Cure Kinetics of a Carbon Fiber/Epoxy Prepreg by Dynamic Differential Scanning Calorimetry

Investigating the curing kinetics of a fiber prepreg system is beneficial to the controlling of prepreg laminate curing process. In the present work, a dicyandiamide (DICY)-cured carbon fiber/epoxy prepreg system was investigated by non-isothermal differential scanning calorimetry (DSC) at 2, 5, 10, and 20 degrees C/min to attain the glass transition temperature for uncured prepreg and fully cured sample, which were estimated to be 7.6 degrees C and 106.2 degrees C, respectively. The activation energy (E-a) of the prepreg system was evaluated by Kissinger and Ozawa methods, and Friedman method was also employed to reveal the evolution of E-a as a function of curing degree. The kinetic parameters were determined by fitting the average E-a value obtained by Friedman method into Malek methodology, and the two parameters Sestak-Berggren model was found to best describe the curing kinetic of the prepreg system. The preexponential factor was calculated to be 6.0 x 10(8) min(-1), with the overall reaction order at nearly 2.5. The prediction curves, based on Friedman method and autocatalytic model, were in good agreement with the experimental data.