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

Abstract 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 (T_max = 650.2°C) and glass transition temperature (T_g = 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.