Diallyl bisphenol A-novolac epoxy system cocured with bisphenol-A-bismaleimide-cure and thermal properties

Novolac epoxy (EPN)—2,2′‐diallyl bisphenol A (DABA) resin system was modified by cocuring it with bisphenol A bismaleimide (BMI). Molar concentration of BMI in the stochiometric blend of EPN and DABA was varied from 0.5 to 2.0. The cure optimization was done using DSC, IR spectroscopy, and rheological studies. The curing proceeded by phenol‐epoxy and Alder‐ene reactions. The performance of the ternary Epoxy‐Allyl phenolic‐Bismaleimide system was evaluated through their thermal and dynamic mechanical characterization. BMI improved the overall thermal stability and the modulus of the resultant composites. The increase in BMI concentration in the system resulted in enhanced glass transition temperature with a consequent improvement in high temperature performance typically estimated by their lap shear strength at high temperatures. The high temperature performance of the epoxy‐phenol‐bismaleimide (EPB) system was found to be far superior to the epoxy‐phenol (EP)system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007