HMX及TATB热分解的分子动力学研究

Molecular Dynamics Studies of Thermal Decomposition of HMX and TATB

为了探究HMX及TATB在较低温度下长时间缓慢热分解的机理与现象的差异,使用Lammps软件对HMX和TATB的热分解过程进行分子动力学(MD)模拟,通过反应力场(Reax FF-lg)描述体系内的化学反应,对体系势能变化、反应物分解趋势、重要产物及团簇进行分析。结果表明:TATB的苯环结构比HMX的四氮杂环辛烷结构更加稳定,在相同温度下TATB产生的小分子气体产物更少,因此在密闭环境下难以通过压强变化判断其热分解程度;TATB生成的大质量团簇结构更多,对热分解抑制作用更明显;低温下TATB热分解过程中N2的生成时间滞后于HMX,且生成速率小于HMX;TATB体系中存在大量NO2的时间占比比HMX的时间占比更长,但是在温度较低、热分解速率缓慢的情况下,TATB只有少量的NO2生成。

In order to explore the differences in the mechanisms and phenomena of long-term slow thermal decomposition of HMX and TATB at lower temperatures,the molecular dynamics(MD)simulations of the thermal decomposition process of HMX and TATB were performed using Lammps software,and the chemical reactions in the system were described through the reaction force field(ReaxFF-lg),analyzing the potential energy changes,reactants decomposition trends,important products and clusters of the system.The results show that the benzene ring structure of TATB is more stable than tetraazaheterocyclic in HMX,and the small molecule gas products produced by TATB at the same temperature are less,so that it is difficult to judge the degree of thermal decomposition of TATB though pressure changes in a closed environment;TATB generates more large mass cluster structures,which has a more obvious inhibitory effect on thermal decomposition;The generation time of N2 during the thermal decomposition of TATB lags behind that of HMX at low temperatures,and the generation rate is lower than that of HMX;The time proportion of a large amount of NO2 in the TATB system is longer than that of HMX,but at low temperatures and slow thermal decomposition rates,only a small amount of NO2 is generated in TATB.