Abstract:

Abstract:Azide-terminated hyperbranched polyesters(HBPE-N₃) were prepared via the reaction between sodium azide and sulfonyloxy-terminated hyperbranched polyesters(HBPE-OTS) in dimethylsulfoxide(DMSO). The reaction conditions were optimized. Results show that up to 99.8% sulfonyloxy group can be substituted by azide groups when the temperature is 95 ℃, reaction time is 24 h, n(sodium azide):n(HBPE-OTS)=1.5 and the tetrabutylammonium bromide dosage is 5.0%(mole ratio)of sodium azide with DSMO as the reaction medium.

Abstract:The JWL equation of state of detonation product for pressed composite explosive based on CL-20 was studied. The driving ability for C-1 explosive(mass ratio: CL-20/insensitive binder=94.5/5.5) was evaluated by 25mm standard cylinder test, and the relationships between expansion velocity/displacement of the cylinder wall and time were analyzed. Under the consideration of the equation close, the JWL equation parameters were obtained by the data processing method. And using these parameters, the cylinder tests for reference explosives LX-19, PBXC-19 were simulated, and the driving ability of the C-1 and LX-19, PBXC-19 were also analyzed. Results show that the relative error of velocity and displacement between the simulation and experiment are less than 2% and 1%, respectively. Compared with LX-19 and PBXC-19, gurney velocity of C-1 increases 2.02%, 2.20%, respectively.

Abstract:To study the corner performance of detonation waves for HMX-based and TATB-based polymer bonded explosive(PBX), the breakout angles, failure angles and delay time for PBX-Ⅰ containing 95%HMX, PBX-Ⅱ containing 85%HMX and 7%TATB, and PBX-Ⅲ containing 95%TATB with initiating diameter of 7 mm and 10 mm were studied by Mushroom test. Results show that with initiating diameter of 7 mm, the breakout angle of PBX-Ⅰ(75.5°) is slightly greater than that of PBX-Ⅱ(74.4°), and the failure angles of PBX-Ⅰ and PBX-Ⅱ are 90°, and they are able to develop for similar spherical. It reveals that HMX-based PBX explosive has better corner performance. With initiating diameter of 10 mm, the breakout angles and failure angles are 78.6° and 90° for PBX-Ⅱ and 16.1° and 60.4° for PBX-Ⅲ, respectively. The breakout angles for HMX-based PBX increase with increasing the initiating diameter, and decreases when TATB is added in HMX-based explosive. The breakout angle decreases significantly as substituting all of HMX with TATB. The corner performance of detonation waves for the three kinds of explosive decreases in the order: PBX-Ⅰ>PBX-Ⅱ>PBX-Ⅲ.

Abstract:In order to study the effect of higher aliphatic ester compounds on the properties of RDX, six insensitive samples (RDX coated by 2, 3-bis(hydroxymethyl)-2, 3-dinitro-1, 4-butanediol tetralaurate (BHDBTL), 2, 3-bis(hydroxymethyl)-2, 3-dinitro-1, 4-butanediol tetrastearate (BHDBTS), 2, 3-bis(hydroxymethyl)-2, 3-dinitro-1, 4-butanediol tetra(12-hydroxyl stearate) (BHDBTHS) with mass fraction of 3% or 5%, respectively)were prepared. All RDX samples were characterized by infrared spectroscopy(IR), scanning electron microscope(SEM), laser particle size analyzer, differential scanning calorimetry(DSC), and their mechanical sensitivity were tested by GJB772-1997. Results show that the particle size of coated RDX decreases signally, and the specific surface area of RDX coated by 5% BHDBTL, BHDBTS, BHDBTHS increase from 0.0374 m²·g^-1 to 0.173 m²·g^-1, 0.344 m²·g^-1 and 0.328 m²·g^-1 , respectively. The decomposition heat of coated RDX increased, for addition of 5% BHDBTHS, the decomposition heat increases from 1479.1 J·g^-1 to 1912.5 J·g^-1. The impact sensitivity of RDX coated by 5% BHDBTL, BHDBTS and BHDBTHS are 28%, 48%, 52% and the friction sensitivity were 20%, 60%, 48%, respectively.

Abstract:Strength plays an important role in structural integrity and safety for explosive parts, and is also the basis for estimation of the structural strength. Based on uniaxial loading technique, strength property of TATB based polymer bonded explosive(PBX) under triaxial tension stress state was studied by an end-restraint cylinder tension collapse method. The stress field under critical load was quantitatively analyzed through finite element simulation according to the tested boundary conditions. At last, the adaptability of three typical criterions(uniaxial-strength, Mohr-Coulomb, twin-shear) in strength analysis was illustrated using principal stresses of initial failure position. Results show that among these three criterions, uniaxial-strength criterion, which is most often used in explosive engineering, has the best safety threshold, about 43.77%, under triaxial compression stress state, but even so, it still can not supply a safety forecast for this TATB based PBX strength failure under triaxial tension stress state. For the representation accuracy, uniaxial-strength criterion has the best precision with an error about 16.90%, Mohr-Coulomb criterion and twin-shear criterion take second and third place with the error of 19.62% and 24.56%, respectively. Moreover, the triaxial tension strength is 0.831 times of the uniaxial tension strength, while Mohr-Coulomb criterion can not predict the strength lower bound precisely. It may be mainly caused by hydrostatic pressure, which must be considered further to establish multiaxial strength criterion with high precision.

Abstract:The solubility of RDX with average particle size of 20 μm, 5 μm, 500 nm and 100 nm in the 8 solvents including the ethyl acetate, ethanol, propyl alcohol, isopropanol, n-butyl alcohol, sec-butyl alcohol, isobutanol and deionized water at 5, 20, 40 ℃ and 60 ℃ respectively were measured by the evaporation method of the solvent in the saturated solution. Results show that the solubility of RDX with the same granularity level is lowest in the deionized water and highest in the ethyl acetate. The solubility in ethanol is higher than that in propyl alcohol and butyl alcohol. The solubility in n-butyl alcohol is higher than that in sec-butyl alcohol and isobutanol. In same solvent, the solubility of RDX at the same temperature increases with decreasing of the particle size. The solubility of RDX with same granularity level increases with the increasing of temperature.

Abstract:To analyze regular of the shift from internal elastic strain to plastic stain for polymer-bonded explosive (PBX), creep curves for HMX based PBX under 80 ℃ were obtained by time temperature equivalence principle, and the creep model based on modified time hardening theory was obtained by ANSYS software. The deformation of HMX based PBX during the thermal-pressure process was simulated. Results shows that compression deformation occurs along the loading stress under thermal-pressure aging treatment(80 ℃, 10 MPa) for HMX based PBX with diameter and height reducing 0.476 mm, 1.306 mm, respectively, and the density increasing 0.047 g·cm^-3, which confirms that the creep behavior of PBX can be accelerated by the thermal-pressure aging treatment.

Abstract:Thermal explosion tests of double-base propellant charges and modified double-base propellant charges with diverse diameters were studied to explore the feasibility of evaluating the thermal safety of propellant charge by the critical temperature of thermal explosion (T_cr) and appropriate test conditions and data processing methods. The time to ignition and critical temperature of thermal explosion of propellant charge occurred at certain temperature were obtained. Results show that T_cr can be used to evaluate the thermal safety of propellants and the appropriate test diameter range is from 20 mm to 25 mm. Assumptions that the maximum test time is 10h and the test can be ended as the difference between the lowest explosion (ignition) temperature and the highest non-explosion (no-ignition) temperature is less than 5 ℃ for double-base propellant and modified double-base propellant are reasonable. The values of T_cr predicted by extrapolating through fitting equation of lnr-T_cr are lower than those predicted by other fitting methods cited in references.

Abstract:The damage process of hydroxyl-terminated polybutadiene(HTPB) propellant/liner adhesive interface was observed by scanning electron microscope(SEM)in situ tension system. The real-time SEM images of deformation and failure for interface were collected. The micro mechanism of deformation and failure of adhesive interface was analyzed combining with the macroscopic stress(σ)-strain(ε) curve. Results show that the tensile failure process of adhesive interface can be separated into four stages:l inear interval with larger slope(0 < ε < 5%), linear interval with smaller slope(5% < ε < 25%), nonlinearity interval(25% < ε < 29%) and failure interval(29% < ε < 35%). The two specimens used in verification test reach their ultimate stress when strain arrives at 25% and 30%, respectively. It is also found that dehumidification of internal grain and interfacial debonding have much to do with the change of mechanical property and interface failure. And the interface failure can be reflected by the laws between dehumidification size and strain: when dehumidification size increases linearly with strain, the specimen does not failure. If the increasing rate decreases or the size does not increase, the specimen are damaged.

Abstract:The non-isothermal curing kinetics of acrolein-pentaerythritol resin system were studied by dynamic differential scanning calorimetry(DSC). The DSC data were analyzed by the Kissinger and Crane equations. The kinetic parameters were calculated and the curing kinetic model for acrolein-pentaerythritol resin system was also established. Based on the viscosity experiments at 341, 347, 353 K and 359 K, the rheological model on the foundation of Arrhenius equation was built. Results show that the apparent activation energy, reaction order and frequency factor of curing reaction are 14.32 kJ·mol^-1, 0.95, 3.84×10³ K, respectively. The curing degree are 0.9503, 0.9147, 0.8871 and 0.8695 at the heating rates of 10, 15, 20 ℃·min^-1and 30 ℃·min^-1, which indicates that with the decreasing of heating rate, the curing degree increases.

Abstract:Cook-off test of GATo-3 propellant with different aging degree was carried out by a self-designed device. The self-ignition temperature and time to self-ignition of GATo-3 propellant under the different experimental conditions were experimentally obtained. The related kinetic parameters of GATo-3 propellant were obtained via calculation and the experimental phenomenon and law were analyzed. Results show that the self-ignition temperature of GATO-3 propellant is about 130 ℃, activation energy is 147.66 kJ·mol^-1 and pre-exponential factor is 2.72×10¹⁵ s^-1. The ignition temperature of the GATo-3 propellant at different environmental temperature mostly remains the same, but its time to self-ignition and intensity degree are different. The higher the temperature, the shorter the time to self-ignition and there is the more intense response degree. With increasing the storage time, the decrease of stabilizer content makes the decomposition rate accelerate, and the time to self-ignition short.

Abstract:Effect of triphenyl bismuth(TPB)and tri (exhoxyphenyl) bismuthine(TEPB) on kinetics of hydroxyl terminated polybutadiene-toluene diisocyanate(HTPB-TDI) curing reaction were studied by non-isothermal differential scanning calorimetry(DSC).Characteristic temperature of curing systems were measured for calculating kinetic parameters by Kissinger and Crane method and the curing reaction kinetic equations was established. Results show that catalysts decrease the curing temperature and shorten the curing temperature gradient. Activation energy(E_a) of uncatalyzed HTPB-TDI curing system is 51.29 kJ·mol^-1, the E_a of HTPB-TDI are decreased to 46.43 kJ·mol^-1 and 40.14 kJ·mol^-1 by using TPB and TEPB. Both catalysts lower reaction temperature and curing time through decreasing activation energy of curing reaction and accelerating reaction rate. The reaction rate constant value of HTPB-TDI catalyzed by TEPB at 34℃ is similar to that of HTPB-TDI catalyzed by TPB at 50 ℃, indicating that the catalytic activity of TEPB is higher than that of TPB and it′s available for ambient catalyst.

Abstract:To further study the combustion characteristics of magnesium metal particles, based on the Arrhenius law, a one-dimensional spherical symmetric quasi-steady combustion model of limit reaction rate of magnesium particle was established. The combustion process of a magnesium particle with a diameter of 120 μm was simulated in the atmospheric environment. The combustion field temperature distribution, composition distribution of reactants and combustion time of particle were obtained. Results show that the highest temperature obtained by the limit-rate combustion model in the reaction zone is 3568 K, and the combustion time of magnesium particle is 21.9 ms. The calculated results agree well with the experimental in literatures. Reactant of oxygen and magnesium vapor can spread to the outside of the reaction zone, which is qualitatively in accordance with the experimental phenomenon that oxygen atoms are detected in the quenched magnesium particle, indicating that the limit-rate combustion model can describe more precisely the actual condition of magnesium particle combustion than traditional fast-rate combustion model.

Abstract:The response of exploding bridgewire detonators with two different(pin-pin and pin-shell)discharge types to high voltage electrostatic discharge(ESD) was studied using a high voltage ESD test system at the circuit parameters of 250 kV, 1000 pF, 1 Ω. Results show that melting, fracture or explosion(without ignition)of bridgewire detonators can be observed when ESD was applied to pin-pin discharge. The 50% broken voltage of bridge wire is 56.33 kV. The typical response of detonators to ESD is electrode plug breaking away from shell when ESD applied to pin-shell. The response characteristic of detonator to high voltage ESD is found to be ralated with the ESD energy distribution, the structure and the ignition mechanism of detonator.

Abstract:An impinging nozzle was designed to investigate the motion properties of spray particles from impinging nozzle at atmospheric environment. Phase doppler particle analyzer(PDPA) was used to record the effects of the nozzle pressure on the motion properties of spray particles. The distributions of axial velocity and radial velocity for particles were analyzed emphatically. Results indicate that as the distance between the measurement section and the nozzle increases from 25 mm to 100 mm, the mean diameter (D₃₀) of the particles at the pressure drop of 2.2 MPa increases from 44.26 μm to 61.26 μm and from 42.88 μm to 55.49 μm at the pressure drop of 2.6 MPa. The further away from the nozzle, the smaller the axial velocity and the radial velocity of the particles. The axial velocity of the particles decreases and the radial velocity fluctuation increases with distance between the measuring points and the center axis increasing. The D₃₀ of the particles decreases when the nozzle pressure increases, and the distribution uniformity of the particles is better for the axial velocity but worse for the radial velocity.

Abstract:To reduce the content of nitrobenzene in wastewater, an air stripping-O₃/H₂O₂ oxidation treatment process enhanced by high gravity technology was established for the first time. The pretreatment of high concentration nitrobenzene-containing wastewater was conducted by air stripping method, which was enhanced by high gravity technology. The effects of high gravity factor β, gas-flow rate G, liquid-flow rate L and stripping times on the nitrobenzene stripping efficiency were investigated. The experimental results show that the combination of high gravity technology can effectively improve the nitrobenzene removal rate. When the G=20 m³·h^-1, L=20 L·h^-1, β=80, the concentration of nitrobenzene after stripping for 10 times is decreased to 100 mg·L^-1. Then the changes of stripping efficiency are significantly weakened. The lower content wastewater is further treated by advanced oxidation process of O₃/H₂O₂ enhanced by high gravity technology. When L=120 L·h^-1, β=80, gas phase O₃ concentration C_O3=50 mg·L^-1, the concentration of H₂O₂ C_H2O2=4.9 mmol·L^-1, initial pH=10.5 and the processing time is 25 min, the removal efficiency of nitrobenzene can reach 99.6% and BOD₅/COD_Cr=0.38; the wastewater treated can meet the standard of biochemistry treatment of integrated wastewater discharge standard(GB8978-1996).

Abstract:The composition and application of gas generantt were briefly introduced. The explosive performances and research progresses in the domestic and foreign synthesis for azole, guanidine and azine etc. gas producing fuel were mainly reviewed. The performances of traditional azide gas generants were compared, pointing out that new gas generant having the advantages of high gas producing amount, fast burning rate, low combustion temperature, good thermal stability, good process performance, non-toxicity, and green environmental protection is the focus of future research.

Abstract:Two types of porous reticular HMX, PHMX-A and PHMX-B, were prepared by adding octogen(HMX)/ dimethylsulfoxide(DMSO)complex, which was obtained by mixing HMX and DMSO, into pure distilled water or the solution containing polyvinyl pyrrolidone. Their structures were characterized by scanning electron microscope, X-Ray diffraction, mercury pressure method and thermogravimetry-differential scanning calorimetry. Results show that both porous reticular HMXs are consist of homogeneous continuous skeleton and many pores, and have high specific surface area and porosity. PHMX-A is absolutely β-type crystal, while PHMX-B contains a little γ-type crystal. The SSAs for PHMX-A and PHMX-B are 5.3 m²·g^-1 and 19.0 m²·g^-1, the mean pore diameters are 501nm and 75nm, and the porosities are 56.1% and 37.2%, respectively. The phase inversion temperature, thermal decomposition temperature and initial decomposition temperatures for PHMX-A and PHMX-B compared with those of raw HMX, are all advanced by 2.8 ℃ and 17.5 ℃, 0.3 ℃ and 1.3 ℃, 4 ℃ and 14 ℃, respectively.

Abstract:A nitrogen-rich, polynitro energetic compound with an N, N-azo linkage, 1, 1′-azobis(3, 5-dinitropyrazole)(ABDNP), was synthesized using 3, 5-dinitropyrazole(DNP) as starting material via neutralization, N-amination and oxidative coupling reaction etc, and its structure was characterized by IR, ¹H NMR, ¹³C NMR, MS and elemental analysis. The effect of oxidizing agents on the coupling reaction were investigated. Results show that tert-butyl hypochlorite(t-BuOCl) is a better oxidizing agent with yield of ABDNP up to 43.5%. The physical-chemical and detonation performance of ABDNP were calculated by Gaussian 09 and VLW equation with density 1.94 g·cm^-3, detonation velocity 9309.0 m·s^-1 and detonation pressure 42.2 GPa, better than those of RDX.

Abstract:

Abstract:

Abstract: