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

Abstract 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.