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Abstract:Dilithium 5, 5′-bistetrazole-1, 1′-diolate(Li₂DHBT), disodium 5, 5′-bistetrazole-1, 1′-diolate(Na₂DHBT) and dipotassium 5, 5′-bistetrazole-1, 1′-diolate(K₂DHBT)were synthesized from 5, 5′-bistetrazole-1, 1′-diole with high yields over 90%, while dihydroxylammonium 5, 5′-bistetrazole-1, 1′-diolate(HATO) was synthesized by ion exchange reaction with lithium ions with high yield of 94.1%.Using the laser monitoring technique, the solubilities of HATO、Li₂DHBT、Na₂DHBT and K₂DHBT in water from 20 ℃ to 60 ℃ were measured by dynamic method.The experimental data were correlated with the ideal solution model and Apelblat equation.Results show that the solubilities of four kinds of salts increase with increasing temperature.The average relative deviations between experimental and calculated data by ideal solution model and Apelblat equation are less than 3.5%, while the Apelblat equation gives the better fit with the experimental data.The enthalpies of dissolution of HATO, Li₂DHBT, Na₂DHBT, K₂DHBT are 27.991, 27.632, 31.125 kJ·mol^-1 and 17.991 kJ·mol^-1, and the entropy of dissolution of HATO, Li₂DHBT, Na₂DHBT, K₂DHBT are 23.431, 36.807, 41.251 J·mol^-1·K^-1 and 3.139 J·mol^-1·K^-1, respectively.

Abstract:A novel energetic ionic salt 1-amino-2-nitroguanidinium 4-nitroamino-1, 2, 4-triazole salt was synthesized using 1-amino-2-nitroguanidine and 4-nitroamino-1, 2, 4-triazole as the starting materials, and its reaction conditions were optimized.Its thermal decomposition behavior was investigated by TG-DSC.Its detonation properties were predicted using Kamlet-Jacobs formula.Results show that the yield of 1-amino-2-nitroguanidinium 4-nitroamino-1, 2, 4-triazole salt is up to 86.5% under the optimum synthetic conditions of reaction time 4 h and reaction temperature 50 ℃.The compound decomposes sharply around 175.5 ℃, revealing a better thermal stability.The heat of formation of the compound obtained by Born-Haber cycle is 551.3 kJ·mol^-1.The determined value of density is 1.59 g·cm^-3.Based on the heat of formation and density obtained, the detonation velocity and detonation pressure of the compound are 8.05 km·s^-1 and 26.6 GPa, respectively.

Abstract:In order to develop new nitratopolyether binders, 2-nitratomethyltetrahydrofuran(NMTHF) was synthesized with 2-hydroxymethyltetrahydrofuran(HMTHF) as starting material and dinitrogen pentoxide(N₂O₅) as nitrating agent with yield of 90.6% and purity of 98.9%.The structure of NMTHF was characterized by IR, ¹H NMR and element analysis. The effects of synthetic conditions on nitration reaction were discussed.The optimized synthetic conditions are as follows:n(N₂O₅):n(HMTHF)=1.0:1.0, reaction temperature -10 ℃, and keeping reaction for only 5 min when the CH₂Cl₂ solvent of HMTHF was dropped over.

Abstract:1-Methyl-3, 4-dinitropyrazole(MDNP) was synthesized using 3-nitropyrazole as starting material via nitration and methylation, and its structrue was characterized by infrared spectrum(IR), proton nuclear magnetic resonance(¹H NMR) and differential scanning calorimetry(DSC).The methylation reaction conditions were optimized.Results show that its thermal decomposition temperature is 298 ℃, and melting point is 20 ℃, having good thermal stability.The optimum conditions of methylation reaction is as follows:the reaction temperature 90 ℃, the reaction time 6.5 h, the molar ratio of 3, 4-dinitropyrazoles, DMC(dimethyl carbonate) to anhydrous potassium carbonate 1:10.5:1.5, and the yield of target product is 55.6%.

Abstract:1-Diazidecarbonimidoyl-5-azidotetrazole(DACAT) was prepared via diazotized substitution reaction and cyclization reaction using triaminoguanidinium as raw material.Its structure was confirmed by IR, ¹³C NMR and ¹⁴N NMR.The influence of triaminoguanidinium/sodium nitrite molar ratio, reaction temperature, reaction time and pH of system on the yield of reaction was examined.The geometry of DACAT were optimized at the B3LYP/6-31G(d, p) basis set level using a density functional theory(DFT) Theoretical density(ρ), enthalpy of formation of gas phaseΔ_fH_{g, m}^θ, enthalpy of formation of solid phaseΔ_fH_{s, m}^θ, detonation velocity(D) and detonation pressure(p) for DACAT were calculated by Monte-Carlo method, complete base set method(CBS-4M) and Kamlet-Jacobs formula, respectively.Results show that the optimized process conditions were determined as:n(triaminoguanidinium):n(sodium nitrite)=1:2, diazotized substitution reaction temperature 0 ℃, cyclization reaction temperature 20 ℃, pH=8.0, diazotization reaction time 30 min and cyclization reaction time 30 min.The total yield of the two steps reactions was 12.6%.The obtained values of ρ, Δ_fH_{g, m}^θ, Δ_fH_{s, m}^θ, D and p are 1.7628 g·cm^-3, 1590.42 kJ·mol^-1, 1435.44 kJ·mol^-1, 8725 m·s^-1 and 34.52 GPa, respectively.

Abstract:To research the change rule of temperature field and stress field in the curing process for cast PBX(Polymer Bonded Explosive, PBX), the temperature field in the curing process of cast PBX under 60 ℃ was tested by Bragg gratings.The numerical simulation of temperature fields and stress fields under different heat transfer coefficient during curing process of the cast PBX explosive were conducted by finite element method.Results show that in the first stage of curing reaction, the temperature of the grain is higher than 60 ℃.The temperature in the central portion of the grain reach 65 ℃.The decreasing trend of temperature is revealed from the center to internal wall of the mold.Largest temperature gradient appears at the 3.88×10⁵ s.Stress concentration area is mainly located in the bottom of the grain.The effective stress concentration area and the maximum effective stress enlarge with increasing the heat transfer coefficient between model and grain.When the value of heat transfer coefficient is 12 W·m^-2·K^-1, the grain has the maximum stress concentration area at 3.88×10⁵s and the maximum effective stress is 6.69 kPa.

Abstract:The spherical micron RDX particles were prepared by the spray drying method.The effects of four low-boiling solvents, including methyl acetate, acetonitrile, acetone, butanone, on morphology and properties of RDX samples were studied.Scanning Electron Microscope(SEM) was employed to characterize the samples.The impact sensitivity and thermal decomposition properties of the samples were also measured and analyzed.Results show that the as-prepared RDX particles are all spherical in shape and range from 1 μm to 5 μm in size.The RDX particles from butanone disperse evenly and have a relatively smoother surface and fewer defects.Compared with that of raw RDX, the impact sensitivity of as-prepared RDX samples are all decreased obviously due to the facts that the drop height is about 2 times of raw RDX.For the spherical RDX prepared by the spray drying method, the apparent activation energy of thermal decomposition(E) and the thermal explosion critical temperature(T_b) decreases.The RDX particles from methyl acetate decreases 33.35 kJ·mol^-1 and 7.77 ℃.

Abstract:To simulate the combustion property of seven-hole variable burning rate gun propellant, a combustion model of seven-hole variable burning rate gun propellant was established.On the basis of the geometric combustion law, the function relation of combustion gas generation brisance(Γ)against the percentage of gun propellant burned(Ψ) was deduced.The Γ-Ψ curves were obtained by programming and calculation.The effects of burning rate ratio, inner pore diameter of the fast burning layer, length-to-diameter ratio and thickness of the slow burning layer on the combustion progressive property of seven-hole variable burning rate gun propellant were analyzed.Results show that the seven-hole variable burning rate gun propellant under the following conditions has better combustion progressive property:the burning rate ratio of the fast burning layer to slow burning layer in 1.5-2.5, length-to-diameter ratio ranging from 2 to 3, the thickness ratio of slow burning layer and fast burning layer in the range of 0.1-0.22, and the inner pore diameter of the fast buruing layer ranging from 0.2 mm to 0.3 mm.

Abstract:Boron based ducted rocket experimental system for ground simulation was established to study the boron combustion.Through heating the boron in a primary chamber by the combustion gas of the ethanol and oxygen, and using air react with boron in the secondary chamber, the working process under the condition of the flow field was simulated, and the similar condition for the real ducted rocket was obtained as following:the compositions of primary products are H₂, CO and boron particles, and in the secondary chamber, the total and static temperatures 1300-1400 K, total and static pressures 0.4-0.5 MPa and Mach number about 0.35.With the experimental system, the condensed products at different axial locations including the primary chamber, secondary chamber inlet, mixture region, combustion region, nozzle, were collected and analyzed by the Scanning Electron Microscope, X-ray diffraction and the energy dispersive X-ray spectroscopy.Results show that boron particles are grain during the reaction and its morphology changes a little.The boron is combusted mainly in the secondary chamber, and most in the combustion region, less in the region before the nozzle, and the lest in the mixture region.

Abstract:In order to study the effects of the initial temperature of AP/HTPB(ammonium perchlorate/hydroyl-terminated polybutadiene)composite base bleed propellant on the hitting points of the projectile scatter quantitatively, the initial temperature sensitivity factor(σ_p) of burning rate for AP particles was introduced, and calculated by three models, Glick, Kubota and BDP considering that the burning rate of AP was dominate in base bleed propellant.Based on the calculated σ_p, the internal ballistic model and 6D external ballistic model for a 155 mm base bleed projectile were built and solved simultaneously to simulate the hitting points of the projectile scatter.Results show that σ_p=0.43%/K obtained from model BDP is appropriate owing that the inner pressure of base bleed unit is close to 0.1 MPa and changes little.The sensitivity factor for the range and cornering of the projectile affected by the initial temperature of AP/HTPB propellant are 8.22 m·K^-1 and 0.477 m·K^-1, respectively, and the calculated range changing with initial temperature is very close to that from literature with the error of 12%.

Abstract:To study the effect of explosive/tungsten powder mass ratio on dispersal velocity of tungsten powder for low collateral damage(LCD) ammunition, a model describing the theoretical relation of initial dispersal velocity of tungsten powder and explosive/tungsten powder mass ratio was established based on the related theory of explosion mechanics.To analyze the axial velocity of tungsten powder, seven plans of explosive/tungsten powder mass ratio from 0.0335 to 0.3636 were numerically simulated by ATUODYN-3D software.The axial dispersal velocity of tungsten powder under different plans was analyzed and compared.To verify the theoretical model of initial dispersal velocity of tungsten powder and mass ratio and simulation results of initial dispersal velocity of tungsten powder with different explosive/tungsten powder mass ratio, the experiments of three LCD simulated projectile with mass ratio as 0.0335, 0.0875 and 0.2113 were performed.Results show that the relationship of initial dispersal velocity of tungsten powder and explosive/tungsten powder mass ratio is nonlinear increasing.Increasing the explosive/tungsten powder mass ratio can effectively increase the velocity of tungsten powder, but when the explosive/tungsten powder mass ratio is greater than 0.1734, the promotion effect on the velocity of tungsten powder will began to decrease.The simulated results and the theoretical calculation results of initial dispersal velocity of tungsten powder are in better agreement with the experimental ones under same mass ratio.

Abstract:By using magnetron sputtering and micro-manufacturing technology, the(B/Ti)_n/TaN thin-film initiator bridge was fabricated, with the 40 layers B/Ti multi-layers(4 mm×4 mm) deposited on TaN thin-film 80 μm×40 μm×2 μm initiator bridge contained 40 layers of B and Ti, where the first layer was 40 nm thickness B, and others were 200 nm B or Ti.The ignition performances of the samples were tested by a 47 μF tantalum capacitor with voltage of 40 V.Results show that the ignition delay time, input ignition energy, explosion temperature, duration time and height of flame for TaN thin-film initiator bridge are 85 μs, 15 mJ, 2500-3500 K, 0.15 ms, 5 mm, while, for(B/Ti)_n/TaN thin-film initiator bridge, they are 37 μs, 6 mJ, 4000-8500 K, 0.25 ms, 10 mm, respectively.It is found that the introduction of B/Ti multi-layers can decrease the ignition delay time and input ignition energy, improve the ignition performances of TaN thin-film initiator bridge.

Abstract:In order to improve the reliability analysis of the explosive initiator with small sample size, a method based on generalized linear models of reliability analysis for explosive initiator was proposed according to sensitivity test and characteristics of reliability analysis.The likelihood function was transformed to a generalized linear expression of binomial variable.Using the generalized linear model for binomial distribution, the maximum likelihood estimations of the model coefficients were obtained, and corresponding arithmetic was put forward.With the asymptotic normality of maximum likelihood estimations, the approximated confidence interval for the reliability was obtained by logit transform of reliability fuaction.The present method was validated by the test data of stab detonator and electronic detonator.Results show that using about 150 samples is available to analysis the explosive initiator with a reliability goal of 0.999 by the method in this research.

Abstract:In order to investigate the characteristic of the acoustic radiation induced by the interaction between water and high temperature particles produced by underwater combustion of pyrotechnic composition, a bubble dynamic model was deduced based on the heat transfer and mass transfer theory.The effect of initial temperature and radius for high temperature particles on the bubble dynamic behaviors and acoustic radiation characteristics were calculated and analyzed with the burning depth of 1 m.Results show that with the increase of the initial temperature and the radius, the bubbles volume, volume change acceleration and the sound pressure all increase.With the initial temperature of high temperature particle increasing by 200 K, the volume of the bubbles, the volume change acceleration and the sound pressure all increase by an average of 1.01 times, 1.78 times and 1.04 times, respectively.And with the initial radius of high temperature particle increasing by 0.4 mm, the volume change acceleration and the sound pressure all increase by an average of 1.78 times, 2.28 times and 1.15 times, respectively.

Abstract:When the explosive and propellant samples are analyzed by chromatography, firstly, the tested substances need to be extracted into solvent from solid matrices.The time required for traditional pretreatment methods of explosive and propellant samples such as Soxhlet′s extraction(SE) method and solvent-dissolve-water-precipitation extraction(SDWP) method is too long, which can not meet the needs of modern rapid detection.The extraction effect of some explosive and propellant samples by the ultrasound-assisted extraction(UAE), microwave-assisted extraction(MAE) and pressurized-liquid extraction(PLE) were examied.Results show that MAE and PLE have to choose the extraction solvent, which can not dissolve nitrocellulose(NC), only dissolve the tested substances.The extraction time of UAE, MAE and PLE is shorter than that of SE and SDWP.UAE is used to extract the explosive and propellant samples with loose texture and without NC polymer as binder.The use of higher MAE temperature is limited due to volatile obviously after nitroglycerin(NG) heating under normal pressure, i.e.the effect of microwave is restricted, the price ratio of extraction efficiency relative to expensive instrument is not high.PLE can restrain the volatilization and decomposition of NG, having the very strong dissolution ability for the tested substances, including cyclotrimethylene trinitramine(RDX), and the advantages of high extraction efficiency and wide application.Its shortcoming is that running cost is higher.

Abstract:NO is difficult to be rapidly oxidized and absorbed in the wet oxidation method used in the treatment of the NO_x exhaust gases produced in the production process of propellants and explosives, which cause the low absorption rate.To solve this problem, ferrous complex Fe^Ⅱ(EDTA)^2-(Ethylene Diamine Tetraacetic Acid, EDTA)was used as the absorbent of NO in a bubbling reactor.The effects of absorbing solution concentration and NO gas concentration on the absorption rate were investigated.The mass transfer-reaction process of NO absorption was analyzed.The theoretical model describing the NO absorption process was derived.Results show that:under experimental conditions, the absorption rate increases linearly with the increase of NO concentration, and the NO absorbed by Fe^Ⅱ(EDTA)^2- is a pseudo first-order reaction process.The error between calculated values obtained by absorption process model and experimental ones is within 5%, both have good consistency, which can be used to describe the mass transfer-reaction process of NO absorbed by Fe^Ⅱ(EDTA)^2- solution.

Abstract:Bis-azoles and energetic ion derivatives are a new class of energetic materials, which have the features of high nitrogen content, high formation enthalpy, high detonation performance, and insensitivity.Recently, they have attracted more and more attention in the field of energetic materials due to their widely potential applications in the areas of new explosives, low signature propellant, gas generator, low smoke or smokeless fireworkss and so on.The progresses and properties of bis-1, 2, 4-triazoles, bistetrazoles, 5-(1, 2, 4-triazol-3-yl)tetrazoles and its energetic ion derivatives were reviewed.Nine kinds new type bis-azoles were designed in this paper and their performance is predicted by quantum chemistry methods.Researches on the law of various nitrogen-rich cations on sensitivity and detonation performance of bis-azoles and synthesis of new type bis-azoles with better performance are the keys of further work.

Abstract:A novel energetic plasticizer containing —N—NO₂, —N₃ and —ONO₂ groups in molecular structure, pentanol-3-nitraza-5-azidonitrate(PNAN)(crude product) was designed and synthesized for the first time via reaction in dimethyl sulfoxide, using 1, 5-dinitrato-3-nitraza pentane(DINA) and sodium azide as raw materials The crude product was separated and purified bysilica gel column chromatography with the purity of 98.60%.The structure of PNAN was characterized by IR, ¹HNMR and elemental analyses.Some physicochemical properties of PNAN were obtained by the tests.Results show that the density is 1.46 g·cm^-3, decomposition temperature 172 ℃, glass transition temperature -41℃, viscosity 19.5 mPa·s, friction sensitivity 12% and impact sensitivity 56%.

Abstract:1-Methyl-3, 4, 5-trinitropyrazole(MTNP) as an insensitive energetic compound was one-step synthesized with 1-methylpyrazole via direct nitration using mixture of nitric acid and fuming sulfuric acid for the first time.The structure of MTNP was characterized by IR, NMR, elemental analysis, and mass spectrum.The reaction conditions were optimized as following:reaction temperature 90 ℃, reaction time 6 h, molar ratio of HNO₃ and fuming sulfuric acid 1:8.At this condition, the yield of MTNP can reach up to 15.2%.Thermal behavior of MTNP was studied by DSC.Results show that its decomposition temperature is 272.0 ℃, indicating a good heat stability.

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