The effect of functionalized benzoxazine with allyl groups on the dielectric, mechanical and thermal properties of BMI/BADCy composites

Abstract

Functionalized benzoxazine with allyl groups has recently attracted a great deal of attention due to its polymerizable group. In order to improve the properties of 4,4′-bismaleimidodiphenyl methane (BMI)/cyanate ester (BADCy), benzoxazine (Boz) was added into the BMI/BADCy system in this paper. The effect of functionalized Boz with allyl groups on the dielectric, mechanical and thermal properties of BMI/BADCy composites was systematically investigated in detail using mechanical measurements, scanning electron microscopy (SEM), dynamic mechanical analysis (DMA) and thermo-gravimetric analysis (TGA). The results showed that the formation of Mannich bridge networks and an interpenetrating polymer network through the polymerization of Bz-allyl and BMI/BADCy increased the cross-linking densities and thermal stability. Allyl-based polymers also exhibited high glass transition temperatures, and higher char yields. The dielectric constant value and the dielectric loss factor of BBz2 reached minimum values of 3.17 and 0.083 at 10⁶ Hz respectively. The mechanical properties (a high flexural modulus of 4.18 GPa and flexural strength of 120 MPa) of BBz2 were superior. Scanning electron microscopy analysis showed a distinct characteristic of ductile fractures for the blends.