Chemorheology of polycyanate for resin transfer molding

Chemorheology of a liquid dicyanate ester resin for resin transfer molding (RTM) has been studied. The objectives of this project are two fold: the first is to characterize material functions of the liquid dicyanate for RTM, the second is to investigate the molding behavior of this highly exothermic, low viscosity resin used for high performance composites. Reaction kinetics of 1,1-bis (4-cyanatophenol) ethane was characterized with FTIR and DSC. Simple, two step n'th order reaction kinetics with diffusion-control was developed to describe cyanate trimerization. Viscosity was measured at different isothermal temperatures by parallel disk rheometers and correlated as a function of conversion by an empirical viscosity model developed by Castro and Macosko. An efficient numerical scheme was used to solve this coupled reaction, heat transfer, and Darcy's flow problem. Results show that careful control of heat transfer from/to the mold wall is critical for preventing thermal degradation due to the high exotherm of dicyanate resin.