CL-20/DNDAP共晶含能材料的晶体结构与性能研究

以乙酸甲酯为溶剂,采用溶剂挥发法制得六硝基六氮杂异伍兹烷(CL-20)/2,4-二硝基-2,4-二氮杂戊烷(DNDAP)共晶含能材料。利用扫描电子显微镜和单晶X射线衍射仪对其形貌和结构进行表征,采用差示扫描量热法测试其热性能,并研究了该材料的机械感度和爆轰性能。结果表明,CL-20/DNDAP晶体属于单斜晶系,P21/c空间群,晶胞参数a=1.3022(2)nm,b=2.2619(4)nm,c=1.2962(2)nm,α=90°,β=104.648(3)°,γ=90°(a,b,c均为晶胞长度;α,β,γ均为空间角)。CL-20/DNDAP共晶含能材料在210～260℃集中放热分解,熔点明显高于DNDAP;共晶含能材料特性落高值为33.1cm,摩擦感度为48%,摩擦感度较CL-20大幅降低;应用Kamlet-Jacobs方程预测得到共晶含能材料的理论爆速为8870m/s,理论爆压为36.40GPa,具有较高的能量。

一种新型CL-20/TKX-50共晶炸药的制备、表征和性能研究

为降低六硝基六氮杂异伍兹烷(CL-20)的感度,通过溶剂-非溶剂法制备了CL-20和1,1′-二羟基-5,5′-联四唑二羟胺盐(TKX-50)共晶炸药;通过Materials Studio 5.0软件分析了CL-20和TKX-50分子的表面静电势,并预测了共晶分子间可能的非共价键作用;采用扫描电镜(SEM)、X射线衍射(XRD)、红外(IR)和拉曼光谱(Raman)对其形貌和结构进行了表征;采用DSC测试了其热性能,并测试了其撞击感度,预测了其爆轰性能。结果表明,制备的CL-20/TKX-50共晶呈扁平的片状形貌;XRD、IR和Raman谱图中出现峰的生成、消失、偏移和强度的改变,证明有新的晶格结构形成;升温速率8℃/min下,CL-20/TKX-50共晶的主要热分解峰温为222.8℃,与CL-20、TKX-50的热分解峰温240.3、234.9℃相比,分别提前了17.5℃和12.1℃,明显区别于具有两个放热过程的CL-20/TKX-50混合物的热分解行为;CL-20/TKX-50共晶炸药的感度显著低于原料CL-20,同时也优于β-HMX,说明其具有良好的安全性能;CL-20/TKX-50共晶的预测爆速和爆压分别为9264m/s和43.8GPa,较CL-20均略微下降,但和β-HMX相比,爆轰性能明显提高。表面静电势能和建模分析均表明,CL-20中—NO2的O与TKX-50中—NH+3的H之间易于形成氢键。

CL-20/HMX共晶含能材料研究进展

含能材料共晶化是获得高能低感含能材料的重要途径,不同含能材料形成共晶可以有效改善含能材料的氧平衡及感度,提高其爆热、做功能力及安全性等性能。CL-20/HMX共晶含能材料是高能低感共晶含能材料的代表,CL-20/HMX共晶既保留了CL-20的能量水平又降低了CL-20的感度,是解决CL-20应用问题的有效途径。通过对比CL-20/HMX共晶与CL-20及HMX性能上的差异,说明了CL-20/HMX共晶研究的必要性,并从CL-20/HMX共晶的制备方法、形成机制、性能及应用方面,综述了CL-20/HMX共晶研究的最新进展。重点对比了CL-20/HMX共晶制备方法的优劣,总结了CL-20/HMX共晶形成机制,分析了不同制备方法获得的CL-20/HMX共晶性能差异,评述了CL-20/HMX共晶的发展现状及应用前景。

CL-20共晶含能材料计算模拟及实验制备研究进展

含能化合物六硝基六氮基杂异伍兹烷(CL-20)是现阶段获得实际应用的能量最高的非核单质炸药,但其高感度问题限制了在实际中的应用。而CL-20与其他化合物形成的共晶能够在保留高能量的基础上,大幅降低感度、提高材料的安全性,有效扩展应用范围,为高能低感含能材料的制备提供了新的思路。在总结现有的量子化学和分子动力学相关研究的基础上,综述了CL-20与TNT、FOX-7、HMX和RDX等不同共晶体系的成键机理、性能特点。汇总了CL-20共晶的常见制备方法,分析比较了其优缺点及应用范围。最后,提出了现有的共晶体系及研究在共晶机理解释方面仍存在不足,并展望了未来共晶研究应以分子水平的计算模拟为理论依据,优化生产工艺,设计新的共晶体系和合成方法。

Formation and characterization of core-shell CL-20/TNT composite prepared by spray-drying technique

The core-shell 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/2,4,6-Trinitrotoluene(CL-20/TNT)composite was prepared by spray-drying method in which sensitive high energy explosive(CL-20)was coated with insensitive explosive(TNT).The structure and properties of different formulations of CL-20/TNT composite and CL-20/TNT mixture were characterized by scanning electron microscopy(SEM),Transmission electron microscopy(TEM),Laser particle size analyzer,X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),differential scanning calorimetry(DSC),impact sensitivity test and detonation performance.The results of SEM,TEM,XPS and XRD show that e-CL-20 particles are coated by TNT.When the ratio of CL-20/TNT is 75/25,core-shell structure is well formed,and thickness of the shell is about 20e30 nm.And the analysis of heat and impact show that with the increase of TNT content,the TNT coating on the core-shell composite material can not only catalyze the thermal decomposition of core material(CL-20),but also greatly reduce the impact sensitivity.Compared with the CL-20/TNT mixture(75/25)at the same ratio,the characteristic drop height of core-shell CL-20/TNT composite(75/25)increased by 47.6%and the TNT coating can accelerate the nuclear decomposition in the CL-20/TNT composites.Therefore,the preparation of the core-shell composites can be regarded as a unique means,by which the composites are characterized by controllable decomposition rate,high energy and excellent mechanical sensitivity and could be applied to propellants and other fields.

微纳米CL-20/HMX共晶含能材料的制备与性能

通过机械球磨法制备出微纳米CL-20/HMX共晶含能材料,对其进行SEM、粒度、XRD、DSC和Raman表征,以及撞击感度、摩擦感度和钢凹值测试分析。结果表明:球磨时间120min制得的CL-20/HMX共晶颗粒呈近球状,粒径分布在80~250nm。微纳米CL-20/HMX共晶含能材料展现出不同于各自单一组分的晶体结构和热分解特性,其机械感度较原料HMX大幅度降低,能量输出性能与原料CL-20相当。

外电场对共晶含能材料CL-20/TNT感度的影响

为了研究外电场对六硝基六氮杂异伍兹烷/2,4,6-三硝基甲苯(CL-20/TNT)共晶含能材料感度的影响,采用M06-2X-D3、B3LYP-D3BJ和ωB97XD 3种方法在6-311+G(d,p)(基组)水平下分析不同强度的外电场对CL-20/TNT共晶含能材料的静电势(ESP)、引发键键长(R(N—NO_(2)))、硝基基团电荷(Q(—NO_(2)))、相互作用能(Eint)和键解离能(E_(BDE))的影响。结果表明:随着N→NO_(2)方向电场(正电场)强度增强,引发键键长变短,局域正静电势极值减小,然而硝基基团负电荷增多,键解离能数值增大,使得CL-20/TNT共晶含能材料的感度降低;随着NO_(2)→N方向电场(负电场)强度增强,引发键键长变长,局域正静电势极值增大,硝基基团负电荷减少,键解离能数值减小,使得CL-20/TNT共晶含能材料的感度增大。与无外电场相比,Eint随着正电场强度的增强而逐渐减小;采用M06-2X-D3和ωB97XD方法计算时,Eint随着负电场强度的增强先增大后减小,但采用B3LYP-D3BJ方法计算时,Eint随着负电场强度的增强逐渐增大。在同一电场强度下对比3种方法所得数值大小,ωB97XD与另外两种方法所得数值差异明显。因此,通过相互作用能判断电场对共晶材料感度的影响存在一定的局限性。

Molecular dynamics simulations on the structures and properties of ε-CL-20-based PBXs ——Primary theoretical studies on HEDM formulation design

Five polymer bonded explosives (PBXs) with the base explosive ε-CL-20 (hexanitrohexaazaisowurtzi- tane), the most important high energy density compound (HEDC), and five polymer binders (Estane 5703, GAP, HTPB, PEG, and F2314) were constructed. Molecular dynamics (MD) method was employed to investigate their binding energies (Ebind), compatibility, safety, mechanical properties, and energetic properties. The information and rules were reported for choosing better binders and guiding formula- tion design of high energy density material (HEDM). According to the calculated binding energies, the ordering of compatibility and stability of the five PBXs was predicted as ε-CL-20/PEG > ε-CL-20/ Estane5703 ≈ε-CL-20/GAP > ε-CL-20/HTPB > ε-CL-20/F2314. By pair correlation function g(r) analyses, hydrogen bonds and vdw are found to be the main interactions between the two components. The elasticity and isotropy of PBXs based ε-CL-20 can be obviously improved more than pure ε-CL-20 crystal. It is not by changing the molecular structures of ε-CL-20 for each binder to affect the sensitivity. The safety and energetic properties of these PBXs are mainly influenced by the thermal capability (C°p) and density (ρ) of binders, respectively.

High energy and insensitive explosives based on energetic porous aromatic frameworks

The design and synthesis of energetic materials with a compatibility of high energy and insensitivity have always been the research fronts in military and civilian fields.Considering excellent performances of porous organic frameworks and the lack of research in the field of energetic materials,in this study,a new concept named energetic porous aromatic frameworks(EPAFs)is proposed.The strategy of coating high energy explosives such as 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20)and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane(HMX)in the EPAFs by wet-infiltration method has successfully realized the assembly of target energetic composite materials.The results show that the 75 wt.%CL-20@EPAF-1 possesses the safer impact sensitivity of 31.4 J than that of CL-20(4.0 J).Notably,for 75 wt.%CL-20@EPAF-1,in addition to the superior detonation performances of the detonation velocity(8,761 m·s^(-1))and detonation pressure(31.27 GPa),the synergistic effect of the nitrogen-rich EPAFs and the nitramines high energy explosives results in a higher heat of detonation that surpasses the most of pristine high explosives and reported novel energetic materials.In prospect,energetic porous aromatic frameworks could be a promising and inspiring strategy to build high energy insensitive energetic materials.