Abstract:

Abstract:

Abstract:A novel energetic salt of diaminoglyoxinium 1H, 1′H-5, 5′-bitetrazole-1, 1′-diolate (DAGBTO) was synthesized by using diaminoglyoxime(DAG) and 1H, 1′H-5, 5′-bitetrazole-1, 1′-diol(BTO) as raw materials, and its structure was characterized by elemental analysis, Fourier transform infrared spectroscopy(FT-IR) spectroscopy, ¹H NMR, ¹³C NMR and mass spectrometry. The single crystal of DAGBTO was obtained and its structure was determined by X-ray single-crystal diffractometer. Results show that DAGBTO belongs to monoclinic space group C2/c with a density of 1.782 g·cm^-3, and the cell parameters are as follows: a=11.3121(11) Å, b=6.4480(4) Å, c=15.3202(16) Å, β=105.990(2) °, V=1074.23(17) ų, F(000)=592. The thermal decomposition behavior was investigated by differential scanning calorimetry(DSC) technology, and non-isothermal kinetic parameters were also calculated. Results indicate that it has a good thermal stability with the decomposition temperature above 190 ℃. The apparent activation energy are 210.6 kJ·mol^-1 (Kissinger) and 207.9 kJ·mol^-1(Ozawa-Doyle), respectively, and the critical temperature of thermal explosion is 200.7 ℃.

Abstract:The dynamic laser method was adopted to measure the solubility and supersolubility of 3, 4-bis(3-nitrofurazan-4-yl)furoxan(DNTF) in V(acetic acid):V(water)=7:3 mixed solvent. The Apelblat equation was used to fit the experimental solubility data. The influence of four main crystallization process factors of initial temperature, stirring speed, cooling rate and the mass of seed crystal were investigated by orthogonal experiments. Results show that the best product was obtained under initial temperature of 85 ℃, stirring speed of 400 r·min^-1, cooling rate of 0.25 ℃·min^-1 and seed crystal mass: solid mass of DNTF=5:95. The yield, purity, crystal density, characteristic height H₅₀ (2 kg drop hammer)of the best product are 91.7%, 99.72%, 1.876 g·cm^-3, 36.38 cm, respectively. The morphology of the product is regular, and the crystal size distribution of the product is narrow. Besides, the result of X-Ray powder diffraction demonstrates that the crystal structure does not change during the crystallization process.

Abstract:The 2, 6-diamino-3, 5-dinitropyrazine-1-oxide (LLM-105) micro-rods with cross section of rectangular were prepared by solvent-induced self-assembly process using nano-LLM-105 as raw materials. And the LLM-105 twin crystal synthesized directly were compared. The effects of solvent, nano-LLM-105 addition, stirring rate and self-assembly time on the crystal morphology of LLM-105 prepared by self-assembly were studied and the possible growth mechanism of rectangular micro-rods was proposed. The morphology, structure, thermal property and purity of crystals prepared by self-assembly were characterized by scanning electron microscopy, X-ray powder diffraction, different scanning calorimetry-thermogravimetry and high performance liquid chromatography. Results show that the regular rectangular micro-rods are assembled under the optimal conditions with dimethylsulfoxide as solvent, nano-LLM-105 addition of 40 g·L^-1, stirring rate of 600 r·min^-1. Comparing to LLM-105 twin crystals synthesized directly, the assembled regular rectangular micro-rods have the same diffraction peaks, but the intensities weaken at 11.1°, 22.3°, 24.8°, and 33.0°, which indicates that the crystal may be preferred to grow in the direction of the (1 0 0), and, its purity was improved by 1.8% to 98.8%. The regular rectangular rod-like crystals exhibit better thermal stability with only one exothermic peak of 356.7 ℃, and the thermo-gravimetric starting temperature(266.3 ℃) improves by 34.8 ℃ compared with 231.5 ℃ of LLM-105 twin crystals.

Abstract:Using acetone as solvent, the process conditions of preparing the spherical HMX by spray drying method were optimized by the orthogonal test L₉(3⁴), and the spherical HMX obtained under the optimal condition was characterized by scanning electron microscope (SEM). The morphology of the obtained HMX was quantitatively analyzed by the scoring method. Results show that the optimal preparation conditions of the spherical HMX are inlet temperature of 70 ℃, feed rate of 1.5 mL·min^-1, spraying gas flow rate of 473 L·h^-1, mass fraction of 1.5%. The median particle size of the spherical HMX obtained under optimal experimental conditions is 997.56nm and the crystalline form is the β type. Compared with raw HMX, the characteristic drop height of impact sensitivity for spherical HMX is increased by 28.21 cm.

Abstract:Using 4-(2, 4, 6-trinitroanilino)benzoic acid (TABA) as the ligand, a noval lead complex, {[PbL₂(DMF)H₂O]·2(C₃H₇NO)H₂O}_n(1) (L=4-(2, 4, 6-trinitroanilino) benzoate, DMF=N, N′-dimethylformamide), was synthesized by a solvent evaporation method. Its structure was determined by a X-ray single crystal diffractometer. Its thermal decomposition process was determined by TG-DSC. DSC curves of the 50/50-complex 1 /RDX mixture at different heating rate were determined and the kinetic parameters of the thermal decomposition reaction of the mixture were calculated. Results show that the crystal is monoclinic, its space group is P2(1)/c with crystal parameters a=6.900(2)Å, b =19.162(6)Å, c=34.866(11)Å, β=94.261(4)°, V=4597(3)ų, Z=4. Pb(Ⅱ) ions are connected by 4-(2, 4, 6-trinitroanilino) benzoate and 1-D coordination polymer chains are formed. The thermal decomposition of complex 1 mainly undergoes four stages. The first stage occurs between 58 ℃ to 84 ℃ and complex 1 mainly loses its crystallized and coordinated water molecules and part of crystallized DMF molecules. The temperature range of 84 ℃ to 231 ℃ is the second thermal decomposition stage with complete loss of the rest DMF molecules.The energetic organic ligand TABA^2-decomposes mainly at stages 3 and 4 of the process and exothermal peaks appear at 296 ℃ and 335 ℃, respectively. The thermal decomposition of RDX was accelerated by complex 1.

Abstract:The geometrical structures, front orbit energy and enthalpies of formation(ΔH_f) of thirty kinds of 1, 2, 4, 5-tetrazine derivatives were studied by using DFT-wB97/6-31+G^** method. On this basis, the detonation parameters of the derivatives were estimated by Kamlet-Jacobs equation. The bond dissociation energy of the title compounds was analyzed. The thermodynamic properties of part of the title compounds at different temperatures from 200 K to 800 K were calculated by statistical thermodynamics. The detonation performances and stability of 1, 2, 4, 5-tetrazine derivatives were compared. Results show that their ΔH_f are between 920.46 and 2610.45 kJ·mol^-1and the detonation velocities are between 7.69 and 9.31 km·s^-1. —NO₂ and —N＝N— is not conducive to increase the stability of the derivatives. The values of standard molar heat capacity c_p、standard molar entropy S_m and standard molar enthalpy H_m gradually increase with the temperature. i2 (3-(5-Nitro-1, 2, 3, 4-tetrazol)-6-nitro-1, 2, 4, 5-tetrazine), ii2 (3-(azo-5-nitro-1, 2, 3, 4-tetrazol)-6-nitro-1, 2, 4, 5-tetrazine) and iv2 (3, 6-azo-bis(5-nitro-1, 2, 3, 4-tetrazol)-1, 2, 4, 5-tetrazine) may be considered as potential candidates for energetic materials.

Abstract:Aiming at the thermodynamic state description of high temperature and high pressure gases under detonation circumstance, a contrast state type virial equation of state(EOS) named as VHL(Viral-Han-Long) based on Lennard-Jones(LJ) potential function is presented in this study. Based on the VHL EOS and optimized LJ potential parameters, the thermodynamic relations of pressure, volume and temperature(pVT)of detonation products component carbon dioxide (CO₂) were calculated and compared with the calculated results by VLW EOS. Results show that the average absolute deviation(AAD) of the volume is about 0.971% and the maximum error is 4.04%, the average absolute deviation(AAD) of the volume obtained by VLW EOS is about 20.2% and the maximum error is 87.149%. In describing the thermodynamic state of CO₂ at high temperature and high pressure, VLW EOS has an obvious dependence on temperature. At the detonation environment temperature, the calculated deviation of the volume decreases with the rise of temperature. Compared with VLW EOS, VHL EOS can better describe the pVT thermodynamic relations of high temperature and high pressure CO₂ gas under detonation environment.

Abstract:In order to explore more effective approach in molecular design of neutral polymeric bonding agent(NPBA) than semi-empirical and semi-quantitative method, MesoDyn module of Materials Studio was used to simulate mesoscopic phase segregation of three NPBAs in energetic plasticizer/prepolymer mixture, as described in U.S. Patent No.4915755. It is shown that the order parameter of NPBA in the mixture at 303 K (30 ℃) is higher than that of the NPBA at 333 K (60 ℃), which means that phase segregation at low temperature is stronger and agrees well with the goal of NPBA tailoring. On the other hand, increasing molecular mass of NPBA and percent of NPBA in the mixture and decreasing processing temperature can increase phase segregation. These results can be explained by related theory of polymer solution and indicate the mesoscopic simulation method can be used for verifying of NPBA molecular design in a straightforward way.

Abstract:In order to study the storage characteristic of exploding foils, the accelerated life test at high temperature of 90 ℃ and high temperature and humidity of 80 ℃, RH 95% were carried out. The appearance, morphology, burst characteristic and flyer velocity were studied by photograph, SEM, fire test and photonic doppler velocimetry(PDV) method. Results show that after aging at 80 ℃, RH 95%, the surface of exploding foil is oxidized, and the surface color changes significantly due to the Cl element and humidity, and the average resistance obviously increases from 30.3 mΩ(before aging)to 66.8 mΩ(after aging). There is no remarkable influences of high temperature(90 ℃) on burst current, burst voltage and explosion time of exploding foil. While the burst voltage and explosion time significantly decrease after aging at 80 ℃, RH 95%. The performance of exploding foil adhesion to polyimide film becomes poor after aging. The PDV test results show that with the increasing of acceleration time, the flyer velocity decreases from 3600 m·s^-1 to 2100 m·s^-1 at 90 ℃ and 1200 m·s^-1 at 80 ℃, RH 95%. The ability to drive slapper decreases after aging. The storage condition of high temperature and humidity has a stronger effect on flyer velocity than that of high temperature.

Abstract:To improve the damage ability of integral multiple explosively formed projectiles (MEFP), the effect of configuration parameters of liner on projectile formation was studied using LS-DYNA code. Based on the simulating results, a integral charge structure was optimized and designed and its experiment verification was carried out.Results show that liner configuration parameters have great effect on projectile shape. With increasing the liner curvature radius, the length-diameter ratio of central projectile and the length of surrounding projectile decrease by 40% and 41.2%, respectively. The shape of surrounding projectile changes from rods to ball shape gradually. With increasing the liner thickness, the length-diameter ratio of central projectile and the length of surrounding projectile decrease by 22.2% and 19.7%, respectively. The trail of surrounding projectile decreases gradually and the flight stability of projectile enhances. The curvature radius obtained by optimization and optimal value of thickness are 77-82 mm and 2.2-2.6 mm, respectively. Designed warhead can effectively penetrate the 45^# steel target plate with a thickness of 15 mm, which is in good agreement with the simulation results.

Abstract:To study the technology of improving the propellant increase burning area based on the principle of manufacturing the special shape objects by the 3D printing technology and the law of propellant burning parallel layers, the integral propellant with high increase burning area having multi empty annular groove tubular structure was designed. The changing rules of area of burning surface and the generation amount of burning gas and generation rate of burning gas for the integral propellant along with burning were analyzed. The calculation method of changing rule of the relative area of burning surface and the relative generation amount of burning gas along with burning were established. The changing rules of the relative area of burning surface and the relative generation amount of burning gas of the integral propellant and 19 holes granular propellant with the relative burning thickness were compared and analyzed. Results show that the designed integral propellant has higher burning area increase. The relative area of burning surface at the end of combustion for the integral propellant used for 155 mm howitzer is 3.1 times more than that of 19 holes granular propellant. The burning gas generation rate of the integral propellant reveals the status of first low and than high in the combustion process. The generation amount of burning gas in the integral propellant combustion after the half is about more than 75.612% of total generation amount of burning gas, 27.575% more than 19 holes granular propellant.

Abstract:To determine the decomposition kinetic parameters of urotropin, the differential scanning calorimeter(DSC) and accelerating rate calorimeter(ARC) were employed to study its thermal behavior at different heating rates. DSC results show that the exothermic decomposition and endothermic melting are overlapped, the activation energies of the two peaks in isothermal test are all about 150 kJ ·mol^-1. The temperature at which the time to maximum rate is 24 h(T_D24) was calculated by the AKTS code, the value was 216.26 ℃. ARC results show that the initial temperature of urotropin is 230.28 ℃, T_D24 is 212.5 ℃, which is near to the prediction (216.26 ℃)based on the isothermal DSC results.

Abstract:The quantitative calibration models of three polymorphs α-CL-20、γ-CL-20、ε-CL-20 in ε-CL-20 product were established by mid-infrared diffuse reflectance spectroscopy combined with partial least squares(PLS) method of chemometrics, and the cross-validation and external validation to the models were performed. Results show that three models have high accuracy and precision, the determination coefficients of cross-validation(R²) are 0.9973, 0.9714, 0.9848, respectively, and the root mean square error of cross-validation (RMSECV) are 0.222%, 0.650%, 0.670%, respectively. In the external validation, the root mean square error of prediction(RMSEP) are 0.422%, 0.813%, 1.02%, respectively, and the paired t-test results show that there is no significant difference between predicted values and actual ones. The quantitative analysis method of CL-20 polymorphs based on the above models can be applied to the product quality test of ε-CL-20, and the studies on the polymorph stability of ε-CL-20 in technical process and long-time storage of explosives and propellants.

Abstract:Rotating packed bed(RPB) was applied in adsorption removal of phenol from simulation wastewater, with the activated carbon as adsorbent. The influence of operating parameters of RPB on removal efficiency such as high gravity factor, flow rate and initial concentration of phenol wastewater were examined to determine the optimum operating conditions. The pseudo-first-order model and the pseudo-second-order model were used to study the adsorption kinetics. The effect of operating parameters on the adsorption rate constant were studied. The removal efficiency and adsorption rate constant were compared with those of traditional adsorption method. Results show that under the operational conditions: high gravity factor of 44.68, flow rate of 35 L·h^-1, initial concentration of phenol wastewater of 1000 mg·L^-1, the adsorption time of 2 h, the removal efficiency of phenol can reach maximum about 90%, which is 30% higher than the traditional adsorption method. The adsorption rate constant obtained by pseudo-second-order model increases with the increasing of high gravity factor and flow rate. The kinetics equations in RPB and traditional adsorption method under the optimum condition are as follows: t/q_t=0.02648+0.77932t, t/q_t=0.02869+1.55707t, and the adsorption rate constant improves from 5.28×10^-4 to 9.02×10^-4.

Abstract:1, 8-dihydroxy-anthraquinone lead(DHAAPb) and 1, 8-dihydroxy-anthraquinone cupper(DHAACu) were synthesized with 1, 8-dihydroxy-anthraquinone as raw material. Their structures were confirmed by IR, element analysis and X-fluorescence. The catalytic actions of DHAAPb and DHAACu on double-base propellant and RDX-modified double base propellant(CMDB) were analyzed. Results show that DHAAPb can increase the burning rates of double-base propellant in the low pressure range(2-6 MPa) obviously, and the catalytic efficiency is above 2.0. The pressure exponent in the pressure range of 10-16 MPa of double-base propellant decreases to 0.1 with the catalysis of DHAAPb. DHAAPb and DHAAPb/DHAACu can increase the burning rate of RDX-CMDB over 2 times in the pressure range of 2-6MPa, and make the pressure exponents of RDX-CMDB propellant decrease to 0.29 and 0.16 in the pressure range of 6-18 MPa, respectively.

Abstract:

Abstract:

Abstract: