Kinetics, cure 4,4 -diaminodiphenyl

Mechanism and Kinetics of the Cure Process in Tetraglycidyl-methane Dianiline-Diaminodiphenyl Sulphone Thermoset System... 

Dielectric spectroscopy techniques (3) represent an exception to this limitation. In fact, Senturia et al. (4) recently described a microdielectrometric method for in situ measurement of epoxy cure. Using a novel microdielectric probe, they studied isothermal cures of digylcidyl ether bisphenol-A (DGEBA) epoxy in which the low-frequency dielectric relaxation time, r, is correlated with the bulk viscosity (4). In this paper we report preliminary results on the utilization of a viscosity-dependent fluorescence probe as an alternative (and possibly complementary) new approach with potential for in situ monitoring of epoxy cure kinetics. We also report the observation of a unique fluorescence "self-probe capability of tetraglycidyl-diaminodiphenyl methane (TGDDM) epoxy which has not been reported previously. 

The microwave and thermal cure processes for the epoxy-amine systems (epoxy resin diglycidyl ether of bisphenol A, DGEBA) with 4,4 -diaminodiphenyl sulfone (DDS) and 4,4 -diaminodiphenyl methane (DDM) were investigated for 1 1 stoichiometries by using fiber-optic FT-NIR spectroscopy. The kinetic rate parameters for the consumption of amines were determined by a least squares curve fit to a model for epoxy/amine cure. The activation energies for the polymerization of the DGEB A/DDS system were determined for both cure processes and found to be 66 and 69 kJ/mol for the microwave and thermal cure processes, respectively. No evidence was found for any specific effect of the microwave radiation on the rate parameters, and the systems were both found to be characterized by a negative substitution effect [99]. 

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