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

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

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

Abstract:In order to explore the processing parameters for the continuous production of double-based spherical propellants with particle sizes in the range of hundred microns， a Co-axial flowing microfluidic installation was used to process the dispersed phase of a 10 % double-based propellant solution and prepare the double-based spherical propellants with a controllable particle size in the range of 400-700 μm. The effects of two-phase flow ratio（Q_c/Q_d） and chip size on the morphology and particle size of double-based spherical propellants were investigated. Moreover， the morphology， particle size distribution， and constant volume combustion performance of samples were characterized using scanning electron microscopy， optical microscope， and closed bomb test，respectively. Results show that， the median particle size （D₅₀） of the samples prepared into the same type of chip increases first and then decreases with the decrease of two-phase flow ratio. As the internal diameter of the continuous phase or the dispersed phase channel increases， the D₅₀ of the samples obtained at the same two-phase flow ratio increases successively. When the internal diameter of the continuous phase and the dispersed phase channels are 2 and 0.85 mm， and the two-phase flow ratio is 200.00， the resultant sample displays high monodispersity， smooth surfaces， dense inside， regular spherical shapes （average sphericity φ_K=0.949） and narrow size distribution （span=0.09）. Its D₅₀ is 539.94 μm， and the average particle density is 1.601 g·cm^-3. In the closed bomb test， the pressure-time curve shows that the samples with two varied packing densities （Δ₁=0.12 g·cm^-3， Δ₂=0.20 g·cm^-3） can burn stably， and the dynamic vivacity-relative pressure curve follows the regressive burning law of the dense spherical propellants.

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

Abstract:The launching device of 105 mm short tube gun was designed to carry out the armor piercing projectile test under dynamic shooting condition. Transient pressure measurement system and high-speed camera were used in the experiment to obtain the chamber pressure and projectile motion parameters during the engraving process. The engraving resistance characteristic curves of projectile were calculated by projectile dynamics equation. Besides， the influence of different pressure rise rate on the process of projectile engraving was analyzed under two conditions. Based on the test conditions， the engraving deformation process of nylon belt of armor piercing projectile was numerically simulated by using the C-S model with elastic-plastic large deformation of belt material. The experimental data indicated that the engraving resistance increases first and then decreases with the engraving displacement in the engraving process. Therefore， when the engraving resistance reaches the maximum， only part of the nylon belt was completely squeezed. The elasticity of the nylon elastic band increases the contact area with the groove. When the average pressure rise rate of projectile bottom increases from 2.92 MPa·ms^-1 to 3.28 MPa·ms^-1， the engraving time shortens by 4.36% and the maximum engraving resistance increases by 5.12%. The nylon belt cross deformation stress cloud diagram was obtained by the numerical calculation to show that the elastic-plastic deformation of the nylon belt occurred. The interior of the elastic belt is mainly in the state of compression shearing and the main failure form of the elastic belt is tensile shearing failure. The displacement curves obtained by simulation and experiment have the same trend and the error is 5.24%.

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

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

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