On polyetherimide modified bismaleimide resins, 1 : Effect of the chemical backbone of polyetherimide

Four kinds of polyetherimides with different diamines were prepared and used to improve the toughness of bismaleimide resins composed of bis(4-maleimidediphenyl)methane and o,o'-diallyl bisphenol A. Dynamic mechanical analysis and scanning electron microscopy were used to characterize the phase structure of the modified resins. The modified resins display different phase morphologies depending on the polyetherimide backbone structure. The results indicate that the degree of phase separation leads to different morphologies and toughening. The fracture energy (G IC ) was increased by 300% with the PIM modified system.