TTT cure diagram for an epoxy system diglycidyl ether of bisphenol A/1,2 diamine cyclohexane/calcium carbonate filler

Curing reactions of the epoxy system consisting of a diglycidyl ether of bi sphenol A (BADGE n = 0); 1,2 diaminecyclohexane (DCH); and calcium carbonat e filler were studied to calculate a time-temperature-transformation (TTT) isothermal cure diagram for this system. Gel times were measured as a funct ion of temperature using two experimental methods: solubility test and dyna mic mechanical analysis (DMA). The results obtained are in fair agreement w ith that obtained for the two component system BADGE n = 0/1, 2 DCH. Vitrif ication times for the three component system was higher than those obtained for the system BADGE n = 0/1,2 DCH and the conversions achieved were very close to maximum values. The activation energy for the overall polymerizati on reaction was calculated from the gel times obtained using the two above mentioned methods: solubility test (57.12 KJ/mol) and DMA (54.12 kJ/mol). T hese values are of the same order than those obtained for the two component epoxy system. It was established that the addition of calcium carbonate fi ller avoids the appearance of physical aging, thus making easier both the d etermination of glass transition temperatures, and the calculation of the T TT diagram. (C) 2001 Elsevier Science Ltd. All rights reserved.