Diffusion phenomena during cyanate resin cure

The diffusion phenomena, including the molecular diffusion processes and the effect of diffusion on the cure kinetics and molecular size distribution, during the curing of a zinc-catalysed cyanate ester resin have been studied. The average diffusivity, which was estimated using the dielectric analysis-based approach, decreased by several orders of magnitude during the curing process. The molecular size distribution measured with size exclusion chromatography was found to deviate from the mean-field prediction at relatively high conversions. By using the Rabinowitch model, a diffusion-controlled kinetic model was formulated, which adequately predicted the experimental cyanate conversion profiles over the entire range of cure.