Kinetic analysis of isothermal and nonisothermal epoxy-amine cures by model-free isoconversional methods

Model-free and model-fitting kinetic approaches were applied to isothermal and nonisothermal DSC data on epoxy cure. The dependence of the effective activation energy on the extent of cure was determined using integral and differential isoconversional methods. A different shape of the dependence in the kinetically controlled regime (alpha < 0.4) was found when compared to the dependence typically reported for epoxy-amine systems. This result was shown to arise from the presence of low amounts of bisphenol A in the present epoxy that are efficient catalysts for epoxy amine reaction. A model-free method prediction of isothermal cure from isothermal data has also been considered.