A kinetic model for free-radical crosslinking co-polymerization of styrene/vinylester resin

Vinylester resin is a major thermoset polymer used in low temperature composite manufacturing processes, such as the Seemann Composite Resin Infusion Molding Process (SCRIMP). In this study, the effect of temperature on the cure kinetics of a vinylester resin in the range of 35 to 90°C was investigated using a differential scanning calorimeter (DSC) an a Fourier transform infrared spectrometer (FTIR). A mechanistic kinetic model was developed to simulate the reaction rate and conversion profiles of vinylester vinylene and styrene vinyl groups, as well as the total reaction rate and conversion. Experimental results from DSC and FTIR at different temperatures were compared with model predictions. The glass transition temperature of the vinylester resin cured at different temperatures was identified and used to monitor the final conversion change. A series of SCRIMP molding experiments were conducted. The developed kinetic model in conjunction with a heat transfer model was used to simulate the temperature and conversion changes inside the SCRIMP-molded composites.