Tuning the mechanical performance efficiently of various LLM-105 based PBXs via bioinspired interfacial reinforcement of polydopamine modification

Inspired by mussel adhesion, the self-polymerization of dopamine was adopted to coat 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) crystals with different crystal characteristics. It has been demonstrated that the crystal quality and surface roughness played a crucial role in mechanical sensitivity and bioinspired interfacial reinforcement of LLM-105 based energetic composites. The high crystal quality brought benefits for the safety performances of polydopamine (PDA) modified LLM-105 crystals, with the drop height of 50% explosion probability (H₅₀) higher than 112.2 cm. After PDA coating for 6 h, the compressive and tensile strength of LLM-105 based polymer bonded explosives (PBXs) could be improved by 27%–52% and 47%–100%, respectively. The enhancing effect in mechanical properties was more pronounced for LLM-105 crystals with smooth surface, due to the physical “interlocking block” at the interface induced by the increase of surface roughness after PDA modification. The overall results indicated that PDA coating had great potential in improving the mechanical properties of different LLM-105 based PBXs while maintaining safety performance.