Cure kinetics and modeling of an epoxy resin cross-linked in the presence of two different diamine hardeners
Résumé
An epoxy resin diglycidyl ether of bisphenol A (DGEBA) is cross-linked with the help of two aromatic diamine 4,4'diaminodiphenylsulfone (DDS) + 4,4'-methylenebis 3-chloro 2,6-diethylaniline (MCDEA) of nearly equal flexibility but different reactivities. The ratio of the two amines is varied while keeping the stoichiometry of the epoxy/amino hydrogen groups constant. The experimental cure kinetics are studied at four different isothermal temperatures. Their modeling is carried out by a phenomenological Kamal-Sourour kinetic model. The procedure is two-fold: 1) linear combinations of the values of rate constants from the two neat thermosets (based on only one amine) and 2) values calculated directly from isothermal cures of reactive amine mixtures. A good correlation was observed between the experimental data and the model predictions (both procedures). These amine formulations provide "mixed" epoxy thermosets and will be used later to control thermoset/thermoplastic blend morphologies for which reaction kinetics need to be predicted.