Cure kinetics and modeling of an epoxy resin cross‐linked in the presence of two different diamine hardeners

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. POLYM. ENG. SCI. 45:1581–1589, 2005. © 2005 Society of Plastics Engineers