Dynamic modeling of curing process of epoxy prepreg

The dynamic curing process was studied by using differential scanning calorimetry (DSC) and modeled by two methods. One was based on the Kissinger and Ozawa approach, in which the activation energy was taken as a constant for all the heating rates. The whole curing process was modeled with two cure reactions. Reaction 1 exhibited the behavior of the autocatalytic reaction, whereas Reaction 2 was the nth order reaction. The effect of heating, rate on the preexponential factor A(1) of Reaction 1 was apparent. As the heating rate increased, the A(1) decreased. There was no significant effect of heating rate on the preexponential factor A(2) of Reaction 2 and the reaction orders for both reactions. The calculated results showed that the contributions of these two reactions to the total curing. process were very different and changed with the heating rate. Except in the early cure stage, the calculated total degree of cure agreed well with the experimental data. Another method was based on the Borchardt and Daniels kinetic approach, where the activation energy of the cure reaction at each heating, rate was determined separately. The whole curing process was modeled with one autocatalytic reaction. The fitting results showed that both preexponential factor and activation energy increased with the increment of the heating rate. As in the first method, the effect of heating rate on the orders of reaction was very small. The calculated results agreed well with experimental values in the early cure stage. (C) 2002 Wiley Periodicals, Inc.