Abstract:With the help of the amount of the complex (a), the concentration of the solution (b), the heat effect of dissolution process (Q) and the molar enthalpy of dissolution in water (Δ_dissH) of M(NTO)_n·mH₂O (M=Ba, n=1, m=3; M=Li, n=1, m=2; M=Ca, n=2, m=4; M=Na, n=m=1; M=Co, Mg, n=2, m=8; M=Ce, Pr, Gd, n=3, m=7; M=Tb, Dy, n=3, m=5; M=Y, Yb, n=3, m=6; NTO=3-nitro-1, 2, 4-triazol-5-one) obtained by a Calvet microcalorimeter, five empirical formulae describing the differential enthalpy of dissolution(Δ_difH^θ_m), standard molar enthalpy of dissolution ［Δ_dissH^θ_m(b=0)］, relative apparent molar enthalpy (Δ_dissH_apparent), relative partial molar enthalpy (Δ_dissH_partial) and enthalpies of dilution (Δ_dilH_1,2) in water of these metal complexes of NTO were obtained.

Abstract:With the help of the initial temperature(T₀), at which DSC curves deviate from the basline, the onset temperature(T_e) and maximum peak temperature(T_p) from the non-isothermal DSC curves at different heating rates(β), the thermal decomposition activation energy(E_K and E_O) and pre-exponential constant(A_K) obtained by Kissinger′s method and Ozawa′s method, the value of b_{e0(or p0)} from Hu-Zhao-Gao′s equation and the value of a_{e0(0r p0)} from Zhao-Hu-Gao′s equation, the values of specific heat capacity(C_p) obtained by microcalorimetry, density(ρ) and thermal conductivity(λ), the decomposition heat(Q_d, taking half-explosion heat), Zhang-Hu-Xie-Li′s formula, Hu-Yang-Liang-Xie′s formula, Hu-Zhao-Gao′s formula, Zhao-Hu-Gao′s formula, thermodynamic relation formulae, Smith′s equation, Friedman′s formula, Bruckman-Guillet′s formula, Frank-Kamenetskii′s formula， Wang-Du′s formulas and Yoshida′s formulas, the values(T₀₀, T_e0 and T_p0) of T₀, T_e and T_p corresponding to β→0, thermodynamic parameters of activation reaction(ΔG^≠、ΔH^≠、ΔS^≠), thermal explosion temperature(T_be0 and T_bp0), adiabatic time-to-explosion(t_Tiad), 50% drop height(H₅₀) of impact sensitivity, critical temperature of hot-spot initiation(T_{cr, hot-spot}), critical ambient temperature of thermal explosion(T_acr), safety degree(S_d), thermal explosion probability(P_TE), explosion potential(E_p) and shock sensitivity relative to m-dinitrobenzene(S_S) of 1,1′-Dimethyl-5,5′-azotetrazole monohydrate(1, 1′-DMATZ) and 2,2′-Dimethyl-5,5′-azotetrazole(2, 2′-DMATZ) are calculated. The results show that(1) 1, 1′-DMATZ is thermally stable;(2) the heat-resistance ability of 1, 1′-DMATZ is better than that of 2, 2′-DMATZ; (3) the different positions of the methyl group in the molecules are the principal factor affecting the thermal safety.

Abstract:Twenty expressions describing the overall standard deviation(σ) of thermal safety criteria of small-scale energetic materials were presented. The values of σ and relative standard deviation of thermal safety criteria for 1, 1′-dimethyl-5, 5′-azotelrazol monohydrote, 3-nitro-1, 2, 4-triazol-5-one, bis(2,2,2-trinitroethyl) formal and double-base propellant composed (56±1) wt% of NC, (27±0.5) wt% of NG, (8.5±0.15) wt% of DNT, (2.5±0.1) wt% of methyl centralite, (5.0±0.15) wt% of catalyts and (1.0±0.1) wt% of other were reported.

Abstract:In order to reduce the mechanical sensitivity of HMX efficiently, polyurethane in-situ crystallization coating method was used to modify HMX. The particle morphology, particle size, crystal type, impact sensitivity and friction sensitivity of original HMX and modified HMX were characterized by scan electric microscopy(SEM), laser light scattering sizer, X-ray diffraction(XRD) and mechanical sensitivity test．The results show that the crystal quality of modified HMX has been improved significantly, crystal shape is more orbicular and particle surface has less defects compared with the original HMX sample. The crystal type of modified HMX is β which is the same as that of original HMX. The impact sensitivity and friction sensitivity of modified HMX reduce from 90% and 70% of original HMX to 12% and 36% respectively which indicates in-situ crystallization coating method is an efficient means of decreasing the mechanical sensitivity of HMX.

Abstract:2,4,6-trinitroaniline (TNA) was synthesized by trinitro-chlorobenzene and aqueous ammonia in alcohol, and then reacted with 4-amino-1,2,4-triazole (ATA) to generate 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) by VNS（Vicarious nucleophilic substitution） reaction with total yield of 95.7％.The structures of TNA and TATB were characterized by FTIR, NMR, MS and elementary analysis. Effects of CH₃ONa， ATA and the reaction time were investigated on the overall yield of TATB. The optimized conditions of VNS reaction were： the mass ratio of TNA, ATA and NaOCH₃ is 1：6：14, reaction temperature is 70 ℃, and time is 2 hours. The ultra fine TATB with average particle diameter D₅₀ of 0.151 μm was obtained using aqueous mineral acid solutions to quench the reaction. The particle-size and crystal were analyzed.

Abstract:Ultra-fine RDX was coated with FPM₂₆₀₂ by Rapid Expansion of Supercritical Solutions method (RESS). The influence of factors, such as different system temperature, the system pressure, solution concentration and the molding on the coated RDX powder were studied. And the impact sensitivity of coated RDX was tested. Results indicate that the FPM₂₆₀₂ in the RDX powder bonded together with poor dispersivity when system temperature was above 45 ℃. The size of RDX powder is increased when the concentration of FPM₂₆₀₂ is above 0.3 g/mL. There are not completely granular surface coated of RDX when the system pressure reduce to 12 MPa below. The optimum technology condition are as follow: the system temperature was 40 ℃, the concentration of FPM₂₆₀₂ is 0.3 g/mL, the system pressure is 14 MPa. The value of characteristics height H₅₀ for coated samples is higher than that of ultra-fine RDX（H₅₀=25.2 cm）9.48 cm.

Abstract:Poly(N-methyl-5-vinyltetrazole)s (PMVT) was synthesized with poly(5-vinyltetrazole) (PVT) and dimethyl sulfate as primary materials with yield of up to 97.36%. The structure of PMVT was identified by IR and NMR. Further, the thermodynamic behavior of PMVT was studied by DSC-TG analysis, while the safety performance of PMVT was evaluated by the mechanical sensitivity testing. Results show that the temprature of thermal decomposition of the pendanted tetrazole group of PMVT is higher than that of PVT, and the sensitivity of PMVT is closed to that of PVT.

Abstract:1H,4H-3,6-dinitropyrazolo［4,3-C］pyrazole (DNPP) was synthesized from acetylacetone via monocyclization, diazotization， bicyclization, nitration, oxidation, and decarboxylative nitration. The overall yield of DNPP was 11.3% and 4% higher than that reported before. The synthesis of 4-amino-3,5-dimethylpyrazole was carried out by one-pot method which shows a number of advantages in comparison with the procedure adapted in the literature, including eliminating the use of mixture acid and iron power, shorting the reaction time (from 72 h to 24 h), improving the yield (from 79.1% to 92.0%), and simplifying the post-treatment. In addition, both nitration and decarboxylative nitration were studied.

Abstract:Dinitrourea is an important precursor in the synthesis of the cyclic nitroamine energetic compounds. Dinitrourea was synthesized through nitrification of urea by 100% HNO₃/20% oleum via mononitrourea as an intermediate. Under the optimal condition: 100% HNO₃/20% oleum(V/V)=0.6/1,temperature of the first stage at -15 ℃ and temperature of the second stage at 5 ℃,reaction time 50 min,the yield of dinitrourea is 83.2%. The structure of dinitrourea was also estimated by a B3LYP method based on 6-31+G (d,p) basis set and the stable geometric configuration was obtained. The thermodynamic properties at different temperatures were obtained from vibrational analysis,and the relationship between temperature and thermodynamic properties was deducted. Results show that dinitrourea has two stable conformations with energy difference of 12.621 kJ·mol_-1. The calculated vibrational frequencies and intensities of DNU are in good agreement with the experimental values, and the values of E^Θ_t,m,C^Θ_p,m and S^Θ_m are increased with increasing of the temperature.

Abstract:The effects of alcohol compound (A₁) and carboxylic compound (A₂) as crystal modifiers on the crystal morphology of ε-HNIW were investigated by the process of crystal transition from γ-HNIW to ε-HNIW in the ethyl acetate/cyclohexane system. It has been found by scanning electron microscope (SEM) that the crystal shape of ε-HNIW changes and the crystal surface is smoother with less surface defects. Compared with the crystals obtained without crystal modifier, the area of {110} planes of the crystal obtained with A₁, and the area of {011} planes of the crystal obtained with A₂ are increased. It is proved that A₁ could inhibit the growth of {110} planes and A₂ could inhibit the growth of {011} planes. The interaction between crystal modifiers and ε-HNIW crystal surface is studied by molecular dynamic simulation, which is consistent with the experimental results.

Abstract:The geometries of β-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (β-HMX) and its complexes with the pyrolysis products (NH₃,ClO₃) of ammonium perchlorate (AP) were optimized using density function theory (DFT) at the B3LYP/6-31g(d) level. The bond dissociation energies for N—NO₂ in β-HMX and its complexes at normal, 4 MPa and 6 MPa pressures were obtained. Results show that the geometrical configuration of HMX complexes with NH₃ and ClO₃ are similar to β-HMX structure. It indicates that, the equatorial nitryls of NH₃—,ClO₃— complexes are also prior to the axial nitryls in its pyrolysis process and there are trivial changes on the N—NO2 bond dissociation energies when β-HMX combines with NH₃ or ClO₃. However, once the complexes decompose, the product NO₂ can react with NH₃ more easily. This exothermic reaction may induce the subsequent pyrolysis process of HMX. The high pressure has no influence on the effects of NH₃ and ClO₃ on the initial pyrolysis mechanism of β-HMX.

Abstract:Black powder is usually used as propellant in fireworks industry. To solve problem of the huge smoke produced in fireworks, a new smokeless propellant was designed with the formula of: NC 77%, NH₄ClO₄ 13%, HTPB 5% and deterrent material 5%. Its ignition and working capacity, smoke performance and mechanical sensitivity of smokeless propellant were tested and compared with that of black powder. Results show that the smoke volume of smokeless propellant decreases by 79.5% compared to black powder. The ignition has been delay time and pressure impulse of smokeless propellant are 72.7 ms and 320.0 MPa·ms, which indicates the ignition performance has been improved. The working capacity is increasd by 28% compared with black powder. The mechanical sensitivity meet the requirements of propellant used in fireworks.

Abstract:In order to study the formula and preparation of a new type safe ignition compositions, based on the typical formula of boron/potassium nitrate (B/KNO₃), the ultra-fine KNO₃ was used to improve its ignition performance, and then the B/KNO₃ molding powder was obtained by manual mixing while adding phenol formaldehyde resin or fluorine rubber as the binder. The test of flame sensitivity indicates that the sensitivity will rise with the increase of KNO₃ mass content, especially the B/KNO₃ (50/50) adding 2.5% phenol formaldehyde resin as additive binder is more sensitive, but the electrostatic sensitivity test shows that sensitivity will fall with the decrease of KNO₃ mass content. When the mass ratio of B/KNO₃ keeps constant, the ignition powder adding fluorine rubber binder is less sensitive than that of phenol formaldehyde resin.

Abstract:The safety tests of 2,5-dipicryl-1,3,4-oxadiazole (DPO) and its application test in slapper detonator were studied. The slow cook-off test of DPO was conducted and its potential application for insensitive booster composition was discussed. Results show that DPO is an excellent booster explosive with good thermal stability and comparative shock wave sensitivity with HNS, and its basic physical, chemical and thermal performances are similar to that of hexanitrostibene (HNS). DPO is capable of passing the safety tests for booster explosive and used for in-line explosive as the permissive booster explosive. DPO is acted mildly at heat stimulating, and the performance of slow cook-off is excelled to booster.

Abstract:The excitation energy (3.4 eV) and emission energy (2.7 eV) of 9-ethynyl-9-hydroxyanthrone (EHAO) were obtained from time-dependent theoretical functional theory (TDDFT) and single-excitation configuration interaction (CIS) method. The effects of CH₃OH and TNT on the fluorescence spectrum of 9-ethynyl-9-hydroxyanthrone were described by the front orbital theory. Results show that the electronic transition of the first excited state of the EHAO-CH₃OH complex only occurs in the EHAO moiety,while the fluorescence properties were changed. In the complex of EHAO and TNT, HOMO is located in EHAO, and LUMO in TNT molecule. It suggests that intermolecular electron transfer occurs during the transition of the first excited state,which results in the fluorescence quenching effect.

Abstract:Tensile mechanical properties of some PBXs were evaluated by Flattened Brazilian Disc (FBD) and Split Hopkinson Press Bar (SHPB). Quartz transducers and digital image correlation（DIC) technology were used to measure stress and strain information. Stress-strain curves of three types of PBXs under strain rate of 10² s^-1 were obtained. Results show that all of the tensile strength, failure strain and dynamic modulus have relationship with the loading strain rate. A constitutive model had been established based on the experimental data.

Abstract:TATB-based PBX samples with different densities were prepared by different press process, and their position lifetime spectra were measured. The spectra show that the positronium formation is negligible in TATB-based PBX, therefore the 2-component fit is applicable. The result shows an increasing dimension but decreasing concentration of nano-void during PBX pressing,which means the nano-void in TATB crystalline increased due to the damage and crack under pressure, however the nano-void of intergranular interface decreased.

Abstract:A multi-wavelength temperature-measuring system based on the atomic emission spectroscopy was used to measure the transient high temperature during the explosion process of thermo-baric explosive (TBE). The time resolution of the measurement system could achieve μs scale. By measuring the explosion temperature of TBEs, the curves of temperature vs time were obtained. There are two temperature peaks corresponding to the oxygen-free reaction and oxygen reaction phases of TBE explosion process, respectively. Results show that the relative error of measured temperature is less than 2.6%, showing a good repeatability. Compared with the double line of atomic emission spectroscopy, the multi-wavelength temperature-measuring system can minimize the errors resulting from the selection of spectral lines.

Abstract:A device of simulating drop test was designed to study the safety drop of Φ98 mm×39 mm PBX-2 explosive under the shell confinement. The pressure change was measured by PVDF gauges. Acceleration change at two positions were obtained by PCB acceleration gauges. Ignition process was analyzed by high-speed motion pictures. The reaction overpressure was measured by blast pressure gauges. Reaction of explosive was obtained from different velocity fragment impacts. Results show that the relative release energy for PBX-2 explosive is about 35%, which is higher remarkedly than that in Spigot test, and the test established to simulate drop can provide a new means to evaluate explosive safety under the unexpected scenarios.

Abstract:In order to study the equation of state (EOS) of the detonation products of RDX-based PBX at small scale,cylinder tests were carried out to identify the power of RDX-based PBX with density of 1.65 g·cm^-3 . The copper tubes with diameter in 10 mm and 25 mm were used. The scale of the wall expansion and the velocity were measured. The cylinder tests were numerically simulated by nonlinear finite element dynamic program Ansys/Ls-Dyna. The parameters of the JWL EOS for RDX-based PBX were calculated and corrected according to the numerical simulation results.

Abstract:Detonation-confinement Sandwich Test of PBX-9502 was simulated using a simple one-term reaction rate model. The simulation result was compared with results of tests and detonation shock dynamics (DSD) analysis, it can be found that the reaction rate model can be used to model Detonation-confinement Sandwich Test accurately. The results show that shock shape is dependent on the confined inert material under certain conditions.

Abstract:The numerical simulation was employed to the design of a mone reliable bulkhead initiator. The explosion transimission was simulated using LS-DYNA code. The simulation results show that when the thickness of bulkhead is between 2.0 mm and 5.0 mm, the bulkhead will transmit shock wave well without being penetrated, and the bulkhead initiator can perform its normal function when the thickness of bulkhead is between 1.5 mm and 2.4 mm. The simulation result agrees with the test result.

Abstract:Long term storage experiment was conducted to analyze the storage performance of hydroxylammonium nitrate (HAN) hydrogel which was made from polyvinyl (PVA) as gel agent. There was precipitation liquid which contains HAN under the open system, while under sealed condition, this phenomenon of precipitation liquid did not occur and the combustion performance of HAN hydrogel did not change significantly. Results show that HAN hydrogel should be storied under sealed condition and the temperature should not exceed 40 ℃.

Abstract:The influence of tightness on the storage stability of GATo-3 propellant was studied by ageing test,gas phase chromatography (GC) and microcalorimeter. The influence rules of tightness on the storage stability of GATo propellant at 55 ℃,65 ℃ and 75 ℃ are different,which is caused by sublimation of resorcinol (Res), catalysis of H₊ and sealing pressure. Sealing pressure accelerates the thermal decomposition of GATo propellant, which is proved by microcalorimeter.

Abstract:The applications of nano-metal powders,with high reaction activity and combustion heat,are a crucial approach to increase the performance of explosives and propellants products. This article reviewed the latest improvement of nano-metal powders to propellants, condensed explosives, fuel-air explosives and thermites, and summarized a few methods to modify nano-metal powders, such as nano-metal/polymer compounding,nano-metal/carbon compounding, surface coating with small molecular agents, surface inarching with macromolecule polymer, gas phase depositing, and shape modifying of particles. The important directions of nano-metal powders, are nano-boron, nano-zirconium and composite nano-aluminium.

Abstract:Hexanireobibenyl (HNBB) is an important intermediate of hexanitrostibene (HNS). And the low yield of HNBB is the primary influence factor of gross yield of HNS. Therefore, how to increase the yield of HNBB was investigated in the article. The relation between the pH value of sodium hypochlorous acid solution and the yield of HNBB was detailedly discussed in the coupled reaction. The molecule structure of HNBB have been determined by NMR and Mass spectrum. Furthermore, the sensitivity performance was researched.

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