Zhang Yaping, Li Qikai, He Yuanhang
State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China.
MOE Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China.
ACS Omega. 2020 Jul 17;5(29):18535-18543. doi: 10.1021/acsomega.0c02829. eCollection 2020 Jul 28.
The physical and chemical properties of typical nitrate energetic materials under hydrostatic compression and uniaxial compression were studied using the ReaxFF/lg force field combined with the molecular dynamics simulation method. Under hydrostatic compression, the - curve and the bulk modulus ( ) obtained using the VFRS equation of state show that the compressibility of the three crystals is nitroglycerine (NG) > erythritol tetranitrate (ETN) > 2,3-bis-hydroxymethyl-2,3-dinitro-1,4-butanediol tetranitrate (NEST-1). The - and -axis of ETN are easy to compress under the action of hydrostatic pressure, but the -axis is not easy to compress. The -axis of NEST-1 is the most compressible, while the - and -axis can be compressed slightly when the initial pressure increases and then remains unchanged afterward. The -, -, and -axes of NG all have similar compressibilities. By analyzing the change trend of the main bond lengths of the crystals, it can be seen that the most stable of the three crystals is the N-O bond and the largest change is in the O-NO bond. The stability of the C-O bond shows that the NO produced by nitrates is not from the C-O bond fracture. Under uniaxial compression, the stress tensor component, the average principal stress, and the hydrostatic pressure have similar trends and amplitudes, indicating that the anisotropy behaviors of the three crystals ETN, NEST-1, and NG are weak. There is no significant correlation between maximum shear stress and sensitivity. The maximum shear stresses τ and τ of the ETN in the [010] direction are 1.5 GPa higher than τ . However, the maximum shear stress of NG shows irregularity in different compression directions, indicating that there is no obvious correlation between the maximum shear stress and sensitivity.
采用ReaxFF/lg力场结合分子动力学模拟方法，研究了典型硝酸酯含能材料在静水压力和单轴压缩下的物理化学性质。在静水压力下，利用VFRS状态方程得到的-曲线和体积模量（）表明，三种晶体的压缩性为硝化甘油（NG）>四硝酸赤藓醇（ETN）>四硝酸2,3-双羟甲基-2,3-二硝基-1,4-丁二醇（NEST-1）。在静水压力作用下，ETN的-轴和-轴易于压缩，但-轴不易压缩。NEST-1的-轴最易压缩，而-轴和-轴在初始压力增加时可略有压缩，随后保持不变。NG的-轴、-轴和-轴的压缩性都相似。通过分析晶体主键长的变化趋势可以看出，三种晶体中最稳定的是N-O键，变化最大的是O-NO键。C-O键的稳定性表明，硝酸盐产生的NO不是来自C-O键的断裂。在单轴压缩下，应力张量分量、平均主应力和静水压力具有相似的趋势和幅度，表明ETN、NEST-1和NG三种晶体的各向异性行为较弱。最大剪应力与感度之间没有显著相关性。ETN在[010]方向上的最大剪应力τ和τ比τ高1.5 GPa。然而，NG的最大剪应力在不同压缩方向上表现出不规则性，表明最大剪应力与感度之间没有明显的相关性。
