Fabrication and properties of aluminum phosphate framework/bismaleimide composites with double‐crosslinking structures

Aluminum phosphate (AP) framework/bismaleimide (BMI) composites were successfully prepared by the direct blending with phosphates and α‐Al2O3. Among them, the flexural strength of 20 wt% AP/BMI composites approached 47.5 MPa after thermal treatment at 300°C. The maximum decomposition temperature (Tmax = 650.2°C) and glass transition temperature (Tg = 299.8°C) was increased by 67.7 and 19.1°C, respectively. Furthermore, the dielectric constant (ε) of 20 wt% AP/BMI composites was approximately 3.12 at 500 kHz. After pyrolysis of BMI matrix, the reserved AP reinforcement was the three‐dimensional (3D) crosslinking framework. Therefore, the direct blending is a facile method to obtain double‐crosslinking inorganic/organic composites, and they would be potentially used as the high‐performance, low defect, and thermal resistant composites. Aluminum phosphate/bismaleimide (BMI) composites were prepared by direct blending and thermal treating at 240°, where Al2O3‐phosphate frameworks with 3D crosslinking structures in BMI matrix. The mechanical, dielectric, and heat‐resistant properties could be significantly improved and enhanced, and the maximum decomposition temperature and glass transition temperature are increased by 67.7 and 19.1°C.