Heat- and shock-induced pyrolysis of crystalline and amorphous TNT revealed by ReaxFF-lg simulations

The decomposition mechanisms of crystalline and amorphous TNT were studied through ReaxFF-lg simulations under the heat-loaded and shock-loaded. Their differences were elucidated from the initial decay reactions, activation energy, products and the clusters. Results showed that the heat-induced pyrolysis of two systems differed slight, but the shock-induced pyrolysis differed large. The decomposition reactions of amorphous and crystalline models are similar, but the nitro oxidation of TNT is only found in amorphous. Dimerization and intermolecular H-transfer were found at the constant temperature and MSST simulations, and intermolecular O-transfer were only found at the constant temperature simulations. For MSST simulation, products in crystalline formed later than in amorphous, and the number of clusters in crystalline is much larger than in amorphous, which indicating crystalline TNT would be induced early through shock wave. These findings could help to increase the understanding for the thermolysis behavior and safety of crystalline and amorphous energetic materials.