Desensitization of HMX crystals by formation of co-particles with insensitive LLM-105 or FOX-7

To advance the potential application of high-energy nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocin (HMX), a molecular-level confinement-driving co-particle strategy has been developed for its desensitization with maintained high energy level. The construction of HMX-based co-particles has been demonstrated by assembling insensitive 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) and 1,1-diamino-2,2-dinitroethylene (FOX-7), confined/bonded by a 2D triaminoguanidine-glyoxal polymer (TAGP) interfacial layer. The TAGP-induced confinement drives the formation of monodisperse spherical architectures with coherent core–shell interfaces, where the stabilizing effect of TAGP significantly modulates the thermal decomposition pathways of HMX. Systematic characterization reveals that the energetic performances and decomposition kinetics of these co-particles exhibit composition-dependent tunability by changing the content of LLM-105 or FOX-7. Remarkably, the obtained co-particles achieve an optimal energy-safety balance, showing two times reduction in the mechanical sensitivities compared to pristine HMX. Mechanistic investigations combining pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) analysis and reactive molecular dynamic simulations elucidate that the N-NO₂ bond cleavage remains the predominant initial decomposition pathway, in agreement with that of HMX. Notably, the TAGP incorporation enhances nitrogen liberation during decomposition, with increased N₂ yield compared to HMX. This work establishes a structure–property correlation for energetic composites, providing fundamental insights into the rational design of balanced energy and safety explosives through interfacial control of hybrid energetic crystals.