• Syntheses and Characterizations of New Energetic Dinitramide Nitrogen-rich Copper Complexes

  MU Guo-zhu, LI Xin, LI Shuang, LEI Qing, YUE Si-jia, GAO Yang

  Online:March 17, 2023  DOI: 10.11943/CJEM2022221

  Abstract(21) HTML(206) PDF(1.59 M)( 171)

  Abstract:To explore low sensitivity and environmental-friendly energetic combustion catalysts， three new energetic copper complexes， ［Cu（NH₃）₄（DN）₂］， ［Cu（IMI）₄（DN）₂］， ［Cu（ATO）₄］（DN）₂ were synthesized. Ammonium dinitramide （ADN） was used as a precursor to prepare dinitramide acid （HDN） by ion exchange reaction， and the resultant solution reacted with basic copper （Ⅱ） carbonate continually to produce copper （Ⅱ） dinitramide， which reacted further with nitrogen-rich ligands （ammonia， imidazole， 4-amino-1，2，4-triazole-5-one）. The structures of the three complexes were characterized accurately by X-ray single crystal diffraction， infrared spectroscopy and elemental analysis. Their thermal stability， hygroscopicity， sensitivities toward impact （IS）， friction （FS） and electrostatic discharge （ESD） were investigated. Furthermore， the effect of ［Cu（IMI）₄（DN）₂］ towards the burning rate of propellants were performed. Results show that the thermal stability of three complexes can meet the application requirement of solid propellants， and the initial decomposition temperatures are all higher than 140 ℃. The hygroscopicity of the complexes were improved obviously， which could be as low as 2%-5% of the precursor ADN. ［Cu（IMI）₄（DN）₂］ has the lowest sensitivity （IS 28.6 J， FS 0%， ESD 185 mJ） of the three complexes. With 4% of ［Cu（IMI）₄（DN）₂］， the burning rate of the basic formula propellants was increased by 27.7%， which was expected to be used as low sensitivity burning rate catalyst in high burning rate solid propellants.

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• Effects of Particle Properties of Energetic Materials on Laser-induced Micro-explosive Shock Waves

  BAO Yuan, GUO Wei, LI Ming, XUE Peng-yi, WANG Xiang, HAO Shi-long, CHEN Si-tong, CAO Wei, XU Jin-jiang, LI Hong-zhen

  Online:March 17, 2023  DOI: 10.11943/CJEM2022291

  Abstract(18) HTML(166) PDF(3.73 M)( 77)

  Abstract:The Laser-induced Air Shock from Energetic Materials （LASEM）， a laser-induced air shock performance test method based on milligram-scale energetic materials on microsecond time scales， was combined with a pulsed laser system and high-speed ripple shadowing. The effects of different particle sizes and different stacking densities on the characteristic velocities of shock waves from five energetic materials （CL-20， HMX， RDX， FOX-7， LLM105） were investigated. The results show that when the particle size is less than 75 μm， the measurement results deviation is large. When the particle size is in the range of 75-500 μm， the measurement results are less volatile and consistent with the order of the burst pressure value， which can be used as reference data to assess the actual burst performance. When the bulk density is less than 0.7 g·cm^-3， the measurement results fluctuate in a wide range. When the bulk density is in the range of 0.7-1.35 g·cm^-3， the measurement results are more stable and consistent with the order of the burst pressure value， and thus the measurement value is more valuable.

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• Reaction Initiation Mechanism of Caged Energetic Crystals under Shock Compression from ab initio Molecular Dynamics

  SONG Qing-guan, ZHANG Lei, MO Ze-yao

  Online:March 17, 2023  DOI: 10.11943/CJEM2023017

  Abstract(9) HTML(136) PDF(2.27 M)( 54)

  Abstract:Energetic molecules with caged-like backbones， owning additional strain energy and stability， are potential candidates for optimizing the long-known contradiction between high energy density and low sensitivity of energetic materials. However， the reaction mechanism of caged energetic materials under shock compression is still unclear. Here， a series of ab initio molecular dynamics calculations were conducted to simulate the early decay of typical caged energetic compounds when compressed by shock waves of 8 to 11 km·s^-1，and the studied compounds included octanitrocubane （ONC）， hexanitrohexaazaisowoodethane （CL-20）， 4，10-dinitro-2，6，8，12-tetraoxa-4，10-diazatetracyclododecane （TEX）， and the reference plane system triaminotrinitrobenzene （TATB）. The shock sensitivity of the four studied systems was calculated as ONC > CL-20 > TEX > TATB， which is in good agreement with reference experimental shock/impact sensitivity tests. The reaction initiation mechanism was revealed （i） The presence of electron-rich oxygen/nitrogen elements increases electron delocalization over the cage and the proper degree of freedom of the covalent bonds confers them additional elastic deformation capacity upon shock stimulus， both enhance the structural stability of hetero-cage， （ii） the dissociation of the nitro groups takes precedence over the collapse of the hetero-cage， which can delay the reaction process and reduce the shock sensitivity， and （iii） intermolecular hydrogen bonds （HB） is highly plastic deformable and enriched HB can delay the onset of reactions by buffering shocks. The current study proposed that the hetero-cage backbone with enhanced electron delocalization effect and proper degree of freedom， and the enriched intermolecular hydrogen bonding interactions can reduce the shock wave sensitivity， thereby providing theoretical guidance for the rational design of novel insensitive energetic materials.

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• Preparation and Properties of Inkjet Printing Silver Film Bridge

  YI Zhen-xin, LI Lin, WEI Meng-yan, ZHU Shun-guan, LI Yan, ZHANG Lin

  Online:March 16, 2023  DOI: 10.11943/CJEM2022205

  Abstract(6) HTML(84) PDF(2.44 M)( 54)

  Abstract:In order to solve the problems of long time consumption， high cost and low material utilization in the deposition and forming methods of commonly used thin-film energy conversion component， silver film bridge were prepared by inkjet printing. The morphology and thickness of the silver film bridge were test by scanning electron microscopy （SEM） and atomic mechanics microscopy （AFM）， and the ignition performance was studied. The results show that the thickness of the silver film bridge is 2.1 μm， and the surface roughness is good. The performance test results show that the silver film bridge has two situations of electric heating and electric explosion under different input energy. Under 47 μF pulse discharge， the 50% ignition voltage of the silver film bridge dipped with lead stiphenate （LTNR） is 6.65 V. and the foot-to-foot can withstand 25 kV electrostatic discharge （discharge capacitance is 500 pF， 5 kΩ resistor in series）， which can pass the 1A1W5min test of insensitive electric initiating device.

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• Research Progress on Green Primary Explosive Copper（Ⅰ） 5-Nitrotetrazolate （DBX-1）

  NI De-bin, HOU Jian, REN Wei, JIA Yu-xin, ZHANG Meng-yao, CHEN Li, YU Guo-qiang

  Online:March 16, 2023  DOI: 10.11943/CJEM2022210

  Abstract(6) HTML(86) PDF(2.58 M)( 55)

  Abstract:Copper（Ⅰ） 5-Nitrotetrazolate （DBX-1） is a green primary explosive without toxic heavy metal， which has been always attracted much attention since its discovery. DBX-1 is considered to be the most likely to replace lead azide （LA） as a result of its suitable ignition sensitivity， excellent detonation ability and output ability， good compatibility and temperature resistance. Sodium 5-nitrotetrazolium （5-NaNT） is the starting material for the preparation of DBX-1. This work addresses the synthesis problems of 5-NaNT based upon the review on the research progress of DBX-1. This article introduces both the development process of DBX-1 from laboratory synthesis to 100-gram preparation and the synthetic path evolution of 5-NaNT. Here is mainly focused on the synthesis method， performance evaluation and verification of DBX-1.Finally， it points out that some key issues must be cracked before application， such as the synthesis of 5-NaNT with safety and efficiency， the optimal technology of preparation， the sensitivity adjustment of DBX-1.

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• Synthesis and Characterization of 6-nitro-2-oxa-6-azaadamantane-4，8-diol dinitrate

  LIU Yun-zhi, CAI Rong-bin, HOU Tian-jiao, WANG Gui-xiang, LUO Jun

  Online:March 15, 2023  DOI: 10.11943/CJEM2022264

  Abstract(9) HTML(96) PDF(908.97 K)( 80)

  Abstract:A novel cage-like energetic compound， 6-nitro-2-oxa-6-azaadamantane-4，8-diol dinitrate， was synthesized from 1，5-cyclooctadiene via oxidative cyclization， O-acylation， elimination， epoxidation， aminolysis and nitration with an overall yield of 20.7%. The single crystal structure of 6-nitro-2-oxa-6-azadamantane-4，8-diol dinitrate was obtained by X-ray single crystal diffraction. Its structure was characterized using NMR， IR， and elemental analysis. Thermogravimetric analysis （TG） and differential scanning calorimetry （DSC） were used to study the thermal stability of the target compound. Density functional theory method was used to study the detonation properties of the target compound. Result show that it has a density of 1.75 g·cm^-3， a thermal decomposition temperature of 184 ℃， a detonation velocity of 7730 m·s^-1， and a detonation pressure of 26.07 GPa.

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• Reactive Characteristics of La₂O₃-Doped Al/CuO Thermite

  CHEN Zhi-yi, SHI An-ran, ZHANG Wei, SHEN Rui-qi, YE Ying-hua

  Online:March 14, 2023  DOI: 10.11943/CJEM2022245

  Abstract(18) HTML(134) PDF(2.44 M)( 82)

  Abstract:To investigate the effect of doping La₂O₃ on the reactive characteristics of Al/CuO thermite， Al/CuO powders with equivalent ratio（φ） of 1.0， 1.4 and 1.8 doped with different content of La₂O₃ were prepared by mechanical mixing method. The samples were characterized by scanning electron microscope（SEM）， X-energy dispersive spectrometer（EDS）， X-ray diffractometer（XRD） and differential scanning calorimetry（DSC）， respectively. Combustion and gas production performances were evaluated by using flame propagation experiment， T-jump ignition and pressure cell test. The results show that the initiation reaction temperature and the peak temperature for the Al/CuO thermite doped with La₂O₃ were significantly lower than those of Al/CuO thermite powders without doping La₂O₃ at φ=1.4. The heat release of Al/CuO thermite was 1772 J·g^-1 when 2% La₂O₃ was doped， which increased by 15.1% compared with that of the undoped Al/CuO thermite （~1540 J·g^-1）. The combustion rate of Al/CuO thermite with 2% La₂O₃ was 90.8 m·s^-1 at φ=1.0， which was 46.7% higher than that of the undoped Al/CuO thermite （61.9 m·s^-1）. The ignition temperature of Al/CuO thermite was also raised when La₂O₃ was added. It is suggested that La₂O₃ improved the gas production performance of Al/CuO thermite to varying degrees. The peak pressure of Al/CuO thermite formulated at φ=1.0 and φ=1.8 increased by 34.5% and 13.7%， respectively. The effect of equivalent ratio at φ=1.4 on peak pressure of Al/CuO thermite was unclear. The combustion results indicated that doping La₂O₃ will alter the flame propagation mode of Al/CuO thermite. The combustion state was observed to be changed from deflagration to slow combustion with the increase of La₂O₃. The inclusion of La₂O₃ in Al/CuO thermite is suggested to be used as a means to control the propagation velocity and energy release.

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• Synthesis and Performance of High-Energy Oxidizer ONPP

  YAN Chao, SUN Rui, ZHU Jin-li, REN Xiao-ting, LU Yan-hua, HE Jin-xuan

  Online:March 14, 2023  DOI: 10.11943/CJEM2022275

  Abstract(5) HTML(124) PDF(973.31 K)( 85)

  Abstract:For the problems of low nitrification yield and the use of highly toxic substances in the synthesis of high?energy oxidant 1，4?bis（trinitromethyl）?3，6?dinitropyrazole［4，3?c］pyrazole （ONPP）， a new synthetic process of ONPP was developed. The single crystal of ONPP was cultivated by slow evaporation from an ethyl acetate solution. The energy levels of different formulations based on ONPP were estimated. In the presence of base and phase transfer catalyst Bu4NBr (TBAB), 3, 6-dinitropyrazole [4, 3-c] pyrazole （DNPP） reacted with bromoacetone to introduce two acetone groups on pyrazole ring. Followed by nitrating with HNO3/H2SO4/P2O5， ONPP was obtained in the total yield of 31%. Compared with the literature （10.4% total yield from two steps）， the yield of new synthetic route from DNPP increase by nearly three times. Meanwhile the use of highly toxic butenone is avoided， which is more suitable for large?scale production. The crystal structure of ONPP belongs to the monoclinic crystal system， P21/c space group. Its crystal density is 1.983 g cm-3 at 293 K. Through the energy estimation of HTPB （10%）， Al （20%） and oxidizer （70%） formulations， the energy level is optimal when ONPP （40%） and AP （30%） are used together as oxidizers， which is significantly higher than the formulation energy levels when they used as single oxidant.

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• Failure Causes and Restraining Method of Fiber Contact Laser Ignited Initiators in Temperature Alternation

  XIAN Ming-chun, TONG Le-le, JIAO Jin-fu, XIE Jun-yao, ZHANG Yue-ping, MENG Yan-gang, CHEN Yong, ZHOU Bin, SHEN Rui-qi

  Online:March 14, 2023  DOI: 10.11943/CJEM2022218

  Abstract(9) HTML(144) PDF(1.52 M)( 95)

  Abstract:In order to explore the influence of temperature impact and cycling on ignition time of laser pyrotechnics，the laser initiators with carbon doped tetraammine bis（5-nitrotetrazolato） cobalt（Ⅲ） perchlorate （BNCP） as primary explosive and fiber-window structure are employed to study performance of BNCP， structure change of laser initiators and structural constraint between fiber and explosive under different temperature alternating experiments （47 h and 94 h）. The experiment results show that the ignition time can reach less than 0.2 ms indicated a great ignition performance before temperature alternating experiment. However， the ignition time delayed more than 0.5 ms after 47 h temperature alternating experiment and some initiators delayed more than 1 ms even misfired after 94 h temperature alternating experiment. The crystal grains of BNCP broke up and the bulk density decreased from 0.43 g·cm^-3 to 0.32 g·cm^-3 after alternating temperature experiment. However， the change of bulk density has no influence on thermal decomposition and ignition performance. The difference of expansion coefficient between ceramic fiber optic components and igniter shell leads to a gap between fiber and doped BNCP during alternating temperature experiment. The gap has a great influence on both laser spot intensity and hot spot diffusion. With structural constraints of fiber and explosive increasing， the ignition gap can decrease effectively during alternating temperature environment and the environment adaptability of laser initiators can be improved.

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• Design of a MEMS Ignition Device with a Double-layer Barrier Electro-thermal Safety and Arming Device

  WANG Ke-xin, HU Teng-jiang, ZHAO Yu-long, REN Wei

  Online:March 13, 2023  DOI: 10.11943/CJEM2022211

  Abstract(11) HTML(78) PDF(1.44 M)( 96)

  Abstract:In order to achieve the high safety of ignition device and micro package volume， a MEMS ignition device has been designed with a double-layer barrier electro-thermal safety and arming devicein this work. The device is of three core components including an igniter， a safety and arming device， and an ignition powder， all of which are assembled linearly within an overall size of Φ10 mm×3.3 mm. The S&A device has a double-layer structure with bistable function. The frontend initiator， which is fabricated on a ceramic circuit board， is a NiCr bridge foil to be covered with an Al/CuO energetic film. The two pads from the circuit board lead the bridge foil electrode to the backend device， thereby reducing the package volume of the sequence. BPN is selected as the ignition powder in the device. According to the safety and arming function test， the ignition device can prevent the igniter from lighting the ignition powder in safety condition， when the size of the Al/CuO is set to Φ800 μm×30 μm. Otherwise， the BPN ignition powder can be ignited in arming condition.

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• Experimental Study and Numerical Analysis of Dynamic Engraving Characteristics of Nylon Belt

  YANG Ming, YU Yong-gang

  Online:March 09, 2023  DOI: 10.11943/CJEM2022208

  Abstract(8) HTML(54) PDF(3.73 M)( 136)

  Abstract:The launching device of 105 mm short tube gun was designed to carry out the armor piercing projectile test under dynamic shooting condition. Transient pressure measurement system and high-speed camera were used in the experiment to obtain the chamber pressure and projectile motion parameters during the engraving process. The engraving resistance characteristic curves of projectile were calculated by projectile dynamics equation. Besides， the influence of different pressure rise rate on the process of projectile engraving was analyzed under two conditions. Based on the test conditions， the engraving deformation process of nylon belt of armor piercing projectile was numerically simulated by using the C-S model with elastic-plastic large deformation of belt material. The experimental data indicated that the engraving resistance increases first and then decreases with the engraving displacement in the engraving process. Therefore， when the engraving resistance reaches the maximum， only part of the nylon belt was completely squeezed. The elasticity of the nylon elastic band increases the contact area with the groove. When the average pressure rise rate of projectile bottom increases from 2.92 to 3.28 MPa·ms^-1， the engraving time shortens by 4.36% and the maximum engraving resistance increases by 9.03%. The nylon belt cross deformation stress cloud diagram was obtained by the numerical calculation to show that the elastic-plastic deformation of the nylon belt occurred. The interior of the elastic belt is mainly in the state of compression shearing and the main failure form of the elastic belt is tensile shearing failure. The displacement curves and resistance curves obtained by simulation and experiment have the same trend and the errors are 5.3% and 8.9%， respectively.

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• Molecular Dynamics Simulation on the Effects of Vacancy Defects on the Sensitivity， Mechanical Properties and Detonation Performance of TKX-50

  GUO Zhi-wei, Hao Ga-zi, Hu Yu-bing, Feng Xiao-jun, Yang Jun-qing, Jiang Wei

  Online:March 06, 2023  DOI: 10.11943/CJEM2022274

  Abstract(28) HTML(184) PDF(2.78 M)( 161)

  Abstract:Molecular dynamics simulations were used to investigate the effects of a series of vacancy defect concentrations (0%, 1.56%, 6.25% and 12.5%) on the sensitivities, mechanical properties and bursting properties of dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50). Firstly, perfect crystal model and vacancy defect models were first constructed, and the correctness and validity of the Dreiding force field used in the study were verified. Then the models were geometrically optimized and molecular dynamics simulated, and the trajectory files to reach thermodynamic equilibrium were statistically and analytically analyzed. It was found that vacancy defects lead to decreases in the cohesion energy density and in the number of total hydrogen bonds of TKX-50, indicating that TKX-50 containing vacancy defects has increased susceptibility and decreased safety. And with the increase of vacancy defects, the number of hydrogen bonds between hydroxylamine cations remains almost constant, and the number of hydrogen bonds whose hydrogen bond acceptor is oxygen atom on bitetrazolium anion is significantly reduced compared with other hydrogen bonds. Besides, the vacancy defects reduce the bulk modulus (K), elastic modulus (E), and shear modulus (G) of TKX-50 by 1.530~4.122 GPa, 3.066~10.652 GPa, 1.216~4.202 GPa, respectively. It indicates that the stiffness of TKX-50 crystal decreases with the increase of vacancy defect concentration. The positive Cauchy pressure (C12-C44) of all models indicates that all models exhibit ductility, and the values of K/G and Poisson's ratio (γ) increase with the increase of vacancy defect concentration, indicating that the toughness and plasticity of TKX-50 are enhanced by the increase of vacancy defects. In addition, the vacancy defects also reduce the detonation velocity and detonation pressure of TKX-50 by 93~317 m·s-1 and 1.0~3.5 GPa, respectively, indicating that the damage power of defect crystals is reduced.

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• Thin Film Transducer Chip with an Integrated PN Junction Protective Structure

  LI Hui, LUO Jian-jun, REN Wei, FENG Chunyang, CHU En-yi, CHEN Jian-hua, LI Jiao

  Online:March 01, 2023  DOI: 10.11943/CJEM2022278

  Abstract(28) HTML(92) PDF(1.56 M)( 206)

  Abstract:The planar thin film transducer chip was designed with longitudinally integrated PN junction structure diode， and integrated through microelectronics technology for excellent security performance and high integration characteristics. Each of three different-sized chips with 1.0 mm×1.0 mm，1.5 mm×1.5 mm and 2.0 mm×4.0 mm， were designed under four breakdown voltages of 8， 18， 28， 34 V， and two kinds of resistance ，3 Ω and 4 Ω. The ignition tests were carried out on the integrated chip to study the impact of the integrated structure on the burst performance of the transducer. Results from the static electricity of these chips show that the larger the size of the integrated thin film chip is， the stronger the antistatic ability， the greater the resistance in the bridge area of the chip， and the more vulnerable to electrostatic interference are. The electrostatic protection performance of designed chip can reach 500 pF/500 Ω/25 kV. The smaller the breakdown voltage is， the greater the bypass current capacity， the greater the impact on the burst performance of the transducer， and the greater the breakdown voltage， but the smaller the electrostatic protection effect are on the energy converter. For initiating explosive devices to be ignited under 33 μF/16 V， the integrated chip with an 18V breakdown voltage should be selected. Therefore， when the integrated thin film chip is applied， it is necessary to select an appropriate breakdown voltage according to the working voltage of the transducer for both a protection against static interference and a necessary avoidance in failure of its normal function.

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• Oxidation Behavior and Energy Performance of the Spherical Al-25W Alloy Fuel Powder

  HU Ao-bo, CAI Shui-zhou, ZOU Hui

  Online:February 17, 2023  DOI: 10.11943/CJEM2022294

  Abstract(45) HTML(134) PDF(4.45 M)( 345)

  Abstract:In order to obtain a new type of alloy fuel with excellent thermal oxidation and energy release performance， the spherical aluminum-tungsten alloy fuel powder （Al-25W） was prepared by the combination of aluminothermic reduction and ultra-high temperature gas atomization. The phase structure， oxidation behavior， and energy properties of the new powder were studied. The results show that the metastable Al/W alloy phase in the spherical Al-25W alloy powder particles is uniformly distributed in the pure Al matrix， and transform into the Al₁₂W phase after the stabilization treatment， and the energy is released to the outside. The spherical Al-25W alloy powder has higher oxidation heat release and oxidation weight gain than pure Al powder. It can be completely oxidized in air at 1400 ℃， with all W atoms oxidized to WO₃ and volatilized in the gaseous form. The residual oxidation product is only Al₂O₃. The measured volumetric combustion enthalpy of the spherical Al-25W alloy powder is higher than that of pure Al powder （83000 J·cm^-3） calculated theoretically， up to （83132.1±608.5） J·cm^-3， and the gaseous combustion product WO₃ is generated during the violent combustion.

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• Effect of Biodiesel on Thermal Decomposition Characteristics and Anti-vibration Performance of On-site Mixed Emulsion Explosives

  YANG Ce, LI Hong-wei, YANG Sai-qun, SUN Jian-hui, ZHANG Bin-bin

  Online:February 17, 2023  DOI: 10.11943/CJEM2022262

  Abstract(26) HTML(96) PDF(2.34 M)( 307)

  Abstract:In order to explore the effect of biodiesel on the thermal decomposition characteristics and vibration resistance of on-site mixed emulsion explosives， the microscopic structure， thermal decomposition characteristics and vibration resistance of the matrix samples of on-site mixed emulsion explosives with biodiesel as the oil phase material were studied by laser particle size analyzer， optical microscope， synchronous thermal analysis technology， vibration experiment and water dissolution method， in which the mass contents of biodiesel were 0%， 1%， 2% and 3%， respectively. The results show that the average particle size of the on-site mixed emulsion explosive matrix samples with biodiesel is smaller， the uniformity of the internal phase particles is better， and the average particle size and dispersion index are reduced by 12.9% and 38.0% respectively， compared with the sample without biodiesel. When the mass content of biodiesel in the sample is 3%， the initial temperature， peak temperature and activation energy of the decomposition reaction are reduced by 5.8%， 3.7% and 12.3%， respectively， compared with the in-situ mixed emulsion explosive matrix sample without biodiesel， indicating that the thermal stability is reduced. The anti-vibration performance of the on-site mixed emulsion explosive matrix sample with 3% biodiesel is the worst. The dissolution loss rate increases from 0.117% to 0.313% after 6 vibration periods， and the crystallization phenomenon appears after 4 vibration periods. The on-site mixed emulsion explosive matrix sample with 1% biodiesel has the best anti-vibration performance. After 6 vibration periods， the dissolution rate increases from 0.070% to 0.197%， and no crystallization occurs. When the content of biodiese is 1%， the average particle size of the internal phase is small， the distribution uniformity is good， the thermal safety is high and the vibration resistance is the best.

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• Advances in the Application of Hyphenated Techniques in the Thermal Analysis of Energetic Materials

  WANG Chen, WAN Chong, CHEN Su-hang, MA Hai-xia, ZHAO Feng-qi, XU Kang-zhen

  Online:February 14, 2023  DOI: 10.11943/CJEM2022111

  Abstract(76) HTML(298) PDF(1.21 M)( 392)

  Abstract:Hyphenated techniques of thermal analysis， including common thermogravimetric-differential scanning calorimetry （TG-DSC）， thermogravimetric-infrared/mass spectrometry （TG-FTIR/MS）， Fourier transform infrared spectroscopy/solid-state in situ reaction techniques （Thermolysis/RSFTIR） and thermogravimetric-infrared-mass spectrometry （TG-FTIR-MS）， are effective ways to study the thermal decomposition properties and mechanisms of energetic materials. Compared to the single thermal analysis techniques， the hyphenated techniques of thermal analysis are more adequate， efficient and comprehensive ways to evaluate the thermal behaviors and thermal stability and to reveal the thermal decomposition mechanism of energetic materials. A comprehensive and in-depth study of the physicochemical properties of energetic materials by hyphenated techniques of thermal analysis is of great practical significance and value in improving and enhancing the performance of energetic materials in applications. Herein， this paper presents a comprehensive review of the advance in the application of TG-DSC， TG-MS， TG-FTIR-MS， TG-FTIR-GC-MS and Thermolysis/RSFTIR hyphenated techniques in the study of energetic materials. The research contents， important results， features and advantages of these techniques are analyzed， and related perspectives are presented， such as developing high-performance computational analysis software， solving the problems such as the deconvolution of overlapping mass spectral peaks in mass spectral analysis， and introducing a new extension system in the thermal analyzer to expand the scope of their application， thus providing technical support for the thermal analysis of new energetic materials.

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• Thermal Protection and Explosive Performance of Charge Structure with Thermally Insulating Colloid

  WANG Fei, MA Hong-hao, SHEN Zhao-wu

  Online:January 13, 2023  DOI: 10.11943/CJEM2022199

  Abstract(73) HTML(0) PDF(2.11 M)( 640)

  Abstract:In order to study the safety protection issues and explosion characteristics of colloidal charge structure under high temperature environment， the charge structure consisting of a thermally insulating outer layer， an endothermic colloid and an emulsion explosive was designed. The effects of three colloid proportions and two sensitizing modes （emulsion explosives are sensitized by sodium nitrite and expanded perlite respectively） of explosive in the charge structure on thermal insulation and explosion performance were studied by physical property measurement， thermometric analysis， explosion testing technology （underwater explosion， detonation velocity experiment， near-field detonation pressure measurement） and field experiment （sympathetic detonation， blasthole blasting）. The results show that the colloidal material containing 0.5% high molecular water-absorbent resin is suitable for the charge structure， attributing to the fire resistance， high specific heat and low thermal conductivity， which extends the thermally insulating protection time to 55 min. In underwater explosion and detonation velocity experiments， as the heating time of 100 ℃ water bath increases， all detonation parameters （peak shock wave pressure， specific impulse， detonation velocity， and total explosive energy） of the charge of two sensitizing modes decrease. Affected by the demulsification of emulsion explosive and the reduction of sensitization hot spots， the detonation performance of emulsion explosive sensitized by sodium nitrite （EE-SN） is attenuated greater than that of emulsion explosive sensitized by expanded perlite （EE-EP）. After heating for 2 hours， the total explosive energy loss of EE-EP and EE-SN is 4.76% and 17.62%， respectively. In the near-field explosion pressure measurement of colloidal medium， the colloidal layer in charge structure will weaken the strength of explosion shock wave. However， the blasting effect is good in the field experiment， and the charge structure has realized the 30 mm sympathetic detonation and the stable detonation propagation in the blast hole， indicating that the colloidal charge structure has a good application prospect for high-temperature blasting.

• Simulation Study on the Effects of the Process Parameters of Sequential Solidification on the Quality of Casting Charge

  NIU Kai-bo, CAO Hong-song, LIU Heng-zhu, SHI Hui-fang, WANG Zhao-guo, YI Mao-guang

  Online:January 05, 2023  DOI: 10.11943/CJEM2022136

  Abstract(94) HTML(162) PDF(1.78 M)( 676)

  Abstract:Sequential solidification process has a great application prospect in casting explosives. In order to study the correlation between process parameters and charge quality， a simulation study of sequential solidification process was carried out， based on the moving boundary modeling method， where TNT/RDX （33.8/65） was taken as an illustration example. The effects of process parameters， such as water injection speed（0.15， 0.20， 0.25 mm·s^-1）， water temperature（30， 40， 50 ℃）and preheating temperature（60， 70， 80 ℃）， on temperature field and shrinkage defects in the solidification process were studied， based on three-factor orthogonal tests， and a optimized process parameter program was obtained. It can be seen that water injection speed has the greatest impact on charge solidification quality， followed by the water temperature and preheating temperature of mold. Compared with experimental program（water injection speed is 0.15 mm·s^-1， water temperature is 50 ℃）， preheating temperature is 70 ℃）， the optimized program of orthogonal tests（water injection speed is 0.15 mm·s^-1， water temperature is 50 ℃， preheating temperature is 60 ℃） reduces the shrinkage volume by 74%. This implies that the matching of process parameters is an effective method in improving charge solidification quality in the future. The simulation results and experimental design methods in this paper can provide references for process parameter matching optimization of charge solidification.

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• Synthetic Progress of Furazan based Polycyclic Energetic Compounds

  SHI Jun-hao, ZHANG Wen-quan, ZHANG Qing-hua

  Online:December 28, 2022  DOI: 10.11943/CJEM2022187

  Abstract(127) HTML(260) PDF(1.62 M)( 820)

  Abstract:Polycyclic structures with high nitrogen content exhibit great potential in balancing the contradiction between energy and safety of energetic compounds. As an important structural unit for the design of high nitrogen content polycyclic energetic molecules， furazan has the characteristics of good stability， high nitrogen content， high positive enthalpy of formation and good oxygen balance tendency. The design and synthesis of polycyclic energetic compounds containing furazan unit have become a focus that has been studied extensively and deeply in the research field of energetic materials. This review article summarized and evaluated the molecular structures， synthetic methods， physicochemical properties of furazan based polycyclic energetic compounds. Meanwhile， the potential applications of these compounds in high energy and low sensitivity explosives， heat-resistant explosives and primary explosives were also prospected， providing a reference for the design and synthesis of new polycyclic energetic compounds.

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• Research Progress on Efficiency Improvement of Electrical Initiator Transducers

  GU Bo-nan, XU Jian-yong, SHI Wei, SONG Chang-kun, YU Chun-pei, CHENG He, YE Jia-hai, REN Wei, ZHANG Wen-chao

  Online:December 07, 2022  DOI: 10.11943/CJEM2022216

  Abstract(89) HTML(196) PDF(2.60 M)( 941)

  Abstract:As the core components of electrical initiators， transducers are essential for the safety and reliability of electrical initiators. The development trends of miniaturization of the structure of electrical initiators， informatization the transducing process and integration of the firing sequence have put forward higher requirements for transducers. How to realize reliable ignition under low energy stimulation and enhance the ignition output capacity has become one of the major issues for the current research of transducers. To this end， this review summarized the latest research progress on the low-energy firing and output efficiency enhancement of electrical initiator transducers in recent years from the perspectives of the preferential selection of transducer substrate and resistive materials， the optimal design of firing structure， the efficiency enhancement of self-contained energetic integration and energetic film composite. On this basis， the focuses of future research on the efficiency enhancement of transducer are discussed： establishing a gene pool of transducer material parameters， improving the efficiency of transducer firing structure optimization design by means of machine learning algorithms， conducting basic research on novel transducer systems such as wide-bandgap semiconductor materials， and exploring the integration of novel energetic films such as energetic Metal-Organic Frameworks （MOFs） and chalcogenide on transducers.

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• Effect of RDX Content on Thermal Safety of Modified Double base Propellant

  CHENG Wan-li, GAO Peng, LV Chun-ling, YU Si-yu, LIU Meng-hui, XIE Mu-yang

  Online:November 18, 2022  DOI: 10.11943/CJEM2022194

  Abstract(118) HTML(210) PDF(1.98 M)( 1011)

  Abstract:In order to explore the thermal safety characteristics of modified double base propellants， the thermal decomposition behaviors of modified double base propellants with RDX content of 0， 18%， 46% and 54.6% were studied by differential scanning calorimetry （DSC） respectively， and the thermal decomposition temperatures at different heating rates （2， 5， 10 and 20 ℃·min^-1）were obtained. The apparent activation energy， activation pre-exponential factor， reaction rate， Gibbs free energy， activation enthalpy and activation entropy were calculated by thermal reaction kinetics analysis， and the influence of RDX content on the double base components and apparent activation energy was also analyzed. The response characteristics of modified double base propellants with different RDX contents were obtained by slow cook-off and 5 s burst point temperature tests. Results showed that when RDX content is 18%， the apparent activation energy is the highest， and the response temperature and the response intensity of slow cook-off test and 5 s burst point temperatures all are the lowest. The first decomposition peak temperature of samples moved backward， the apparent activation energy decreased， the slow cook-off response temperature moved to higher temperature， the thermal sensitivity of the system decreased， but the response level increased with the increase of RDX content. The response level is explosion， which could not pass the slow cook-off test when the RDX content is 46% or above. The 5 s burst point temperature moves towards high temperature with the increase of RDX content and presents a significant rising trend， and the thermal stability of modified double base propellants is improved.

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• Quantum Chemistry Database of Energetic Compounds： Design and Application

  HUANG Xin, ZHANG Chao-yang

  Online:November 04, 2022  DOI: 10.11943/CJEM2022177

  Abstract(145) HTML(126) PDF(1.11 M)( 1075)

  Abstract:Data derived from high-accuracy quantum-chemistry calculations play a significant role in designing， synthesizing， and characterizing energetic compounds. Therefore， constructing a quantum-chemistry database of energetic compounds， which collects high-accuracy quantum-chemistry calculation data， can circumvent massive duplicated calculation research and resource consumption. In addition， such an approach guarantees the quality of data， facilitates in-depth analysis and data mining， and obtains reliable analytical and predictive models for the structures and properties of energetic compounds. This review summarized data related to critical structures and properties of energetic compounds from quantum-chemistry calculations and the development of molecular design using a database and high-throughput virtual screening technique. The design and application of the quantum-chemistry database of energetic compounds were envisioned， including （1） the establishment of calculation standards and prediction models to generate customized data in the field of energetic materials； （2） the construction of an open and shared database to join high-throughput virtual screening； and （3） the development of database management systems to realize data inquiry， acquisition， and data mining. It is hopeful to provide insights for the design and practical application of the quantum-chemistry database of energetic compounds.

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• Progress in the Synthesis and Properties of Fluorodinitromethyl Energetic Compounds

  WANG Shao-qing, YIN Hong-quan, MA Qing, CHEN Fu-Xue

  Online:October 21, 2022  DOI: 10.11943/CJEM2022159

  Abstract(114) HTML(218) PDF(2.04 M)( 1103)

  Abstract:The introduction of fluorodinitromethyl group into energetic molecules can not only improve oxygen balance， density and explosive performance， but also increase thermal decomposition temperature and reduce sensitivity. The construction of energetic compounds containing fluorodinitromethyl groups has become a hot research topic in the field of high energy dense and insensitive materials. By reviewing the energetic compounds containing fluorodinitromethyl groups in the past two decades， we analyzed and compared the molecular structures， summarized the synthesis methods of fluorodinitromethyl-containing compounds， physicochemical and explosive properties of these compounds， providing some references for the molecular design and synthesis of novel fluorodinitromethyl substituted compounds.

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• Effects of Temperature on the Electrical Explosion of SCB

  WANG Cheng-ai, XU Jian-bing, SHEN Yun, WANG Yue-ting, SHEN Rui-qi, YE Ying-hua

  Online:September 26, 2022  DOI: 10.11943/CJEM2021226

  Abstract(87) HTML(304) PDF(1.52 M)( 1380)

  Abstract:To investigate the effects of temperature on the electrical explosion and ignition of semiconductor bridge （SCB）， the electrical explosion characteristics and ignition performance of SCB with the ambient temperature of 25 ℃ and -40 ℃ were studied by a capacitive discharge method， and a mathematical model was established. The ignition temperature of Al/CuO nanothermite was tested at ambient temperature of 25 ℃ and -40 ℃， respectively. The ignition sensitivity of SCB was measured by the D-optimization method. When the charging voltage increases from 30 to 50V， the difference of critical initiation time reduced from 0.47 to 0.25 μs. The difference of critical initiation energy increased from 0.16to 0.65 mJ. Results shown that with the increase of charging voltage， the influence of ambient temperature on the critical initiation time decreased， and the influence on the critical initiation energy increased. Both the ignition temperatures of Al/CuO nanothermite at 25 ℃ and -40 ℃ are 740.7 ℃. The 50% ignition voltage at ambient temperature of 25 ℃ is 0.6 V lower than that at -40 ℃.

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• Review on Energetic Compounds Based on Triazoles

  LIU Yang, CHEN Ya-hong, GOU Rui-jun, ZHANG Shu-hai

  Online:August 26, 2022  DOI: 10.11943/CJEM2022131

  Abstract(194) HTML(362) PDF(4.09 M)( 1825)

  Abstract:Triazole-based energetic compound is a new class of energetic materials with the features of high heat of formation， high nitrogen content and good thermal stability. In this paper， the latest research achievements on synthesis of more than 40 series of energetic compounds based on mono-triazole， bis-triazole， pyrazole-triazole， oxadiazole-triazole and tetrazole-triazole were reviewed， and the performances of some compounds were introduced in detail. It is showed that designing new triazole-based energetic compounds based on structure-performance relationship and balancing energy and safety are the effective strategy to develop high energy and insensitive energetic compounds. On this basis， design and synthesis of cage triazole-based energetic compounds are the promising developing direction. The application study of existing triazole-based energetic compounds with outstanding overall performance is proposed.

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• Shock Initiation Measurement of RDX-based Aluminized Explosives with Reverse-impact Method

  PEI Hong-bo, LI Shu-rui, GUO Wen-can, ZHANG Xu, ZHENG Xian-xu

  Online:July 15, 2022  DOI: 10.11943/CJEM2021285

  Abstract(103) HTML(258) PDF(1.24 M)( 1801)

  Abstract:A new shock initiation measuring system is developed with the reverse-impact method， in which the explosive sample was driven by a gas gun and impacted the LiF window at a certain speed. The photonic Doppler velocimetry （PDV） was used to measure the interfacial particle velocity profile between the explosive sample and the LiF window. This measuring system has higher accuracy （3%）， higher time resolution （5 ns） and lower requirement of explosive samples than previous shock initiation measuring methods. Moreover， to explore the effect of aluminum powder， the shock initiation characteristics of three RDX-based aluminized explosives （RDX/Al） with different contents of aluminum powder （0， 15% and 30%） were investigated by this measuring system. The experimental data indicates that with the same impacting speed， the shock initiation reaction growth becomes slower with a higher content of aluminum powder. The interfacial particle velocity of the RDX-based aluminized explosive with 30% aluminum powder requires more time to arrive at a peak value， which is 47% longer than that of the RDX explosive. The aluminum powder makes the shock sensitivity significantly decrease and it plays a dilute role in explosive energy during the shock initiation process of aluminized explosives.

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Vol, 31, No.2, 2023    

>Preparation and Property

• Synthesis and Characterization of 4，8-Di（2，4，6-trinitro-3，5-diaminophenyl）difurazanopyrazine

  ZHANG Qian, DUAN Bing-hui, TAN Bo-jun, LU Xian-ming, WANG Bo-zhou, LIU Ning

  2023,31(2):107-113, DOI: 10.11943/CJEM2022248

  Abstract(69) HTML(25) PDF(1.21 M)( 355)

  Abstract:In order to explore new energetic material with both good thermal stability and high safety performance， 4，8-di（2，4，6-trinitro-3，5-diaminophenyl）difurazanopyrazine （NADFP） was synthesized by substitution reaction using 1-chloro-2，4，6-trinitro-3，5-diaminobenzene and 4H，8H-difurazanopyrazine as raw materials. Its structure was characterized by nuclear magnetic resonance （¹H and ¹³C spectrum）， infrared spectroscopy and element analysis. The single crystal of NADFP·DMF was obtained by solvent evaporation method， and the crystal structure was determined by single crystal X-ray diffraction. Results show that NADFP·DMF belongs to monoclinic system， space group P2₁/c， a=7.854（3） Å， b=18.466（6） Å， c=11.093（3） Å， ρ=1.640 g·cm^-3. The inter-/intramolecular interactions were calculated by Hirshfeld surfaces analysis with hydrogen bond interactions accounting for 53.5%. The thermal behavior of NADFP was studied by DSC and TG/DTG methods， which show that its decomposition peaks are 337.2 ℃ and 368.8 ℃. The theoretical detonation performances and mechanical sensitivities of NADFP were investigated. The measured density is 1.81 g·cm^-3， the solid formation enthalpy is 827.1 kJ·mol^-1， the calculated detonation velocity and pressure are 7968 m·s^-1 and 36.0 GPa， respectively. The impact sensitivity is above 40 J， and the friction sensitivity is above 360 N. The overall performance of NADFP is obviously better than that of traditional heat-resistant explosive 2，2′，4，4′，6，6′-hexanitrostilbene.

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• A Simple Synthesis Method of Sodium Pentazolate

  ZHANG Si-yu, LONG Ting, LIU Tian-lin, HUANG Ming, LI Jin-yong, YANG Hai-jun

  2023,31(2):114-120, DOI: 10.11943/CJEM2022042

  Abstract(53) HTML(25) PDF(1.09 M)( 368)

  Abstract:In order to easily synthesize sodium pentazolate， the synthesis method and conditions of sodium pentazolate were studied. Diazoniums 4a-b and sodium pentazolate were characterized by infrared （IR）， nuclear magnetic resonance （NMR）， mass spectrometry （ESI-MS）， or ion chromatography （IC）. Results show that sodium pentazolate can be easily synthesized via the cyclization/C—N cleavage one-pot method； the appropriate reaction conditions for the synthesis of sodium pentazolates from diazonium chloride 4a are as follows： the molar ratio of NaHCO₃ to 2，6-dimethyl-4-aminophenol is 0.6， the cyclization temperature is -45 ℃， the cyclization time is 2 h， the C—N cleavage temperature is -35 ℃， the C—N cleavage reaction time is 24 h， and the molar ratio of m-CPBA to 2，6-dimethyl-4-aminophenol is 3∶1； the suitable reaction conditions for synthesizing sodium pentazolate from diazonium tetrafluoroborate 4b are as follows： the molar ratio of NaHCO₃ to diazonium tetrafluoroborate is 0.3， the cyclization temperature is -45 ℃， the cyclization time is 7 h， the C—N cleavage temperature is -35 ℃， the C—N cleavage reaction time is 24 h， and the molar ratio of m-CPBA to diazonium tetrafluoroborate is 4∶1； sodium pentazolate can be easily isolated by ethanol extraction， of which the purity is up to 98.87 % （area normalization）.

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• Preparation of Submicron HNS-based PBX Composite Microspheres by Droplet Microfluidics

  LIU Yi, ZHU Rui, SHI Jia-hui, HAN Kai, WU Bi-dong, AN Chong-wei, WANG Jing-yu

  2023,31(2):121-129, DOI: 10.11943/CJEM2022184

  Abstract(40) HTML(64) PDF(2.19 M)( 329)

  Abstract:In order to obtain spherical granulations with regular shape， good dispersibility and uniform particle size， the effects of different binders on 2，2"，4，4"，6，6"-hexanitrodiphenylethylene （HNS） composite microspheres were studied by using droplet microfluidic technology. Fluoroelastomer （F₂₆₀₄）， nitrocellulose （NC） and glycidyl azide polymer （GAP） were selected to prepare spherical granulation of submicron HNS， and submicron-level HNS/F₂₆₀₄ （95/5）， HNS/NC （95/5） and HNS/GAP （95/5） composite microspheres were successfully prepared. Resultant microspheres were characterized by scanning electron microscope， X-ray diffractometer， specific surface area， thermal analyzer， true density tester and mechanical sensitivity tester. Results indicated that such methods could obtain the HNS composite microspheres with high sphericity， monodisperse， narrow size distribution， good roundness and improved safety performances. The average circularities were 0.934， 0.915 and 0.925 with D₅₀ of 45.39， 58.68 μm and 45.43 μm （the span was less than 0.55）， respectively. Thermal decomposition peak temperatures were 354.44， 349.53 ℃ and 339.37 ℃ for HNS/F₂₆₀₄， HNS/NC and HNS/GAP， respectively. The spheroidization process increases the true density of the microspheres to 1.9408， 1.9383 g·cm^-3 and 1.9204 g·cm^-3， respectively， which can effectively improve the HNS charge performance. The cone angles of 27°， 24.3°， and 24° indicated that microspheres have good dispersion performances. Compared with submicron HNS， the impact sensitivity of the three microspheres was increased by 5.5， 4， 3.5 J， and the friction sensitivity was increased by 52， 36 N and 4 N， respectively， indicating a better safety performance.

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• Preparation and Properties of TNBA/TNAZ Lowest Eutectic Mixture

  YU Zhi-hong, RAO Wen-jun, SONG Xiao-lan, KOU Yong, WANG Yi, AN Chong-wei

  2023,31(2):130-141, DOI: 10.11943/CJEM2022059

  Abstract(49) HTML(35) PDF(3.79 M)( 332)

  Abstract:The eutectic mixtures of 2，4，6-trinitro-3-bromoanisole （TNBA） and 1，3，3-trinitroazetidine （TNAZ） with different mass ratios were prepared by the electrostatic spray method. T-X and H-X phase diagrams were drawn according to the differential scanning calorimetry （DSC） curves of the eutectic mixtures to obtain the mass ratio of the lowest eutectic. Scanning Electron Microscopy （SEM）， Energy Dispersive Spectroscopy （EDS）， High Performance Liquid Chromatography （HPLC）， X-ray Powder Diffraction （XRD）， Infrared （IR）， X-ray Photoelectron Spectroscopy （XPS）， DSC， and thermogravimetry-mass （TG-MS） spectrometry were used to determine the morphology， component content， element distribution， crystal structure and thermal decomposition properties of the lowest eutectic. And the mechanical sensitivity， thermal sensitivity and detonation performances of the lowest eutectic were tested and theoretically calculated. The results showed that 60.95∶39.05 is the optimal mass ratio of TNBA/TNAZ lowest eutectic mixture； the microscopic morphology has no sharp edges and corners； the component proportion is the same as before electrostatic spraying； the surface elements are evenly distributed； and the crystal structure is basically the same as that of the raw materials. The eutectic temperature is 350.18 K， which is 22.72 K and 24.82 K lower than that of raw materials TNBA and TNAZ. The thermal decomposition reaction rate constant （k）， activation enthalpy （ΔH^≠）， activation energy （E_K）， activated Gibbs free energy （ΔG^≠）， and activation entropy （ΔS^≠） of the lowest eutectic are 0.33 s^-1， 60.10 kJ·mol^-1， 64.44 kJ·mol^-1， 135.21 kJ·mol^-1， and -143.78 J·（mol∙K）^-1， respectively. The impact sensitivity （H₅₀）， friction sensitivity （FS）， and 5s explosion temperature of the lowest eutectic mixture are 42 cm， 20%， and 558 K， respectively. Its detonation performance （OB=-34.83%，Q=5101.78 kJ·kg^-1，V_D=7598.37 m·s^-1） is between TNBA and TNAZ. The main detonation products are N₂、C（d）、CO、CO₂ and H₂O.

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• The Effect of Crystallization Characteristics on Polymorphic Transformation Laws and Kinetics of CL‍-20

  WANG Zhi-qiang, ZHANG Hao-bin, LIU Yu, HU Shuang-qi, HU Li-shuang, XU Jin-jiang

  2023,31(2):142-151, DOI: 10.11943/CJEM2022122

  Abstract(54) HTML(39) PDF(1.68 M)( 353)

  Abstract:The polymorphic transformation （PT） and control technology of hexanitrohexaazaisowurtzitane （CL‍-20） has been a hot area of research in energetic materials， which is also the key issue must be addressed to promote its application. In order to further understand the PT characteristics and mechanism of ε‍-CL‍-20 with different crystallization characteristics， the PT laws and isothermal PT kinetics of ε‍-CL‍-20 were studied based on in‍-situ X‍-ray powder diffraction （XRD） technology. The effect of surface and internal defects on the ε→γ PT behavior of CL‍-20 was discussed. The isothermal PT kinetics of ε‍-CL‍-20 with different crystallization characteristics was analyzed and the related parameters were calculated. The results show that temperature is the dominant factor affecting the solid‍-solid PT of ε‍-CL‍-20. For the conventional particle ε‍-CL‍-20， with the increase of internal and surface defects in the crystal， the initial temperature of PT decreases and the PT rate increases. Compared with 100 μm CL‍-20， ultrafine （0.5-1 μm） ε‍-CL‍-20 has higher starting temperature of PT， but its PT rate is also faster. The abnormal PT behavior of ultrafine ε‍-CL‍-20 is explained from the two‍-sidedness of crystal defects. When CL‍-20 undergoes ε→γ PT under thermal stimulation， both the surface and internal defects of the crystal have an induction effect on the PT process， and the γ crystal preferentially nucleates at the defects such as vacancies， impurities or dislocations with low nucleation barrier on the ε‍-CL‍-20 crystal， and then gradually grows up at these positions.

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• Insensitivity Performance of GAP/NC-based Gun Propellants

  SONG Yu-fang, XIAO Le-qin, LI Chun-zhi, TANG Fang-yuan, LONG Yi-qiang, ZHOU Wei-liang

  2023,31(2):152-159, DOI: 10.11943/CJEM2021301

  Abstract(34) HTML(13) PDF(1.39 M)( 317)

  (Supporting information)

  Abstract:The research on low-sensitivity gun propellants has a vital impact on the survivability and safety performance of weapon system. Gun propellant （IM） with nitrocellulose （NC） and glycidyl azide polymer （GAP） as binder was prepared. N-butyl-N- nitramine （Bu-NENA） was used as low sensitive energetic plasticizer， hexogen （RDX） was used as high-energy filler and graphite as additive of thermal conductive. The physicochemical， combustion， mechanical， and sensitivity properties of the IM gun propellant were studied， and the insensitivity properties were further studied by slow cook-off， fast cook-off， bullet impact， fragment impact and sympathetic detonation tests. Results showed that the gun propellant had stable combustion performance， and the impetus was1050 kJ·kg^-1. Theoretical explosion temperature was 2677 K. The impact strength and the compressive strength were 8.2 kJ·m^-2 and 131.5 MPa at -40 ℃， respectively. The sensitivity of the gun propellant （H₅₀=62.62 cm，P=28%，V₅₀=1.95 kV） was greatly reduced compared with TEGN gun propellants（H₅₀=16.33 cm，P=100%，V₅₀=2.02 kV）. Moreover， only combustion reactions were observed in slow cook-off， fast cook-off， bullet impact， fragment impact and sympathetic detonation tests. It demonstrated that the prepared gun propellants possessed good low vulnerability characteristics.

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>Damage and Ignition

• Dynamic Damage Response of PBX with Different Coating Structures via Peridynamic Simulation

  HUANG Ya-fei, DENG Xiao-liang, BAI Jing-song

  2023,31(2):160-169, DOI: 10.11943/CJEM2022145

  Abstract(33) HTML(18) PDF(2.32 M)( 325)

  Abstract:The polymer bonded explosive （PBX） model containing different coating structures is established based on the peridynamics theory and Voronoi method. The dynamic damage behaviors of PBX under different impact speeds are simulated. The simulation results indicate that double-layer coating structure can better protect HMX crystal compared to single-layer coating structure. For single-layer coating structure， the damage mode is mainly transgranular fracture. By contrast， the damage is dominated by intergranular fracture in the case of double-layer coating structure. Moreover， for double-layer coating structure， the quantitative results on damage ratio of HMX is obtained and the performance of different coating structures is ordered. By analyzing the stress state of HMX， it is found that the coating structure can greatly impact the stress distribution. This study can help better design the coating structures in PBX.

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• Ignition and Combustion Characteristics of HATO-AP Composite

  FENG Bo, FENG Xiao-jun, ZHANG Kun, XUE Le-xing, PAN Wen, TAO Jun, WANG Xiao-feng

  2023,31(2):170-176, DOI: 10.11943/CJEM2021225

  Abstract(35) HTML(21) PDF(1.28 M)( 315)

  Abstract:The mixture and composite of dihydroxylammonium-5，5"-bistetrazole-1，1"-diolate （HATO） and ammonium perchlorate （AP） were prepared by dry-mixing and solvent-nonsolvent recrystallization， respectively. The microstructure and mechanical sensitivity of HATO， AP， HATO+AP mixture and HATO-AP composite were analyzed by scanning electron microscope （SEM） and military standard methods， and the ignition and combustion pressure characteristics of four materials mentioned above were also compared experimentally. In addition， the reaction characteristics of HATO-AP composite was discussed based on the thermogravimetry-mass spectrometry （TG-MS） results. Results show that HATO and AP may be cocrystal， crystal mixed or coated with each other in HATO-AP composite， which makes the mechanical sensitivity of HATO-AP composite significantly lower than that of HATO+AP mixture. The peak of combustion pressure and pressurization rate of HATO are much higher than that of AP. The HATO-AP composite can eliminate the adverse effects of AP in combustion property， and increase the peak of combustion pressure by 17.3% compared with raw. Because of the intimate contact between HATO and AP on a smaller microscopic scale in the composite， this allows these two molecules to react directly. The N element may directly react to form NH₃， HCN， NO or other NO_x instead of N₂ in the reaction process. The changes in reaction mechanism may make a difference on combustion pressure characteristics of HATO-AP composite.

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>Reviews

• Synthetic Strategy， Cyclization Mechanism of Furoxan and Its Application in Energetic Materials

  ZHANG Jun-lin, ZHOU Jing, SHE Wei-qing, WANG Bo-zhou

  2023,31(2):177-189, DOI: 10.11943/CJEM2022068

  Abstract(46) HTML(22) PDF(1.36 M)( 372)

  Abstract:Furoxan is a nitrogen-rich aromatic ring with a potential "nitro" fragment. The compactness of the skeleton and outstanding enthalpy of formation make it an important molecular skeleton for the research of energetic materials. The unique arrangement of nitrogen and oxygen atoms significantly increases the tendency of furoxan to tautomerism， and the presence of tautomers reduces the stability of the furoxan skeleton and increases the difficulty of its synthesis. This account reviews the research on the synthetic methodologies of furoxan based on different strategies. Focusing on the synthetic mechanism of furoxan framework itself， the advantages and disadvantages of different synthetic methodologies are analyzed and compared. Moreover， the progress of energetic materials based on the strategy developed for the synthesis of furoxan is also summarized. Considering the high density， high oxygen balance and high enthalpy of formation of furoxan ring， energetic structures based on the furoxans will still be a key direction of research and development of high energy density materials.

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• Progress in the Synthesis and Chemical Modification of Glycidyl Azide Polymer

  YAN Yi-teng, BAI Sen-hu, XUE Jin-qiang, LIU Shan, TONG Bin, QIAN Lu, JI Ying-xu

  2023,31(2):190-200, DOI: 10.11943/CJEM2022200

  Abstract(48) HTML(14) PDF(1.47 M)( 366)

  Abstract:Glycidyl azide polymer （GAP） has been considered as excellent energetic binder or plasticizer in high energetic solid propellants because of its high heat of combustion， low burning temperature， good thermal stability， clear exhaust and good compatibility with oxidizers. However， the presence of bulky， polar azide side group and reduced backbone flexibility， causing poor mechanical properties， especially the inferior low-temperature mechanical properties. Owing to chemical modification could better regulate the performance of GAP， it has attracted extensive attention. This paper illustrates the synthetic methods and processes of GAP， such as direct and indirect methods； summarizes various chemical modification methods of GAP and clarifies the relationship between the structures and properties of the GAP-based copolymers. At last， the future development of controllable， facile and green synthesis strategies for high molecular weight GAP， performance research methods and application prospects in high energy thermoplastic elastomers are described and discussed.

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• Review on Microwave Application in Energetic Materials

  CHENG Jian, ZHANG Ze-hua, LI Fu-wei, WANG Hui, YE Ying-hua, SHEN Rui-qi

  2023,31(2):201-212, DOI: 10.11943/CJEM2022089

  Abstract(71) HTML(36) PDF(3.23 M)( 374)

  Abstract:As a kind of clean energy， microwave is widely used in energetic materials due to its unique penetrability and high safety， which can interact with energetic materials in volume. The application of microwave in the testing of energetic materials， microwave assisted synthesis of energetic materials， excitation of energetic materials and enhancement of propellant combustion were summarized. The mechanism of microwave-assisted synthesis of energetic materials is not clear， the absorption materials introduced in microwave sensitized explosives is relatively single， and the microwave enhanced combustion is only suitable for some propellants were pointed out. The future development directions were put forward： expanding the types of absorbing materials， activating non-metallic energetic materials by microwave ignition of nano-thermites， and realizing the dexterity and convenience of microwave devices.

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