Thermal, mechanical and dielectric properties of BMI modified by the Bis allyl benzoxazine

In this paper, Bis allyl benzoxazine (Bz-allyl) was blended with 4, 4′-Bismaleimidodiphenyl methane (BMI) to improve the properties of BMI. The properties of Bz-allyl/BMI copolymers, such as mechanical properties, thermal properties and dielectric properties were systemically investigated in detail by mechanical measurement, scanning electron microscope (SEM), dynamic mechanical analysis (DMA) and thermo-gravimetric analysis (TGA). The results show that a suitable addition of Bz-allyl can enhance the impact strength and flexural strength as well as reduce the dielectric constant and the dielectric loss of BMI. The dynamic mechanical analysis reveals that the cross-link density of the blend is higher than neat BMI. Scanning electron microscopy analysis shows distinct characteristics of ductile fracture of the blends. In addition, the dielectric constant and the dielectric loss of modified system decreases, compared with the cured BMI. BMI containing suitable Bz-allyl still remains a good thermal resistance. All these changes in properties are closely correlated to the copolymerization between Bz-allyl and BMI, which could form an interpenetrating polymer network in the system.