COMPARATIVE-STUDIES ON THE NONISOTHERMAL DSC CURING KINETICS OF AN UNSATURATED POLYESTER RESIN USING FREE-RADICALS AND EMPIRICAL-MODELS

In this paper, we study the kinetics of the curing of an unsaturated p olyester resin initiated with MEKP by means of DSC. DSC runs were perf ormed at different heating rates. The experimental curves were fitted using two kinetic models: one involving the concept of free-radical po lymerization, and the other an empirical model that does not take into account the different steps involved in the curing. A computer progra m was developed to find the parameters involved in each kinetic model. The calculation algorithm uses the Runge-Kutta numerical integration and the ''downhill simplex method''. The experimental data are very we ll fitted by using both models. The activation energy values are in co ncordance with the values tabulated by Odian. In the model theoretical calculation, it is useful to know the decomposition rate constant of the initiator. We determined the decomposition constant by using two d ifferent methods. Both methods give similar values of the activation e nergy Ed and they are in agreement with those tabulated in the literat ure. (C) 1997 Elsevier Science B.V.