Cure Kinetics of Hexcel W3T282-42/F155 Graphite/Epoxy Prepreg

In this work, differential scanning calorimetry (DSC) in dynamic and isothermal modes is used to develop a cure kinetics model for the graphite/epoxy prepreg Hexcel W3T282-42/F155. The evolution of heat from the composite system was measured from dynamic DSC scans and the total heat of reaction of the system calculated. Isothermal heat flow measurements were then taken at different constant temperatures, and the isothermal heat of reaction, the rate of cure, and the degree of cure were calculated as a function of time for each temperature. A variety of different cure kinetics models proposed in the literature were examined in order to develop an expression for resin cure rate as a function of degree of cure and temperature. Best results were obtained by using a semi-empirical equation in which the maximum achievable degree of cure was considered to be temperature dependent. A least squares technique based on the Levenberg-Marquardt algorithm was used for curve fitting. Very good agreement between experimental measurements and model results was observed.