Xue Zhong-Qing, He Jing, Zhang Jun, Zhang Xi-Liang, Chen Yin-Gang, Ren Fu-de
Department of Environmental and Safety Engineering, Taiyan Institute of Technology, Tai Yuan, 030008, China.
Department of Computer Science, Wu han Polytechnic, Wu Han, 430074, China.
J Mol Model. 2017 Nov 20;23(12):346. doi: 10.1007/s00894-017-3519-1.
In order to elucidate why the inclusion of a nonpolar desensitizing agent in polymer-bonded explosives (PBXs) affects their sensitivity and safety, the intermolecular interactions between nitroguanidine (NQ: a high-energy-density compound used as a propellant and in explosive charges) and FC=CF were investigated theoretically at the B3LYP/6-311++G(2df,2p) and M06-2X/6-311++G(2df,2p) levels of theory, focusing especially on the influence of intermolecular interactions on the strength of the trigger bond in NQ. The binding energies and mechanical properties of various β-NQ/polytetrafluoroethylene PBXs were also studied via molecular dynamics simulation. The results indicated that the weak intermolecular interactions between NQ and FC=CF have almost no effect on the strength of the trigger bond or the energy barrier to the intramolecular hydrogen-transfer isomerization of NQ, as also confirmed by an AIM (atoms in molecules) analysis. However, the mechanical properties of the β-NQ/polytetrafluoroethylene PBXs were found to be significantly different from those of pure β-NQ: the PBXs showed reduced rigidity and brittleness, greater elasticity and plasticity, and-in particular-better ductility. Thus, β-NQ-based PBXs with polytetrafluoroethylene are predicted to be less sensitive to external mechanical stimuli, leading to reduced explosive sensitivity and increased safety. Only mechanical properties influence the safety of nitroguanidine-based PBXs.
为了阐明为何在聚合物粘结炸药（PBXs）中加入非极性脱敏剂会影响其敏感性和安全性，我们在B3LYP/6 - 311++G(2df,2p)和M06 - 2X/6 - 311++G(2df,2p)理论水平上对硝基胍（NQ：一种用作推进剂和炸药装药的高能量密度化合物）与FC=CF之间的分子间相互作用进行了理论研究，特别关注分子间相互作用对NQ中触发键强度的影响。还通过分子动力学模拟研究了各种β - NQ/聚四氟乙烯PBXs的结合能和力学性能。结果表明，NQ与FC=CF之间的弱分子间相互作用对触发键强度或NQ分子内氢转移异构化的能垒几乎没有影响，这也通过分子中的原子（AIM）分析得到了证实。然而，发现β - NQ/聚四氟乙烯PBXs的力学性能与纯β - NQ的力学性能有显著差异：PBXs表现出更低的刚性和脆性、更大的弹性和可塑性，特别是更好的延展性。因此，预计含聚四氟乙烯的基于β - NQ的PBXs对外部机械刺激的敏感性较低，从而降低炸药敏感性并提高安全性。只有力学性能会影响基于硝基胍的PBXs的安全性。
