Thermal decomposition of cocrystal BTF/TNB nanoparticles simulated using density functional tight-binding molecular dynamics

Abstract

To understand the nano effect on the thermal decomposition of cocrystal explosives, this study simulated the initial decomposition of cocrystal BTF/TNB nanoparticles (NPs) with diameters of 2.2–3.0 ​nm at high temperatures of 2400–3000 ​K using density functional tight-binding molecular dynamics (DFTB-MD) with dispersion corrections. As indicated by the simulation results, the volume expansion of the nanoparticles competed with its decomposition, and smaller nanoparticles promoted the diffusion of the molecules and products in the nanoparticles. Moreover, the nanoparticles had a higher decomposition rate at higher temperatures, and smaller nanoparticles were associated with a higher decomposition rate and weaker interactions between intermediates and lattice. The number of clusters first increased and then decreased during the decomposition of the nanoparticles. The results of this study may help in understanding the effects of temperature and particle size on the thermal decomposition mechanisms of cocrystal explosives.