Influence of Atmospheres on the Initial Thermal Decomposition of 1,3,5-Trinitro-1,3,5-triazinane: Reactive Molecular Dynamics Simulation

Energetic materials (EMs) are usually surrounded in atmospheres during manufacture, storage, transportation, and application. Thus, an insight into the influence of atmospheres on the EM decay becomes of significance. In the present work, molecular dynamics simulations are separately performed on 10 systems of one 1,3,5-trinitro-1,3,5-triazinane (RDX) nanoparticle in vacuum and in nine atmospheres including CO2, CO, H2O, H-2, N-2, NH3, O-2, NO, and NO2 to identify the influence. No evident reaction between RDX and any atmosphere is found at room temperature, suggesting such a negligible influence. Nevertheless, the influences of the nine atmospheres are variable at high temperatures and can be classified into three cases. NH3, CO, NO, and NO2, in particular NH3, promote the RDX decay by consuming RDX and the intermediates generated from it. Because NO2 that serves as a catalyzer to accelerate the RDX decay is considerably consumed by O-2, the decay is significantly prohibited by O-2. In addition, a few prohibition effects of CO2, H2O, H-2, and N-2 on the decay are confirmed because of their dilution effects, with a few or even without reaction involving them. Besides, the NO2 partition dominates the initial steps of the RDX decay, followed by the ring cleavage. In addition, the population of ONDNTA that is an intermediate by partitioning one O atom from RDX is found to be indicative of the decay degree of RDX in various atmospheres. This work presents a comprehensive insight into the influence of atmospheres on the thermal decay of RDX.