Curing kinetics and viscosity change of a two-part epoxy resin during mold filling in resin-transfer molding process

Abstract

The curing kinetics and the resulting viscosity change of a two-part epoxy/amine resin during the mold-filling process of resin-transfer molding (RTM) of composites was investigated. The curing kinetics of the epoxy/amine resin was analyzed in both the dynamic and the isothermal modes with differential scanning calorimetry (DSC). The dynamic viscosity of the resin at the same temperature as in the mold-filling process was measured. The curing kinetics of the resin was described by a modified Kamal kinetic model, accounting for the autocatalytic and the diffusion-control effect. An empirical model correlated the resin viscosity with temperature and the degree of cure was obtained. Predictions of the rate of reaction and the resulting viscosity change by the modified Kamal model and by the empirical model agreed well with the experimental data, respectively, over the temperature range 50-80 degrees C and up to the degree of cure alpha = 0.4, which are suitable for the mold-filling stage in the RTM process. (C) 2000 John Wiley & Sons, Inc.