Cure Kinetic Behavior of Structural Epoxy Adhesive Film by Isothermal Differential Scanning Calorimetry

Isothermal differential scanning calorimetry (DSC) was used to study the curing behavior of structural epoxy adhesive film, AF163-2K, based on an Urone accelerated dicyandiamide (DICY) cured Epoxy system supported by knit supporting carrier. 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, simple Kamal equation, was used to predict the overall kinetic behavior in the studied cure temperature range (115-130°C). The activation energy and pre-exponential factor were determined as: E=89.5kJ/mol and A=3.85×109 sec-1 and reaction order as 1.88 (m+n=0.39+ 1.49=1.88). A kinetic model based on these values was developed by which the prediction is in good agreement with experimental values