Abstract: The properties of a bismaleimide resin QY8911-Ⅳ with low viscosity for resin transfer molding (RTM) were reported in this work. Its viscosity characteristic and curing characteristic were studied firstly. The heat resistance, mechanical properties and water absorption of the resin cast cured at different post-curing temperatures were investigated and compared. The results suggest that this resin system show good performance including low viscosity (200 mPa·s at 80 ℃), low curing shrinkage (1%), good heat resistance (a T_g of 260 ℃), good mechanical property (flexural strength is 170 MPa and impact strength is 20 kJ/m²) and low water absorption (0.39%). The appropriate injection process and curing process were selected to prepare the carbon fiber reinforced composites by RTM, and the mechanical properties of the composites were tested. The flexural modulus is 754 MPa and the impact strength is 110.9 kJ/m².

Key words: RTM molding, low viscosity, bismaleimide, composite materials