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Abstract:Four ionic liquids with formula of [Rdmaz][N(CN)₂], R=ethyl(e), n-butyl(b), n-hexyl(C₆) and n-octyl(C₈), were synthesized through a metathesis reaction of quaternized N, N-dimethyl-2-azidoethylamine (DMAZ) with different alkyl chain length with silver dicyanamide. The density, dynamic viscosity and thermal properties of these ionic liquids were measured over a wide temperature range. The effect of the alkyl chain length was discussed on the physicochemical properties. Density decreases while dynamic viscosity and molar heat capacity increase with increasing number of carbon atoms in the alkyl chain. The density shows a linear decrease with temperature, and the dynamic viscosity decreases with temperature following the Vogel-Fulcher-Tamman (VFT) equation. The molar heat capacity (C_{p, m}) increases with temperature following the equation C_{p, m}=a+bT+cT². No melting points were found for these four ionic liquids except for a glass transition temperature (T_g). The T_g values were -102 ℃ for [edmaz][N(CN)₂], -92 ℃ for [bdmaz][N(CN)₂], -89 ℃ for [C₆dmaz][N(CN)₂], and -91 ℃ for [C₈dmaz][N(CN)₂]. The decomposition temperatures of these four ionic liquids range from 241 ℃ to 242 ℃, independent of the alkyl chain length.

Abstract:With petroleum ether and acetone as mixed solvents, the photoisomerization of norbornadiene to quadricyclane was studied, including the influences of initial concentration, amount and type of photosensitizer and reaction time. The optimal reaction conditions were obtained as follows: room temperature, initial reaction concentration 1.0 mol·L^-1, 6% benzophenone, ultraviolet radiation 15 h, which make norbornadine′s conversion up to 93% and selectivity of 100%. After vacuum distillation, high purity quadricyclane fuel (95% purity) was gained with 73% isolated yield.

Abstract:Derivatives of pentacyclo[5.4.0.0^{2, 6}.0^{3, 10}.0^{5, 9}]undecane and methylpentacyclo [5.4.0.0^{2, 6}.0^{3, 10}.0^{5, 9}]undecane were prepared from cyclopentadiene and methylcyclopentadiene by Diels-Alder reaction, [2+2] cycloaddition and carbonyl addition reaction with nitrogen-containing reagent. The products were characterized by MS, IR and ¹H NMR. The thermal decomposition properties of some compounds were studied by PDSC. Results show that the decomposition of derivatives of caged hydrocarbon is an exothermic process and the heat of decomposition increases with the pressure. The volatility of caged hydrocarbon was improved by derivatives. The results indicate that derivatives of caged hydrocarbon could be used as the components of new explosives or high energy fuels.

Abstract:MnO_x/CeO₂-Al₂O₃ monolith catalysts were prepared by impregnation method. The catalysts were characterized by X-ray diffraction (XRD) and temperature-programmed reduction (TPR) methods, The H₂O₂ decomposition reaction activity was determined by oxygen-gasometry of the reaction kinetics in a constant pressure reactor. The stability of monolith catalysts for the decomposition of high concentration hydrogen peroxide was evaluated in a monopropellant thrust hot test system using 90% H₂O₂. The results show that CeO₂ can promote the interaction between MnO_x and CeO₂, the dispersion of Mn species, and the oxidation of low value Mn³⁺ to more active high value Mn⁴⁺, through the formation of surface active oxygen and Mn-Ce-O solid solution. The rise of more active Mn species of Mn⁴⁺ increases the number of low temperature active sites and the ability of reduction-oxidation of catalysts. MnO_x/CeO₂-Al₂O₃ monolith catalyst has a higher activity and stability for high concentration hydrogen peroxide decomposition reaction, compared to MnO_x/Al₂O₃ monolith catalyst.

Abstract:To study the arcless electrical ignition mechanism of hydroxylammonium nitrate (HAN)-based liquid monopropellant LP1846 droplet, based on the two step irreversible chemical reaction mechanism, at the same time, considering the changes of physical parameters with temperature, the numerical simulation for the arcless electrical ignition process of single HAN-based liquid monopropellant LP1846 droplet was performed in the atmospheric environment combined with the related experiments. Results indicate that, according to the variation of reaction rate and temperature distribution, when maximum load voltage is 80 V, the arcless electrical ignition process can be divided into three feature stages: preheating (0~695 ms), thermal decomposition (695~805 ms) and combustion (805~1000 ms). At the preheating stage, the droplet is spherical and the center temperature rises slowly. At the thermal decomposition stage, the reaction occurs in the center of the droplet and develops outwards, the droplet expands and the umbrella distribution of temperature gradient appears inside the droplet. At the combustion stage, the flame is spawned inside the droplet. LP1846 burns vigorously, forming a large amount of products. The temperature of the flow field first increases and then decreases. Ignition delay time decreases with the increase of maximum load voltage. The simulated results has the same trendline of change with the experiment data, and the maximum error is 2.9%.

Abstract:By the minimum free energy method, the thermodynamic properties of the acetylene-ammonia propellant with different content of acetylene, and six propellants of liquid oxigen(LO_X) with acetylene-ammonia, rocket kerosene, CH₄, etc were calculated and analyzed. Results indicate that the acetylene-ammonia propellant with acetylene content of 25% is best in aspect of the specific impulse and security. When the ratio of the chamber pressure to nozzle exit pressure is 180:1, and ratio of the nozzle exit area to nozzle throat area is 35:1, the theoretical equilibrium specific impulse of LO_X/acetylene-ammonia is 372.63 s, which is higher than that of LO_X/rocket kerosene.

Abstract:The long-term storage properties of a notric acid ester (OTTO-II) were investigated by elevated-temperature aging test, natural environment storage test, hydrothermal environment metal compatibility (causticity) test. Results show that its safe storage life estimated at 30 ℃ is not less than 11 a and its ingredients unchanged after stored for 2.4 a under the natural environment. The water in OTTO-II is saturation after storied under the hydrothermal environment conditions of 60 ℃, 85%RH, and 30 d, but the content of the stabilizer and notric acid ester is stable. The magnesium flakes in the hydrothermal environmental, machined by 6 different ways, are not corroded by OTTO-II. Only one flake catalyzes the decomposition of PGDN because of unsuitable machining technique for metal surface.

Abstract:The status of high energetic density diamondoid compounds from the relationship of molecular structure and properties, the synthesis of energetic adamantane derivatives and applications of high energetic density diamondoid compounds are reviewed. Furthermore, the possible orientation of high energy diamondoid fuels was predicted. The green and efficient synthesis process and fuel blending technology of high energy diamondoids are worthy of further study.

Abstract:An energetic complex—[Cu₃(C₄H₂N₆O₅)₃(H₂O)₃]·5NMP(NMP=N-Methyl pyrrolidone)— based on ligand 2, 6-diamino-3, 5-dinitropyrazine-1-oxide(LLM-105) was synthesized and characterized by FT-IR spectroscopy, elemental analysis, single-crystal X-ray diffraction, differential scanning calorimetry (DSC) and thermogravimetry (TG). The Cu(Ⅱ) complex belongs to the triclinic system (space group P-1). The non-isothermal kinetics of the exothermic decomposition process was also studied by the Kissinger and Ozawa methods, the apparent activation energy is calculated as 161 kJ·mol^-1. The catalytic performance towards the thermal decomposition of ammonium perchlorate (AP) has been explored, showing significant catalytic effects on the thermal decomposition of AP.

Abstract:1-Amino-3, 5-dinitro -1, 2, 4-triazole(ADNT) was synthesized by amination of the sodium salt of 3, 5-diamino-1, 2, 4-triazole (DNT-Na⁺) with mesitylene sulfonyl hydroxylamine (MSH) with yield of 66%, in which the DNT-Na⁺was obtained from 3, 5-diamino-1, 2, 4-triazole. The structure of ADNT was characterized by IR, MS, ¹H NMR, ¹³C NMR and elemental analysis, the thermal behavior was studied by differential scanning calorimetry(DSC). The factors effecting amination were investigated as well. Results show that the optimum reaction conditions are the molar ratio DNT-Na⁺ to MSH is 1:1.5, reaction time 12 h at room temperature. The melting and decomposition temperatures are 128.7, 225.8 ℃, respectively, and the impact sensitivity (H₅₀) with 2 kg drop weigh is beyond 112cm, which showing ADNT is an energetic insensitive explosive with good comprehensive performance.

Abstract:A new energetic burning rate catalyst, fullerene ethylenediamine nitrate, was synthesized using fullerene, ethylenediamine and dilute nitric acid as raw materials. The structure was characterized by UV-Vis, FT-IR, elemental analysis and XPS. The thermal decomposition characteristics were investigated by thermogravimetric analysis(TG) and differential thermal analysis (DTA), and the thermal decomposition process was traced through TG-FTIR technique. Results show that the molecular formula of fullerene ethylenediamine nitrate is H₁₆C₆₀(H₂NCH₂CH₂NH₂·HNO₃)₁₆. The degradation of fullerene ethylenediamine nitrate is two-stages process : the first-stage with 40.8% weight loss occurred in the temperature range 100~250 ℃, intense decomposing of NO₃^-, part of the branched chain decomposing, and releasing H₂O, CO₂, CO, N₂O and NO₂. The second-stage with 59.2% weight loss occurrs in the temperature range 250~580 ℃, decomposing of residual branched chain on carbon cage, carbon cage decomposiing and releasing CO₂, revealing that the fullerene ethylenediamine nitrate has good thermal stability.

Abstract:To reduce the acidity of 3-nitro-1, 2, 4-triazol-5-one(NTO), a new energetic ionic compound guanylurea salt of 3-nitro-1, 2, 4-triazol-5-one(GUNTO) was designed and synthesized by two methods of a pot method and distribution method using guanylurea hydrochloride and NTO as starting material with total of yields over 85%.Its structure was characterized by IR, NMR, MS, elemental analysis and X-ray single crystal diffraction. The physiochemical properties and detonation parameters of GUNTO were studied. Results show that by the real density of 1.72 g·cm^-3 and the calculated enthalpy of formation of -347.35 kJ·mol^-1, the theoretical detonation velocity and detonation pressure predicted by the Kamlet formulas are 6683.49 m·s^-1 and 19.27 GPa, respectively. The mechanical sensitivities are determined as: the impact sensitivity is 0%, friction sensitivity is 0% and characteristic drop height of impact sensitivity H₅₀ is more than 125.8 cm. The peak temperature of DSC curve at 10 ℃·min^-1 is 236.8 ℃. In comparison with other amine salts of NTO, GUNTO has higher nitrogen content, better thermal stability and lower sensitivity.

Abstract:To enhance the efficient and rate of magnesium/seawater reaction, Mg-based hydro-reactive materials were prepared via a multiple variable speed cycle process by high-energy milling method in inert atmosphere. Scanning electron microscope (SEM), thermogravimetry (TG) and specific surface test were used to characterize the microstructure and oxidation characteristic of the materials. The real-time amount of hydrogen produced by reaction of Mg-based materials and seawater was recorded using an independent designed metal/water reaction device. The hydro-reactivity of Mg-based hydro-reactive metal materials was studied. Results show that the high-energy milling can significantly enhance the reaction activity of Mg-based materials and seawater. The reaction efficiency of magnesium powder after ball mill reaches 80.5%. Addition of catalyst in the process of ball mill can further enhance the reaction activity of Mg-based hydro-reactive materials. The total yield of reaction can reach 91.1%. The hydrogen generation reaction rate in the fast stage is 741 mL·min^-1·g^-1.

Abstract:X-ray micro-tomography (X-μCT) was applied to obtain the complete three-dimensional (3D) recordings of the PBX under unidirectional warm die compaction based on TATB granules. The loose-packed granules obtained through heating up to softening, compaction and friction were still complete and were preserved in different morphological features. The typical form of compacted granules reveals a polygon at radial direction and oblong shape at axial direction in the PBX. There is an obvious angle between axial direction and radial direction. The axial and radial morphology distributions reveal the mechanics response and internal friction mechanism. X-μCT provides a analysis method of non-invasion into heterogeneous material internal and can probe the arrangement of compacted granule material and high density interface layers in PBXs.

Abstract:For fully understanding the thermal properties of Cu-FOX-7 complexes [FOX-7=1,1-diamino-2,2-dinitroethylene], thermal decomposition behavior of Cu(NH₃)₂(FOX-7)₂ was studied with DSC and TG-DTG methods. The kinetic equation of the first exothermic decomposition process is $\frac{{{\rm{d}}\alpha }}{{{\rm{d}}T}} = \frac{{{{10}^{15.12}}}}{\beta }4{\alpha ^{3/4}}\exp ( - 1.429 \times {10^5}/{RT})$. The self-accelerating decomposition temperature and critical temperature of thermal explosion are 145.5, 156.2 ℃, respectively. The thermal stability of Cu(NH₃)₂(FOX-7)₂ is much lower than that of FOX-7. The specific heat capacity of Cu(NH₃)₂(FOX-7)₂ was determined with a micro-DSC method. Molar heat capacity is 447.3 J·mol^-1·K^-1 at 25 ℃. Adiabatic time-to-explosion was also estimated to be about 9.5 s. The thermal stability of Cu(NH₃)₂(FOX-7)₂ is much lower than that of (FOX-7).

Abstract:A quasi-isentropic compression loading technique (ICE) driven by electro-magnetical was applied to investigate the dynamic behaviors of an un-reacted HMX based polymer-bonded explosive(PBX). Multiple samples with different thicknesses were loaded up to 8 GPa. Particle velocities of the interface between sample and LiF windows were measured by laser interference method, and by Lagrange data processing, the experimental isentropes within 8 GPa of this explosive were obtained. Based on the fitting parameters of the isentropes, the isentropic compression procedure was numerically simulated by one dimensional hydrodynamics code, and the calculated particle velocities are consistent with the experimental results.

Abstract:Stress-strain curves of a RDX Based cast PBX were obtained using an INSTRON testing machine and an optimized Split Hopkinson pressure bar(SHPB) at different strain rates(10^-4~10^-2/s and 843²~1490⁴/s). Results show that mechanical properties of the material including elastic modulus, compressive strength, and strain at-maximum-stress, increase linearly with strain rate in quasi-static tests. With in small dynamic strain rate range, weak rate dependence is observed in SHPB tests, especially at the initial loading stage. The dynamic failure criterion were controlled by stress, and materials failure occurrs at 12MPa. Based on rate-dependent phenomenological material models of solid propellants and rubber materials, one-dimension constitutive equations for quasi-static and dynamic compression are presented, showing a good agreement with experimental data with error less than 10%.

Abstract:In order to improve the prediction accuracy of the detonation parameters, a new method based on Support Vector Machine(SVM) theory and Hessian Local Linearly Embedding algorithm (HLLE) was proposed to predict 16 traditional composite explosives. The original data after dimension reduction with HLLE, was input to regressively predict the heat and velocity of composite explosion by SVM. The best kernel function parameter and penalty factor are selected by Genetic Algorithm(GA). The calculated results of the explosives almost agree with those of the literature, and the relative error is within ±3%. Using the method, the values of detonation velocity for 2, 4-diamino-3, 5-dinitro pyrazine-1-oxide/1-methyl-3, 5-dinitro-1, 2, 4-triazole and 2, 4-diamino-3, 5-dinitro pyrazine-1-oxide/1-methyl-4, 5-dinitroimidazole were predicted and compared with experimental and the relative errors are 2.91% and 3.72%, respectively, showing that the proposed method is comparatively accurate.

Abstract:In order to study the influence of V-shaped cavity degree(θ), length(L) and depth(H) on the damage efficiency of half-premade fragmented Penetrator with Enhanced Lateral Efficiency (HF-PELE), numerical simulations of HF-PELE penetrating 4340 steel were carried out by ANSYS/LS-DYNA. Based on the influence of V-shaped cavity degree on damage efficiency of HF-PELE, the optimized structure parameters were acquired by orthogonal test with θ, L and H as variables and maximum radial velocity(v_{r, max}) as the objective function: θ=40°, L=8mm, H =3.5mm and v_{r, max}=161.82 m·s^-1. Results indicate that the V-shaped cavity depth makes a big difference on the damage efficiency of PELE, the V-shaped cavity degree follows behind, and the V-shaped cavity length′s is minimum.

Abstract:To analyze the impact of VESF on Jetting Projectile Charge(JPC) formation, nonlinear dynamics analysis software AUTODYN-2d was used for numerical simulation. The simulation results of penetrator formation were obtained with different VESF materials, shapes(K shape, rectangular, triangular) and the distance between VESF and main charge. Results show that the main charge initiation point transfers from center to outside gradually with the increase of VESF material density and the distance between VESF and main charge. Different initiation modes are formed with different transverse shapes of VESF, and it is a point initiation for K shape and rectangle, and the plane initiation for triangle. The optimum conditions to JPC formation are: steel plate, K shape and 6 mm (distance from VESF to charge).

Abstract:Taking non-ideal explosive composed of hexogen (RDX), oxidant ammonium perchlorate (AP) and combustible agent aluminium(Al) powder as the research object, the gas products and condensed phase products of eight non-ideal explosives exploded and produced in a confined explosion container were collected and analyzed by thermal analysis-mass spectrometry technology, Fourier infrared spectrometer, gas chromatograph analysis and X-ray fluorescence analyzer. The heat of detonation was calculated by Hess′s law and compared with the experimental value. Results show that under the condition of the detonation, the detonation products mainly are composed of gases N₂, H₂, CO₂, H₂O, CH₄, CO and O₂ etc and solid compositions Al, Al₂O₃, AlCl₃ and C etc. With the increase of the positive oxygen balance, the generation quantities of N₂, H₂O, CO₂, O₂ and HCl increase, while those of Al₂O₃, AlCl₃, H₂ and CO increase firstly, and then decrease, The generation quantities of Al and C decrease. The measured heat of detonation of non-ideal explosive with oxygen-balance in the range of -22.4%~-29.7%, is between 8773 and 8813 J·g^-1, and the relative error between theoretical and expermetal values is less than 1%, showing a good agreement.

Abstract:To understand the solidification process of 2, 4-dinitroanisole(DNAN), the temperature field in the central axis in the solidification process was tested by Bragg gratings. The microscopic phenomenon of natural convection of liquid phase was considered. The temperature field, flow field and phase interface position for the solidification process of DNAN were calculated by volume-control method. The formation of shrinkage holes and shrinkage porosities were predicted by considering both critical solid phase fraction and feeding length. Results show that the temperature hysteresis appears at about 96 ℃ and most obvious in the center. The maximum velocity of natural convection of the early stage of liquid reaches 10^-3 magnitude(m·s^-1). This natural convection helps to transfer mass and to accelerate the process of solidification. Under no feeding conditions, the phase interface in the solidification process of DNAN is V-shaped, it shrinks and transfers from bottom to top. After contraction and solidification, the shrinkage holes distribute continuously in the central axis of explosive, and the maximum porosity in the center is 0.38.

Abstract:In order to solve the plug hole and distortion during nitroguanidine propellant cutting process, a high-pressure water jet cutting system device was designed, and its mechanical model was established. The jet cutting technology conditions were studied. The safety of cutting process was also evaluated. The combustion performance of jet cutting propellant samples was analyzed by the closed bomb test. Results show that, the jet cutting depths is inversely proportional to cutting velocity and strength of propellants. The kerf width increases with increasing target distance, which is consistent with theoretical analysis. Abrasive water jet can be used for cutting the propellants whether the solvent is removal or not, but water jet only used for cutting propellants unremoval of solvent. The max temperature of the nitroguanidine propellant surface is only 60 ℃ during the jet cutting process, which is below its initial thermal decomposition temperature(178.1 ℃). There is no significant difference in the combustion performance between the propellants cutting by jet and hand.

Abstract:In order to obtain the appropriate incision parameters, stick propellant of 19 holes with different web, synclastic incision intervals, incongruous incision intervals and incision web were prepared and studied by closed-bomb test. The influence of incision parameters on constant volume combustion performance was studied and compared with that of porous granular propellant. Results show that the partially cut multiperforated long stick propellant with proper incisions can obtain similar static combustion performance with the granular propellant. In this study, the progressive burning is good and erosion burning is not obvious when synclastic incision intervals is less than 20 mm.

Abstract:The combustion characteristics and thermal behavior of modified double base propellant containing Trans-1, 4, 5, 8-tetranitro-1, 4, 5, 8-tetraaza dacalin (TNAD) were investigated by burning rate test and PDSC. Results show that there was a general increase(greater than 9%) in burning rate when RDX is replaced by TNAD in propellant in the tested pressure range of 9-22 MPa. The pressure exponent in the pressure range of 9-15 MPa decreases from 0.26 to 0.18, but increases from 0.10 to 0.14 when the pressure is above 15 MPa. By analyzing from PDSC data, it is suggested that there is a strong interaction between NC/NG and TNAD, which increase the burning rate of propellant by enhancing the decomposition rate and heat release of the mixed system.

Abstract:The velocity histories of the Mylar flyer, Al/Mylar double-layer and Cu/Mylar double-layer driven by electric explosion of metallic foil were recorded by displacement interferometer system for any reflector (DISAR). Results show that at the charging voltage of 25.4 kV, the effective driven time and maximum flyer velocity in acceleration cavity is 1.6 μs and 4.4 km·s^-1 for the Mylar flyer, and longer than 3.0 μs and lower than 4.0 km·s^-1 for the Al/Mylar double-layer and Cu/Mylar double-layer, respectively. The materials of flyers play significant roles in their movement when it is driven by electric explosion. In comparison with the Mylar flyer, the metal/Mylar double-layer flyer is more conducive to keep running posture of flyer, but its speed is lower when flying the same distance.

Abstract:The synthesis of cyclourea nitro-amine energetic compounds is reviewed. Two synthetic methods of cyclourea nitro-amine derivatives through urea condensation-nitration method or small molecule condensation-nitration method are summarized. Compared to other energetic compounds, the characteristics of N-dinitro-substituted cyclourea nitro-amine derivatives have high density, high detonation velocity and poor hydrolytic stability, and possible reasons for these performances are preliminarily discussed. Their importance in energetic materials are revealed.

Abstract:2-Azido-4-nitroimidazole was synthesized using 2-amino-4-nitroimidazole or 2-azidoimidazole as raw materials with yield of 87% or 78%, respectively, and its structure was confirmed by MS, IR and ¹H NMR. The calculated detonation velocity and detonation pressures are 7.59 km·s^-1and 24.39 GPa, respectively.

Abstract:Using dichloroglyoxime as raw material, dihydroxylammonium 5, 5′-bistetrazole-1, 1′-diolate (HATO) was synthesized via substitution, cyclization and metathesis reaction with a total yield of 81.7%. Wet diazidoglyoxime was experimentally found to increase the operational safety, and dilithium 5, 5′-bistetrazole-1, 1′-diolate with high solubility in water was employed to increase the yield of metathesis reaction. Further more, the properties of HATO such as thermal stability, mechanical sensitivity, morphology, size and particle distribution were investigated. It was found that the values of exothermic peak, standard volume of gas evolved, explosion probability of impact sensitivity, 50% drop height of impact sensitivity, explosion probability of friction sensitivity, and mean volume diameter are 249.14 ℃ (10 ℃·min^-1), 0.3 mL·g^-1(100 ℃/48 h), 16% (10 kg drop hammer, 25 cm drop height), 100 cm (5 kg drop hammer), 24% (3.92 MPa, 90 °), 334 μm.

Abstract:A novel energetic compound, 6-dinitroethylene-4, 5, 8-trinitro -5, 6, 7, 8-tetrahydro -4H-imidazo [4, 5-e] furazano [3, 4-b] piperazine (PNEIFP), was designed and synthesized from glyoxal and FOX-7 by two cyclizations and nitration. In addition, some properties of PNEIFP were calculated by Gaussian 09 program and VLW formula. The results show that its density is 2.02 g·cm^-3, and the detonation velocity is 9681.0 m·s^-1, and the enthalpy of formation is 724.1 kJ·mol^-1. PNEIFP easily decomposes at room temperature.

Abstract:The cylindrical and plate-like HMX crystals were prepared by the slow evaporated crystallization in the capillary tube and the petri dishes, respectively, and were characterized by optical microscope and powder x-ray diffraction (XRD). Results show both HMX crystals present the striking (011), (022), (033) peaks, which suggests the appearance of (011) face. It demonstrates that the restricted crystallization could be used as a method to control the HMX morphology.

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