Rheological behavior of a bismaleimide resin system for RTM process

The curing properties and rheological behavior of a bismaleimide resin system were studied with differential scanning calorimetry (DSC) analysis and viscometer measurements, respectively. A dual-Arrhenius viscosity model and an engineering viscosity model were established to predict the resin rheological behavior of this resin system. The two viscosity models were compared. The results show that the two models are both suitable for predicting the viscosity in the mold filling stage of resin transfer molding (RTM). However, the engineering model provides a more accurate prediction of the viscosity near the gel point. The effectiveness of the engineering viscosity model is verified both in isothermal and nonisothermal conditions. The limitation of the engineering model is that it cannot be used to predict the viscosity after cross-linking of the curing system. The engineering viscosity models can be used to predict the processing windows of different processing parameters of the RTM process, which is critical for the simulation and the optimization of composite manufacturing processes.