Chemorheological model of a bisphenol-F epoxy resin system for VARTM processes with amendment of time-temperature equivalence

The chemorheological behavior of A40/DDM/DMTDA curing bisphenol-F epoxy resin for vacuum assisted resin transfer molding (VARTM) was studied by means of isothermal and dynamical viscosity experiments. A dual-Arrhenius viscosity model was established and used to simulate the rheological behavior of the epoxy resin system. The time-temperature equivalence of the system was also analysed with the reference temperature 100℃,and the shift factor a_T was calculated by the dual-Arrhenius equation which was then used to predict the viscosity data at other temperatures. It was also used to modify the established viscosity model in order to deal with certain differences between the experiments and calculations for the resin with high viscosity. The viscosity values estimated from the modified model under isothermal and dynamic condition are in good agreement with the experimental ones. The dual-Arrhenius model can be used to predict the chemorheology of different processing parameters of VARTM process, which can be useful for optimization of composite manufacturing processes.