Atmosphere effects on 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) nanoparticle pyrolysis: A ReaxFF molecular dynamics study

1,3,5-Triamino-2,4,6-trinitrobenzene (TATB), an insensitive explosive, is exposed to the atmosphere during manufacture, storage and use, which can lead to changes in energy and sensitivity, particularly in nanoparticles. However, the underlying mechanisms of atmosphere effect on TATB pyrolysis remain poorly elucidated due to the limitations of experimental techniques in terms of temporal and spatial scales. This study employs molecular dynamics simulations to explore the impact of common atmospheres, including N 2 atmosphere, H 2 O atmosphere, and NH 3 atmosphere, on the pyrolysis of TATB nanoparticles at the atomic level. The results demonstrate that all three atmospheres inhibit TATB pyrolysis, with N 2 atmosphere exhibiting the strongest inhibition, followed by NH 3 atmospheres, and H 2 O atmosphere. Regarding the intrinsic mechanism, the inhibitory effects of different atmospheres can be classified into two categories: The influence of N 2 atmosphere and H 2 O atmosphere is inert, as they hardly directly react with TATB but instead hinder the initial dehydrogenation reaction, thereby affecting the formation of key intermediates and final products; in contrast, NH 3 atmospheres not only inhibits these reactions but also tends to directly react with TATB to form larger molecules, which remain stable under thermal stimulation and suppress further decomposition of TATB. Thermal stimulation molecular dynamics of TATB nanoparticles in the various atmospheres of H2O, N2 and NH3 revealed the inhibition of atmospheres on the pyrolysis of TATB by exerting differential effect on the key active intermediates. • MD simulations showed that H 2 O, N 2 , and NH 3 atmospheres inhibit TATB pyrolysis, with N 2 exhibiting the strongest inhibition. • Atomic-level insights uncovered that H 2 O, N 2 , and NH 3 indirectly hindered pyrolysis by regulating key intermediates. • The unique interaction between NH 3 and TATB formed stable clusters that directly inhibited the pyrolysis of TATB.