Comparison study of carbon clusters formation during thermal decomposition of hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine and benzotrifuroxan: a ReaxFF based sequential molecular dynamics simulation

Carbon rich clusters are usually found after the detonation of explosives, which greatly hinder their further decomposition into small molecules. The comparison study of thermal decomposition and clusters formation between hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine (TATB) and benzotrifuroxan (BTF) crystals was conducted to uncover the mechanisms behind their distinct differences in sensitivity and reaction violence, which has not been detailly investigated. The simulations of heating at 3500 K, then expansion and cooling were conducted through reactive molecular dynamics using ReaxFF-lg force field. As a result, the beginning low decay rate indicates that TATB is more stable than BTF under high temperature, while once ignited it decays faster than BTF. Nevertheless, BTF decomposes more deeply with higher potential energy release, larger final products amounts, and higher reaction frequencies, which shows higher reaction violence than that of TATB. More and heavier clusters occur in TATB crystal compared with those in BTF. Large clusters form during the heating process and then partly dissociate during expansion and cooling. A faster cooling rate facilitates larger clusters formation. Graphitic geometries as well as carbon rings and carbon chains are common in the stable clusters. Besides, further simulations show that a lower heating temperature facilitates larger clusters formation both in TATB and BTF. Our results are expected to deepen the insight into the mechanisms of carbon clusters formation and the different performance between TATB and BTF.