CHINESE JOURNAL OF ENERGETIC MATERIALS
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  • Flow and Casting Process Simulation of Unsaturated Polyester Coating Layer
    CJEM | 2022 No.11
  • Isolation and Identification of a Highly Efficient Strain of Aniline Degrading Bacterium Q6 and Degradation Characteristics
    CJEM | 2022 No.10
  • Construction and Combustion Performance of Al/PTFE-based Reactive Materials with Hollow Structure
    CJEM | 2022 No.9
  • Combustion Performance of Solid Propellant Based on New Fluorocarbon Binder
    CJEM | 2022 No.8
  • A Device for the Determination of the Heat of Combustion of Small Mass and the Measurement of the Heat of Combustion of Several Typical Energetic Materials
    CJEM | 2022 No.7
  • Effect of HMX Content on Agglomeration and Condensed Phase Combustion Products of AP/HMX/Al/HTPB Propellants
    CJEM | 2022 No.6
  • Measuring Method of Solubility and Metastable Zone of HNS Based on Optofluidics
    CJEM | 2022 No.5
  • Preparation and Performances of Active Coordination Compounds and Their Composite Ignition Powders
    CJEM | 2022 No.4
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    • HU Li-jingcao, ZENG Zhi-wei, WEI Xiang-shuai, YU Ru-jing, Huang Wei, TANG Yong-xing

      Online:December 01, 2022  DOI: 10.11943/CJEM2022176

      Abstract:A series of energetic salts (5-11) were synthesized by reacting polyamino-fused heterocyclic 4,7-diaminopyridazino[4,5-c]furoxan (4) with nitrogen-rich energetic acids including NTO or some other high-nitrogen nitroamino derivatives. The structures of 5-11 were characterized by nuclear magnetic resonance (NMR) spectroscopy, elemental analysis and infrared spectroscopy. In addition, the 15N NMR spectrum of 6 was measured and assignedbased on the quantum calculations. The crystal structure of 9 was also confirmed by single crystal X-ray diffraction. The detonation properties of these compounds (5-11) were calculated by Explo5 (version 6.05.02) software, and the impact and friction sensitivities were also measured. Among them, compound 5 exhibits good detonation performances (Dv: 8816 m·s-1P: 32.1 GPa) and low sensitivities(IS: 15 J, FS: 200 N).

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

      Online:November 17, 2022  DOI: 10.11943/CJEM2022184

      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 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, 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, and 4 N, respectively, indicating a better safety performance.

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    • LI Dan, CHEN Yang, LI Ke-wu, ZHAO Feng

      Online:November 04, 2022  DOI: 10.11943/CJEM2022118

      Abstract:To study the relationship between shear band and brittle-ductile transition behavior of typical polymer bonded explosive (PBX) under the influence of temperature, the mechanical response of PBX at 323-363 K was tested by using DIC digital image technology, in-depth analysis of shear band evolution law and failure mode. At the same time, the brittle-ductile transition mechanism of PBX under temperature effect was analyzed based on the theoretical model of crack slip. And the critical conditions of wing crack development and plastic slip area were obtained by considering the effect of temperature. The results showed that at 323-363 K, the variation of the shear band width of the PBX depended on the competition mechanism of dilation and shrinkage. There are four main mechanisms: Ⅰ. Dilatation and shrinkage reach equilibrium; Ⅱ. Shrinkage is dominant; Ⅲ. Dilatation is the main controlling factor; Ⅳ. Dilatation dominates intermittently. Combined with the principle of Griffith energy release, it is found that the shear strength, cohesion and fracture toughness of the specimen are the key controlling factors of the brittle-ductile transition. Under the condition, the judging basis of PBX brittle-ductile transition was obtained. When the condition of wing crack instability was met, the macroscopic failure mode tends to split failure; and when the critical condition of the plastic slip area was achieved, the multiple slip zones are connected to each other to form a plastic slip surface, and the macroscopic failure mode was dominated by the ductile fracture of shear crack slip.

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    • HUANG Xin, ZHANG Chao-yang

      Online:November 04, 2022  DOI: 10.11943/CJEM2022177

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

      Online:November 01, 2022  DOI: 10.11943/CJEM2021225

      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 plausible reaction mechanism of HATO-AP composite was discussed based on the thermogravimetry-mass spectrometry (TG-MS) results. Results show that HATO and AP may be eutectic, 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. Although the peak of combustion pressure and pressurization rate of HATO are both much higher than that of AP, the peak of combustion pressure exhibits by HATO-AP composite is 17.3% higher than that of raw HATO, which is attributed to that the composite has eliminated the adverse effects of AP in combustion property. 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 NOx 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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    • LUO Zheng-hang, WANG Jia-xuan, WANG Yu-qing, WANG Xin-yu, ZHANG Xiao-tian, ZHANG Li, ZHANG Yong, HANG Ming, YANG Hai-jun

      Online:October 31, 2022  DOI: 10.11943/CJEM2022051

      Abstract:In order to synthesize high-purity 3,5-diamino-2,4,6-trinitrochlorobenzene (DATNCB), the synthesis route screening and process optimization of DATNCB were studied with 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) or picric acid (2) as raw materials, respectively. The structure of the product was characterized by IR, NMR and MS; the thermal behavior of DATNCB was studied by DSC-TG; the purity of DATNCB was analyzed by HPLC. The results show that: the best synthetic route of DATNCB is starting from picric acid, then by via VNS amination followed by chlorination. The total yield is 39.2%. The highest yield of 3,5-diamino-2,4,6-trinitrophenol (3) was 74.8% when VNS amination temperature was 90 ℃ and post-treatment pH value was 3; the highest yield of DATNCB was 52.4% when phosphorus oxychloride/N,N-dimethylaniline was used as the chlorination reagent, the reaction temperature was 80 ℃ and the reaction time was 10 h. The melting point of DATNCB is 224.0 ℃. There is only one weight loss stage in the range of 179.7 ℃-270.9 ℃ and the weight loss rate is 91.6%; the peak decomposition temperature is 256.1 ℃. The purity of DATNCB reach 97.09% without further purification, and up to 99.8% after recrystallization with ethyl acetate/petroleum.

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    • HU Shou-tao, LI Ru-xia, NIE Bai-sheng, HONG Zi-jin, GAO Jian-cun, YANG Xi-gang, SUN Xu

      Online:October 26, 2022  DOI: 10.11943/CJEM2022143

      Abstract:To explore the effect of magnetic field on the explosion characteristics of premixed gas and its mechanism, taking ethylene as an example, the influence law of magnetic field on the explosion characteristics of premixed ethylene/air was experimentally studied. The chain reaction process of ethylene explosion was numerically simulated. The influence of magnetic field force on key free radicals was theoretically analyzed. The transient pressure of ethylene explosion was measured by pressure sensors and the flame propagation velocities were measured by explosion velocity apparatus. Results show that under the maximum magnetic field intensity of 3300 Gs, the maximum explosion pressure of 6.5% ethylene decreased by 18.18% and the explosion pressure rise rate reduced by 17.33 %. Along the flame propagation direction, the magnetic field firstly promoted and then suppressed the flame propagation speed of ethylene explosion, in which the suppression effect was greater than the promotion effect. The ethylene explosion was simulated by Chemkin-pro software, and the key free radicals in ethylene explosion were obtained. Different types of free radicals have different intensities of magnetization. Force of free radical under magnetic field is proportional to magnetization of free radical. The magnetic field force has a greater impact on free radicals with high magnetization, and no impact on anti-magnetic substances. Different types of free radicals appear stratification phenomenon under magnetic field. The collisions between different types of free radicals were reduced, and the elementary reaction rate was decreased, which suppressed the ethylene explosion.

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

      Online:October 26, 2022  DOI: 10.11943/CJEM2022145

      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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    • WANG Sheng-hui, JONG Rong-hui, LUO Yi-ming, XIAO Ji-jun, MA Hai-xia

      Online:October 25, 2022  DOI: 10.11943/CJEM2022163

      Abstract:To determine the compatibility of 3,4-Dinitrofurazanfuroxan (DNTF) with different polymeric passivators, models of fusion-cast explosives were constructed. These fusion-cast explosives were mixtures of DNTF with polymethyl methacrylate(PMMA), fluororubber (F2603), cis-butadiene rubber (BR), or polyvinylidene fluoride (PVDF). The molecular dynamics (MD) simulation method was used to study the compatibility between DNTF and the above-mentioned four polymer passivators from the radial distribution function, solubility parameter and Flory-Huggins interaction parameter under the COMPASS force field. The nature of the intermolecular interaction force in the blends was revealed. The compatibility of the four blend systems was further experimentally verified by using the vacuum stability tests (VST). The results show that the intermolecular radial distribution function values for individual components are lower than that between two different components in the blends. The solubility parameters of these systems are less than 3 J1/2·cm-3/2. The interaction parameter values of the systems are less than the critical interaction parameter value. The outgassing volume of these systems are all less than 0.6ml, indicating that DNTF is compatible with PMMA, F2603, BR and PVDF. The numerical simulation results are well consistent with the experimental results.

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    • LIN Xiang-yang, CAO Yu-peng, ZHANG Xi-ya

      Online:October 25, 2022  DOI: 10.11943/CJEM2022008

      Abstract:This review focused on the four major construction methods of 1,2,3-triazole energetic materials and corresponding research progress since the 1960s, including: Ⅰ) energetic compounds constructed based on 1-amino-1,2,3-triazole; Ⅱ) energetic compounds constructed based on dicyano substituted 1,2,3-triazole; Ⅲ) 1,2,3-triazole based energetic compounds prepared through azide involved cyclization reaction; Ⅳ) fused polycyclic energetic compounds built from 1,2,3-triazole. By analyzing the relationship between the molecular structure and energetic properties of several representative 1,2,3-triazole based energetic compounds, the influence of molecular structures on their energetic performances and stabilities could be profoundly clarified. Meanwhile, the potential application values of the mentioned high-performance 1,2,3-triazole based energetic compounds, such as their application prospects of main explosives, heat-resistant explosives and lead-free primary explosive, were discussed, providing a reference for the design and development of next-generation high energy density materials (HEDMs).

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    • WANG Run-wen, YANG Chun-ming, LIU Jian

      Online:October 24, 2022  DOI: 10.11943/CJEM2022088

      Abstract:The design efficiency of energetic compounds depends on many factors, such as the proportion of potential high performance samples in the screening space and the accurate prediction method of key properties. In this study, we proposed a scheme to improve the overall performance of virtual screening space by pre-screening molecular skeletons, and a method combining high-throughput computing and deep learning is applied to the design of energetic compounds. It was found that there is a moderate positive correlation between the crystal density of energetic molecules and their skeleton density, and the overall density of virtual screening space can be effectively improved by pre-screening high-density molecular skeletons. Based on the density data set of energetic crystals collected from the crystallography database CCDC, a new density prediction model of energetic crystals was obtained via deep learning, which has reliable accuracy and generalization. Based on these, we took fused-ring energetic molecules as the research object, obtained high-density fused-ring skeletons through skeleton pre-screening, and then the virtual screening space composed of potential high-density molecules was constructed through fragment docking. The formation enthalpy, detonation performance and chemical stability were predicted by quantum chemical calculation and the equation of state of detonation products. Finally, 6 novel energetic molecules with energy level better than RDX and stability better than TNT were selected by performance ranking. This study shows that the overall performance of virtual screening space can be effectively improved by pre-screening molecular skeletons, and on this basis, high-throughput computing and deep learning can be used to achieve efficient design of energetic molecules.

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    • WANG Teng, ZHOU Xin, HAO Shi-long, ZHANG Shu-hai, GOU Rui-jun, LI Hong-zhen

      Online:October 24, 2022  DOI: 10.11943/CJEM2022134

      Abstract:Aiming at the problems that the crystallization methods (evaporation, dissolution and cooling, etc.) of the conventional explosive are difficult to accurately control the uniformity of supersaturation and the low solvent recovery rate, an organic solvent nanofiltration(OSN) membrane crystallization apparatus based on pressure-driven and cross-flow filtration was designed and used to study the membrane crystallization process of 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane(HMX). The effects of key process parameters (temperature and pressure) on the crystal morphology and particle size were discussed, and the crystal morphology and structure were compared with those of evaporative crystallization. The HMX crystals after recrystallization by both methods were characterized by scanning electron microscopy(SEM),X-ray powder diffractometer(XRD) and thermogravimetric-differential scanning calorimeter(TG-DSC). The long-term operational stability of the nanofiltration membrane was further investigated, and the solvent recovered by permeation was used to re-crystallize. Results show that by the optimal control of temperature and pressure, the membrane crystallization process can obtain β-phase HMX with narrow particle size distribution (coefficient of variation < 46%), high crystal density (ρavg=1.8997-1.9004 g·cm-3) and excellent thermal stability. Compared with evaporation crystallization, the supersaturation control in the membrane crystallization process is easier to operate, and the prepared crystal morphology is more uniform. After repeated use, the rejection of HMX molecules in the solvent still remained above 92%, showing a good permeation selectivity stability. The β-phase HMX crystals with an average particle size of 37.05 μm and a coefficient of variation of 37.22% can still be prepared by membrane crystallization using permeation-recovered solvent, indicating that this technology can realize the efficient recovery and reuse of the crystallization solvent.

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

      Online:October 21, 2022  DOI: 10.11943/CJEM2022159

      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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    • MA Tian-yi, TAO Ru-yi, SEN Si-yi, WANG Hao

      Online:September 29, 2022  DOI: 10.11943/CJEM2022198

      Abstract:Modular artillery charge system (MACS) is one of the main charge structures for large-caliber howitzers. To accurately study the interior ballistic characteristics of single modular artillery charge system and analyze the variation law of gas flow and pressure wave in the chamber, a combustion experiment platform for MACS was designed to carry out the combustion experiment of single modular artillery charge system. According to the characteristics of modular artillery charge system, the axisymmetric two-dimensional two-phase flow interior ballistic model of modular charge was constructed in different regions. Based on the high-order accurate Monotonic Upstream-centered Scheme for Conservation Laws (MUSCL), the numerical simulation of the ignition process of single-module charge was carried out. The results show that the calculated results are in good agreement with the experimental results. The calculated maixmum errors of the pressures at different test points are less than 4%, indicating that the mathematical model established and calculation method used can describe the combustion process of single modular artillery charge system well. The results also show that before t=5.0 ms, the combustion of the module cartridge has little effect on the internal flow field of the module. The gas of main propellant can"t diffuse into the charge chamber in time due to the obstruction of the end cover of the cartridge.Only the gas of the ignition tube has a certain effect on the flow field in the chamber. The maximum pressure in the chamber during this period is about 4.3% higher than that before the right end of the fire tube is not broken. After the rupture of the cartridge, there is a pressure difference of 3.05 MPa at the boundary between the cartridge and the chamber, so that the propellant gas and solid particles flow rapidly along the axial direction to the free space of the chamber. A strong reflection of the pressure wave is formed at the bottom of the projectile. After that, the pressure wave oscillates repeatedly and gradually weakens.

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    • WANG Yan-jun, ZOU Xiang, PAN bing, GUO Yu-chen, LIU Chen, HAN Chao, LV Ke-zhen

      Online:September 28, 2022  DOI: 10.11943/CJEM2021267

      Abstract:In order to accurately understand the mechanical characteristic of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB)-based polymer bonded explosive (PBX) under compressive loading, an in-situ measurement technique based on micro X-ray computed tomography (μ-CT) imaging and digital volume correlation (DVC) was proposed. The in-situ scanning for TATB based PBX sample under uniaxial compression was carried out by using μ-CT and the three-dimensional digital volume images of the samples under different loading were obtained. Then, two sets of digital volume images obtained before and after loading respectively were analyzed by using local DVC method based on the Inverse Compositional Gauss-Newton (IC-GN) algorithm and the three-dimensional internal displacement and strain fields with sub-voxel accuracy were obtained. The internal stress fields were finally rebuilt according to the elastic Hook’s rule. The results show that the generation and development process of the strain localization zone inside the sample could be directly revealed based on the internal measurement technique combining DVC and μ-CT. In addition, the Zero-mean Normalized Cross-Correlation (ZNCC) coefficients are commonly lower at the microcracks. In practical applications, the location of sub-voxel microcracks could be identified by the distribution of ZNCC coefficients.

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    • ZHANG Yan-kang, XIAO Zhong-liang, LIU Xiang, ZHANG Hua-jun, LI Shi-ying, LIN Zhao-qiang

      Online:September 27, 2022  DOI: 10.11943/CJEM2022128

      Abstract:In order to obtain the gun propellants with progressive combustion characteristic and corresponding control methods at multi-dimensions, according to the principle of internal ballistics, the concept of the pre-grooved gun propellant was proposed. The physical and mathematical models of the combustion process were established, and the Г-Ψ relationship was deduced. The principle of progressive combustion and multi-dimensional control methods were demonstrated. The method used for preparation of the pre-grooved gun propellant was described. The pre-grooved gun propellant structured with a center opening was designed, and the propellants having different groove numbers and various length/outside diameter ratios were prepared. In order to compare with the seven-hole propellants with and without coating , the combustion performance of the pre-grooved gun propellant was characterized by the closed bomb test. The experimental results show that the pre-grooved gun propellant has the progressive combustion behavior as theoretically designed. Compared with the seven-hole propellant, the combustion enhancement value(ΔL) value obtained by using this method is increased by 2 folds, the progressive combustion characteristic(Lm/L0) value is increased by 24.4%, and the the relative pressure at split point(Bm) value is increased by 32.4%. The progressive combustion feature exhibited by pre-grooved gun propellants outperforms that of the seven-hole propellant, and was comparable to that of the coated seven-hole propellant.

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    • 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: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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    • FAN Jun-yu, SU Yan, ZHAO Ji-jun

      Online:September 23, 2022  DOI: 10.11943/CJEM2022137

      Abstract:To study the fundamental physical properties and intermolecular interaction of energetic materials under the loading temperature, the first-principle calculation was performed combined with zero-point energy and temperature effect corrections. The accuracy of lattice parameters at experiment temperature (173 K) can be significantly improved, and the deviations between the calculated lattice parameters and available experimental data are within 1%. The unit cell volume change with temperature is relatively reasonable compared with the experimental value at 0-500 K, and their deviation is mainly from the lack of interactions between phonons. Furthermore, the basic thermodynamic properties such as heat capacity, entropy and bulk modulus were predicted, and the results indicate that the lattice parameters and thermal expansion coefficient of FOX-7 have strong anisotropy in 0-500 K. Especially, the thermal expansion coefficient of interlayer direction is higher than that of inner layer direction, which is closely related to the molecular configuration and stacking. Importantly, when the temperature reaches 200 K, the shrinkage of thermal expansion coefficient of FOX-7 is related to the rotation of NO2 group. The NO2 group would regulate the intermolecular interaction by changing the dihedral angle with the molecular plane, thereby triggering potential phase transformation of FOX-7. In addition, the bulk modulus under the adiabatic conditions is consistent with the experimental values reasonably, and the evolution of adiabatic bulk modulus with temperature reflects the softening behavior of FOX-7 at the finite temperature. With the increase of temperature, the calculated heat capacity and entropy increase gradually, showing obvious numerical differences under the constant volume and pressure due to the anharmonic effect.

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    • JIN Wu-jing, YE Jin, ZENG Jian-you, AN Jing, MA Hai-xia

      Online:September 22, 2022  DOI: 10.11943/CJEM2022169

      Abstract:To investigate the effect of mesoporous carbon nanospheres (MCS) on the thermal decomposition properties of cyclotrimethylenetrinitramine(RDX), MCS was prepared by double template method with the particle size of about 350 nm. RDX crystals were introduced into the pore and surface of MCS by host-guest chemistry technology. The morphology and structure of MCS and MCS/RDX composite were characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The interface interaction between MCS and RDX was studied by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry-thermogravimetry (DSC-TG). Compared with pure RDX, the decomposition temperature of MCS/RDX composite decreased by 13 ℃ and the heat release increased. The apparent activation energy decreased from 234.87 kJ·mol-1 to 126.48 kJ·mol-1. The sensitivity tests were carried out by the drop hammer impact sensitivity instrument and the electrostatic spark device. Compared with the pure RDX, the impact sensitivity and electrostatic spark sensitivity of the obtained MCS/RDX composite are apparently reduced. Therefore, the obtained MCS has good catalytic performance for the thermal decomposition of RDX and can reduce the sensitivity of RDX.

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    • LI Hui-ying, WANG Xuan-yu, SUN Shu-bao, LIU Zhi-long, DONG Wen-jie

      Online:September 21, 2022  DOI: 10.11943/CJEM2022164

      Abstract:In order to investigate the infrared extinction performance of nickel-plated graphene and explore the best formulation, nickel-plated graphene was prepared by the redox and chemical plating methods. The influence of various factors on the extinction performance of nickel-plated graphene was analyzed by designed orthogonal experiments with the infrared decay rate as the evaluation index, and the optimal formulation was determined. The infrared transmittance of nickel-plated graphene was measured in a smoke-screen chamber test. The average mass extinction coefficient of nickel-plated graphene was calculated by linear fitting according to the “Lambert-Beer” law. The results showed that the optimal process parameters for the preparation of nickel-plated graphene were: c(NiSO4·6H2O)=20 g·L-1c(NaH2PO2·H2O)=24 g·L-1c(C6H5Na3O7·2H2O)=10 g·L-1 c(NH4Cl)=30 g·L-1, pH=8-9, and plating temperature of 65 ℃. The nickel-plated graphene prepared under the optimal conditions exhibited good infrared extinction in both mid- and far-infrared wavelengths. The average mass extinction coefficients of the nickel-plated graphene in the infrared bands of 3-5 μm and 8-14 μm were 2.38 m2·g-1 and 2.19 m2·g-1, respectively. Compared with the modified graphene, the average mass extinction coefficients of nickel-plated graphene in the mid-infrared bands were improved by 30% and 35%, respectively, which have broader application prospects.

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

      Online:September 21, 2022  DOI: 10.11943/CJEM2022068

      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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    • LI Wen-zhe, WANG Gao, WEI Zhi-fang, ZHAO Cong-cong, ZHANG Jun-hu, NIE Peng

      Online:September 20, 2022  DOI: 10.11943/CJEM2022120

      Abstract:In order to evaluate the output energy characteristics of ignition cap, it was proposed to conduct the ignition cap firing test in an open burster container and use a high-speed mid-wave infrared thermal imager to capture the whole process of the ignition cap firing. Since it was difficult to measure the output flame temperature of ignition cap, the drop weight instrument was used to give the corresponding initial firing energy of ignition cap. At the same time, the infrared thermal imager was triggered to collect the flame information. The experimental data and infrared images of ignition cap under three test conditions of normal(25℃), heated(50℃) and frozen(-49℃) temperature were processed. The results show that the output flame maximum temperature can reach up to 1204 ℃, and the flame duration is about 3-4 ms. The whole process of the flame with time can be divided into four stages: firing, diffusion, forming and dissipation, and the temperature in the top and bottom area of flame is much higher than in other areas. Through calculation and software correction, the measurement error of this test is below 6.6%, which can prove the reliability of the method and provide a new way for evaluating the output energy characteristics of ignition cap.

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    • MA Long-fei, XU Bin, LIAO Xin

      Online:September 19, 2022  DOI: 10.11943/CJEM2022165

      Abstract:To improve the compatibility of dihydroxylammonium 5,5′-bitetrazole-1,1′-diolate(TKX-50) with nitrocellulose(NC), silane coupling agent (KH550) was used as the coating agent and three TKX-50/KH550 composites (TK1, TK2, TK3) were obtained.The morphology, structure and thermal stability of the composites were studied by using scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Accelerating rate calorimeter (ARC) and DSC were used to examine the compatibility of TKX-50/KH550 composites with NC. The results show that the apparent activation energy of thermal decomposition of the prepared TKX-50/KH550 composites are 190.03, 195.82 and 194.42 kJ·mol-1 respectively, and all higher than that of TKX-50 (138.86 kJ·mol-1), indicating the thermal stability of TKX-50 is improved by KH550 coating. In adiabatic conditions, the initial thermal decomposition temperature of the mixtures of TKX-50/KH550 composites and NC are 14.93, 18.18 and 17.90 ℃ respectively, higher than that of TKX-50 and NC. After coated with KH550, the compatibility of TKX-50 and NC is improved, and the compatibility level of TKX-50/KH550 composites and NC is raised from Level 3 to Level 2.

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

      Online:August 26, 2022  DOI: 10.11943/CJEM2022131

      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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    • WU Bo, CUI Yao-zhong, MENG Guo-wang, XU Shi-xiang

      Online:August 25, 2022  DOI: 10.11943/CJEM2022126

      Abstract:In order to study the influence of degree of cone angle, cone diameter and thickness of conical liner on shaped charge jet effect and optimize the structure of liner, orthogonal test with three factors and four levels was designed. ABAQUS software was used to simulate the shaped charge jet to penetrate the target, and weighted gray correlation method was used to analyze the orthogonal test results of jet target penetrating. The correlation degree between the angle, diameter and thickness of the cartridge and the effect of jet target penetrating was obtained. The results show that the cone angle has the greatest effect on shaped charge jet, and the cone diameter and thickness have the secondary effect. The parameter combination of liner for the best shaped charge jet target penetrating is: cone angle 61.2°, cone radius 18 mm, thickness 1.05 mm. Using the best combination of parameters, the maximum velocity of the shaped charge jet is 5855 m·s-1, the depth of the penetrating target is 59.43 mm, and the opening diameter of the penetrating target is 8.24 mm. The research results can provide theoretical guidance for the application of shaped charge jet penetration.

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

      Online:August 19, 2022  DOI: 10.11943/CJEM2022089

      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 thermite, and realizing the dexterity and convenience of microwave devices.

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

      Online:July 22, 2022  DOI: 10.11943/CJEM2021301

      Abstract:The research on low-sensitivity 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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    • PEI Hong-bo, LI Shu-rui, GUO Wen-can, ZHANG Xu, ZHENG Xian-xu

      Online:July 15, 2022  DOI: 10.11943/CJEM2021285

      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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    • LOU Jian-feng, ZHANG Shu-dao

      Online:July 14, 2022  DOI: 10.11943/CJEM2021219

      Abstract:In order to study the law of crack initiation, growth and evolution of explosives under weak load. The numerical simulation of crack initiation and evolution of explosives was carried out by using the material model considering the phenomena of tensile and compressive anisotropy with strain rate effect. The numerical results are in good agreement with the test data, and the applicability of the numerical model is verified. The typical characteristic images of crack generation and evolution of explosives were obtained through a series of numerical simulations, and the effects of initial crack size, loading rate and loading position on the crack propagation process of explosives were also analyzed, which can provide reference for the analysis of damage and fracture process as well as the dynamic response of explosives.

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

      Online:July 05, 2022  DOI: 10.11943/CJEM2022059

      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. Binary T-X and H-X phase diagrams were drawn according to the differential scanning calorimetry (DSC) curve 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 (EK), 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 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-1VD=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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    • SUN Bao-liang, HUANG Wen-yao, WANG Quan, CHAO Jie, TAN Xin, NIU Cao-yuan, HU Jie

      Online:June 30, 2022  DOI: 10.11943/CJEM2022092

      Abstract:Diatomite particles with size distribution of 200-300 μm were used as emulsifying matrix carrier to prepare low detonation velocity emulsified explosive. The microscopic properties of diatomite were characterized. The effects of diatomite mass fraction on the particle size and detonation mechanism of explosive were analyzed. The density, detonation velocity and air explosion shock wave pressure of explosive were measured. The compatibility of diatomite and emulsified matrix was tested. The results show that when the mass fraction of diatomite increases from 15% to 35%, the particle size of explosive is negatively correlated with the content of diatomite, the density of explosive decreases from 0.79 g·cm-3 to 0.51 g·cm-3, and the detonation velocity decreases from 2561 m·s-1 to 1655 m·s-1. The peak pressure of air explosion shock wave decreases from 0.061 MPa to 0.023 MPa. The addition of diatomite has no effect on the thermal stability of emulsified matrix, and the diatomite and emulsified matrix do not react with each other under room temperature or heating conditions. The detonation velocity and the peak pressure of air explosion shock wave of the explosive stored for 2 d and 120 d drop less than 5%, indicating that diatomite has good compatibility with emulsified matrix.

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    • SONG Jiang-wei, YANG Wen-jin, ZHANG Jun-qi, ZHANG Jin-song, XU Sen

      Online:May 27, 2022  DOI: 10.11943/CJEM2021198

      Abstract:Aluminum based hydrogen storage composite fuel namely Q3 with a content of boron 15% and MgH2 15% was prepared by means of chimeric assembly. The powder had a spheroidic morphology. Its theoretical combustion heat was as high as 34.8 MJ·kg-1. Thermogravimetric Analysis (TGA) was employed to test the oxidation performance of spherical aluminum and Q3. The results indicated that the initial oxidation temperature of Q3 was 430 ℃, which was around 100 ℃ lower than that of spherical aluminum. When the temperature was up to 1000℃, the weight of Q3 increased by 60% due to the oxidation, which was higher than that of spherical aluminum (23%). This result indicated that the aluminum based hydrogen storage composite fuel had a better ignition performance and higher oxidability. The tests of underwater explosion with two RDX based explosive formulas containing 35% metal powder or equivalent Q3 were carried out respectively. The test results showed that for the formula with equivalent Q3, the explosion specific shock wave energy was reduced by 3.0%, the specific bubble energy was increased by 9.5%, and the total explosion energy was increased by 7.6% in contrast to the counterpart formula containing aluminum. The metal hydride and aluminum in aluminum based hydrogen storage composite fuel could effectively improve the energy release efficiency and rate of boron, resulting in increasing the total energy of the explosive in underwater explosion.

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    • YUAN Ye, LI Chun-zhi, DONG Jun, LI Bin, YANG Li-yuan, ZHANG Chong, SUN Cheng-guo, HU Bing-cheng

      Online:May 23, 2022  DOI: 10.11943/CJEM2022053

      Abstract:For achieving engineering application of pentazolium anionic energetic materials, it is necessary to realize large-scale production of 3,5-dimethyl-4-hydroxyphenylpentazole (HPP) as the precursor of pentazole. The pilot synthesis techniques of HPP were performed based on accessibly lab-leveled method using 10 L and 100 L reactors for scale-up experiments. The dropping time of aqueous solutions of sodium nitrite and sodium azide, the purity of 3,5-dimethyl-4-hydroxyaniline hydrochloride (DAC) and the feeding weight on the production of HPP were investigated. Results indicate that HPP production increases with the increasing of the total dropping time of sodium nitrite aqueous solution and sodium azide aqueous solution. After a certain value, the production of HPP remains. The purity of DAC affects the HPP production significantly that the production increases with the increasing of purity. With the scale up, HPP production increases along with the reducing of production ratio. With the feeding mass of DAC reached to 6 kg, a batch of product increased to 11.5 kg as well as the production rate decreased to 1.91.

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    • Du Xin-yi, LI Gang

      Online:May 11, 2022  DOI: 10.11943/CJEM2021341

      Abstract:Addition of high energy boron into the liquid fuel is an effective method to improve the energy density of the blended fuel. However, the added content of boron is limited, due to the dramatic increase in the viscosity of the blended fuel. So it is important to increase the boron content as much as possible without obvious viscosity increase. Four organosilanes including propyltrimethoxysilane (C3-silane), octyltrimethoxysilane (C8-silane), dodecyltrimethoxysilane (C12-silane) and hexadecyltrimethoxysilanes (C16-silane) were used to modify boron particles. First, the modified boron particles were characterized by scanning electron microscopy, contact angle measurement, X-ray diffraction, particle size analysis (using dynamic laser scattering) and thermogravimetric analysis. Then the rheological properties of organosilane modified boron/JP-10 blend fuels were investigated. Finally, the effect of temperature on the apparent viscosities at different shear rates was studied. The results show that boric acid on the boron surface was removed upon surface modification with organosilanes and the surface characteristics of boron powder were transformed from hydrophilicity to hydrophobicity. The content of organosilane was less than 1.5% in the organosilane modified boron particles, which would have marginal effect on the total heat value. Organosilane modified boron/JP-10 blend fuels with solids content of 50% showed good fluidity and their apparent viscosities were lower than 0.3 Pa·s at 25 ℃ and 100 s-1 of shear rate. Keeping other conditions the same, the apparent viscosity of blend fuels depends on the length of side chain alkyl group of organosilane: C3-silane>C8-silane≈C12-silane≈C16-silane. Organosilane modified boron/JP-10 blend fuels showed shear-thinning characteristics and the relationship between the apparent viscosity and the shear rate could be well fitted by power-law equation. The apparent viscosity of blend fuels depends strongly on the temperature and their relationship could be well expressed by Arrhenius equation. The shear activation energy of blend fuels increases with increasing the length of side chain alkyl group of organosilane coated on the boron.

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    • ZHANG Meng-meng, WANG Hong-xing, CUI Xue-jin, LI Bing-bo, FANG Xue-qian, LUO Yi-ming

      Online:April 18, 2022  DOI: 10.11943/CJEM2021264

      Abstract:In order to study the effect of polymers such as polyolefin, polyester, polyurethane and polyether on the mechanical properties of DNAN and its mixed explosives, the physical miscibility of different polymers with DNAN was studied by X-ray testing, in which polymers were microcrystalline wax(WAX), polyisobutylene(PIB), polybutylene succinate(PBS), polyadipic acid hexanediamine(PA) and poly(3,3-di(nitrate ester methyl) oxybutyl)(PBNMO). The solidification process of the polymer-containing samples was observed by microscopic. The dynamic crystallization characteristics of the samples during solidification were analyzed, and the linear velocity of crystal growth was calculated. Based on the optimized polymer, the influence of polymer content on the mechanical strength of DNAN and its mixed explosives was studied by material testing machine. The mechanical strengthening mechanism of polymer to DNAN and DNAN based explosives was analyzed. The results show that PBS, PA and PBNMO have good mutual solubility with DNAN under the action of hydrogen bonds or π bonds. The addition of fusible polymer makes the solid-liquid interface of DNAN crystals smooth and the solidification linear velocity decreases by more than 54%. Among them, the PBNMO has the most obvious improvement on the crystal morphology and solidification linear velocity of DNAN. PBNMO could significantly improve the mechanical properties of DNAN and its based explosives, and the mechanical strength increases with the increase of polymer content. When the polymer PBNMO content was 2%, the tensile strength and shear strength of DNAN based explosives increase more than 100%. The mechanism study shows that the fusible polymer can improve the mechanical properties of DNAN-based explosives by improving the microstructure of the sample and forming the “reinforced concrete” structure to reduce the internal defects and improve the crack growth resistance.

    • YUAN Wan-li, JIANG Bi-tao, ZHANG Chong, SUN Cheng-guo, GAO Chao, HU Bing-cheng, DU Yang

      Online:February 17, 2022  DOI: 10.11943/CJEM2021336

      Abstract:The preparations of high-energy pentazolate salts is a research hotspot in the field of energetic materials. The preparation of pentazolate anion is a key step in the preparations of high-energy pentazolate salts. However, as the important precursors for pentazolate anion, the stability of existing arylpentazoles is generally not high. In order to develop new precursors of pentazolate anion with better properties, 18 substituted derivatives of PyN5 with the electron-withdrawing and electron-donating groups, i.e., R-PyN5 (R=-NO2, -CN, -NF2, -OH, -OMe, -N(Me)2), were designed and studied by using the density functional theory method. The bond dissociation energy(EBD), and the activation energy(Ea1) of the bridged C—N bond and the activation energy(Ea2) of the cracking of the N5 ring were calculated, and the stability of the bridged C—N bond and pentazolate ring were discussed. Ea1 of all molecules is smaller than EBD, indicating that the breakage of the bridged C—N bond is more likely to follow the path 2 rather than path 1. Ea2 of all molecules is smaller than Ea1, indicating that the stability of the N5 ring is the key factor to determine the stability of the arylpentazoles. Compared with PhN5, —N(Me)2 meta-substituted and bis-substituted compounds have lower Ea1, higher Ea2 and lower ΔE Ea2Ea1). Therefore,—N(Me)2 meta-substituted and bis-substituted compounds are the most potential precursors of N5ˉ ion for replacing PhN5.

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    • Du Xin-yi, LI Gang

      Online:May 11, 2022  DOI: 10.11943/CJEM2021341

      Abstract:Addition of high energy boron into the liquid fuel is an effective method to improve the energy density of the blended fuel. However, the added content of boron is limited, due to the dramatic increase in the viscosity of the blended fuel. So it is important to increase the boron content as much as possible without obvious viscosity increase. Four organosilanes including propyltrimethoxysilane (C3-silane), octyltrimethoxysilane (C8-silane), dodecyltrimethoxysilane (C12-silane) and hexadecyltrimethoxysilanes (C16-silane) were used to modify boron particles. First, the modified boron particles were characterized by scanning electron microscopy, contact angle measurement, X-ray diffraction, particle size analysis (using dynamic laser scattering) and thermogravimetric analysis. Then the rheological properties of organosilane modified boron/JP-10 blend fuels were investigated. Finally, the effect of temperature on the apparent viscosities at different shear rates was studied. The results show that boric acid on the boron surface was removed upon surface modification with organosilanes and the surface characteristics of boron powder were transformed from hydrophilicity to hydrophobicity. The content of organosilane was less than 1.5% in the organosilane modified boron particles, which would have marginal effect on the total heat value. Organosilane modified boron/JP-10 blend fuels with solids content of 50% showed good fluidity and their apparent viscosities were lower than 0.3 Pa·s at 25 ℃ and 100 s-1 of shear rate. Keeping other conditions the same, the apparent viscosity of blend fuels depends on the length of side chain alkyl group of organosilane: C3-silane>C8-silane≈C12-silane≈C16-silane. Organosilane modified boron/JP-10 blend fuels showed shear-thinning characteristics and the relationship between the apparent viscosity and the shear rate could be well fitted by power-law equation. The apparent viscosity of blend fuels depends strongly on the temperature and their relationship could be well expressed by Arrhenius equation. The shear activation energy of blend fuels increases with increasing the length of side chain alkyl group of organosilane coated on the boron.

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    • YUAN Wan-li, JIANG Bi-tao, ZHANG Chong, SUN Cheng-guo, GAO Chao, HU Bing-cheng, DU Yang

      Online:February 17, 2022  DOI: 10.11943/CJEM2021336

      Abstract:The preparations of high-energy pentazolate salts is a research hotspot in the field of energetic materials. The preparation of pentazolate anion is a key step in the preparations of high-energy pentazolate salts. However, as the important precursors for pentazolate anion, the stability of existing arylpentazoles is generally not high. In order to develop new precursors of pentazolate anion with better properties, 18 substituted derivatives of PyN5 with the electron-withdrawing and electron-donating groups, i.e., R-PyN5 (R=-NO2, -CN, -NF2, -OH, -OMe, -N(Me)2), were designed and studied by using the density functional theory method. The bond dissociation energy(EBD), and the activation energy(Ea1) of the bridged C—N bond and the activation energy(Ea2) of the cracking of the N5 ring were calculated, and the stability of the bridged C—N bond and pentazolate ring were discussed. Ea1 of all molecules is smaller than EBD, indicating that the breakage of the bridged C—N bond is more likely to follow the path 2 rather than path 1. Ea2 of all molecules is smaller than Ea1, indicating that the stability of the N5 ring is the key factor to determine the stability of the arylpentazoles. Compared with PhN5, —N(Me)2 meta-substituted and bis-substituted compounds have lower Ea1, higher Ea2 and lower ΔE Ea2Ea1). Therefore,—N(Me)2 meta-substituted and bis-substituted compounds are the most potential precursors of N5ˉ ion for replacing PhN5.

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    • SUN Bao-liang, HUANG Wen-yao, WANG Quan, CHAO Jie, TAN Xin, NIU Cao-yuan, HU Jie

      Online:June 30, 2022  DOI: 10.11943/CJEM2022092

      Abstract:Diatomite particles with size distribution of 200-300 μm were used as emulsifying matrix carrier to prepare low detonation velocity emulsified explosive. The microscopic properties of diatomite were characterized. The effects of diatomite mass fraction on the particle size and detonation mechanism of explosive were analyzed. The density, detonation velocity and air explosion shock wave pressure of explosive were measured. The compatibility of diatomite and emulsified matrix was tested. The results show that when the mass fraction of diatomite increases from 15% to 35%, the particle size of explosive is negatively correlated with the content of diatomite, the density of explosive decreases from 0.79 g·cm-3 to 0.51 g·cm-3, and the detonation velocity decreases from 2561 m·s-1 to 1655 m·s-1. The peak pressure of air explosion shock wave decreases from 0.061 MPa to 0.023 MPa. The addition of diatomite has no effect on the thermal stability of emulsified matrix, and the diatomite and emulsified matrix do not react with each other under room temperature or heating conditions. The detonation velocity and the peak pressure of air explosion shock wave of the explosive stored for 2 d and 120 d drop less than 5%, indicating that diatomite has good compatibility with emulsified matrix.

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

      Online:July 05, 2022  DOI: 10.11943/CJEM2022059

      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. Binary T-X and H-X phase diagrams were drawn according to the differential scanning calorimetry (DSC) curve 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 (EK), 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 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-1VD=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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    • LOU Jian-feng, ZHANG Shu-dao

      Online:July 14, 2022  DOI: 10.11943/CJEM2021219

      Abstract:In order to study the law of crack initiation, growth and evolution of explosives under weak load. The numerical simulation of crack initiation and evolution of explosives was carried out by using the material model considering the phenomena of tensile and compressive anisotropy with strain rate effect. The numerical results are in good agreement with the test data, and the applicability of the numerical model is verified. The typical characteristic images of crack generation and evolution of explosives were obtained through a series of numerical simulations, and the effects of initial crack size, loading rate and loading position on the crack propagation process of explosives were also analyzed, which can provide reference for the analysis of damage and fracture process as well as the dynamic response of explosives.

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    • MA Long-fei, XU Bin, LIAO Xin

      Online:September 19, 2022  DOI: 10.11943/CJEM2022165

      Abstract:To improve the compatibility of dihydroxylammonium 5,5′-bitetrazole-1,1′-diolate(TKX-50) with nitrocellulose(NC), silane coupling agent (KH550) was used as the coating agent and three TKX-50/KH550 composites (TK1, TK2, TK3) were obtained.The morphology, structure and thermal stability of the composites were studied by using scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Accelerating rate calorimeter (ARC) and DSC were used to examine the compatibility of TKX-50/KH550 composites with NC. The results show that the apparent activation energy of thermal decomposition of the prepared TKX-50/KH550 composites are 190.03, 195.82 and 194.42 kJ·mol-1 respectively, and all higher than that of TKX-50 (138.86 kJ·mol-1), indicating the thermal stability of TKX-50 is improved by KH550 coating. In adiabatic conditions, the initial thermal decomposition temperature of the mixtures of TKX-50/KH550 composites and NC are 14.93, 18.18 and 17.90 ℃ respectively, higher than that of TKX-50 and NC. After coated with KH550, the compatibility of TKX-50 and NC is improved, and the compatibility level of TKX-50/KH550 composites and NC is raised from Level 3 to Level 2.

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    • WANG Run-wen, YANG Chun-ming, LIU Jian

      Online:October 24, 2022  DOI: 10.11943/CJEM2022088

      Abstract:The design efficiency of energetic compounds depends on many factors, such as the proportion of potential high performance samples in the screening space and the accurate prediction method of key properties. In this study, we proposed a scheme to improve the overall performance of virtual screening space by pre-screening molecular skeletons, and a method combining high-throughput computing and deep learning is applied to the design of energetic compounds. It was found that there is a moderate positive correlation between the crystal density of energetic molecules and their skeleton density, and the overall density of virtual screening space can be effectively improved by pre-screening high-density molecular skeletons. Based on the density data set of energetic crystals collected from the crystallography database CCDC, a new density prediction model of energetic crystals was obtained via deep learning, which has reliable accuracy and generalization. Based on these, we took fused-ring energetic molecules as the research object, obtained high-density fused-ring skeletons through skeleton pre-screening, and then the virtual screening space composed of potential high-density molecules was constructed through fragment docking. The formation enthalpy, detonation performance and chemical stability were predicted by quantum chemical calculation and the equation of state of detonation products. Finally, 6 novel energetic molecules with energy level better than RDX and stability better than TNT were selected by performance ranking. This study shows that the overall performance of virtual screening space can be effectively improved by pre-screening molecular skeletons, and on this basis, high-throughput computing and deep learning can be used to achieve efficient design of energetic molecules.

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    • LI Dan, CHEN Yang, LI Ke-wu, ZHAO Feng

      Online:November 04, 2022  DOI: 10.11943/CJEM2022118

      Abstract:To study the relationship between shear band and brittle-ductile transition behavior of typical polymer bonded explosive (PBX) under the influence of temperature, the mechanical response of PBX at 323-363 K was tested by using DIC digital image technology, in-depth analysis of shear band evolution law and failure mode. At the same time, the brittle-ductile transition mechanism of PBX under temperature effect was analyzed based on the theoretical model of crack slip. And the critical conditions of wing crack development and plastic slip area were obtained by considering the effect of temperature. The results showed that at 323-363 K, the variation of the shear band width of the PBX depended on the competition mechanism of dilation and shrinkage. There are four main mechanisms: Ⅰ. Dilatation and shrinkage reach equilibrium; Ⅱ. Shrinkage is dominant; Ⅲ. Dilatation is the main controlling factor; Ⅳ. Dilatation dominates intermittently. Combined with the principle of Griffith energy release, it is found that the shear strength, cohesion and fracture toughness of the specimen are the key controlling factors of the brittle-ductile transition. Under the condition, the judging basis of PBX brittle-ductile transition was obtained. When the condition of wing crack instability was met, the macroscopic failure mode tends to split failure; and when the critical condition of the plastic slip area was achieved, the multiple slip zones are connected to each other to form a plastic slip surface, and the macroscopic failure mode was dominated by the ductile fracture of shear crack slip.

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    • FAN Jun-yu, SU Yan, ZHAO Ji-jun

      Online:September 23, 2022  DOI: 10.11943/CJEM2022137

      Abstract:To study the fundamental physical properties and intermolecular interaction of energetic materials under the loading temperature, the first-principle calculation was performed combined with zero-point energy and temperature effect corrections. The accuracy of lattice parameters at experiment temperature (173 K) can be significantly improved, and the deviations between the calculated lattice parameters and available experimental data are within 1%. The unit cell volume change with temperature is relatively reasonable compared with the experimental value at 0-500 K, and their deviation is mainly from the lack of interactions between phonons. Furthermore, the basic thermodynamic properties such as heat capacity, entropy and bulk modulus were predicted, and the results indicate that the lattice parameters and thermal expansion coefficient of FOX-7 have strong anisotropy in 0-500 K. Especially, the thermal expansion coefficient of interlayer direction is higher than that of inner layer direction, which is closely related to the molecular configuration and stacking. Importantly, when the temperature reaches 200 K, the shrinkage of thermal expansion coefficient of FOX-7 is related to the rotation of NO2 group. The NO2 group would regulate the intermolecular interaction by changing the dihedral angle with the molecular plane, thereby triggering potential phase transformation of FOX-7. In addition, the bulk modulus under the adiabatic conditions is consistent with the experimental values reasonably, and the evolution of adiabatic bulk modulus with temperature reflects the softening behavior of FOX-7 at the finite temperature. With the increase of temperature, the calculated heat capacity and entropy increase gradually, showing obvious numerical differences under the constant volume and pressure due to the anharmonic effect.

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    • HU Shou-tao, LI Ru-xia, NIE Bai-sheng, HONG Zi-jin, GAO Jian-cun, YANG Xi-gang, SUN Xu

      Online:October 26, 2022  DOI: 10.11943/CJEM2022143

      Abstract:To explore the effect of magnetic field on the explosion characteristics of premixed gas and its mechanism, taking ethylene as an example, the influence law of magnetic field on the explosion characteristics of premixed ethylene/air was experimentally studied. The chain reaction process of ethylene explosion was numerically simulated. The influence of magnetic field force on key free radicals was theoretically analyzed. The transient pressure of ethylene explosion was measured by pressure sensors and the flame propagation velocities were measured by explosion velocity apparatus. Results show that under the maximum magnetic field intensity of 3300 Gs, the maximum explosion pressure of 6.5% ethylene decreased by 18.18% and the explosion pressure rise rate reduced by 17.33 %. Along the flame propagation direction, the magnetic field firstly promoted and then suppressed the flame propagation speed of ethylene explosion, in which the suppression effect was greater than the promotion effect. The ethylene explosion was simulated by Chemkin-pro software, and the key free radicals in ethylene explosion were obtained. Different types of free radicals have different intensities of magnetization. Force of free radical under magnetic field is proportional to magnetization of free radical. The magnetic field force has a greater impact on free radicals with high magnetization, and no impact on anti-magnetic substances. Different types of free radicals appear stratification phenomenon under magnetic field. The collisions between different types of free radicals were reduced, and the elementary reaction rate was decreased, which suppressed the ethylene explosion.

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    • LI Hui-ying, WANG Xuan-yu, SUN Shu-bao, LIU Zhi-long, DONG Wen-jie

      Online:September 21, 2022  DOI: 10.11943/CJEM2022164

      Abstract:In order to investigate the infrared extinction performance of nickel-plated graphene and explore the best formulation, nickel-plated graphene was prepared by the redox and chemical plating methods. The influence of various factors on the extinction performance of nickel-plated graphene was analyzed by designed orthogonal experiments with the infrared decay rate as the evaluation index, and the optimal formulation was determined. The infrared transmittance of nickel-plated graphene was measured in a smoke-screen chamber test. The average mass extinction coefficient of nickel-plated graphene was calculated by linear fitting according to the “Lambert-Beer” law. The results showed that the optimal process parameters for the preparation of nickel-plated graphene were: c(NiSO4·6H2O)=20 g·L-1c(NaH2PO2·H2O)=24 g·L-1c(C6H5Na3O7·2H2O)=10 g·L-1 c(NH4Cl)=30 g·L-1, pH=8-9, and plating temperature of 65 ℃. The nickel-plated graphene prepared under the optimal conditions exhibited good infrared extinction in both mid- and far-infrared wavelengths. The average mass extinction coefficients of the nickel-plated graphene in the infrared bands of 3-5 μm and 8-14 μm were 2.38 m2·g-1 and 2.19 m2·g-1, respectively. Compared with the modified graphene, the average mass extinction coefficients of nickel-plated graphene in the mid-infrared bands were improved by 30% and 35%, respectively, which have broader application prospects.

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    • ZHANG Yan-kang, XIAO Zhong-liang, LIU Xiang, ZHANG Hua-jun, LI Shi-ying, LIN Zhao-qiang

      Online:September 27, 2022  DOI: 10.11943/CJEM2022128

      Abstract:In order to obtain the gun propellants with progressive combustion characteristic and corresponding control methods at multi-dimensions, according to the principle of internal ballistics, the concept of the pre-grooved gun propellant was proposed. The physical and mathematical models of the combustion process were established, and the Г-Ψ relationship was deduced. The principle of progressive combustion and multi-dimensional control methods were demonstrated. The method used for preparation of the pre-grooved gun propellant was described. The pre-grooved gun propellant structured with a center opening was designed, and the propellants having different groove numbers and various length/outside diameter ratios were prepared. In order to compare with the seven-hole propellants with and without coating , the combustion performance of the pre-grooved gun propellant was characterized by the closed bomb test. The experimental results show that the pre-grooved gun propellant has the progressive combustion behavior as theoretically designed. Compared with the seven-hole propellant, the combustion enhancement value(ΔL) value obtained by using this method is increased by 2 folds, the progressive combustion characteristic(Lm/L0) value is increased by 24.4%, and the the relative pressure at split point(Bm) value is increased by 32.4%. The progressive combustion feature exhibited by pre-grooved gun propellants outperforms that of the seven-hole propellant, and was comparable to that of the coated seven-hole propellant.

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    • YUAN Ye, LI Chun-zhi, DONG Jun, LI Bin, YANG Li-yuan, ZHANG Chong, SUN Cheng-guo, HU Bing-cheng

      Online:May 23, 2022  DOI: 10.11943/CJEM2022053

      Abstract:For achieving engineering application of pentazolium anionic energetic materials, it is necessary to realize large-scale production of 3,5-dimethyl-4-hydroxyphenylpentazole (HPP) as the precursor of pentazole. The pilot synthesis techniques of HPP were performed based on accessibly lab-leveled method using 10 L and 100 L reactors for scale-up experiments. The dropping time of aqueous solutions of sodium nitrite and sodium azide, the purity of 3,5-dimethyl-4-hydroxyaniline hydrochloride (DAC) and the feeding weight on the production of HPP were investigated. Results indicate that HPP production increases with the increasing of the total dropping time of sodium nitrite aqueous solution and sodium azide aqueous solution. After a certain value, the production of HPP remains. The purity of DAC affects the HPP production significantly that the production increases with the increasing of purity. With the scale up, HPP production increases along with the reducing of production ratio. With the feeding mass of DAC reached to 6 kg, a batch of product increased to 11.5 kg as well as the production rate decreased to 1.91.

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    • LI Wen-zhe, WANG Gao, WEI Zhi-fang, ZHAO Cong-cong, ZHANG Jun-hu, NIE Peng

      Online:September 20, 2022  DOI: 10.11943/CJEM2022120

      Abstract:In order to evaluate the output energy characteristics of ignition cap, it was proposed to conduct the ignition cap firing test in an open burster container and use a high-speed mid-wave infrared thermal imager to capture the whole process of the ignition cap firing. Since it was difficult to measure the output flame temperature of ignition cap, the drop weight instrument was used to give the corresponding initial firing energy of ignition cap. At the same time, the infrared thermal imager was triggered to collect the flame information. The experimental data and infrared images of ignition cap under three test conditions of normal(25℃), heated(50℃) and frozen(-49℃) temperature were processed. The results show that the output flame maximum temperature can reach up to 1204 ℃, and the flame duration is about 3-4 ms. The whole process of the flame with time can be divided into four stages: firing, diffusion, forming and dissipation, and the temperature in the top and bottom area of flame is much higher than in other areas. Through calculation and software correction, the measurement error of this test is below 6.6%, which can prove the reliability of the method and provide a new way for evaluating the output energy characteristics of ignition cap.

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    • WANG Yan-jun, ZOU Xiang, PAN bing, GUO Yu-chen, LIU Chen, HAN Chao, LV Ke-zhen

      Online:September 28, 2022  DOI: 10.11943/CJEM2021267

      Abstract:In order to accurately understand the mechanical characteristic of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB)-based polymer bonded explosive (PBX) under compressive loading, an in-situ measurement technique based on micro X-ray computed tomography (μ-CT) imaging and digital volume correlation (DVC) was proposed. The in-situ scanning for TATB based PBX sample under uniaxial compression was carried out by using μ-CT and the three-dimensional digital volume images of the samples under different loading were obtained. Then, two sets of digital volume images obtained before and after loading respectively were analyzed by using local DVC method based on the Inverse Compositional Gauss-Newton (IC-GN) algorithm and the three-dimensional internal displacement and strain fields with sub-voxel accuracy were obtained. The internal stress fields were finally rebuilt according to the elastic Hook’s rule. The results show that the generation and development process of the strain localization zone inside the sample could be directly revealed based on the internal measurement technique combining DVC and μ-CT. In addition, the Zero-mean Normalized Cross-Correlation (ZNCC) coefficients are commonly lower at the microcracks. In practical applications, the location of sub-voxel microcracks could be identified by the distribution of ZNCC coefficients.

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    • LUO Zheng-hang, WANG Jia-xuan, WANG Yu-qing, WANG Xin-yu, ZHANG Xiao-tian, ZHANG Li, ZHANG Yong, HANG Ming, YANG Hai-jun

      Online:October 31, 2022  DOI: 10.11943/CJEM2022051

      Abstract:In order to synthesize high-purity 3,5-diamino-2,4,6-trinitrochlorobenzene (DATNCB), the synthesis route screening and process optimization of DATNCB were studied with 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) or picric acid (2) as raw materials, respectively. The structure of the product was characterized by IR, NMR and MS; the thermal behavior of DATNCB was studied by DSC-TG; the purity of DATNCB was analyzed by HPLC. The results show that: the best synthetic route of DATNCB is starting from picric acid, then by via VNS amination followed by chlorination. The total yield is 39.2%. The highest yield of 3,5-diamino-2,4,6-trinitrophenol (3) was 74.8% when VNS amination temperature was 90 ℃ and post-treatment pH value was 3; the highest yield of DATNCB was 52.4% when phosphorus oxychloride/N,N-dimethylaniline was used as the chlorination reagent, the reaction temperature was 80 ℃ and the reaction time was 10 h. The melting point of DATNCB is 224.0 ℃. There is only one weight loss stage in the range of 179.7 ℃-270.9 ℃ and the weight loss rate is 91.6%; the peak decomposition temperature is 256.1 ℃. The purity of DATNCB reach 97.09% without further purification, and up to 99.8% after recrystallization with ethyl acetate/petroleum.

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    Display Method: |

    Vol, 30, No.11, 2022    

      >Energetic Express
    • Wang Xu-dong, LIU Yu-ji, TANG Yong-xing

      2022,30(11):1081-1082, DOI:

      Abstract:

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    • >Propulsion and Projection
    • LU Xin-hao, YE Bao-yun, CHENG Wang-jian, AN Chong-wei, WANG Jing-yu, ZHAO Feng-qi, QIN Zhao

      2022,30(11):1083-1089, DOI: 10.11943/CJEM2021324

      Abstract:To study the rheological properties and to cure the reaction process of branched polyglycidyl azide (B-GAP)-based propellent, the slurries were tested by rheological research methods, and the changes of viscosity with shear rate and modulus with time at 50, 55, 60 ℃ and 65 ℃ were studied. The results indicate: B-GAP propellant slurry has a shear thinning properties and belongs to pseudoplastic non-Newtonian fluid; The curing reaction rate of the propellant slurry increases as the curing reaction progresses, reaching a maximum value when the curing degree is 0.3, and then the reaction rate begins to decrease until zero; Temperature has a great influence on the kinetics of propellant curing reaction. Within a certain temperature range, the peak value of the curing reaction rate increases with the increase of temperature, and the maximum value of storage modulus decreases with the increase of temperature; Based on the power law equation and Arrhenius equation, the constitutive equation and curing kinetic reaction equation of B-GAP slurry was obtained.

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    • XIAO Yun-dong, WANG Yu-feng, LI Gao-chun, KONG Ling-ze, WU Peng, LAI Shuai-guang

      2022,30(11):1090-1098, DOI: 10.11943/CJEM2022174

      Abstract:Aiming at the problem that the cohesive zone model parameters, describing the mechanical properties of the adhesive interface, which can′t be obtained by traditional experimental method accurately,the inversion research on the relevant parameters of bilinear cohesive zone model used for the adhesive interface is carried out by using the digital image correlation method and Hooke-Jeeves optimization algorithm based on the tensile test results of solid rocket motor rectangular adhesive specimens. The inversion results show that the maximum adhesive strength, modulus and failure fracture energy are 0.55 MPa, 0.57 MPa and 2.26 kJ·m-2, respectively, when the tensile rate is 5 mm·min-1. The relative error of simulated and measured stress-strain curves is corrected from 44.7% to 4.3%. When the tensile strain is 0.05 and 0.08, the maximum displacement errors of simulated and measured region of interest is 0.64 mm and 1.76 mm, respectively, and the average displacement errors of simulated and measured region of interest is 0.38 mm and 0.45 mm, respectively. The validation results indicate that the accuracy of the inversion identification method is high enough and the established cohesive zone model can be used to characterize the mechanical properties of the adhesive interface.

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    • XU Fei-yang, YAO Ya-dong, WU Xing-liang, WANG Xu, LI Wen-hai, CHENG Shi-xiong, LIU Da-bin, XU Sen

      2022,30(11):1099-1105, DOI: 10.11943/CJEM2021327

      Abstract:To improve the hazard classification of anhydrous hydrazine, the extremely insensitive detonating substance (EIDS) gap test and external fire test were conducted for the standard packaging anhydrous hydrazine (18 kg and 120 kg) in accordance with the United Nations “Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria”. The deflagration process, the highest temperature of the fireball surface and shock wave effect of samples were obtained by a high-speed camera, an infrared thermal imaging and a shock wave pressure acquisition system. The experimental results show that, under external fire conditions, the TNT equivalence of the anhydrous hydrazine-18 kg was 0.724, which was 1930.67 times that of anhydrous hydrazine-120 kg. Under certain conditions, anhydrous hydrazine has obvious explosive properties and can be assigned to Division 1.1 C or Division 1.3 C for different packaging design pressures. The hazard class of anhydrous hydrazine is closely related to the standard packaging design pressure. For safety purposes, the design pressure of packaged anhydrous hydrazine should be properly reduced within the allowable range to effectively reduce its hazard.

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    • ZHANG Yu-lu, LIU Ben-ben, CHEN Guo-hui, CAO Bei-bei, HE Ji-yu, LI Xiang-mei, YANG Rong-jie

      2022,30(11):1106-1127, DOI: 10.11943/CJEM2022045

      Abstract:The new challenge to the existing coating layer process was put forward by the development of solid rocket motor technology. In recent years, thermosetting resin as the matrix was used, combined with continuous automatic coating technology, the popular coating production method of coating layer lies in whether complete molding and excellent performance can be obtained quickly. The flow properties and casting condition of unsaturated polyester (UPR) coating layer were studied. The chemical rheological model of the UPR coating layer during continuous automatic manufacturing is obtained by introducing exponential function based on Kinua-Fontana model. The functional relationship of viscosity versus time and temperature of cured UPR is established. The suitable temperature for casting operation was obtained. The filling volume fraction distribution, flow rate distribution and weld line position of coating layer were predicted by introducing of POLYFLOW simulation software, which the constitutive equations is established on the base of Bird-Carrea power-law equation. The casting process was simulated at the constant rate and pressure, respectively. The results show that the casting temperature is below 35 ℃, the casting pressure is more than 1 MPa, and the inlet flow rate is more than 150 mm3·s-1 and less than 175 mm3·s-1 in the coating layer casting process.

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    • KONG Hong-jie, YE Ji-fei, MAO Chen-tao, DU Bao-sheng, ZHENG Yong-zan, CUI Hai-chao

      2022,30(11):1128-1134, DOI: 10.11943/CJEM2022015

      Abstract:The aim of this study is to explore the effect of absorption coefficient on propulsion performance of the laser ablated ammonium dinitramide (ADN)-acetone based liquid propellant. ADN and absorbent were mixed with different proportions in the range of 0-80% and a proportional distance of 10% to form ADN-acetone based liquid propellants. The absorption coefficients of propellants with different proportions were measured and calculated using a near-infrared spectrometer. Under the laser energy of 60 mJ and liquid film thickness of 300 μm condition, the impulses generated by laser ablation of propellants with different proportions were measured using a high-precision torsion pendulum. Results show that the absorption coefficient decreased with the increase of ADN content. In addition, the impulse decreased after peaking at ADN content of 30%, but increased again at ADN content of 80% sharply. The decrease of impulse in the ADN content range of 30%-70% is mainly caused by the decrease of absorption coefficient which leads to the decrease of laser energy deposited by the propellant. The impulse increase at ADN content of 80% is caused by the propellant whose absorption coefficient approaches to 0 and constitutes a “water cannon target” with the container. After the container is ablated by the laser, the propellant will act as a constraint, and result in the increase of impulse.

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    • >Preparation and Property
    • QIAO Chen, LIANG Yi, WU Jin-ting, SHEN Si-jia, ZHAO Ting-xing, ZHANG Yong, HUANG Ming, LI Hong-bo

      2022,30(11):1135-1141, DOI: 10.11943/CJEM2022154

      Abstract:High purity 2,4,6-trinitro-5-ethoxy-1,3-phenylenediamine (DATNEB) can be used as an internal standard in high performance liquid chromatography (HPLC) to accurately analyze the purity of TATB synthesized by the chlorine-containing method. To study the synthesis and energetic properties of DATNEB, high purity DATNEB was prepared from picric acid by aminating with 4-amino-1,2,4-triazole (ATA) and then ethylating with triethyl orthoformate. The overall yield was 32.5% and the purity was over 99.8%. The structure of the product was characterized by IR, 1H NMR, 13C NMR, MS and X-ray single crystal diffraction. The mechanisms of amination and ethylation were discussed, the thermal and detonation properties of DATNEB were also studied. The results show that DATNEB crystallizes in a monoclinic system, space group P21/c with a=1.21261(7) nm, b=0.89654(4) nm, c=1.12310(6) nm, V=1.17675(11) nm3Z=4, ρ=1.62 g·cm-3. DATNEB exhibits an endothermic peak at 193.9 ℃ and exothermic peak at 236.0 ℃, indicating a good thermal stability. It has a detonation velocity of 7.05 km·s-1 and detonation pressure of 21.14 GPa,which is comparable to TNT, while the sensitivityis much lower than that of TNT and RDX. Therefore, the synthesized high-purity DATNEB can not only be used as an internal standard, but also an auxiliary component of molten-cast explosives.

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    • LI Hui-ying, WANG Xuan-yu, LIU Zhi-long, SUN Shu-bao, WEI Qing-lian

      2022,30(11):1142-1147, DOI: 10.11943/CJEM2022119

      Abstract:In order to explore the infrared extinction properties of three-dimensional graphene, three-dimensional (3D) graphene powders were prepared by thermochemical deposition method. The morphological and structural characteristics of the three-dimensional graphene powder were confirmed by electron microscopy and X-ray diffractometer, and the dispersion properties were tested by using a comprehensive powder characteristic tester. Then the infrared extinction properties of three-dimensional graphene were tested by using smoke chamber test, and compared with the extinction properties of composite graphite and carbon fiber under the same test conditions. The results show that the infrared extinction performance of three-dimensional graphene is excellent. The average mass extinction coefficients are about 1.32 m2·g-1 and 1.09 m2·g-1 in the infrared wavelength range of 3-5 μm and 8-14 μm, respectively. Compared with composite graphite and carbon fiber, the average mass extinction coefficients of 3-5 μm are improved by 57% and 132%, respectively. And the average mass extinction coefficients of 8-14 μm are improved by 35 % and 102 %, respectively. It can be seen that 3D graphene shows better infrared extinction ability.

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    • NAN Jun-ping, WANG Yu-ling, SONG Jian-wei, WEI Gai-xia, CHEN Yun, DING Xin-lei, DAI Heng-wei, BAI Guang-mei, QIU Wen-ge

      2022,30(11):1148-1156, DOI: 10.11943/CJEM2022044

      Abstract:In order to improve the activity of hydrogenolytic debenzylation catalyst and reduce the dosage of noble metal palladium during the synthesis of hexanitrohexaazaisowurtzitane(CL-20), carbon supports were prepared by ball-milling/carbonization method using sodium gluconate as a raw material. The effects of carbonization temperature, heating rate and additive addition of sodium gluconate on the support structure and the catalytic activity of the corresponding Pd(OH)2/C catalysts in the hydrogenolytic debenzylation of hexabenzylhexaazaisowurtzitane(HBIW) and tetraacetyldibenzylhexaazaisowutzitane(TADB) were explored. The pore structure, particle morphology, crystal phase structure, chemical composition and surface chemical properties of carbon supports were characterized by nitrogen sorption isotherm measurement(BET), scanning electron microscope(SEM), transmission electron microscopy(TEM), powder X-ray diffraction(XRD), element analysis and temperature programmed desorption (TPD). The results show that the optimized carbonization condition of sodium gluconate was calcination at 700 ℃ with a heating rate of 10 ℃·min-1 in the presence of additive, NaHCO3, which could adjust the puffing carbonization of sodium gluconate. The received carbon supports have rich hierarchical pore structure and appropriate amount of surface oxygen containing groups, and the corresponding Pd(OH)2/C catalysts exhibit high activities in the hydrogenolytic debenzylation reaction of HBIW and TADB.

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    • LOU Ying-jie, CHEN Jian-bo, DING Huan, LIU Yu, WANG Tao

      2022,30(11):1157-1164, DOI: 10.11943/CJEM2022166

      Abstract:The fluorescence properties and fluorescence stability of 2,4,8,10-tetrabroitro-benzopyrido-1,3a,6,6a-tetraazapentylene (BPTAP) were comprehensively investigated. The spectral properties of BPTAP in different solvents (acetonitrile, methanol, tetrahydrofuran, acetone, trichloromethane, ethyl acetate, N"-N"-dimethylformamide, dimethyl sulfone), content of water (0-100%), pH (2.0-12.0) were studied in detail. The effects of light, temperature and pH value on the fluorescence stability of BPTAP solution were investigated, and the mechanism of fluorescence decay of BPTAP solution was analyzed by ultra performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). The results show that although BPTAP has four nitro groups, it exhibits strong green fluorescence in some organic solvents. The fluorescence intensity of BPTAP in acetonitrile is the highest, and its maximum absorption/emission wavelength is 460 nm/508 nm. Low content of water (≤10%) can increase fluorescence intensity of BPTAP, while high content of water (>10%) decrease the fluorescence of BPTAP sharply. BPTAP has higher fluorescence in acidic, neutral and weak alkaline conditions. When the pH value is above 9.0, the fluorescence of BPTAP decreases rapidly with the increase of pH value. BPTAP shows good stability in room temperature and natural light. The closer the light wavelength is to the maximum absorption wavelength of BPTAP and the higher the temperature, the worse the fluorescence stability of BPTAP. The increase of pH value not only reduces the fluorescence intensity of BPTAP, but also accelerates the decline of BPTAP fluorescence. The mechanism of fluorescence decay of BPTAP under alkaline condition is based on nucleophilic substitution. The nitro group at para site of pyridine ring is replaced by the hydroxyl group in alkaline solution to form a new compound 1 (the elemental composition [M-H]- is C11H3N8O7).

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    • >Reviews
    • FU Li-yan, JIAO Bing-jing, WANG Bang-bang, CUI Shang-ping, HAO Yin-wei

      2022,30(11):1165-1176, DOI: 10.11943/CJEM2021310

      Abstract:Boron-based hypergolic ionic liquids, which exhibited low viscosity, short ignition delay time and low cost, were considered as the powerful candidate for conventional liquid propellants. Here, the research progress of design, synthesis and physical chemical properties on boronium-anion-based HILs were systematically reviewed. The theoretical and applied studies including thermal decomposition, hypergolic reaction, combustion mechanism and relationship between structure and performance were briefly summarized. The practical application and development tendency of boronium-anion-based HILs were also discussed.

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    • YU Rui, LIU Xian-long, SHI Cheng-xiang, PAN Lun, ZHANG Xiang-wen, ZOU Ji-jun

      2022,30(11):1177-1176, DOI: 10.11943/CJEM2022071

      Abstract:High-energy-density hydrocarbon fuels are important aerospace power source, which mainly developing direction is high-energy and green, especially under the requirements of low carbon and sustainable development, the green synthesis of high-energy-density hydrocarbon fuel becomes essential. The green synthesis technology of high-energy-density hydrocarbon fuel has been reviewed. Compared with traditional synthesis of JP-10 (exo-THDCPD) and Adamantane, the advanced synthesis for fuel is improved by changing the synthesis route or using green catalysts such as solid acids and ionic liquids. Using biomass as feedstock is another strategy for green synthesis, covering terpenoids and lignocellulose-derived platform molecules such as cyclic ketones/alcohols, furanic aldehydes/alcohols, etc., and the alternative fuels such as bio-based RJ-4(endo-THDMCPD and exo-THDMCPD) and JP-10 have been synthesized. In addition, the photocatalytic technology is used to synthesis of fuel with high tension and polycyclic structures from the perspective of green synthesis process view point, an outlook on further development of high-energy-density hydrocarbon fuel is also given. This review article will be helpful to explore and develop better approach and process for the synthesis of high-energy-density hydrocarbon fuel and upgrade for advanced aerospace vehicles.

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    • Zhou Zhi-yu, Liao Si-cheng, Liu Tian-lin, Zhang Qing-hua

      2022,30(11):1177-1186, DOI: 10.11943/CJEM2022013

      Abstract:Bridged nitrogen-rich heterocyclic energetic compounds are of the rich diversity, good thermal stability and excellent energy density. They are potential materials with high energy density and have been widely studied and reported by scholars all over the world. Among them, the imino group (—NH—), which acts as bridged unit, can not only improve the enthalpy of formation and energy density, but also reduce the sensitivity by the formation of hydrogen bonds through the bridged imino group, thereby constructing high-energy and low-sensitivity energetic materials. This paper introduces the research progress of imino-bridged nitrogen-rich heterocyclic energetic molecules and their salts, and reviews the preparation methods, physicochemical properties and detonation properties of these energetic compounds, the future development potential and research trend of imino-bridged nitrogen-rich heterocyclic compounds are prospected, so as to provide a reference for the design and synthesis of imino-bridged energetic compounds.

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