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Abstract:1, 1-Bis(picrylamino)-2, 2-dinitroethylene (TFT) was synthesized using 2, 4, 6-trinitrochlorobenzene and 1, 1-diamino-2, 2-dinitroethylene (FOX-7) as raw materials and KF and imidazole as catalysts by condensation with the yield of 71.3% and melting point of 225-226 ℃. Its structure was identified by IR, NMR and MS. Its thermal stability was analyzed by DSC and the decomposition temperature was 331.3 ℃, which indicating that its thermal stability was better than that of FOX-7. The theoretical density of TFT after optimizing predicted by Monte-Carlo method is 1.85 g·cm^-3. The heat of detonation, detonation velocity and detonation pressure predicted by Kamlet-Jacobs formula are 1751.26 J·g^-1, 8.83 km·s^-1 and 36.25 GPa, respectively. Impact sensitivity(H₅₀) is 156 cm. All the results show that TFT is more insensitive and has higher detonation pressure than FOX-7.

Abstract:The key intermediate diazidoglyoxime(DAG) of synthesizing 5, 5′-bistetrazole -1, 1-diolate dihydrate(BTO) was synthesized by "one pot" method using glyoxime as starting materials. The potassium salts of 5, 5′-bistetrazole -1, 1′-diolate(PBTOX) was synthesized by metathesis reaction. Its structure was characterized by IR and elemental analysis. DTA-TG technique was used to study the thermal decomposition of PBTOX. The surface morphology and mechanical properties of PBTOX crystal were tested by atomic force microscopy(AFM) and Lorentzian contact resonance(LCR) imaging technique. The sensitivity tests were performed. Results show that the crystal structure of PBTOX is layered one. Its decomposition peak temperature at a heating rate of 5 ℃·min^-1 is 383 ℃. Its explosion percentage is 0% for impact sensitivity and friction sensitivity.

Abstract:A novel acidic ionic liquid(ILs), 1-dodecyl-3-(3-sulfopropyl)-imidazolium hydrogen sulfate [C₃SO₃HDoim]HSO₄ was designed and synthesized, and used for condensation reaction of aldehyde and amine to synthesize the energetic material intermediates. Taking the synthesis of tetrahydroimidazo[4, 5-d]imidazol-e-2, 5-(1H, 3H)-dione, 2, 5, 7, 9-tetrazobicyclo[4,3,0]nonan-8-one and hexabenzylhexaazaisowurtzitane (HBIW) as the example, the influences of reaction temperature, reaction time, amount of ILs and types of ILs on condensation reaction were investigated. Results show that ILs [C₃SO₃HDoim]HSO₄ has good catalytic activity, high cyclic utilization reusability and the yields of three kinds of multi-nitrogen heterocyclic compounds glycoluril, 2, 5, 7, 9-tetrazobicyclo[4,3,0]nonan-8-one and HBIW, can reach 95%, 89% and 81%, respectively.

Abstract:1, 1′-Dihydroxy-5, 5′-bitetrazole compound is hot spot of high-energy insensitive materials in recent years. To explore the thermal safety of these kinds of compounds, the thermal decomposition processes of 1, 1′-dihydroxy-5, 5′-bitetrazole cobalt salt (1, 1′-BTOCo), copper salt (1, 1′-BTOCu) and lead salt (1, 1′-BTOPb) were studied by differential scanning calorimetry (DSC) and thermogravimetry (TG) at heating rates of 5, 10, 15, and 20 K·min^-1, respectively. The apparent activation energy (E_K and E_O) and pre-exponential factor (A_K) for thermal decomposition reaction were calculated by Kissinger′s and Ozawa′s method, respectively. The kinetic parameters and mechanism functions of thermal decomposition were obtained. Results show that for 1, 1′-BTOCo, E_K=162.35 kJ·mol^-1, A_K=1.83×10¹⁵ s^-1, self-accelerating decomposition temperature T_SADT =534.46 K, critical temperature of thermal explosion T_bpo=542.22 K; for 1, 1′-BTOCu, E_K=217.95 kJ·mol^-1, A_K=12.58×10²⁰ s^-1, T_SADT =527.56 K, T_bpo=539.11 K; for 1, 1′-BTOPb, E_K=223.52 kJ·mol^-1, A_K=4.24×10²⁰ s^-1, T_SADT =525.87 K, T_bpo=580.00 K.

Abstract:2-Nitro-2-azaadamantane-4, 8-diyl dinitrate, a new energetic cage compound, was synthesized with a total yield of 27% from bicyclo[3.3.1]nonane-2, 6-dione via hydrazonation, elimination, epoxidation, cyclization, acetylation and nitration.Nitric-sulfuric acid was applied as nitrating agent and nitration conditions such as molar ratio between H₂SO₄ and HNO₃, reaction temperature and reaction time were investigated and the optimal reaction conditions was as follows:n(H₂SO₄):n(HNO₃)=1:2 and 60 ℃ for 4 h with yield of nitration reaction as 81%.The thermal stability of target product was studied by thermogravimetry(TG) and differential scanning calorimetry(DSC).The detonation properties were predicted by Kamlet-Jacobs formula.Results show that the compound starts to decompose at 170.0 ℃ and the decomposition peak temperature is 193.7 ℃, and the density, detonation velocity, detonation pressure are 1.71 g·cm^-3, 5780 m·s^-1, 11.0 GPa, respectively.

Abstract:As the poor mechanical properties of four-component hydroxy-terminated polybutadiene(HTPB) propellant(ammonium perchlorate/hexogen/Al/HTPB, AP/RDX/Al/HTPB), a modified borate ester bonding agent(BEBA) was synthesized using N, N-dihydroxyethyl-3-amino methyl propionate as the external connection monomer, polybutylene adipate(PBA) with low molecular mass as interconnection monomer, and tributyl borate as material. Polybutylene adipate(PBA) was synthesized using adipic acid and 1, 4-butanediol as materials, and N, N-dihydroxyethyl-3-amino methyl propionate was synthesized from diethanolamine and methyl acrylate. Their structures were characterized by FT-IR, GPC, ¹H NMR, and GC-MS. The application of modified BEBA as bonding agent for four-component HTPB propellant shows that with the curing parameter of 1.01, the crosslinking parameter of 0.22, and the mass ratio between BEBA and JH03 of 0.08/0.04, the mechanical properties of the four-component HTPB propellant are the best at high(70 ℃), constant(20 ℃) and low(-40 ℃) temperatures.

Abstract:To understand the thermal decomposition kinetics and thermal safety property of azido-terminated glycidyl azide polymer (GAPA), its thermal decomposition characteristics was investigated through differential scanning calorimetry(DSC) and thermal gravimetry(TG). The apparent activation energy, pre-exponential factor and thermal decomposition kinetic equation were studied based on the DSC curve peak temperatures and the TG curve decomposition degrees at heating rates of 2 ℃·min^-1, 5 ℃·min^-1, 10 ℃·min^-1 and 20 ℃·min^-1. Its kinetic parameters thermodynamic and thermal safety parameters were calculated. The study indicates that there are two stages in the GAPA thermal decomposition reaction with the apparent activation energy E_K=218.47 kJ·mol^-1, pre-exponential factor A_K=1.06×10²²s^-1, self-ignition temperature T_bpo=506.55 K, self-accelerated decomposition temperature T_SADT=496.78 K, free energy of activation ΔG^≠=132.76 kJ·mol^-1, enthalpy of activation ΔH^≠=214.34 kJ·mol^-1 and entropy of activation ΔS^≠=164.21 J·mol^-1·K^-1.

Abstract:Two types of paraffin gels were prepared by using the fumed silica(type A)and modified castor oil(type B)as gellants respectively. The influence of gel type on physical stability, yield stress, viscosity and thixotropy of differentgel types were investigated. The viscosity curves were fitted by using the Herschel-Bulkley(HBE) constitutive equation. Results show that there is little effect of gellant content and centrifugal force on the physical stability of type B paraffin gel, indicating that the physical stability of type B paraffin gel is better than type A paraffin gel. The yield stress and the viscosity of parffin gels increase with the increasing of the gellant content and the gellant content has less impact on the yield stress of type B than on type A. The viscosity of parffin gels decreases with the incrasing of the shear rate, and the parffin gels are shear thinning. The power-law index(n) of type A paraffin gel is from -0.029 to -0.172 with the increase of the gellant content and n for type B is from 0.510 to 0.342. The type A and type B paraffin gels all have a certain degree of thixotropy and little resilience.

Abstract:The hygroscopicity is one of principal factors affecting the long storage stability of red phosphorus smoke agent. To reduce the hygroscopicity of red phosphorus, the red phosphorus was coated by aluminium hydroxide/phenol formaldehyde resin. The process of preparing the coated red phosphorus was optimized by orthogonal test. The coating layer of red phosphorus was characterized by Fourier transform infrared spectrometer(FTIR) and scanning electron microscopy(SEM).Results show that the optimal process parameters for preparation of coated red phosphorus are: the molar ratio of formaldehyde and phenol 3:1, the mass of aluminum nitrate nonahydrate 0.05 g, the total mass of formaldehyde and phenol 0.4 g, the reaction temperature 30℃, the reaction time 3 h.The moisture absorption ratio of coated red phosphorus obtained reduces by 93.24%. The mass fraction of coating materials is below 4.5%.The moisture absorption rate of coated red phosphorus reduces remarkably as time goes on The coating materials are well coated on the surface of red phosphorus.

Abstract:New nitrification systems of N₂O₅/HNO₃/ ionic liquids(ILs, quaternary ammonium salts, caprolactams, imidazoles, pyridines) were used to nitrify tetraacetyl hexaazaisowurtzitane(TAIW) to prepare hexanitro-hexaazaisowurtzitane(CL-20), instead of the commonly used concentrated nitric and sulfuric acid in industrial scale, which was seriously harmful to the environment. The effects of the type, dosage and acidity of ILs and reaction time on yield and purity of CL-20 were investigated. Results show that acidity of ILs is positively correlated with catalytic performance and the [Et₃N(CH₂)₄SO₃H][BSO] shows the best catalytic activity. The optimum conditions are as follows: reaction temperature 60-80 ℃, reaction time 7 h, m([Et₃N(CH₂)₄SO₃H][BSO]):m(TAIW):m(N₂O₅):V(HNO₃)=0.5 g:3 g:4 g:15 mL, with the yield and purity of 94.5% and 98.1%, respectively. ILs can be reused five times and barely with significant loss of catalytic activity.

Abstract:Encapsulated phase change materials(PCMs) have the potential application value in thermal protection of explosive components and thermoregulation of electronic devices. However, previously reported encapsulated PCMs with inorganic shell materials have a limitation of large particle size, brittleness and poor compatibility with organic polymer. In this study, a series of modified organosilica nanoencapsulated n-octadecane phase change materials were prepared by using interfacial hydrolysis/ polycondensation method of different organic silane precursors in miniemulsion. The chemical and crystallizing structure, morphology, phase change properties, and hydrophobicity of the shell materials were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD), scanning electron microscopy(SEM), differential scanning calorimetry(DSC), and water contact angle(WCA) measurements, respectively. The results show that two kinds of organosilica nanocapsules with spherical and bowl shaped morphologies, sizes of 200-693 nm, melting enthalpy of 93.2-107.5 J·g^-1 and water contact angle(WCA) of capsule shell materials of 67°-155° can be obtained by changing the volume ratios of organic silane precursors. The regulation and control of hydrophilic, hydrophobic and super hydrophobic properties for surface may be realized. Moreover, these nanocapsules with organosilica shells are not easily broken under the effect of ultrasound, indicating that the mechanical properties are improved.

Abstract:The Al-Ni-Ti-Zr non-equilibrium alloy powder was prepared by mechanical alloying method. The Al-Ni-Ti-Zr non-equilibrium alloy powder/polytetrafluoroethylene(PTFE) reactive materials were prepared via mixing/pressing using Al-based non-equilibrium alloy powders and PTFE micro powders. The phase composition and morphology characteristics of the powders during ball milling were characterized by X ray diffraction(XRD) and scanning electron microscopy(SEM). The phase structure of the milled alloy powders was analyzed by high resolution transmission electron microscopy(HRTEM) and selected area electron diffraction(SAED). The thermal behaviors of non-equilibrium Al/PTFE reactive materials were examined by differential scanning calorimetry(DSC). The results show that the Al-based non-equilibrium alloy powders can be prepared by mechanical alloying method. There is a nano scale micro-crystalline island area dispersed in amorphous phase matrix. The peak temperature and exothermic peak area of non-equilibrium Al/PTFE reactive materials at a heating rate of 10 K·min^-1 in air are 495 ℃ and 1775 J·g^-1, respectively. Under the continuous heating condition, the exothermic reaction of the non-equilibrium Al/PTFE reactive materials has the typical kinetic characteristics, and the activation energy E_c of the reaction is calculated as 309.1 kJ·mol^-1 by Kissinger method.

Abstract:A tension-shear work holder with 7 loading angles(0°, 15°, 30°, 45°, 60°, 75° and 90°), which can realize different loading states including pure tension, shear and coupled tension-shear, was devised to investigate the mechanical properties of explosive crystal/binder interface in polymer bonded explosive (PBX). Simulation interface of crystal/binder for PBX was then prepared and tension-shear testing method for mechanical properties of interface was explored. Results show that the shear strength of PBX interface(0.980 MPa) was greater than its tensile strength(0.759 MPa). With the increase of loading angle, tension stress decreases while shear stress increases and total stress increases almost linearly. An elliptical model(σ²/a²+τ²/b²=1) is proposed to describe the relationship between tension stress and shear stress for PBX interface, which can describe the tension-shear strength characteristics of PBX crystal/binder interface well.

Abstract:According to the special solid-liquid state of gel, the gelation mechanism of gel agents (inorganic(B) and organic(A))for gelation aviation kerosene RP-1 were studied. The rheological parameters were measured by Brookfield rotational rheometer. Finally, the time independent, time dependent, and temperature dependent constitutive equations were built. Results show that the anhydrous ethanol is advantageous for the gelation of kerosene by gel agent A. The consistency coefficient k and gallant amount Y_amout have a relationship of power law dependence. The thinning ability of the kerosene gel prepared is stronger than that of typical shear thinned fluid(0 < n < 1). The resilience of inorganic and organic kerosene gel is very weak and not affected by the gel content and type. When shear rate increases, the time needed from intact structure to completely destroyed structure of the gel decreases, and the amplitude of the process curve decreases. When the temperature increases, the viscosity of inorganic kerosene gel decreases first and then increases, while the viscosity of organic kerosene gel decreases gradually and get close to the viscosity of kerosene at 90 ℃.

Abstract:Two types of Al-Teflon specimens were obtained by different heat treatment processes(type A: sintering temperature 380 ℃, cooling rate 50 ℃·h^-1; type B: sintering temperature 350 ℃, cooling rate 70 ℃·h^-1). The reaction phenomenon of two kinds of specimens was tested via quasi-static compression test. The stress-strain curves were obtained. The measurement of density, micro morphology analysis of SEM and observations of high speed photography of the specimens were performed. Results show that a violent exothermic reaction is occurred for type B specimen, while no reaction is occurred for type A specimen. The strain hardening modulus of type B specimen is 5.3 times higher than that of type A specimen. The reaction zone of type B specimen in the stress and strain plane is between true strain of 1.2 and 2.2 and true stress of 60 MPa and 80 MPa. The crystallinity of two types of specimens is 63% for type A and 43% for type B. The crystallinity of two types of Al-Teflon materials is different. A great deal of nanometer Teflon fibrils is found in type A specimen, which may hinder the crack propagation of materials. The reaction phenomenon of type B specimen is closely related to phenomenon of strong shear stress and brittle fractures of the specimen.

Abstract:Nano-TATB (1, 3, 5-triamino-2, 4, 6-trinitrobenzene) is an insensitive high explosive (IHE), some impurities in its preparation process were produced. In this work, the structures of the impurities were studied by liquid-state ¹³C nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy and theoretical simulation method. Results show that the impurity is the proton compound of TATB molecule and it is named as 1, 3, 5-triamino-2, 4, 6-trinitro-2, 5-cyclohexadiene bisulfate. According to the quantum chemical method, the possible formation mechanism of this kind of impurity is the protonation of TATB molecule by H atom in concentrated H₂SO₄ during the dissolution process.

Abstract:The density uniformity of polymer bonded explosives (PBX) has a great effect on its mechanical property and safety performance. A dual-standard computed tomography simultaneous scanning model was applied to measure the cross-section density distribution of PBX component with complex configuration. Polymethyl methacrylate (PMMA) and polytetrafluoroethylene (PTFE) having same configuration of PBX were used as standard density components. The distribution rule of CT values and linear relation of the cross-section of PBX and standard density components were studied by a fan beam CT scanning mode. CT values of different cross-sections were obtained via the threshold of gray-scale and extraction of gray-scale value using MATLAB software. The cross-section density of PBX component was obtained from the volume densities of standard components. The corrected coefficient k was calculated using the volume density of PBX measured by water displacement method. The linear correction of the cross-section density of PBX component obtained by calculation was carried out. The cross-section density distribution of PBX component with complex configuration on different height was obtained. Results show that the maximal relative deviation between the cross-section density and the volume density of PBX is 0.74%.

Abstract:In order to study the dimensional stability of TATB based polymer bonded explosive(PBX) undergoing heating and irradiation environmental impact, the thermal expansion property of the PBX after high temperature accelerated aging test, γ and neutron irradiation test was studied. Results show that the thermal expansion coefficients of the PBX after aging at 55 ℃, 65 ℃ and 75 ℃ for 60 days decreases, and the thermal expansion coefficients decreased more as the age temperature higher. But the thermal expansion properties of the PBX after γ and neutron irradiation under a certain condition are not obviously changed.

Abstract:1-Methyl-3, 4, 5-trinitropyrazole (MTNP) was synthesized by one-step method using 1-methylprazole(1-MP) as raw materials and N₂O₅-oleum(20%) as nitrating agent. Its structure was characterized by IR, NMR, elemental analysis and MS. In addition, the influences of the mass fraction of N₂O₅, molar ratio of 1-MP and N₂O₅, reaction temperature and time on MTNP yield were studied. The optimum reaction conditions were obtained as: mass fraction of N₂O₅ 20%, n(1-MP):n(N₂O₅)=1:5, reaction temperature 165 ℃ and reaction time 1.5 h, respectively. Under such conditions, the yield of MTNP can reach up to 60.32%.

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