Abstract:The latest advances focusing on synthesis of new energetic molecules in past two years have been reviewed from different viewing angle including molecule design, synthetic strategy, reaction pathway optimization, and performance evaluation, etc.This review sorts out the research and development trend in synthesis area of energetic materials(e.g., energetic salts and neutral energetic molecules), and points out promising research directions, including(1) typical strategies including C-or N-nitroamine, N—OH, and gem-dinitro functionalizations will be the most efficient way to synthesize nitrogen-rich energetic salts with desired energy level and sensitivity; (2) more attention should be paid to design and synthesis of high-nitrogen explosive molecules with fused ring, conjugated π structure and bridged frameworks; (3) researches on boron-based explosives have been undervalued and may become the research frontier in the near future; (4) synthetic technologies under extreme conditions such as cryogenic synthesis and supercritical synthesis should be applied to the fields of new energetic materials with improved properties.

Abstract:Four sensitivity criteria of explosives, including the most likely transition method(the minimum energy gaps), the minimum bond orders, the weakest bond dissociation energies, Mulliken charges of nitro groups of X—NO₂(X＝C, N or O), were reviewed.A new sensitivity criterion, named as "bonding & nonbonding coupling related molecular rigidity and flexibility" based on the global stability of an explosive, was proposed for the first time.The correlations between the impact sensitivities and the criteria of 11 typical explosives:1, 3, 5-trinitrobenzene(TNB), 2, 4, 6-trinitrotoluene(TNT), 1, 3, 3-trinitroazetidine(TNAZ), 1, 3, 5-trinitro-1, 3, 5-triazacyclohexane(RDX), 1, 3, 5-trinitro -2-oxo-1, 3, 5-triazacyclohexane(K6), 2, 4, 6, 8, 10, 12-hexanitro-2, 4, 6, 8, 10, 12-hexaazaisowurtzitane(CL-20), 2-picryl-1, 2, 3-triazole(PCTA), 4-nitro-22-picryl-1, 2, 3-triazole(NPCTA), (2, 6-diamino-3, 5-dinitropyrazine-1-oxide(LLM-105), 4, 6-dinitrobenzofuroxan(DNBF) and 5, 7-diamino-4, 6-dinitrobenzofuoxan(DADNBF) were compared. Results show that in the five kinds of sensitivity criteria, the correlation of the "bonding & nonbonding coupling related molecular rigidity and flexibility" evaluation method is the highest.The combination of these criteria can improve the ability to predict sensitivity.Strain energy is a form of the bonding & nonbonding coupling energy in explosive molecules, which not only can be used to measure the sensitivity of explosives, especially for the explosives without nitro group, at the same time also can be used to meaure the energy-stored level of an explosive and has important significance for the designs and evaluations of new explosives.

Abstract:In order to understand the mechanism of the effect of solvent on the crystal morphology of explosives, and provide a gist for solvent selection, the attachment energy(AE) models were employed to predict the growth morphology and the main crystal faces of 2, 6-diamino-3, 5-dinitropyridine-1-oxide(ANPyO) in vacuum.The molecular dynamics(MD) simulation was applied to investigate the interaction of ANPyO crystal faces and N, N-dimethylformamide(DMF) solvent, and the growth habit of ANPyO in DMF was predicted using the modified AE model.Results indicate that the morphology of ANPyO crystal in vacuum is dominated by the four faces of(1 1 0), (1 0 0), (1 0 -1) and(1 1 -2), and the crystal shape is similar to ellipsoid.The radial distribution function analysis shows that the solvent-crystal face interactions mainly consist of van der Waals forces, coulomb interaction and hydrogen bonds.In DMF, the absolute value of the corrected attachment energies change in the order of(1 1 0) < (1 1 -2) < (1 0 -1) < (1 0 0), which causes the crystal morphology to become very close to a flake and accords well with the experiment results.Furthermore, the analysis of diffusion coefficient of DMF molecules on ANPyO crystal faces shows that diffusion coefficient changes linearly with the absolute value of the corrected attachment energies, and the growth habit is also affected by the diffusion capacity of solvent.

Abstract:Fused cast explosive will melt in the process of cook-off, which will affect the thermal reaction of the explosive.In this paper, the cook-off bomb test of carrier explosive 2, 4-dinitroanisole(DNAN) was carried out to measure the temperature change in the explosive center point and observe the melting and reaction situation of explosive.A thermal reaction model of fused cast explosive was established.The melting process of explosive was calculated and analyzed by an enthalpy-porosity method.The autothermic reaction process, thermal conduction, convection after explosive melting and radiation heat transfer of air were considered.The numerical simulations of the explosive cook-off test was performed.Compared with the experimental results, the accuracy of the calculation was verified.The activation energy and pre-exponential(frequency) factor of DNAN explosive were 172 kJ·mol^-1 and 1.20×10¹¹ s^-1, respectively.The cook-off characteristics of DNAN were calculated and analyzed at six kinds of heating rates of 3.3 K·h^-1, 0.3 K·min^-1, 1.0 K·min^-1, 3.0 K·min^-1, 10 K·min^-1 and 60 K·min^-1.The explosive at slow heating rate completely melted before ignition.And the explosive at relativly fast heating rate ignited on the edge, while the explosive inside not completely melted.The images of temperature distribution and liquid phase fraction distribution of ignition time were obtained.Results show that in the cook-off of fused cast explosive, the state of the explosive before ignition will be affected by heating rates, and the intensity of explosive thermal reaction will be affected by that.

Abstract:The ricochet process of shaped charge jet penetration different material target, including 603 armor steel and aluminum, with a small incidence angle ranging from 5° to 7° was numerically simulated by using ANSYS/LS-DYNA software.Their penetration and ricochet process were observed.Results show that the obtained numerical simulation results are consistent with the experimental data.When the velocity of jet head is 6500 m·s^-1, the critical incidence angle of the ricochet is between 6° to 7° for 603 armor steel and between 5° to 6° for aluminum and the ricochet angle of jet decreases with the increase of target strength.The ricochet process of jet includes two stages:at the first, jet head ricochet takes place when jet touch target and the rest of jet invade target.Then, the direction of motion of jet front deflects under an asymmetric resistance from target and jet leave target in the end.Subsequent jet jump out of target.The crater depth ratio under the situation of ricochet and not ricochet of 603 armor steel is 0.389 and lower than that of aluminum, which is 0.795, proving that the energy of jet consume in penetrating target crater and extended crater decreases along with the increase of target strength under the case of ricochet.

Abstract:The simulation of detonation wave pressure of the three-point, four-point, six-point, eight-point synchronization detonation for slapper detonators were performed respectively by the finite element program AUTODYN software.The factors affecting the detonation wave pressure of multi-point synchronization detonation were analyzed.The detonation wave pressure of multi-point synchronization initiation for slapper detonators was measured by a Manganese Bronze manometry.The action process of four-point synchronization slapper detonators were filmed by a high speed photography system.Results show that a four-point detonation slapper detonators overpressure relative to the average of three-point, six-point, and eight-point is the highest; in the center distance of 4 mm and the same loading dose of 180 mg, the detonation wave generated by four initiation points occurs the collision with each other, and the detonation wave superposition forms overpressure detonation, and can reliably detonate insensitive explosive TATB.In the center distance of 8 mm and the same loading dose of 180 mg, due to center distance is far, detonation wave attenuation is faster, adjacent points detonation wave collision happened is less, the overpressure produced also decreases.

Abstract:5-Nitro-3-trinitromethyl-1H-1, 2, 4-triazole(TNNT) and 5, 5′-bis(trinitromethyl)-3, 3′-azo-1H-1, 2, 4-triazole(BTNAT) were synthesized via condensation-cyclization, diazotization-substitution, oxidation-coupling and nitration reaction using aminoguanidinium hydrogen carbonate and malonic acid as raw materials, respectively.Their structures were characterized by IR spectrometry, NMR and elemental analyses.Their whole structure optimization and natural bond orbital(NBO) analysis were carried out at the B3LYP/6-31G(d, p) basis set level.Their decomposition temperature was measured by DSC.Results show that the decomposition temperature of TNNT and BTNAT under the conditions of 10 ℃·min^-1 and N₂ atmosphere is 135 ℃ and 146 ℃, respectively.

Abstract:Five coordination complexes [Cd(HT)₆](ClO₄)₂(1), [Zn(HT)₆](ClO₄)₂(2), [Ni(HT)₃](ClO₄)₂(3), [Co(HT)₆](ClO₄)₂(4), [Mn(HT)₆](ClO₄)₂(5) with 5-hydrazinotetrazole(5-HT) as ligands were prepared.Their structures were characterized by elemental analysis and FT-IR.The thermal decompositions were studied by differential scanning calorimetry and the impact sensitivity and friction sensitivity were also tested.The theoretical calculations of the electronic structure, natural bond orbital charge and frontier orbital energy of 5-HT were studied at B3LYP/6-311++g^** level.Results show that the five complexes have good thermal stability, and the decomposition temperatures are above 200 ℃.N(3) and N(4) atoms of tetrazole ring are easier to coordinate with metal atoms.The friction sensitivity of complex 4 is 96%(90°, 1.96 MPa) and H₅₀ is 25 cm with the 800 g drop hammer, which is similar to that of HTMP and BNCP, indicating a promising application in the field of primary explosive.

Abstract:A novel energetic material, 3, 5-dinitropyrazole-4-nitrate(DNPN), was synthesized via nitration and nucleophilic substitution reaction using 4-chloropyrazole as raw material, and its structure was characterized by FTIR, NMR and elemental analysis.The detonation performances of DNPN were calculated.The effects of sulfonitric acid composition and temperature on nitration was investigated, and the optimal condition was obtained as:V(98% nitric acid):V(98% sulfuric acid) =1:4, the reaction temperature 100 ℃, and the reaction time 5 h, with yield of 65.1%.4-Chloro-3, 5-dinitropyrazole with silver nitrate reacts fast, and the yield can reach up to 35.6% at 40 ℃ for 1 h.The detonation velocity and detonation pressure of DNPN is 8.78 km·s^-1 and 35.12 GPa, respectively, which is better than of TNT.

Abstract:1, 4-Diamino-3, 5-dinitropyrazole(DADNP) as target substance was synthesized by amination of the important precursor 4-chloro-3, 5-dinitropyrazole(CDNP) with the yield of 58.0%, in which CDNP was obtained via halogenation and nitration reaction using pyrazole as raw material.The structure of DADNP was characterized by IR, MS, NMR and elemental analysis.The thermal behavior of DADNP was studied by differential scanning calorimetry(DSC).The factors affecting amination and nitration reactions were investigated.Results show that the optimized amination reaction conditions are determined as mesitylene sulfonyl hydroxylamine(MSH) as amination reagent, room temperature, n(ADNP-NH₄⁺):n(MSH)=1:1.5, reaction time 12 h.The optimized nitration reaction conditions are determined as:V(oleum):V(nitric acid)=2:1, reaction temperature 110-115 ℃, reaction time 4h, the yield 72.0%.The melting point and decomposition peak temperature of DADNP are 192 ℃ and 247 ℃, respectively.

Abstract:5-Nitrobenzene-1, 2, 3, 4-tetrazine-1, 3-dioxide(5-NBTDO) and 7-nitrobenzene-1, 2, 3, 4-tetrazine-1, 3-dioxide(7-NBTDO) were synthesized using benzo-1, 2, 3, 4-tetrazine-1, 3-dioxide(BTDO) as raw materials.Then the 5, 7-dinitrobenzene-1, 2, 3, 4-tetrazi ne-1, 3-dioxide(DNBTDO) was synthesized by 5-NBTDO and 7-NBTDO as raw materials.The structures of synthesized compounds were characterized by ¹H NMR, ¹³C NMR, IR and MS.The effects of nitration system, material ratio n(BTDO):n(NO₃^-) and reaction temperature on the yields of different nitrating products were explored.Possible nitration products were predicted through theoretical method.The yields of the products were detected by HPLC.Results show that the optimum process conditions of synthesizing three substances were determined as:for oleum-KNO₃nitration system.n(BTDO):n(KNO₃)=1:2, reaction temperature 40 ℃, with yield of 5-NBTDO 34.9%;for nitric acid-sulfuric acid mixed system, n(BTDO):n(HNO₃)=1:3, reaction temperature 20 ℃, with yield of 7-NBTDO 77.1%;for oleum-nitric acid system, n(NBTDO):n(HNO₃)=1:8, and reaction temperature 95 ℃, with yield of DNBTDO 90%.The yield of three kinds of nitration products, synthesized via one-step method using BTDO, is consistent with the theory prediction.The order of yield is 7-NBTDO>5-NBTDO>DNBTDO.

Abstract:To understand the reasons for the formation of 3, 4-dinitrofurazanfuroxan(DNTF) charge defects, the solidification behavior of DNTF and TNT was contrasted and analyzed.The volume shrinkage of DNTF and TNT was tested.The solidification defect distributions of DNTF and TNT were observed by industrial CT and scanning electron microscope.Thermal properties of DNTF and TNT were tested by DSC and thermal conductivity measurer.The curves of temperature vs time describing the solidifying process of DNTF and TNT were obtained by a solidification rate testing device.Results show that the volume shrinkage of DNTF and TNT is 11.6% and 12.7% respectively.The defect distribution of DNTF is more dispersive, but the defect distribution of TNT is relatively.concentrative.The solidifying point, solidification heat, specific heat capacity and thermal conductivity are 110.2 ℃, 100.2 J·g^-1, 0.943 J·g^-1· ℃^-1 and 0.197 W·m^-1· ℃^-1 for DNTF and 80.9 ℃; 104.6 J·g^-1; 1.278 J·g^-1· ℃^-1and 0.224 W·m^-1· ℃ for TNT, respectively. The solidification rate of DNTF is higher than that of TNT.With increasing the solidified layer thickness, the interval time of solidification generated between each layer from the lower layer to the upper layer occurs rapidly shortening trend.The solidification process of DNTF has characteristics of volumetric solidification, whereas the solidification process of TNT has characteristics of layer by layer solidification.

Abstract:To solve the aggregation problem of the superfine ammonium perchlorate(AP) powder caused by moisture absorption, the surface modification treatment of the superfine AP powder was performed using a low-temperature plasma equipment.The particle size and morphology of the superfine APs before and after treatment were characterized by a laser granularity analyzer and scanning electron microscope(SEM).The component and purity of the superfine AP before and after treatment were analyzed by Fourier transform infrared(FTIR) spectrometer, Raman spectrometer, X-ray diffractometer(XRD), X-ray photoelectron spectroscopy(XPS) and chemical method.The thermal decomposition performances of AP samples before and after treatment and the corresponding AP/Al system were studied by thermogravimetric analysis(TG) and differential scanning calorimetry(DSC).The impact sensitivities, friction sensitivities and hydroscopicity were measured.Results show that the aggregation phenomenon of superfine AP powder after treatment with low-temperature plasma technology is obviously improved, the particle distribution concentrates, the hydroscopicity decreases, while the component and purity almost do not change.Compared with the superfine AP powder before treatment, its peak temperature of high temperature decomposition increases by 8.3 ℃, the impact and friction sensitivities decrease by 7.1% and 6%, respectively.

Abstract:To investigate the effect of particle sizes on properties of potassium picrate (KP), superfine potassium picrate was prepared by continuous spray addition, controlling speed dropping method and fast mixing method, respectively.The particle morphology, particle size distribution, thermal decomposition temperature, impact sensitivity, friction sensitivity, flame sensitivity, electrostatic spark sensitivity, 5 s delay explosion temperature and heat-wire sensitivity of potassium picrate with different size were measured.Results show that the values of mean particle size D₅₀ of potassium picrate obtained by continuous spray addition, controlling speed dropping method and fast mixing method are 3.9 μm, 8 μm and 16 μm, respectively.With the increase of potassium picrate particle size, the initial thermal decomposition temperature increases, the impact, friction, and flame sensitivity decrease, the electrostatic spark sensitivity is basically unchanged and 5 s delay explosion temperature decreases.Heat-wire sensitivity of superfine potassium picrate with D₅₀=3.9 μm is very low and it is suitable for used as low sensitivity current igniting composition.

Abstract:Different types of nanocrystalline Zr powders were produced by mechanical ball milling method.The effects of milling time on grain size and lattice strain of Zr powders were investigated using X-ray diffraction pattern(XRD).The morphology characteristics and particle size distribution of Zr powders milled for different time were checked by scanning electron microscope(SEM) and Laser particle size analyzer(LPSA), as well as the influence of ball milling on the optical radiation time of Zr/KClO₄.Results show that increasing in milling time can reduce the grain size to nanoscale(15.4 nm after ball milling for 20 h) and increase the lattice strain.After ball milling for 8h, the size distribution of Zr powders are homogeneous with an minimum average particle size of 0.8 μm and grain size of 81.7 nm.The optical radiation time of Zr powders ball milling for 8 h is 17 ms, which shortened by 32% compared with that of raw Zr powders, and the peak intensity of optical radiation increases.

Abstract:To improve the thermal conduction properties of fluoropolymer(F2314), the F2314 was modified by multi-walled carbon nanotubes(MWCNTs).The F2314/MWCNTs composites were prepared by a internal melt mixing method.The effects of MWCNTs content and temperature on the thermal conductivity of F2314/MWCNTs composites were studied.A thermal conduction model for F2314/MWCNTs composites was established.The results show that the thermal conductivity of F2314/MWCNTs composite increases with increasing the MWCNTs content.When the mass fraction of MWCNTs is 0.30, the thermal conductivity of F2314/MWCNTs composite at 30 ℃ is 0.647 W·m^-1·K^-1, which is 3.43 times higher than that of pure F2314.The dependence of thermal conduction property of F2314/MWCNTs composite on the temperature is closely related to the phase transition of F2314.With the increase of temperature, the thermal conductivity of F2314/MWCNTs composite increases firstly, then reaches a maximum near the glass transition temperature, and then decreases gradually.The theoretical calculated results according to the modified model of effective medium approach and experimental ones have a good consistency, indicating that the formula can effectively simulate the thermal conduction property of F2314/MWCNTs composite.

Abstract:To study the method for the fabrication of exploding foil initiator(EFI)) integrated assembly and its performance, the parylene C flyer sheets deposited on the exploding foil substrate were fabricated by the chemical vapor deposition(CVD) method and the Su8-2150 photoresist accelerating barrier was in-situ integrated by the photolithography.The Su8-2150 accelerating barrier with thickness of more than 300 μm and good surface vertical degree was obtained.The acceleration history of flyers of EFI driven with electrical explosion was obtained by the photonic doppler velocimetry(PDV) measurement technique.The acceleration history of flyers of EFI fabricated by the conventional method with polyimide flyer and integrated method with the same parameters were compared.Results show that the two groups of acceleration history are basically the same.Within the first 80ns, the polyimide flyer and PC flyer have completed 77% and 80% of maximum velocity, the velocities of the polyimide flyer and PC flyer at the exit of barrier are 3970 m·s^-1 and 3906 m·s^-1 respectively, two kinds of driving performances of EFI are close.The change of material of flyer and accelerating barrier does not affect observably on the flyer process driven by electrical exploding.

Abstract:In order to solve the problem of the sudden spontaneous firing and premature explosion of high temperature in the blast hole charge, a new type of irreversible detonating network applied in the high temperature coal mine was studied by adapting explosion test method, combustion of thermal analysis and system reliability rule.The experiment tests on the heat resistance property of metal detonation cord in high temperature and detonation propagation reliability and resistance effect of the irreversible initiating component were carried out, and the blasting network security and reliability were evaluated and calculated as well.Results show that the metal detonation cord in the hole can effectively improve the safe time of the high temperature resistant performance, and reduce the probability of sudden spontaneous firing.The irreversible detonating structure, similar to the role of the diode in the circuit, plays a safety control function in the blasting network, and avoids the sudden spontaneous firing of the whole detonating network caused by a certain blasthole, ensuring the safety of the main network.The irreversible detonating network reliability reaches 99.99% with the hole number of 64, better than the traditional blasting network.

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