CL-20及其共晶炸药热力学稳定性与爆轰性能的理论研究

Theoretical Studyon Thermodynamic Stabilityand Detonation Performance of CL-20 and Its Cocrystal

基于自主研发的第一性原理软件研究了六硝基六氮杂异伍兹烷(CL-20)炸药五种晶相、苯并三氧化呋咱(BTF)炸药晶体及CL-20/BTF共晶炸药结构的热力学稳定性、力学性能和爆轰性能。研究表明,弱氢键的静电吸引作用使CL-20/BTF共晶的分子间结合能相对于无氢BTF晶体增加39%,提升了共晶结构的热力学稳定性并较大地改变了其体弹模量和声速等力学性能。CL-20/BTF共晶虽与纯BTF晶体有相近的密度,但由于共晶的氧平衡系数得到优化,因此其爆压、爆速分别相对提高约11%、5%;与β-CL-20晶体相比,共晶的密度与氧平衡均有所下降,因而其爆压、爆速分别相对下降约15%、6%。设计新型钝感共晶炸药应避免共价键强度极弱的分子和具有高密度振动谱特征峰的结构,应有效利用氢键对分子空间堆积的热力学稳定效应,同时适量控制氢元素含量以保障炸药的高能量密度。

Based on the first-principle software developed by ourselves,the thermodynamic stability,mechanical properties,and detonation performances of structure for hexanitrohexaazaisowurtzitane（CL-20）explosive with five crystallline phase,benzotrifuroxane（BTF）crystal explosive and CL-20/BTF cocrystal explosive were studied.Results show that the electrostatic attraction effect of weak hydrogen bonds makes the intermolecular binding energy of CL-20/BTF cocrystal increase by 39% compared with that of hydrogen-free BTF crystal,which improves thermodynamic stability of cocrystal structure and significantly changes its mechanical properties,such as bulk modulus and sound speed etc.Although the BTF/CL-20 cocrystal and pure BTF crystal have the similar density,but due to the oxygen balance coefficient of the cocrystal has been optimized,so its detonation velocity and detonation pressure are improved by about 11% and 5%,respectively.Compared with theβ-CL-20 crystal,the density and oxygen balance of the cocrystal are decreased,the detonation pressure and detonation velocity relatively decrease by about 15% and 6%,respectively.Design of a new type of insensitive cocrystal explosive should avoid the molecule with extremely weak strength covalent bonds and structure with characteristic peaks of high density vibration spectrum,thermodynamic stability effect of hydrogen bond on the molecular space packing should be effectively used,and the hydrogen element content should be moderately controlled to protect the high energy density of explosives.