Abstract:3, 3′-Bis(N-hydroxy amidoxime)difurazanyl ether was synthesized from 3-cyano-4-nitrofurazan via etherification of nitro-group, addition, diazotisation and dioximation reaction with a total yield of 51.0%, and its structure and intermediates were characterized by IR, NMR and elemental analysis. The reaction conditions of dioximation were discussed and the optimum condition was obtained as follows: reaction temperature 20 ℃, n(DCFOF):n(NH₂OH·HCl):n(KOH)=1:4:4. Under alkaline conditions, DOFOF could be easily disproportionated to obtain 3, 3′-diamidoximinodifurazanyl ether. In addition, the reaction mechanism for disproportionation reaction of DOFOF was proposed.

Abstract:A new energetic salt of 2, 4-dinitroimidazole ([(DNI)NH₂ (CH₃)₂]) was synthesized with yield of 62.7% by using 2, 4-dinitroimidazole as starting materials. The structure of [(DNI)NH₂ (CH₃)₂] was characterized by IR, elemental analysis, fourcircle single crystal X-ray diffraction NMR. Results show that the crystal of title compound belongs to monoclinic system, space group C2/c with a=31.403(5)Å, b=6.7133(7)Å, c=22.769(4)Å, α= 90.00°, β =126.80(3)°, γ=90.00°, V=3843.6(10)ų, Z=16, D_c=1.404 g ·cm^-3, F(000) = 1696.0, μ (MoK_α) = 0.121 mm^-1. The molecule packing of [(DNI)NH₂ (CH₃)₂] is not compacted. Intra molecular and intermolecular hydrogen bonds are weak and the density is lower. Thermal properties were tested by TG-DSC. Results reveal that the [(DNI)NH₂ (CH₃)₂] shows good thermal stability.

Abstract:In order to study the properties of 5, 7-diamino -4, 6-dinitrobenzenfuroxan(CL-14), CL-14 was refined via recrystallization of potassium salt of CL-14, acidification at high temperature and acid elimination under heating. The sensitivity and thermal stability of unrefined CL-14 and refined CL-14 were tested by the standardization method GJB772A-1997. The peak temperature of exothermic decomposition reaction of unrefined CL-14 and refined CL-14 was determined by DSC. Results show that the pH of refined CL-14 is 6.5. The impact sensitivity and friction sensitivity are 24% and 16% respectively. The amount of gas evolved of refined CL-14 obtained by Vacuum Stability Test with 200 ℃/48 h is 0.81 mL·g^-1.The peak temperature of exothermic decomposition reaction of refined CL-14 is 313.7 ℃, 13.7 ℃ higher than that of the unrefined CL-14, showing that the refined CL-14 has lower acidity and better thermal stability.

Abstract:Two transition metal complexes as 2, 6-diamino-3, 5-dinitropyridine-1-oxides (ANPyO) with Cr(Ⅲ) and Zn(Ⅱ) were synthesized and characterized by FT-IR spectroscopy and elemental analysis. The effects of Cr(Ⅲ) and Zn(Ⅱ) complexes on the thermal decomposition of RDX, HMX and AP was studied by DSC and TG-DTG. Results show that thermal decomposition of the Cr(Ⅲ) complex only consists of one violent exothermic process with 10.79% residues and the Zn(Ⅱ) complex consists of two consecutive exothermic processes with 12.68% residues. Two complexes have little catalytic effect on the thermal decomposition of RDX and HMX. However, two complexes make the peak temperature of the higher thermal decomposition of AP decrease by 42.40 ℃ and 122.32 ℃, and the exothermic quantity of decomposition reaction increase by 849.5 J·g^-1 and 971.35 J·g^-1, respectively.

Abstract:A novel nitrogen-rich energetic material 5H-[1, 2, 3]triazolo[4, 5-c][1, 2, 5]oxdiazole(2) was prepared via hydrolytic reaction using [1, 2, 5]oxadiazole [3, 4-e][1, 2, 3, 4]tetrazine 4, 6-di-N-oxide(FTDO) as raw material. Four new energetic derivatives, ammonium [1, 2, 3]triazolo [4, 5-c][1, 2, 5]oxdiazole(3), hydrazinium [1, 2, 3]triazolo[4, 5-c][1, 2, 5]oxdiazole(4), guanylureaium [1, 2, 3]triazolo[4, 5-c][1, 2, 5]oxdiazole(5) and triaminoguanidinium [1, 2, 3] triazolo[4, 5-c][1, 2, 5]oxdiazole(6) were designed and synthesized via reactions of compound 2 with ammonia gas, hydrazine hydrate, amidinothiourea hydrochloride and triaminogunidine nitrate, respectively. Their structures were characterized by IR, NMR and elemental analysis. The mechanism and conditions of hydrolytic reaction were analyzed. The optimal reaction conditions were determined as: the reaction time 5 h and reaction temperature 80 ℃ with a yield of 76.92%. The thermal properties of compounds, 2, 4, 5 and 6, were analyzed by DSC. Results show that their peak temperatures of initial decomposition reaction are 173.23, 144.82, 172.81, 164.94 ℃, respectively.

Abstract:2, 4, 6-Trinitro-3, 5-diamino-N-(1, 2, 4-triazole-4)-aniline was synthesized using 2, 4, 6-trinitrochlorobenzene as the start material which firstly reacted with methylamine alcohol solution, then reacted with sulfuric acid and nitric acid, and finally reacted with 4-amino-1, 2, 4-triazole(ATA) and methanol sodium. The total yield is 80.18%. The target compound and its intermediates were identified by IR, MS and ¹H NMR. The main affecting factors of the reactions were discussed based on reaction mechanism. The results of the DSC test show that the two thermal decomposition peak temperature are respectively 210 ℃ and 328 ℃. The results of the TG test show that there is not any obvious quality loss process below 200 ℃, and the residual decomposition is 38.89% when the temperature is up to 500 ℃, indicating the final compoud has good thermal stability.

Abstract:1-(2′, 4′, 6′-Trinitrophenyl)-4, 5-dinitroimidazole was prepared, and its thermal behavior was studied by DSC and TG. Results show that it is melting and decomposition temperatures are 228.98 ℃ and 339.73 ℃, respectively. And the mass loss due to overall reaction (200-440 ℃) is 98%. The structure of the compound belongs to the orthorhombic system, space group P2₁2₁2₁, a=8.2370 (16)Å, b=12.791(3)Å and c=12.916(3)Å. The calculated crystal density is 1.802 g·cm^-3, and the corresponding detonation velocity and pressure are 8296.48 m·s^-1 and 31.00 GPa.

Abstract:1, 2-Dinitroguanidine(DNG) was synthesized via the nitration reaction using nitroguanidine(NQ) as raw material and 100% nitric acid/20% oleum/ammonium nitrate as nitrating system. The structure of DNG were identified by IR, ¹H NMR, ¹³C NMR and MS. The factors affecting the yield of DNG and orthogonal experiment were investigated. The thermal decomposition behavior of DNG was studied using TG and DSC. The results show that the optimized conditions of the nitration reaction are: n(HNO₃):n(NQ):n(NH₄NO₃)=15:2:1, V(H₂SO₄):V(HNO₃)=1.25:1, the reaction time 8 h and reaction temperature 10 ℃. The yield of DNG can reach up to 61.76% under the optimized conditions. The peak temperature of DSC curve for DNG is 182.83 ℃, indicating that DNG has a better thermal stability.

Abstract:With high energy density and self-sustained combustion under the condition of small size, metastable intermolecular composites (MIC) array has potential value in the application of intergrated initiating explosive devices. In the current study, highly ordered MoO₃ nanobelts array was prepared by a flame method. The possible factors which may influence the morphology of MoO₃ nanobelts, such as different substrate, growing time, and the flame source, were also studied. The optimal conditions for growing MoO₃ nanobelts array were obtained as follows: utilizing Si as the substrate and CH₄ gas as the flame source with the growing time of 5 min.The as-synthesized MoO₃ nanobelts possess a thickness of ~5 nm, a width of ~5 μ m, and a length larger than 10 μ m. And then MIC-Al/MoO₃ array was prepared by aluminum plating on the surface of MoO₃ nanobelts via the magnetron sputtering and thermal evaporation method respectively. The results show that MIC-Al/MoO₃ fabricated by thermal evaporation method has higher heat release (3276 J·g^-1) compared that by the magnetron sputtering method with the same aluminum film thickness.

Abstract:The spherical superfine CL-20 were prepared using a physical grinding machine with three kinds of grinding balls, and the mechanism of the machine was introduced. The effects of the density of grinding balls and grinding time on the physical structures such as average particle size, particle size distribution and roundness and mechanical sensitivity of superfine CL-20 were studied. Results show the superfine CL-20 particles obtained with low-density grinding balls are spherical, and its mechanical sensitivity is significantly reduced, and its thermal stability is better than raw CL-20, and the polymorph remains ε-type. The high-density grinding balls can refine the materials well, while the smoothing effect of low-density grinding balls is better, and the particle-size distribution of superfine CL-20 is uniform and concentrated with roundness up to 0.9.

Abstract:In order to protect the activity of aluminum powder in solid rocket propellants and increase the compatibility between the superfine aluminum powder and the other compositions of solid propellants, the superfine aluminum powder with activated surface and particle size about 2 μ m were coated using hydroxyl-terminated polybutadiene (HTPB) as coating agent and isophorone diisocyanate (IPDI) as curing agent. Al/HTPB energetic composite particles were prepared. Effects of Al powder modified by silane coupling agent KH-550 and coating quantity on the morphology and composite particle size of coated aluminum powder were investigated. Composite particles were characterized by SEM, TEM, XRD, FTIR, laser particle size analyzer, TG-DTA. Results show that when the superfine aluminum powders are modified by silane coupling agent and the coating quantity of HTPB is 1.5%, the coating film of the ultrafine composite particles of Al/HTPB are homogeneous, meanwhile the energetic composite particles are spherical with core-shell structures. The coating film of HTPB can prevent the oxidation of aluminum before 400 ℃ and burn quickly and release coated active aluminum between 400~525 ℃.

Abstract:Al/Ni and Al/Ti multilayer nanofilms were prepared by magnetron sputtering method. Field emission scanning electron microscope (FESEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) were used to characterize the deposited films and analyze the components. The heat released in the alloying reaction was measured by differential scanning calorimetry (DSC).The results show that the samples obtained at 0.4 Pa with sputtering power of 200 W for Al, 220 W for Ni and 180 W for Ti, are uniform and its layered structures are clearly visible. The deposited Al/Ni multilayer nanofilms consist of aluminium and nickel. The Al/Ti multilayer nanofilms consist of aluminium and titanium. The heat released in Al/Ni and Al/Ti multilayer nanofilms is 1134.64, 918.36 J·g^-1, which reach to 82.2%, 80.7% of theoretical values, respectively.

Abstract:The interaction of TATB based PBX with rigid polyurethane foam (RPUF) in the linear heating-up process was investigated by TG-IR. The results show that the gas phase products released from the contact system are basically sum of the gas phase products released from the two isolated compositions and no new gas products occur. The curves of change in heat output for TATB based PBX, rigid polyurethane foam(RPUF) and their contacted system during the aging by 140 ℃/10 d were obtained by a microcalorimeter. The surface structures and element contents of the samples before and after heated were characterized by IR and XPS, revealing that the surface structures and element surrounding of the samples before and after contacted do not change and TATB based PBX and polyurethane foam have good compatibility.

Abstract:In order to obtain the thermal physical parameters of nitrocellulose (nitrogen content 11.89%~13.5%) to make the thermal analysis calculations and reveal the reaction dynamics mechanism, laser flash method and differential scanning calorimetric (DSC) method were used to measure the thermal physical parameters of nitrocellulose with nitrogen content 12%(NC(12%N)). The values of thermal diffusivity, specific heat capacity, and thermal conductivity were obtained at temperature ranging from 25 ℃ to 140 ℃. Results show that with the increase of temperature, the specific heat capacity increases, while the thermal conductivity and thermal diffusivity decrease. But the changes are not obvious. So these parameters can be determinatal as: in the calculation of thermal analysis: c_p=1.131 J·g^-1·K^-1, D=0.413 mm²·s^-1, λ=0.142 W·m^-1·K^-1.

Abstract:Molecular dynamics (MD) simulation was applied to investigate cyclotetramethylene (HMX) crystal at 295K using COMPASS force field with the isothermal-isobaric (NPT) ensemble. Six models were considered, which were (4×2×4) and (4×4×4) unit cells and the other models obtained by cutting along their (1 0 0) crystalline surface with different depths. The trigger bond length, the interaction energy between two atoms of trigger bond and the mechanical properties of the HMX crystal were analyzed. Results show that the trigger bond length distribution is approximately symmetrical Gaussian distribution and the average bond length (L_ave) is in good agreement with the experimental. The interaction energy (E_N—N) between two N atoms of the N—N trigger bond increases monotonously with the increasing of atom numbers in the models, and the mechanical properties are independent of models except for Cauchy pressure.

Abstract:Curing processes of hydroxyl-terminated polybutadiene(HTPB) with different molecular weight (M1:1500; M2:2800)/2, 4-toluene diisocyanate (TDI) systems were studied by rotational viscometer and non-isothermal differential scanning calorimetry(DSC), and effect of molecular weight on curing reation kinetic of system was investigated. Results show that the viscosity of M1 system increases faster than that of M2 system, and the curing reaction heat of M1 systems is greater than that of M2 system. The values of apparent activation energy, reaction order and pre-exponential factor of M1 system are 55.87 kJ·mol^-1, 0.88, 4.70×10⁴ s^-1, respectively. While for M2 system, the peak temperature of the curing process increases and the values of apparent activation energy, reaction order and pre-exponential factor increase to 60.77 kJ·mol^-1, 0.89, 1.07×10⁵ s^-1, respectively. The curing reaction mechanism of two curing system follows f(α)=(1-α)ⁿ and index n of M1 system curing reaction is only slightly different from that of M2 system.

Abstract:In order to study the power of one RDX-based aluminized explosive with different charge diameter, the cylinder tests with diameters of 25.4 mm and 50.0 mm were conducted. The experimental results show that the expansion velocity of Φ50.0 mm cylinder is 4.73% higher than that of Φ25.4 mm when the relative volume of detonation product is 10. By using the dynamic finite element program LS-DYNA, two cylinder tests were simulated and the Lee-Tarver ignition and growth trinomial model was adopted. The parameters Jones-Wilkins-Lee equation of state and the reaction rate of the aluminized explosive were obtained through simulation and test results.

Abstract:In order to obtain a potential TNT replacement for melt-cast explosives, the melting process of eutectic based on methyl-nitroguanidine (MeNQ) was studied by differential scanning calorimetry at 50~150 ℃ under different atmosphere (static state and N₂) and heating rates (5, 10, 20, 30 ℃·min^-1). Effects of HNS and HMX on the behaviors of melting of the eutectic were studied. Results show that with the increasing of heating rate, the time of melting and peak temperature of the sample delayed, while the rate of melting increases. HNS and HMX can not accelerate the melting of the eutectic. The melting rate of eutectic based on MeNQ follows the 1/2 order kinetics reaction, and the apparent activation energy of the melting reaction is 11.77 kJ ·mol^-1 at 10 ℃·min^-1.

Abstract:Using glass, polyester, aluminum and carbon fiber as the mechanical modifier of melt-cast explosive RDX/TNT 65/35, the influence of type, content and length on its mechanical property was studied through compressive and tensile experiments. Results show that, the modified effect on compressive strength with polyester fiber is the best, and the compressive strength of the explosive with 0.4% increases to 27.94 MPa. The tensile strength and tensile elongation decreases obviously with decrease of aluminum fiber. The tensile and compressive mechanical properties are degraded when using 0.2% glass fiber than that without fiber. The compressive mechanical performance of RDX/TNT 65/35 increase with the additive amount of glass fiber increase. With 0.01% and 0.05% carbon fiber separately, the tensile mechanical property with 3 mm carbon fiber is better than that with 6 mm carbon fiber, and tensile mechanical properties reach maximum using 0.05% 3 mm carbon fiber.

Abstract:The shear device for explosive tablet was designed by ANSYS/LS-DYNA and the response character was studied using Φ20 mm×5 mm and Φ20 mm×9 mm PBX-2. The pressure change was measured by Manganin pressure gauges. Ignition process was analyzed by high-speed motion pictures. The reaction overpressure of explosive was gained by blast pressure gauges. Results preliminary show that height threshold decreases from 3.5~3.7 m to 3.0~3.1 m with explosive thickness increasing. The height threshold decreases when increasing explosive thickness in shear test for explosive tablet.

Abstract:To improve the combustion performance of azidonitramine gun propellant, the sample was desensitized with the surface layer coated by small-molecule multiple alkynyl compound (TPTM) which was used as insensitive precursor with rotating-drum spraying technique. TPTM was reacted with 1, 5-diazido-3-nitrazapentane (DIANP), which is component of azidonitramine gun propellant, at 60 ℃ to form macromolecule deterrent with cross-linked structure. The effect of deterrent was characterized by closed-bomb test, thermal-aging test and 14.5 mm machine gun test. The interior ballistic properties was checked by the 30 mm gun tests. Results show that initial burning rate of the deterred propellant reduces about 15%, and its progressive burning characters value L_m/L₀ is more than 1.5, the long-storage stability is excellent, and the interior ballistic properties in 30 mm gun is good.

Abstract:To reveal the influence mechanism of the particle size and crystalline form on the combustion of boron particles, the ignition and combustion characteristics of boron particles were studied by using a laser ignition system. Results show that in the particle size range of 25-65 μm, the ignition delay time of crystalline boron is between 13 and 19 ms, and shows no evident regularity as a change of particle size. The combustion efficiency of both amorphous and crystalline boron increases with increasing the particle size. The oxide layer covered on the surface of boron particles is a crucial factor of the reaction efficiency when particle size is less than 65 μm. The ignition delay time is the shortest and the combustion becomes most intense for crystalline boron with a particle size of 55 μm, which indicates that 55 μm may be the optimum size for ignition and combustion. Amorphous boron has a shorter ignition delay time and higher combustion efficiency, compared to crystalline boron. The burning flame and emission spectrum of amorphous boron are also stronger. This implies crystalline form has a more important influence on boron ignition and combustion than particle size.

Abstract:In order to study the influences of end constraint and charge length on the jet formation of single angle cuneiform cover liner shaped charge(LSC) cutter, a three-dimensional full-scale model of charge was established by using ANSYS/LS-DYNA program. The jet formation photographs of different time was reorded by X-ray technique. Results show that the image shape of simulation almost is same with X-ray test. The jet mass and jet velocity were declined because of end constranint. The influence of end constranint on jet formation was different with different charge length. Jet can hardly form when the charge length was less than 20 mm. When the charge length was greater than 20 mm and less than 70 mm, a stable jet can form in charge length range and maximum jet velocity increased gradually to a certain level for a certain length of charge. To minimize the adverse effect of the end constranint on the jet formation, charge length should be greater than 70 mm.

Abstract:Properties of cast PBXs are reviewed including mechanical behaviors, material characteristics, experimental techniques and constitutive models. Some hot-spots and difficulties such as dynamical mechanical properties analysis and constitutive models are summerized. The enablishment of the models of cast PBXs may refer to Visco-elastic models, hyper-elastic models and the constitutive model of solid properlants. Characteristics of energetic sensitivity, soft material and large deformation are suggested to improve the experimental methods. The directions for future research are also forecasted, such as estimation of mechanical properties, dynamic testing methods and numerical simulation.

Abstract:Seven modified nitramine double base propellants with different content of RDX were prepared by screw extrusion process, and their mechanical safety performance, including the friction sensitivity, the impact sensitivity and the shooting sensitivity were studied according to the national military standard methods. Results show that with increasing of RDX, the impact sensitivity, the friction sensitivity and combustion probabilities of shooting of the propellants increase. The friction sensitivity keeps stable at around 60% explosion probability and impact sensitivities increase slowly when RDX content is up to 27%.The combustion probabilities of shooting of the propellant increase with RDX content increasing.

Abstract:3, 3′-Bis(tetrazol-5-yl)-4, 4′-azofurazan(DTZAF) was synthesized from 3-amino-4-(tetrazol-5-yl)furazan, and its four energetic salts were then synthesized via metathesis reaction with total yield of 73.0%, 70.3%, 75.0%, 76.3%. Theri structures were characterized by IR, ¹³C NMR, ¹H NMR, MS and elemental analysis. Their thermal decomposition products were studied by TG-DSC-IR-MS. The thermal prpperties of DTZAF and its energetic salts were studied by differential scanning calorimetry(DSC) and thermogravimetry(TG). Results show that DTZAF and its energetic salts have good thermal stability before 200 ℃.

Abstract:Tris(para-nitrophenyloxymethyl)nitromethane was synthesized via reaction, esterification and substitution reaction using nitromethane as starting material. The structures of intermediate compounds and title compound were confirmed by ¹H NMR and IR. Thermal behavior of the title compound was determined by TG-DSC. Results show that the optimized conditions of substitution reaction are: reagent ratio 1:3.5, reaction temperature 120 ℃, reaction time 24 h, potassium carbonate as acid binding agent. The total yield is 51.2%. The melting point and thermal decomposition temperatures of the title compound are 186.94 ℃ and 340.59 ℃ respectively. The total mass loss in the temperature ranges 246.2-499.3 ℃ is 62%. The title compound does not decompose completely at 500 ℃, showing that the title compound has a good thermal stability.

Abstract:

Abstract:

Abstract:

Abstract: