A Polymer-Modified LLM-105 with Delayed Decomposition Onset and Fast Conversion

A computation-guided framework combining reactive molecular dynamics (MD) simulations with thermogravimetry-differential scanning calorimetry-Fourier transform infrared spectroscopy (TG-DSC-FTIR) was developed to elucidate how interfacial constraint regulates the thermolysis of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) through coupled early- and late-stage mechanisms. Using this integrated approach, we show that introducing triaminoguanidine-glyoxal energetic polymer (TAGP) sheets between LLM-105 crystallites (intergranular/interparticle regions) measurably modulates decomposition behavior. Consistent trends from MD and DSC reveal a delayed decomposition onset and suppressed early NO₂ release, with the minimum NO₂ evolution occurring at ∼2.24 wt % TAGP. At elevated temperatures, the TAGP-modified composite further shifts the reaction network toward a safer product profile, yielding higher N₂, H₂O, and CO₂ while reducing CO formation. This shift is consistent with strengthened NOx reduction and CO oxidation pathways. Mechanistically, the effect originates from the earlier pyrolysis of TAGP, which supplies hydrogen-donating fragments and reactive radicals (e.g., aminyl/imidyl) that regulate interfacial chemistry and redirect dominant decomposition routes. Overall, a small TAGP loading (∼2.24 wt %) both delays decomposition initiation and improves effluent composition by promoting N₂/H₂O-rich decomposition, highlighting interfacial engineering as an effective strategy to enhance the safety performance of insensitive high-energy materials.