Performances and direct writing of CL-20 based ultraviolet curing explosive ink

A new type of explosive ink formulation that can be quickly cured was prepared with unsaturated polyester as binder,styrene as active monomer,2,4,6-trimethylbenzoyl-diphenylphosphine oxide as photoinitiator,and hexanitrohexaazaisowurtzitane(CL-20)as the main explosive.Then the explosive inkdirect writing technology was used to charge the micro-sized energetic devices,the curing mechanism of the explosive ink was discussed,and the microstructure,safety performance and explosive transfer performance of the explosive ink molded samples were tested and analyzed.Results indicate that the composite material has a fast curing molding speed,its hardness can reach 2H within 8 min.The crystal form of CL-20 in the molded sample is still type.The CL-20 based UV-curing explosive ink formulation has good compatibility,its apparent activation energy is increased by about 3.5 kj/mol.The composite presents a significant reduction in impact sensitivity and its characteristic drop height can reach 39.8 cm,whichis about 3 times higher than the raw material.When the line width of charge is 1.0 mm,the critical thickness of the explosion can reach 0.015 mm,and the explosion velocity is 7129 m/s when the charge density is 1.612 g/cm^(3).

3D direct writing and micro detonation of CL-20 based explosive ink containing O/W emulsion binder

The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a novel CL-20 based explosive ink formulation have been developed successfully for MEMS initiation systems via DIW technology.We designed PVA/GAP into an oil-in-water(O/W)emulsion,in the way that the aqueous solution of PVA as water phase,the ethyl acetate solution of GAP as oil phase,the combination of Tween 80 and SDS as emulsifier,BPS as a curing agent of GAP.The ideal formulation with good shear-thinning rheology properties and clear gel point was prepared using only 10 wt%emulsion.The dual-cured network formed during the curing process made the printed sample have good mechanical properties.The printed samples had satisfactory molding effect without cracks or fractures,the crystal form of CL-20 not changed and the thermal stability have improved.Deposition of explosive inks via DIW in micro-scale grooves had excellent detonation performances,which critical detonation size was 1×0.045 mm,detonation velocity was 7129 m/s and when the corner reaching 150°can still detonated stably.This study may open new avenues for developing binder systems in explosive ink formulations.

HMX/CL-20基传爆药的挤注装药工艺及传爆性能

针对爆炸网络沟槽通道尺寸小、长径比大及拐角多且角度各异的结构特点,设计了注射器和分段重复挤注装药工艺,考察了HMX/CL-20基传爆药沟槽挤注装药的密度及分布均匀性,研究了截面尺寸0.5mm×0.5mm～1×1mm沟槽爆轰波直线传播速度、拐角传播能力及临界尺寸。结果表明,用分段挤注工艺制作的爆炸网络可行,其药体成型好,平均密度为1.45g/cm3且分布均匀。截面尺寸大于0.5mm×0.5mm的沟槽装药均可实现可靠传爆,尺寸分别为1mm×1mm、0.8mm×0.8mm、0.6mm×0.6mm、0.5mm×0.5mm沟槽爆轰波直线传播平均速度分别为7 276、7 131、7 013、6 906m/s,临界传播尺寸为0.3mm×0.3mm～0.4mm×0.4mm。

Effect of Magnesium Atom on CL-20------A DFT Treatment

The effect of magnesium atom on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtizane(HNIW,CL-20)explosive is considered within the constraints of density functional theory at the level of B3LYP/6-31++G(d,p).The Mg atom transfers some electron population to CL-20and one of the nitro groups linked to 6-membered piperazine ring system(base)is expelled in the prenitrite form.The total Mulliken charges on the NO2group reveals that the respective nitramine bond in CL-20is the most susceptible one to impact.The calculated IR and UV-VIS spectra are investigated.The effect of Mg atom on the molecular orbital energies,especially the HOMO and LUMO has been discussed.Narrowing of the interfrontier molecular orbital energy gap(Δε)in the composite system occurs.Therefore,the composite system is more susceptible to impact compared to CL-20.

Endohedrally Helium-doped CL-20:A DFT Treatment

In order to investigate whether endohedral He-doping is possible or not in CL-20,a density functional treatment has been carried out at the levels of B3LYP/6-31++G(d,p)and B3PW91/6-31++G(d,p).Some physicochemical and quantum chemical properties of the helium-doped CL-20 (He@CL-20)are compared with the respective values of the parent explosive CL-20.The helium doping caused swelling of CL-20cage but no bond rupture occurred.Doped helium acquired some positive charge.

CL-20基传爆药配方设计与性能影响分析

为探究CL-20传爆药的配方设计方法及参数影响,对GAP/CL-20传爆药试样进行了设计和优化。利用流变仪分析不同比例、粒度对试样黏度的影响,最后利用差示扫描量热法对试样进行了热分解测试。结果表明:CL-20炸药的颗粒越大,黏度就越小,流动性能就越好;主体炸药组分含量越少,配方药剂的黏度越小;并再次验证了GAP是一种同时满足塑化能力和炸药能量要求的良好的含能添加剂。以上结果可为类似炸药的研究提供参考。

水悬浮法制备-εHNIW基传爆药的工艺研究

为获得高能低感传爆药,以六硝基六氮杂异伍兹烷为主体炸药,用水悬浮法制备了ε-HNIW为基的传爆药。通过正交试验优化了制备工艺,并对影响包覆效果的主要因素进行了研究。用傅立叶红外光谱(FT-IR)、扫描电子显微镜(SEM)及撞击感度测试等手段对包覆样品进行表征。结果表明,影响包覆效果的因素顺序为:温度>搅拌速度>加料速度>真空度;确定了最佳工艺条件:试验温度70℃、真空度0.05MPa、搅拌速度700r/min、加料速度0.725mL/s。包覆过程中ε-HNIW晶型结构没有发生改变;包覆后样品撞击感度的特性落高H50比原料ε-HNIW提高了27cm。

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 epsilon-CL-20(hexanitrohexaazaisowurtzi-tane),the most important high energy density compound(HEDC),and five polymer binders(Estane 5703,GAP,HTPB,PEG,and F_(2314))were constructed.Molecular dynamics(MD)method was employed to investigate their binding energies(E_(bind))< compatibility,safety,mechanical properties,and energetic properties.The information and rules were reported for choosing better binders and guiding formulation 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 epsilon-CL-20/PEG < epsilon-CL-20/ Estane5703 ≈ epsilon-CL-20/GAP < epsilon-CL-20/HTPB < epsilon-CL-20/F_(2314).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 epsilon-CL-20 can be obviously improved more than pure epsilon-CL-20 crystal.It is not by changing the molecular structures of epsilon-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^(deg))and density(p)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.