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ABSTRACT:The curing kinetics and mechanisms of diglycidyl ether of bisphenol A (DGEBA) using imidazole (H-NI) and 1-methyl imidazole (1-MI) as curing agents are studied with differential scanning calorimetry (DSC) under isothermal (90 -120°C) and dynamic conditions (50 -250°C). The isothermal DSC thermograms of curing DGEBA with H-NI and 1-MI curing agents show two exothermic peaks. These peaks are assigned to the processes of adduct formation and etherification. These results indicate that there is no difference in the initiation mechanism of 1-unsubstituted (H-NI) and 1-substituted (1-MI) imidazoles in the curing reaction with epoxy resin. A kinetic analysis is performed using different kinetic models. The activation energies obtained from DSC scanning runs using the Ozawa and Kissinger methods are similar and in the range of 75-79 and 76 -82 kJ/mol for DGEBA/H-NI and DGEBA/1-MI systems, respectively. These values compare well with the activation energies obtained from isothermal DSC experiments using the autocatalytic method (74 -77 kJ/mol).

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