Study on Mechanical Improvement of CL-20 Energetic Co-Crystals Based PBX by Surface Modification

Low melting point compound MTNP was usually adopt to form co-crystal explosive with CL-20 to reduce sensitivity, and the co-crystal may have the potential of green engineering application. Improving mechanical properties of co-crystals explosive is one of the effective ways to broaden its practical application. In this work, CL-20/MTNP energetic co-crystal was selected to be coated by polydopamine (PDA) and neutral bonding agent (NBA), with enhanced mechanical properties and developed interfacial strength between crystal and binder. The TG-DSC curve showed that thermal decomposition of co-crystal explosives divided into two steps, and the melting point delayed to 210 °C compared with that of MTNP. After surface modification, the storage modulus of PBX was increased by more than 20 % at the temperature range of (25–120) °C, and creep strain was also effectively reduced. The Brazilian and compressive strength of PDA coating samples increased by 69.89 % and 210.53 % respectively, as well as improved elongation, leading to increased fracture toughness. Here, the highlighted modification on the surface of CL-20/MTNP co-crystal can be used as a reference insight to improve the mechanical properties of new explosives.