Investigating the impact of two representative nitro explosives on the thermal decomposition mechanism of DNTF through ab initio molecular dynamics.

Abstract

Context: To investigate the influence of two typical nitro explosives, 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) and nitroguanidine (NQ), on the thermal decomposition mechanism of 3,4-Bis (3-nitrofurazan-4-yl) furoxan (DNTF). The study simulates the dynamical behavior of the DNTF/DNTF, DNTF/NQ, and DNTF/LLM-105 systems at different temperatures. We analyzed their thermal decomposition mechanisms through decomposition processes, reaction paths, and product evolution. Building on our analysis of thermal decomposition mechanisms, we found that introducing these two components (NQ and LLM-105) significantly alters the decomposition mechanism of DNTF. This introduction promotes the breakdown of DNTF molecules, modifies the thermal decomposition processes, and consequently changes the reaction pathways. In the DNTF/DNTF system, the product C₃N₄O₄ remains stable, while the N-O bond in NO₂ undergoes repeated breaking and formation, ultimately converting into NO. Conversely, in the mixed system, NO₂ persists throughout the simulation, while the reaction product C₃N₄O₄ undergoes additional reactions and eventually disappears at higher temperatures. This behavioral disparity determines distinct decomposition mechanisms between the mixed and pure DNTF systems.

Methods: To investigate the thermal decomposition mechanisms of DNTF/LLM-105 and DNTF/NQ composite energetic materials, the first-principles calculation software CP2K is used. The GFNI-xTB (Geometry, Frequency, and Noncovalent, eXtended Tight Binding) program within CP2K is employed. This method provides a powerful tool for performing calculations with arbitrary accuracy on complex systems.