Study on the modification of HMX/TPU composites with metal-phenolic network

Rapid and facile self-assembly coatings play a crucial role in surface functionalization of materials. In this study, a safe, fast, and environmentally friendly method is proposed to form a metal-phenolic network (MPN) through the assembly of gallic acid (GA) and iron ions (Fe 3+ ), which is used for the in situ polymerization coating of 1,3,5,7-tetranitro-1,3,5-7-tetrazacyclooctane (HMX). The surface of the modified HMX crystals become visibly roughened. Thermoplastic polyurethane (TPU) was coated on the surface of modified HMX by water suspension method to form HMX@MPN@TPU double-layer core-shell energetic composite material. Compared with the raw material HMX, the β-δ phase transition temperature of the double-layer core-shell structure composite increased by 12.36°C, the impact sensitivity and friction sensitivity decreased, and the compressive strength increased by 38%, which effectively improved its mechanical properties. Highlights It has been demonstrated that metal-phenolic networks can self-assemble on the surface of crystals. A water suspension method was employed to prepare energetic material powder into a polymer-bonded explosive (PBX). The modified PBX showed significant improvements in various properties, indicating that metal-phenolic networks can serve as excellent modifying materials.