摘要
共晶技术是降低六硝基六氮杂异伍兹烷(CL‐20)感度的有效方法之一,研究冲击作用下CL‐20共晶的化学反应,有助于理解CL‐20共晶的冲击反应机制,对炸药安全评价分析具有重要意义。本研究采用ReaxFF‐lg反应力场的分子动力学方法,同时结合非平衡加载方法,对CL‐20/2,5‐二硝基甲苯(DNT)、CL‐20/1,3‐二硝基苯(DNB)和CL‐20/1‐甲基‐3,5‐二硝基‐1,2,4‐三唑(MDNT)三种共晶在2~5 km·s^(-1)冲击速度下的冲击压缩过程进行了分子动力学模拟,获得了含能共晶在冲击作用后的热力学演化特征、初始化学反应路径和产物信息,并与CL‐20的情况进行了对比分析。研究发现:CL‐20/DNT、CL‐20/DNB和CL‐20/MDNT 3种共晶都有一定程度的降低冲击感度作用,3种共晶的冲击感度顺序依次为CL‐20/MDNT>CL‐20/DNB>CL‐20/DNT。3种共晶的分解反应均是从CL‐20分解开始,且CL‐20的分解速度比DNT、DNB和MDNT快。在2 km·s^(-1)冲击速度下,CL‐20共晶首先发生聚合反应,CL‐20与共晶配体分子间的聚合反应早于CL‐20分子间的聚合,且反应频次远高于CL‐20分子之间聚合。在3 km·s^(-1)的冲击条件下,CL‐20首先发生了N—N以及C—N键断裂,笼型结构被破坏,同时生成NO_(2),CL‐20初步断键后的结构及产物NO_(2)会进一步与共晶配体分子DNT、DNB、MDNT结合,降低CL‐20反应中间产物的浓度,达到降感作用。在4,5 km·s^(-1)冲击条件下,CL‐20中的环状骨架结构会直接遭到破坏,发生C—N键断裂,产生小分子碎片,直接生成N2,同时有NO_(2)、H_(2)、CO_(2)、H_(2)O等产物生成。
Co‐crystal technology is one of the effective methods to reduce the sensitivity of CL‐20.Studying the chemical reaction of CL‐20 co‐crystal under shock is helpful to understand the shock reaction mechanism of CL‐20 co‐crystal,which is of great significance to the safety evaluation and analysis of explosives.In this study,the molecular dynamics method of ReaxFF‐lg reaction force field and the non‐equilibrium loading method were used to simulate the shock compression process of CL‐20/DNT,CL‐20/DNB and CL‐20/MDNT co‐crystals at 2-5 km·s^(-1)shock velocity.The thermodynamic evolution characteristics,initial chemical reaction path and product information of energetic co‐crystals after shock are obtained and compared with those of CL‐20.It’s discovered that the three co‐crystals of CL‐20/DNT,CL‐20/DNB and CL‐20/MDNT have a certain degree of shock sensitivity reduction,and the order of shock sensitivity of the three co‐crystals is CL‐20/MDNT>CL‐20/DNB>CL‐20/DNT.The decomposition reaction of the three co‐crystals all starts from the decomposition of CL‐20,and the decomposition rate of CL‐20 is faster than that of DNT,DNB and MDNT.At the shock velocity of 2 km·s^(-1),the polymerization reaction of CL‐20 co‐crystal occurs first.The polymerization reaction between CL‐20 and co‐crystal ligand molecules is earlier than that between CL‐20 molecules,and the reaction frequency is much higher than that between CL‐20 molecules.At the shock velocity of 3 km·s^(-1),the N─N and C─N bonds of CL‐20 are first broken,and the cage structure is destroyed.At the same time,NO_(2)is generated.NO_(2)generated by the initial bond breaking of CL‐20 further combines with the eutectic ligand molecules DNT,DNB and MDNT to reduce the concentration of the intermediate products of CL‐20 reaction,so as to achieve the desensitization effect.At the shock velocity of 4 or 5 km·s^(-1),the ring skeleton structure in CL‐20 is directly destroyed,the C‐N bond is broken,generating small molecular fragments,including N2,NO_(2),H2,CO_(2),H2O and other products.
作者
伍俊英
方汇璇
尚伊平
李钧剑
王健宇
陈朗
WU Jun-ying;FANG Hui-xuan;SHANG Yi-ping;LI Jun-jian;WANG Jian-yu;CHEN Lang(State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology,Beijing 100081,China)
出处
《含能材料》
EI
CSCD
北大核心
2024年第1期49-64,共16页
Chinese Journal of Energetic Materials
基金
国家自然科学基金(11832006)。
关键词
含能共晶
反应力场
分子动力学
冲击波
反应机理
energetic co‐crystal
reaction force field
molecular dynamics
shock wave
reaction mechanism
