Enhancement of processability and dielectric properties of bismaleimide resins with benzoxazines containing reactive secondary amine groups

Bismaleimide (BMI) resins are widely used in microelectronics and aerospace materials due to their excellent thermal properties, dielectric performance, and flame retardancy. However, their brittleness, high curing temperature, and narrow processing window limit their applications. In this study, the benzoxazine resin precursor derived from melamine and furylamine (MBF) was synthesized and used to modify BMI. The results indicate that the reactive secondary amine groups in MBF enhance the curing reactivity of the resin system, while the triazine ring structure contributes to the reduction of the dielectric constant. At 1 MHz, the dielectric constant of poly (BDM-10MBF) is the lowest value of 2.85. Moreover, the modified resin exhibits the highest thermal decomposition temperature (T d5 ) of 462°C and a maximum char yield (at 800°C) of 52.7%. Furthermore, the resin was compounded with glass fibers to prepare high-strength composites. The flexural modulus of PP(BDM-MBF) is 73.10 GPa, representing a 24% increase compared to PP(BDM). Additionally, its flexural strength reaches 827.0 MPa, which is 104% higher than that of PP(BDM).