Kinetic model for crosslinking free radical polymerization including diffusion limitations

Abstract

Abstract A kinetic model for crosslinking free radical polymerization is derived to predict the effect of temperature, inhibitor concentration, and initiator concentration on the rate of cure. The model is based on evidence from the literature that termination and comonomer reactivity differences can be ignored in many crosslinking free radical systems. Because of the complexity of the crosslinking chemistry, empirical relationships are used for decreasing initiator efficiency and radical mobility during cure. A sequential parameter fitting procedure is devised for isothermal curing data, and predictions are affirmed with both divinyl benzene and vinyl ester resin at several temperatures and concentrations of initiator and inhibitor. The key advantages of this kinetic model over previous models are its accuracy at high conversions and its ability to predict the effect of inhibitor and initiator concentrations on the rate of cure. This model is readily applicable to process modeling in the polymer composites manufacturing industry, which largely uses unsaturated polyester and vinyl ester resin matrices.