diaminodiphenyl sulfone (DDS) as a hardener, and SiO2/TiO2 (70:30) as a nanofiller was investigated by nonisothermal differential scanning calorimetry (DSC). The effects of different weight contents of SiO2/TiO2 nanoparticles were studied using DSC in Dynamic Mode and the best value of the nanofiller was found to be 5 phr (parts per hundred). Dynamic measurements were used to obtain the total heat of reaction of the epoxy system as well as its activation energy (E-a) based on the isoconversional methods of Kissinger and Ozawa. The process revealed a dependence of the activation energy on conversion (alpha). The morphology of the cured system was investigated by scanning electron microscopy (SEM). It showed a strong cross-linking between the resin and hardner and a relatively better dispersion of surface modified filler nanoparticles. Copyright (C) 2009 John Wiley & Sons, Ltd.