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Abstract:With glyoxal formamide and guanidine hydrochloride as starting materials,N,N′-(4,8-dinitrooctahydrodiimidazo[4,5-b:4′,5′-e]piperazine-2,6(1H,3H)-diylidene)dinitramide(TNIP) was synthesized by two stages of nitration reaction. The title compound and its intermediates were characterized by IR,NMR and MS. The factors affecting nitration reactions were investigated as well. Results show that the optimized conditions of the first stage of nitration are: V(Ac₂O):V(HNO₃)=1.2:1,reaction time 2 h and reaction temperature 45 ℃,and for the second stage of nitration,the optimized conditions are: V(Ac₂O):V(HNO₃)=3:1,reaction time 4h and reaction temperature 50 ℃. Thermal decomposition behavior of TNIP was studied using thermogravimetry and differential scanning calorimetry. The peak temperature is 290 ℃,indicating that TNIP has a better thermal stability. The calculated characteristic drop height of impact sensitivity for TNIP (H₅₀) is 108.1 cm,better than that of RDX(38 cm) and HMX(30-32 cm).

Abstract:The 2, 6-diamino-3, 5-di-nitropyrazine-1-oxide (LLM-105) crystals with three different morphology were recrystallized using two ionic liquids of [Bmim]BF₄ and [Bmim]CF₃SO₃ as solvents under different solvent temperature, water volume and standing conditions. The morphology, crystal structure, thermal property and purity of the crystals were characterized by scanning electron microscope, X-Ray powder diffraction, differential scanning calorimetry-thermogravimetry, fourier transform infrared spectroscopy and purity analysis. Results show that the recrystallized rectangular micro-rod, hole shape and plate-like LLM-105 crystals have the same diffraction peak positions as the raw materials, only the intensity have obviously enhanced at 11°, 21°, 45° and weakened at other positions. Compared with the raw materials, the crystals habits have changed and present different facets, while the purity have slightly improved (above 94%). The relative regular structured rectangular micro-rod crystal exhibits the best thermal stability with the exothermic peak temperature of 353 ℃ and initial decomposition temperature of 323.6 ℃ which have improved by 10 ℃ and 40 ℃ than that of the raw materials, respectively.

Abstract:The high energy compounds bis[4-nitraminofurazanyl-3-azoxy]azofurazan (ADNAAF) was synthesized from bis[4-aminofurazanyl-3-azoxy]azofurazan (ADAAF) using glyoxal as starting material. The structures of ADNAAF and ADAAF were characterized by IR, NMR and MS. With KBrO₃ and glacial acetic acid as oxidation system, the factors affecting the synthesis of ADAAF were studied. The optimum reaction conditions were found to be as follows: the reaction temperature 50 ℃, reaction time 16 h, andn(CH₃COOH) : n(DAOAF)=68:1, with a yield of 58.5%. The thermal properties of ANDAAF and ADAAF were studied by differential scanning calorimetry and thermogravimetry analysis. Results show that the initial decomposition temperature of ADAAF and ADNAAF are 267.18 ℃ and 114.81 ℃, respectively, and the mass loss of ADAAF due to overall reaction (50-500 ℃) is 90.91% and ADNAAF (70-500 ℃) is 100%. The detonation performances of ADNAAF were estimated by Gaussian 03. The detonation velocity of ADNAAF is 9140 m·s^-3 and detonation pressure is 38 GPa, which indicates that ADNAAF is a high energy density compound with potential application value.

Abstract:Hexanitrostilbene (HNS) was synthesized via aerobic dehydrogenation of hexanitrobibenzyl (HNBB) with 4-hydroxyl-2, 2, 6, 6, -tetramethylpiperidine-1-oxyl (4-OH-TEMPO) combined ferrous chloride (FeCl₂) as catalyst in dimethysulfoxide (DMSO). The optimum conditions were obtained as follows: n(4-OH-TEMPO):n(FeCl₂)=4:6, solvent DMSO, reaction temperature 55 ℃, reaction time 8h, flow rate of oxygen 25 mL·h^-1 and the yield is 81%. The possible reaction mechanism is proposed as: HNBB oxidized by O₂ combined with Fe²⁺ to yield HNS, 4-OH-TEMPO as the co-catalyst to promote the circulation of Fe²⁺ and speed up the oxidation.

Abstract:Bis(2, 2, 2-trinitroethyl)amine(BTNA) was synthesized according to literatures and characterized by elemental analysis, infrared radiation and differential scanning calorimetry. Using Growth Morphology methods contained in Morphology module of Materials Studio 6.0, the crystal morphology and crystallization behavior of BTNA were calculated, and the relationship between the structures of important crystal faces and media of crystalization were analyzed. Theoretical research shows that the face (111) is the most important crystal surface if crystallization was carried out in the solvents with strong polarity. The ratio of appearance area of (002), (102) and (020) increases, and the importance of faces (200) and (021) decreases. While the importance of weak polar surface will increase in non-polar or weak polar solvents. By recrystallizing BTNA from dichloromethane (weak polar solvent), it is found that the crystalloid is more uniform and the aspect ratio is smaller compared with that from water, which indicates that the experimental result is consistent with the simulation ones.

Abstract:A new high-energy organic ammonium salt 4, 4′-azo-1H-1, 2, 4-triazol-5-one ammonium salt (AZTO·H₂O) was synthesized via potassium permanganate oxidation using 4-amino-1, 2, 4-triazol -5-one (ATO) as starting material. The thermal behaviors of AZTO·H₂O was studied by differential scanning calorimetry. The kinetic parameters of non-isothermal exothermic decomposition reaction were calculated by Kissinger method and Ozawa method. Results show that the decomposition heat, apparent activation energy and pre-exponential factor of AZTO·H₂O are 247.46 kJ·mol^-1, 177.80 kJ·mol^-1 and 10^15.74 s^-1 respectively. The critical temperature of thermal explosion and molar heat capacity at 298.15 K for AZTO·H₂O is 233.10 ℃ and 271.45 J·mol^-1·K^-1, respectively. The adiabatic time-to-explosion is between 72.8 s and 74.7 s. The kinetic equation describing the exothermic decomposition reaction of AZTO·H₂O is $\frac{{{\rm{d}}\alpha }}{{{\rm{d}}\mathit{T}}}{\rm{ = }}\frac{{{{10}^{15.74}}}}{\beta } \times 4(1 - \alpha ){[{\rm{-ln}}(1 - \alpha )]^{\frac{3}{4}}}\exp ( - 1.774 \times {10^5}/\mathit{RT})$.

Abstract:To explore the application of high-pressure and ultrasonic breaking method in micro-nano TATB preparation, the wet breaking of TATB particles was performed by a nano-machine. The working principle of high-pressure and ultrasonic breaking method was introduced. The effects of breaking pressure, TATB concentration, surfactant and breaking times on the mean particle size and surface area of micro-nano TATB were studied. The change of morphology and thermal performance of TATB particle before and after breaking was compared. Results show that the mean particle size of TATB reduces and its specific surface area enhances with increasing the breaking pressure. The mean particle size reduces first and then enhances when TATB concentration increase. Both sodium dodecyl benzene sulfonate and polyoxyethylene octyl phenyl ethers (OP) have preventing congregation effect for micro-nano TATB particles, but OP has a better effect. The mean particle size reduces first and then increases with the breaking times enhance. Under the breaking conditions of interval mode, TATB concentration 10%, pressure 100 MPa, OP and breaking 10 times, the product has no notable change for particle morphology compared with original TATB materials but the mean particle size decreases from 18 μm to 530 nm and thermal decomposition temperature reduces from 396.6 ℃ to 392.1 ℃.

Abstract:The thermal properties, electronic structure and detonation performances of 3, 7-bis(nitroimino)-2, 4, 6, 8-tetraazabicyclo[3.3.0]octane were investigated by the TG-DTG-DSC method and density functional theory, respectively. Results show that the thermal decomposition of title compoud is a two-stage process and has an evident exothermic peak at around 320 ℃, and the activation energy and pre-exponential factor of thermal decomposition are 225.80 kJ·mol^-1 and 10^17.71 s^-1, respectively. The critical temperature of thermal explosion is 600.25 K, and entropy of activation 80.81 J·mol^-1·k^-1, enthalpy of activation 220.92 kJ·mol^-1, free energy of activation 173.87 kJ·mol^-1, detonation pressure 34.34 GPa, detonation velocity 8.70 km·s^-1, indicating that it can be used as a potential candidate of high-energy and stable energetic material.

Abstract:The vacuum oxidation crystallization process was applied to the preparation of RDX by a direct nitration method, which effectively solved the problem of a large amount of waste acid produced in the direct nitration. The optimum process conditions were experimentally investigated by a single factor method. Results show that optimum process conditions are determined as: with 1 g HA as a reference, in the process of oxidation, the amount of dilution water is 3.51 g, the lowest excited temperature 49.4 ℃, heating temperature 60 ℃ and the adding rate of dilution water amount 0.12 g·s^-1 and in the process of vacuum crystallization, vacuum tightness is 82 kPa, initial evaporation temperature 85.0 ℃, stirring speed 650 r·min^-1, forming 10.34 g of waste acid. Compared with the traditional process, the new process makes the amount of dilution water and waste acid reduce 24.9% and 10.2%, respectively.

Abstract:For further understanding of interaction between phosphatidylcholine and hydroxyl-terminated polybutadiene (HTPB) in styrene solution, the effect of phosphatidylcholine on the rheological properties of HTPB-styrene solution was studied by viscometric method. The viscosity changing factor(|C|) was used to characterize the degree of molecular interaction between phosphatidylcholine and HTPB. In this approach, the blending behavior of phosphatidylcholine and HTPB in mixed solution system was further discussed. Meanwhile, the effect of the relative contents of phosphatidylcholine and HTPB on the interaction degree was researched. Results show that the solution viscosity increases with the increasing of phosphatidylcholine. And the solution exhibits a more remarkable non-Newtonian behavior. The flow activation energy (E) first increases and then decreases, while the interaction degree between phosphatidylcholine and HTPB first decreases and then increases. |C| increases to the maximum value of 0.165 and E/R decreases to the minimum value of 1004.9 as phosphatidylcholine content reaches to 0.053.

Abstract:Main characteristic parameter identification of polymer bonded explosive (PBX) failure is the basis for establishing strength criterion and evaluating structural strength. A series of uniaxial tension and compression-induced direct failure tests, and also failure after creep tests under different initial stresses, were designed within the temperature range of 20-50 ℃ on a type of TATB-based PBX. Based on the acquired failure data, effect of environment temperature and initial creep stress on the failure stress and strain was analyzed. Results demonstrate that for both direct failure and failure after creep: 1)With the increase of environment temperature, failure stress reduces both under tension and compression. Failure strain increases under tension but decreases under compression. 2) Given the same environment temperature, failure stress reduces and failure strain increases as the initial creep stress increases. This reveals that failure stress isn't an appropriate main characteristic failure parameter, because it fluctuates violently when environment temperature and initial creep stress change and has no critical value. On the contrary, failure strain is relative simpler as a main characteristic failure parameter. When strain reaches the critical strain, failure is generated no matter how loading history changes and what causes this strain (load or creep). Direct failure strain can be viewed as the critical failure strain at one temperature point. The critical failure strains at 20 ℃, 35 ℃ and 50 ℃ under uniaxial tension are 0.1330%, 0.1452% and 0.1675% respectively, and it changes to -1.4206%, -1.4159% and -1.1731% respectively under uniaxial compression.

Abstract:Thermal decomposition effects on internal temperature field of explosive cylinders during accelerated aging test was investigated by theoretical analysis, which indicated that main factors are explosive type, test temperature and sample size. Then, internal temperature field of five explosive cylinders, hexogen(RDX), triamino trinitrobenzene(TATB), Tetryl, cyclotetramethylenetetramine(HMX), pentaerythritol tetranitrate(PETN) with different size under different temperature were simulated by finite element analysis. Results show that explosive cylinder type is the key factor of the effect on internal temperature field. Temperature deviations of RDX and PETN cylinder(Ф20 mm×20 mm) at 110 ℃ are 2.59 ℃ and 1.19 ℃, respectively. And, the test temperature and size of explosive cylinders should be rationally controlled to reduce the temperature deviation for explosive cylinders of RDX, PETN.

Abstract:The components of four kinds of JP-10 aviation fuels were analyzed by gas chromatography/mass spectrometry (GC/MS). The linear scope of gas chromatography was researched. The purities of JP-10 fuels were measured with an external standard method. Results show that JP-10 aviation fuels contains not only the main component exo-tetrahydrobicyclopentadiene, but also decahydronaphthalene, endo-tetrahydrobicyclopentadiene, adamantane and their methylated products, etc. The suitable concentration range for external standard method to measure the purity of JP-10 is 0.5-20 mg·mL^-1. This method is reliable, accurate, and can be used for determining the purity of JP-10.

Abstract:Since the electromagnetic environment is getting more complex, the research of igniter electromagnetic protection receives extensive attention. In order to study the electro-explosive performances variations, the variation of the firing time and the firing-required energy were measeured under the condition that the SCB igniters were in parallel with varistors, and capacitor discharge and constant current experiments were adopted when the capacitance (47 μF) was charged to 22 V. Results show that there is no significant difference in the above parameters after the typical SCB igniter in parallel with varistor. But the low-energy SCB igniters are affected by varistor with lower breakdown voltage in the firing-required energy. The firing-required energy increase by 14%, while the firing time does not change. On the contrary, in the constant current duration of 100 ms experiment, varistor has no significant influences on SCB firing time and firing-required energy, indicating that varistor does not affect the SCB igniters′ electro-explosive performances dramatically when employed for the electromagnetic protection of the SCB igniters.

Abstract:In order to study the effects of the crystal size and compactness of copper film on the drive ability of flyer with the exploding foil, X-ray diffraction was applied to analyze the structure of copper film deposited by e-beam evaporated deposition and magnetron sputtering. The exploding bridge foil was fabricated with photolithography. The velocity of the flyer under different voltage was investigated by physical vapor deposition to study the ability of flyer driven by exploding bridge film. The up-and-down method was implemented to analyze the threshold exploding energy of hexanitrostilbene-Ⅳ, which was successfully initiated by flyer. It is found that the copper film deposited by magnetron sputtering has smaller crystal, and is more than 17% higher resistivity, and 2.4 times faster deposition rate than that by e-beam evaporated deposition. It reveals that the capacity of flyer driven by copper film with magnetron sputtering is better than e-beam evaporated deposition, showing the lower threshold energy to initiate hexanitrostilbene-Ⅳ.

Abstract:The thermal decompose characteristics and combustion performance of high-energy TEGN propellant that containing hexogeon(RDX) and thermoplastic polyurethane elastomer(TPUE) was analyzed by differential scanning calorimetry(DSC) and closed-bomb. The combustion mechanism of high-energy TEGN propellant was analyzed and the interrupted burning surfaces was observed by 3D microscope. The results show that the thermal decomposition process of high-energy TEGN propellant mainly contains the thermal decompose of basic body which consists of nitrocellulose(NC), nitroglycerine(NG), nitrotriglycol(TEGN) and the thermal decompose of RDX. The particle size of RDX has a great influence on the combustion process of the modified TEGN propellant. The melting and decomposition process occurs mainly in the condensed phase with the RDX particle size of 8.5 μm and 45 μm. As the RDX particle size increased to 90 μm, some RDX particles separates from the basic body and decomposes in the gas phase, the propellant burning surface and quality combustion speeded increased and the regularity of combustion reduced.

Abstract:To improve the salt/wet prevention and high temperature resistant performance of propellant surface and adjust its combustion performance at the same time, TiO₂-fluorinated acrylate functional additives were synthesized via reaction of titanium dioxide nanoparticle and fluoride monomer. Gun propellant particles were prepared by blending functional additives and triethylene glycol dinitrate (TEGDN) double-base propellant pills and the experiment of the gun propellant was performed by a closed bomb. The influence of fluorinated functional additive content, fluorine content and particle size on the constant volume combustion performance of the gun propellant was studied. Results show that with decreasing the 12F functional additive content, the burning rate of the gun propellant reveals a trend of increase. 12F functional additives make the burning rate of gun propellants increase by 0.1-0.3 cm·s^-1, 3F functional additives make the burning rate of gun propellants reduce by 0.4-1.0 cm·s^-1. Under this experimental condition, the influence of particle size is not obvious on the combustion performance of propellant. To better control the burning rate of gun propellant, the proportion of fluoride and TiO₂ content in the chain segment of functional additives and the physical form of aggregation of gun propellant should be considered comprehensively.

Abstract:The influence of composition on mechanical properties of fuel-rich composite propellants based on hydroxyl-terminated polybutadiene pre-polymer (HTPB)/ammonium perchlorate oxidizer (AP)/aluminum fuel (Al) was experimentally investigated. 11 Batches of 10 kg mixes were prepared in which design factors of mixing, casting, and curing were fixed. Standard JANNAF specimens were tested with Zwick machine at a rate of 50 mm·min^-1 under 25 ℃. The results show that the decreasing of the binder content from 74.5% to 34.5% due to fillers incorporation such as AP an Al powder decreased the strain and increased the tensile strength, Young′s modulus, and hardness. The particle size and amount of AP had influences on the mechanical properties. The fine AP particles acted as active filler and enhanced the mechanical properties of composite propellant. Decreasing AP average particle diameter from 55.9μm to 9μm was helpful to increase the tensile strength, Young′s modulus, and hardness of the propellant and to decrease the strain. It is indicated that the mechanical properties of these fuel-rich composite propellant compositions are mainly affected by the content of the binder and the average particle size of AP.

Abstract:Under standard condition(chamber pressure p_c : nozzle exit pressure p_e=70:1), the energy characteristic parameters of solid propellant containing 5-amino-tetrazolium nitrate (5-ATEZN), a novel kind of high energy compounds with high nitrogen content, were calculated by the least free energy method. Results show that specific impulse of 5-ATEZN monopropellant is 2371.38 N·s·kg^-1, which is similar to that of RDX and HMX monopropellant. Moreover, the oxygen balance of 5-ATEZN (-10.8%) is much higher than that of RDX and HMX. Specific impulse and characteristic velocity of HTPB propellant decrease with substituting 5-ATEZN for the ingredient AP or RDX. But for GAP propellant, specific impulse and characteristic velocity are characterized by a parabola with substituting 5-ATEZN for the ingredient AP. The maximum specific impulse can reach 2580.62 N·s·kg^-1, which is 17.93 N·s·kg^-1 higher than that of previous formula without 5-ATEZN. Since 5-ATEZN has no chlorine, it's helpful to reduce the characteristic signal of propellant. Therefore, substituting 5-ATEZN for the ingredient AP appropriately is a feasible approach to achieve the target of higher-energy and less-smoke for GAP propellant.

Abstract:The ultrafine aluminum powders with diameter of 1-2 μm were surface grafted by energetic glycidyl azide polymer (GAP) using diisocyanate as bridge via consecutive condensation reactions between —OH and —N＝C＝O groups. The surface properties, compatibility with fluorine polymeric binders as well as resistance to water oxidation of the prepared GAP-grafted aluminium powders were studied. Results show that the static water contact angle of surface of aluminum powders before and after grafting is 0-25.7°and 109.9°, respectively. The surface property of aluminum powders is changed from hydrophilic to hydrophobic after surface grafting. The GAP grafted aluminium powders have better compatibility with fluorine polymeric binders. Moreover, The stability tests for aluminum powders were conducted in water at 70 ℃. 39.8%(mass fraction)of active aluminum are oxidized after 15 min, for the untreated fresh aluminium powders. Only 1.4% of active aluminum are oxidized after 60 min for GAP-grafted aluminum powders, revealing that grafting with GAP can effectively protect the aluminum powders under harsh hydrothermal conditions.

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