Relaxations in thermosets. XXIX. Calorimetric studies of the curing kinetics of nonstoichiometric diamine–epoxy mixtures

摘要

AbstractThe curing kinetics of nonstoichiometric mixtures of diglycidyl ether of bisphenol A, with ethylene diamine, propylene diamine, and hexamethylene diamine have been measured under both isothermal and ramp‐curing condition. Their kinetics are faster than for stoichiometric compositions and the reactions reach completion. The total heat evolved for the amine‐rich composition is greater than for the amine‐deficient. None of the available formalisms is consistent with the results. This and the variation in the heat of reaction indicate that steric effects are important for both the reaction rate and the heat evolved. It is argued that the standard heat of reaction of primary amine with the epoxide group differs from that of secondary amine. © 1994 John WileySon