Synthesis and Characterization of 1, 3-Bis(Maleimido) Benzene-Modified and 1, 6-Bis(Maleimido) Hexane-Modified Epoxy-Novolac Interpenetrating Networks

Epoxy-novolac (EPN) resin was modified by blending with in-house-synthesized I, 3-bis(maleimido) benzene and 1, 6-bis(maleimido) hexane. These blends were cured with 4, 4'-methylenedianiline. The cure behaviour of these systems was studied using differential scanning calorimetry (DSC) at different blend compositions of bismaleimide (BMI) varied between 5 and 15% by weight. The thermograms indicated a unimodal exothermic peak for blends containing lower percentages of bismaleimide. All the cured blends showed much higher glass transition temperatures (Tg) than that of the host matrix, namely unmodified epoxy-novolac resin. The thermal stability as studied by thermogravimetric analysis (TGA) of the cured EPN resin was found to improve with BMI blending and varied with the type of BM1. A homogeneous structure of these blends with no phase separation was confirmed both by DSC analysis and scanning electron microscopy (SEM).