CL-20/DNB共晶基PBXs相容性、界面作用和力学性能的MD模拟

为提高六硝基六氮杂异伍兹烷(CL-20)/1,3-二硝基苯(DNB)共晶炸药的实际使用价值,改善其安全性和力学性能,沿其(0 0 1)晶面分别添加了端羟基聚丁二烯(HTPB)和聚乙二醇(PEG)高聚物粘结剂,构建了两种CL-20/DNB共晶基高聚物粘结炸药(PBX)——CL-20/DNB/HTPB和CL-20/DNB/PEG的模型。在COMPASS力场下,对该共晶炸药及其两种PBX模型进行了295 K-NPT分子动力学(MD)模拟研究。结果表明,CL-20/DNB/PEG的结合能大于CL-20/DNB/HTPB的,预示前者的稳定性和相容性优于后者。以对相关函数g(r)揭示了粘结剂与基炸药之间界面的相互作用。与CL-20/DNB共晶炸药相比,少量粘结剂(HTPB或PEG)的加入,使弹性系数(Cij)、拉伸模量(E)、体积模量(K)和剪切模量(G)减小,而柯西压(C12-C44)和K/G值增大,表明PBX体系刚性减小,延展性增强。CL-20/DNB/HTPB的(C12-C44)和K/G值均大于CL-20/DNB/PEG的,表明前者的延展性好于后者,预示粘结剂HTPB比PEG在改变共晶炸药力学性能进而致钝的效果较好。

Molecular Dynamics Simulation of Compatibility, Interface Interactions and Mechanical Properties of CL-20/DNB Cocrystal Based PBXs

To enhance practical values and improve safety and mechanical properties of 2, 4, 6, 8, 10, 12-hexanitrohexaazaisowurtzitane /1, 3-dinitrobenzene (CL-20/DNB) cocrystal explosive, two polymer binders, hydroxyl-terminated polybutadiene (HTPB) and polyethylene glycol (PEG), were respectively added along its crystalline surface (0 0 1) and the models of two kinds of CL-20/DNB cocrystal based polymer-bonded explosives (PBXs), CL-20/DNB/HTPB and CL-20/DNB/PEG were constructed. Under the COMPASS force field, the 295 K-NPT molecular dynamics simulation (MD) study for cocrystal explosive and two kinds of PBXs models was conducted. The interface interaction between binder and explosives was explored using the pair correlation function (g(r)). Results show that the binding energy of CL-20/DNB/PEG is larger than that of CL-20/DNB/HTPB, predicting that the stability and compatibility of former is better than those of latter. In comparison with CL-20/DNB cocrystal explosive, adding of small amount of binder (HTPB or PEG) makes the elastic constants (C_ij), tensile modulus (E), bulk (K) and shear (G) modulus decrease, while Cauchy pressure (C₁₂-C₄₄) and K/G value increase, showing that the stiffness of the PBXs system is weaker, and its ductibility is better. The values of (C₁₂-C₄₄) and K/G of CL-20/DNB/HTPB system are larger than those of PBX CL-20/DNB/PEG, indicating that the ductibility of former is better that of latter, predicting that the desensitizing effect of HTPB by improving the cocrystal explosive''s mechanical properties is better than that of PEG.