Molecular dynamics study on the thermal decomposition of 1,3,5-trinitro-1,3,5-triazinane (RDX) catalyzed by aluminum nanoparticles with different contents

The mechanism of thermal decomposition of 1,3,5-trinitro-1,3,5-triazinane (RDX) catalyzed by nano-sized aluminum powder remains unclarified. In the present study, reactive molecular dynamics simulations using the parameterized reactive force field with low gradient correction (ReaxFF-lg) were conducted to study the microscale process of the RDX thermal decomposition catalyzed by different Al contents, and the density functional theory calculations were used to analyze the initial decomposition pathways of RDX on the Al surface. The thermal disintegration and the released energy of RDX are significantly facilitated by an increase in Al concentration at a lower level and the optimal value is around 35 wt%, while a higher concentration of Al will lead to an opposite effect. The dissociation of nitro group is the most probable initial reaction pathway for RDX decomposition on the Al surface. In addition, the evolutions of Al-containing clusters, key intermediates, and final products were analyzed, providing more information about this reaction. The findings suggest that the addition of Al nanoparticles improves the properties of RDX-based explosives, but the optimal amount of Al is critical for achieving the desired effects. The detailed analysis of the reaction mechanism and intermediate products provides valuable insights into the underlying mechanisms of the Al/RDX system.