The use of thermal analysis methods for predicting the thermal endurance of an epoxy resin used as electrical insulator

For the characterization of an epoxy resin composite material, the following analyses were performed: thermal analysis (TG/DTG/DTA) in nitrogen flow at five linear heating rates and under four quasi-isothermal temperature programs, coupled TG + FTIR analysis, DSC analysis in nitrogen flow, X-ray diffraction and FTIR spectroscopy. The processing of the TG data was performed by using Netzsch Thermokinetics-a software module for kinetic analysis. The dependence of the activation energy, evaluated by isoconversional methods, on the conversion degree shows that the investigated process is a complex one. The kinetic scheme and the corresponding kinetic parameters were determined by multivariate nonlinear regression program. The kinetic scheme and kinetic parameters thus obtained were used to calculate the TG curves corresponding to the quasi-isothermal temperature programs. A good agreement between the experimental and calculated TG curves has been found. The obtained results were used for the prediction of thermal lifetime of this material corresponding to some usage temperatures and to the 5% end-point criterion.