Rheological cure characterization of a polyfunctional epoxy acrylic resin

The curing reaction of a well-controlled epoxy functional acrylic resin based on glycidyl methacrylate (GMA), specifically a statistical copolymer with butyl acrylate (BA), and a commercial linear diamine (Jeffamine® D-230) was monitored using rheological measurements. The evolution of viscoelastic properties, such as storage modulus (G′) and loss modulus (G′′) and complex viscosity (η*) was recorded in both dynamic and isothermal conditions, at six different temperatures (50-100 °C). An autocatalytic kinetic model was proposed, and all the kinetic parameters including reaction orders and kinetic constants were determined for the cross-linking reaction at temperatures above glass transition temperature of fully cured network (Tg∞). The overall curing process was described by a second-order phenomenological rheokinetic equation based on the model of Kamal. In addition, an empirical model was used to predict the change in viscosity of this system with time until gelation is reached.