Non-isothermal Cure Kinetics of Diglycidyl Ether of Bisphenol-A with Various Aromatic Diamines

Cure kinetics of the reaction of diglycidyl ether of a bisphenol-A based epoxy resin (DGEBA) with aromatic diamines , such as 3,6-diaminocarbazole (DAC) and N [ 7-(acetyl-4-am inoanilino )-9,9-dioctylfluoren-2-yl]-N -4-aminophenyl acetamide (ADOAc) as curing agents have been studied by using non-isothermal differential scanning calorimetry (DSC). DAC was prepared according to literature and ADOAc was prepared via the reaction of 2,7-dibromo-9,9-dioctylfluorene with 4-aminoacetanilide in the presence of 10 mol% Cui and 20 mol% N,N-dimethylethylene diamine(DMEDA) as catalysts and K2C03 as a base. The parameters of non-isothermal curing kinetics, activation energy (Ea), pre-exponential factor (A) and rate constant (k) were obtained according to Kissinger, Ozawa, and iso-conversion equations. The activation energy (Ea ) values for DGEBNDAC and DGEBNADOAc systems obtained by Kissinger method are 88.11 and 59.50 kJ/mol, by Ozawa method are 90.75 and 64.15 kJ/mol and by iso-conversion equation are 91.45 and 65.49 kJ/mol, respectively. The values of preexponential factors (A) obtained for DGEBNDAC and DGEBNADOAc systems are 1.29x10 10 and 9.03x105 s·1 with rate constants (K) of 0.90 and 0.12 S·1, respectively. The results show that DGEBNADOAc system has lower Ea and K values than the DGEBNDAC system. The exothermic curing thermograms of DGEBA with ADOAc are much broader than the curing exothermic peak of DGEBA with DAC. At 300°C both cured systems start to lose weight and the final weight loss is higher for DGEBNADOAc system.