Wang Fuping, Du Guangyan, Zhang Chenggen, Wang Qian-You
Department of Chemistry and Material Science, Langfang Normal University, Langfang 065000, China.
Henan Key Laboratory of Crystalline Molecular Functional Materials, Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
Polymers (Basel). 2023 Mar 22;15(6):1576. doi: 10.3390/polym15061576.
High-energy low-sensitivity explosives are research objectives in the field of energetic materials, and the formation of cocrystals is an important method to improve the safety of explosives. However, the sensitivity reduction mechanism of cocrystal explosives is still unclear. In this study, CL-20/TNT, CL-20 and TNT crystals were taken as research objects. On the basis of the ReaxFF-lg reactive force field, the propagation process of the wave front in the crystals at different impact velocities was simulated. The molecular dynamics data were used to analyze the molecular structure changes and initial chemical reactions, and to explore the sensitivity reduction mechanism of the CL-20/TNT cocrystal. The results showed that the chemical reaction of the CL-20/TNT cocrystal, compared with the CL-20 single crystal, is different under different impact velocities. At an impact velocity of 2 km/s, polymerization and separation of the component molecules weakened the decomposition of CL-20. At an impact velocity of 3 km/s, the decay rates of CL-20 and TNT in the cocrystal decreased, and the intermediate products were enhanced, such as nitrogen oxides. At an impact velocity of 4 km/s, the cocrystal had little effect on the decay rates of the molecules and formation of CO, but it enhanced formation of N and HO. This may explain the reason for the impact-sensitivity reduction of the CL-20/TNT cocrystal.
高能低感炸药是含能材料领域的研究目标，而共晶的形成是提高炸药安全性的重要方法。然而，共晶炸药的感度降低机理仍不明确。本研究以CL-20/TNT、CL-20和TNT晶体为研究对象。基于ReaxFF-lg反应力场，模拟了不同冲击速度下晶体中波前的传播过程。利用分子动力学数据分析分子结构变化和初始化学反应，探索CL-20/TNT共晶的感度降低机理。结果表明，CL-20/TNT共晶与CL-20单晶相比，在不同冲击速度下的化学反应不同。在2 km/s的冲击速度下，组分分子的聚合和分离减弱了CL-20的分解。在3 km/s的冲击速度下，共晶中CL-20和TNT的衰减速率降低，中间产物如氮氧化物增加。在4 km/s的冲击速度下，共晶对分子的衰减速率和CO的形成影响较小，但增强了N和HO的形成。这可能解释了CL-20/TNT共晶冲击感度降低的原因。
