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化学学报
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化学学报 ›› 2014, Vol. 72 ›› Issue (9): 1036-1042.DOI: 10.6023/A14040295 上一篇    

研究论文

CL-20/HMX共晶及其为基PBX界面作用和力学性能的MD模拟研究

孙婷a, 刘强a, 肖继军a, 赵峰b, 肖鹤鸣a   

  1. a 南京理工大学化工学院分子与材料计算研究所 江苏 南京 210094;
    b 中国工程物理研究院冲击波物理与爆轰物理国防科技重点实验室 四川 绵阳 621900
  • 投稿日期:2014-04-18 发布日期:2014-08-27
  • 通讯作者: 肖继军 E-mail:xiao_jijun@mail.njust.edu.cn
  • 基金资助:

    项目受国家自然科学基金委员会与中国工程物理研究院联合基金（No. U1230120）资助.

Molecular Dynamics Simulation of Interface Interactions and Mechanical Properties of CL-20/HMX Cocrystal and Its Based PBXs

Sun Tinga, Liu Qianga, Xiao Jijuna, Zhao Fengb, Xiao Heminga   

  1. a Molecules and Materials Computation Institute, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
    b National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
  • Received:2014-04-18 Published:2014-08-27
  • Supported by:

    Project supported by Joint Fund of National Natural Science Foundation of China and China Academy of Engineering Physics (Grant No. U1230120).

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为提高共晶炸药的实际使用价值, 改善其安全性和力学性能, 以CL-20/HMX共晶炸药为基, 分别添加2种高聚物粘结剂Estane 5703(聚氨基甲酸乙酯)和HTPB(端羟基聚丁二烯), 共构建两种共晶基高聚物粘结炸药(PBX)模型, 进行细致的295 K NPT分子动力学(MD)模拟研究. 通过两种PBX模型及其与该共晶炸药的MD模拟结果比较表明, 与基炸药之间的结合能Estane 5703大于HTPB, 预示含少量Estane 5703的PBX稳定性和相容性更佳; 对相关函数g(r)揭示粘结剂与基炸药界面相互作用的方式, 以基炸药中H分别与Estane 5703中羰基O和HTPB中端羟基O之间的氢键较强. 与CL-20/HMX共晶炸药相比, 少量粘结剂Estane 5703或HTPB的加入, 使弹性系数Cij下降, 拉伸模量(E)、体积模量(K)和剪切模量(G)均显著减小, 而泊松比(ν), 柯西压(C12－C44)和K/G值明显增大, 表明PBXs体系刚性减小, 延展性增强, 力学性能大为改善. 少量粘结剂包覆使PBXs致钝, 主要归因于其隔热、吸热并使体系变“软”的缓冲作用, 而界面作用造成的分子结构引发键键长变化变为次要因素.

关键词: CL-20/HMX共晶炸药, 高聚物粘结炸药, 分子动力学模拟, 界面相互作用, 力学性能, 感度

To enhance practical values and improve safety and mechanical properties of cocrystal explosives, molecular dynamics simulations were conducted to investigate the interface interactions and mechanical properties of CL-20/HMX cocrystal based polymer-bonded explosives (PBXs). Two polymers, poly(ester urethane) block copolymer (Estane 5703) and hydroxyl-terminated polybutadiene (HTPB), were respectively put along crystalline surface (1 0 0). Totally, two PBX simulation models were built. The interfacial binding energies between the crystalline surface and polymers were calculated and the binding energy between Estane 5703 and the cocrystal (1 0 0) surface is larger than that of HTPB. This indicates that the stability and compatibility of the PBX containing a small amount of Estane 5703 is better. The interface structures of CL-20/HMX cocrystal (1 0 0) surface with the two polymers were analyzed using pair correlation function (PCF). The results show that hydrogen bonds of H atoms in the cocrystal with carbonyl-O atoms in Estane 5703 and with hydroxyl-O atoms in HTPB are stronger. The elastic constants, moduli and Poisson ratio of the cocrystal and the cocrystal-based PBXs were calculated based on the fluctuation analysis of production trajectories and Reuss average. Compared with the cocrystal, the mechanical properties of the PBXs containing a small amount of binder Estane 5703 or HTPB have changed apparently. It is found that the elastic constants (Cij), tensile modulus (E), bulk (K) and shear (G) modulus all decrease, while Poisson ratio (ν), Cauchy pressure (C12－C44) and K/G all increase. The results show that the stiffness of the PBXs system is weaker, and its elasticity and ductibility is better. And the small amount of polymer binders coating with the cocrystal makes the PBXs more insensitive. The desensitization is mainly attributed to the heat insulation and absorption of the polymers and the buffer action of the system softened by the polymers, while the bond length change for trigger bond caused by interface interactions plays a minor role.

Key words: CL-20/HMX cocrystal explosive, polymer-bonded explosives (PBXs), molecular dynamics simulation, interface interactions, mechanical property, sensitivity