A new bismaleimide system for resin transfer molding

摘要

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 degrees C, while its viscosity is only 0.34Pa . s. In addition, after being maintained at 75 degrees 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 degrees C, respectively; properties include tensile strength of 81 MPa, 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 degrees 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.