Isothermal differential scanning calorimetry study of a glass/epoxy prepreg

Isothermal differential scanning calorimetry (DSC) was used to study the curing behavior of epoxy prepreg Hexply (R) 1454 system, based on diglycidyl ether of bisphenol A (DEGBA)/dicyandiamid (DICY) reinforced by glass fiber. Cure kinetics of an autocatalytic-type reaction were analyzed by general form of conversion-dependent function. The characteristic feature of conversion-dependent function was determined using a reduced-plot method where the temperature-dependent reaction rate constant was analytically separated from the isothermal data. An autocatalytic kinetic model was used; it can predict the overall kinetic behavior in the whole studied cure temperature range (115-130 degrees C). The activation energy and pre-exponential factor were determined as: E=94.8 kJ/mol and A=1.75 x 10(10) sec(-1) and reaction order as 2.11 (m+n = 0.65+1.46 = 2.11). A kinetic model based on these values was developed by which the prediction is in good agreement with experimental values. Copyright (C) 2009 John Wiley & Sons, Ltd.