A new bismaleimide system for resin transfer molding

A new bismaleimide (BMI) resin system, designated 4503A, suitable for resin transfer molding (RTM) has been developed. It is prepared by employing allyl methyl phenol and diallyl bisphenol A as reactive diluents for BMI. The processing properties of 4503A were investigated by time-temperature-viscosity curves, gel characteristics, and differential scanning calorimetry (DSC). Data show that the injection temperature of 4503A prepolymer can be as low as 75°C, while its viscosity is only 0.34Pa.s. In addition, after being maintained at 75°C for 12 h, the viscosity is <0.95Pa.s. The cured 4503A resin has a glass transition temperature (T g ) and a heat deflection temperature (HDT) of 266 and 232°C, respectively; properties include tensile strength of 81MPa, flexural strength of 108MPa, and G 1C of 213J/m 2 . Other properties of a composite based on 4503A system and woven glass cloth are also discussed. Regarding short beam shear (SBS) strength, for tests at 150 and 180°C, 80 and 61% of the original room temperature (RT) strength is retained. A similar strength retention (86 and 68%) is noted for flexural properties.