Abstract:Energetic coordination compounds are potential explosive materials with structural stability, high-energy and low sensitivity. All of these compounds have potential applications in ammunition and civil explosives as primary explosive, ignition composition and energetic catalyst. Many achievements of studying on the crystal structures, thermal decomposition properties and explosive properties of the energetic compounds based on perchlorate compounds, azide compounds, nitrate compounds, polynitrophenol compounds and other compounds were briefly summarized and evaluated. The effects of metal ions on properties of energetic coordination compounds were described in detail. Some prospects of the energetic compounds were proposed based on the results involved.

Abstract:In this article, the prefaces and forewords of several early and newly published and forthcoming academic works were presented. Around the meaning of the statement of "Quantum Explosive Chemistry" and its continuation, the problems of how to undertake relevant theoretical studies and how to assess academic papers etc. were remarked and elucidated briefly in order to promote the healthy development of computational energetic materials science.

Abstract:The current research situation at home and abroad of four types of explosives which can be used as carriers for melt-cast explosive were summarized. The synthesis methods, physical and chemical properties and explosive performance of 16 explosives were introduced in detail for recent twenty years. Their advantages and shortcomings as melt-cast explosive carriers were analyzed, which could provide the basis for promoting the explosives better applied to melt-cast formulations.

Abstract:Theoretical methods play significant parts in design and exploitation of advanced energetic materials. In this review, some important problems in the theoretical design of energetic materials in our study were introduced in detail, including evaluating the densities, heats of formation (HOFs), thermal decomposition mechanisms and detonation properties of usual energetic compounds. It was suggested that the combined ab initio MD and ab intio MO study can successfully revealed the dissociation mechanisms for some simple hydronitrogen compounds. Additionally, the interface interactions of the incompatible energetic copolymer blends in the presence of block copolymers and plasticizers were discussed. And the effect of nanorods on the interface of immiscible A/B homopolymer blends was also indicated. Results show that Dissipative particle dynamics (DPD) are useful analysis tools for studying the self-assembly of energetic polymers and can give physical insight into the problem. The calculation of the above properties may provide useful information for the molecular design of novel high energetic density materials.

Abstract:N-heterocyclic compounds, as typical multi-nitrogen compounds, had currently attracted significant attention in the filed of new energetic materials. Introduction of azo bond into nitrogen-containing heterocyclic compounds was a feasible approach to increase their energy and density. Methods of introducing the azo bond into nitrogen-containing heterocyclic compounds via oxidation-coupling reaction of hydrazo-azo and amino-azo were reviewed. The effects of different oxidants on oxidation-coupling reaction were discussed. Increasing the reactivity and selectivity of oxidants is a main development direction for oxidation-coupling reaction of N—NH₂ in nitrogen-containing heterocyclic compounds. 42 references were included.

Abstract:A method of computing/determining the Arrhenius/non-Arrhenius kinetic parameters of the exothermic decomposition reaction of energetic materials (EMs) was presented from initial temperature (T_e), peak temperature (T_p), conversion degree (α_{ei or pi}) at T_{ei or pi} and data (β_i、T_α,i, i=1, 2, …, L) corresponding to isoconversation degree (α_i) for DSC curves under different constant heating rate (β) conditions. The Arrhenius/non-Arrhenius kinetic parameters of the exothermic decomposition reaction of sodium cis-bis(3-(5-nitro-1, 2, 4-triazolate tetrahydrate) [Na₂(BNT)(H₂O)₄] were obtained by this method. The critical temperature of thermal explosion (T_b) of [Na₂(BNT)(H₂O)₄] was calculated by the non-Arrhenius kinetic parameters obtained and compared with the value of T_b obtained by Arrhenius kinetic parameters. The validity and reliability of non-Arrhenius kinetic parameters of [Na₂(BNT)(H₂O)₄] obtained in this work were verified.

Abstract:The insensitive properties of explosives containing pyridine/aminobenzene rings are combined with the high energy of nitramine explosives, and the concept of new nitramine explosive containing pyridine/aminobenzene ring is proposed, into which the nitramine group with N—N bonds is introduced as much as possible. Based on the research of regular relationship between molecular & crystal structure and explosive property & security performance, the molecular structures of several target compounds and their synthetic method are designed. The simulation results reveal that the detonation properties of these compounds are excellent. According to the calculated bond dissociation energies (BDE), the N—NO₂ bond is the trigger bond during the thermolysis initiation process. The synthetic routes are obtained with different synthetic reactions such as condensation, N-nitration, N-oxidation and C-nitration and so on.

Abstract:The ruptures of RDX crystalline particles in ensembles and mesoscale fracture behaviors of bulk single crystal are presented in this work. First, the particles ruptures of 3 types RDX ensembles subjected to quasi-static compression were investigated. The rupture ratio was defined to describe the coherence strength of crystalline particles. The rupture ration of commercial coarse RDX lot is 1.57 which is much higher than that of re-crystallized lot with 1.47 and, the spheroidized RDX lot bears the minimum ration of 1.17 which shows the highest resistance to rupture. In the case of the nanoindentation of a bulk single RDX crystal, the regular pop in events on face (210) were reported in this work. Through the nanoindention tests, the yield stress or fracture initiation stress of RDX was obtained as 465 MPa, which is far below the hardness of 550 MPa. The mean fluctuation stress on the loading/unloading curve is calculated as approximately 8 MPa and the corresponding indentation depth on the (210) face is 1 micrometer and the implication of the depth is discussed.

Abstract:Thermal-pressure aging treatment was used in the study on cracks healing behavior of PBX, combined with μCT, ultrasonic testing method and mechanical properties testing method. Results show that cracks blow 400 μm heales after treated, and its tensile strength and compressive strength are close to those of same density sample without damage while the crack in excess of 400 μm couldn′t heal. It indicats the treatmeet improves the internal quality of the damaged samples effectively in certain conditions. The width of cracks will affect the healing results.

Abstract:In order to improve the comprehensive performance of nitramine double-base propellant, carried out application of pentaerythrite diazidodinitrate (PDADN) in screw extruded nitramine modified double-base propellant was studied. The mechanical property, burning characteristics, chemical stability, mechanical sensitivity, energy characteristics and gas characteristic signal of propellants were measured. Results show that use of the new-type energetic material not only improves mechanical property of propellants, but also is beneficial for increasing propellant energy and decreasing characteristic signal of burning gas and burning temperature.

Abstract:The structure and properties of 5-aminotetrazolium nitroformate were studied using quantum chemistry method. The density, heat of formation, detonation velocity and pressure were calculated. The calculated density was 1.93 g·cm^-3, and the detonation velocity and pressure were 9.47 km·s^-1 and 38.82 GPa, respectively. The detonation properties were better than those of TNT, RDX, HMX.

Abstract:Fully optimized calculation and vibrational analysis for nitrogen and pseudo-benzene N₆ were carried out using density-functional theory (DFT) at B3LYP/6-311++G(d, p) level. The thermodynamic properties at different temperatures were obtained from vibrational analysis, and the relationship between temperature and thermodynamic properties was deduced. Molecular mechanics (MM) method with Compass and Dreiding force fields were used to predict molecular packing for N₆ among the 7 most probable space groups (P2₁/c, P-1, P2₁2₁2₁, P2₁, Pbca, C2/c, and Pna2₁), respectively. Standard free energy changes of reaction 3N₂(g)→N₆(s) were calculated. The synthetic feasibility was analyzed with thermodynamics and reaction mechanism was predicted. Results show that N₆ belongs to C2/c space group, the reaction 3N₂(g)→N₆(s) is feasible when temperature is below 61.6 K and the π bond delocalization has a decisive role in the reaction.

Abstract:As an important intermediate for new energetic materials, 2-(dinitromethylene)-1, 3-diaza-cyclopentane(DNDZ) attracts more attentions in recent years. Herein the necleophilic reaction between 1, 1-diamino-2, 2-dinitroethylene(FOX-7) and 1, 2-diaminoethane catalyzed by magnesium ion was studied and the DNDZ was synthesized in yield of 83.9% with high purity (99%) under the optimum conditions: the reaction temperature and time were 110 ℃ and 5.5 h respectively and the best catalyst was new prepared Mg(OAc)₂ (30%). The structure of the product was characterized by IR, NMR, MS and elemental analysis.

Abstract:The methods of synthesizing 3-(N-2, 4, 6-trinitrophenyl)-amino-4-nitrofurazan, 3-amino-4-(tetrazole-5-yl) furazan, azotetrazolylfurazan, 3-nitro-4-tetrazolylfurazan and 3-amino-4-(4-cyano-5-amino-1, 2, 3-triazol) furazan were improved. The condition of reaction was mild and the yield of target compounds was increased corresponsively. 3-(N-2, 4, 6-trinitrophenyl)-amino-4-nitrofurazan was synthesized by nucleophilic substitution reaction of 3-amino-4-nitrofurazan and 2, 4, 6-trinitro-chlorobenzene(picrylchloride). 3-Amino-4-(tetrazole-5-yl) furazan was obtained from cycloaddition of sodium azide and 3-amino-4-cyanofurazan. 3-Amino-4-(tetrazole-5-yl) furazan was treated with KMnO₄ as azo coupling reagent or H₂O₂, sodium tungstate and methylsulfonic acid as oxidant to afford azotetrazolylfurazan or 3-nitro-4-tetrazolylfurazan, respectively. 3-Amino-4-(4-cyano-5-amino-1, 2, 3-triazol) furazan was prepared by cycloaddition from 3-amino-4-azidofurazan and malononitrile. The yield of these five compounds was 36.1%, 90.9%, 86.8%, 75.6% and 81.8% respectively. These compounds were characterized by ¹H NMR, ¹³C NMR, IR and MS.

Abstract:In order to utilize the full potentials of the existing energetic materials, nitrocellulose/Al (NC/Al) nano-composite materials were prepared through sol-gel and supercritical carbon dioxide drying methods. The structures of nano-composite materials were characterized by FTIR, BET, SEM and DSC methods. Experimental results show that the nano-composite materials belong to mesoporous material and the nano-aluminum powders is well-distributed in the gel matrix. The specific surface area of the material decreases with the Al powders content increasing. When Al:NC (mass ratio) equals to 5:10, the decomposition heat per unit mass of NC component increases to 2408.07 J·g^-1 from 1689.21 J·g^-1.

Abstract:In order to study the direct write explosive charge methodology applied in micro electro mechanical system (MEMS) fuze security and insure devices, an explosive ink composite of direct write was developed with fine 2, 4, 6, 8, 10, 12-hexanitro-2, 4, 6, 8, 10, 12-hexaazaisowurtzitane(ε-CL-20)and binder system of polyvinyl alcohol (PVA)/H₂O/ethyl cellulose (EC)/isopropyl alcohol (IPA), in which CL-20 was fined by ball milling. And its properties were characterized. Results show that the line width of direct write for the explosive ink is 80.2 μm with no obvious crack by scanning electron microscope (SEM).The crystal polymorph of CL-20 keeps the ε-polymorph before and after direct write by Fourier transform infrare spectroscopy (FTIR). The critical size of detonation is 0.36 mm with 0.54 mm loading thickness by wedge shaped charge test.

Abstract:AC/TiO₂ composite particles were prepared by peptization-reflux method using Ti(OBu)₄ as raw material, and three kinds of samples were obtained by adding phytic acid, BTA and SnCl₄. FE-SEM observation shows the surface of AC is closely coated by TiO₂ about 20-30 nm in size. Spongy TiO₂ coatings were obtained when phytic acid was added, while finer TiO₂ particles were formed on samples with the addition of BTA. XPS of Ti element in three kinds of samples show that the difference in binding energy of Ti 2p_3/2 and Ti 2p_1/2 is about 5.7 eV, indicating the purity of TiO₂ on the surfaces of AC is high. Ramman spectra of TiO₂ particles prepared by blank experiment without AC show that TiO₂ particles are anatase. The photo-catalytic activity and absorptive capability of composite particles are studied by using TNT waste water as target pollutant. The results show that the absorptive capability of composite particles with phytic acid or BTA is slightly higher than that of AC. All samples of AC/TiO₂ have better UV photo-catalytic activity compared with AC, and for AC/TiO₂ particles with BTA the degradation of the TNT reached 99.3%, which was attributed to the synergistc effect of AC and TiO₂.

Abstract:In order to test the electrostatic accumulation of common initiating explosives, the influences of various factors were discussed including temperature, humidity, chute material, length, inclination of flume, quartz mass and size of quartz sand. Results show that the amount of charge increases with the increase of the quartz mass. The electrostatic accumulation is linear relation with the environment temperature and humidity, and exponential relation with the sample size. The smaller the particle size, the more electrostatic accumulation. In addition, the chute material, length and inclination of flume also have a great influence to the electrostatic accumulation. On this basis, the resistivity and electrostatic accumulation of the common initiating explosives such as lead styphnate, lead azide and perchloric acid carbon hydrazide series were tested. Results show that those initiating explosives are high resistivity objects, and the lead styphnate can be accumulated static electrostatic easily. The lead azide with crystal type control agent dextrin and polyvinyl alcohol can be reduced the electrostatic accumulation obviously, and dextrin and polyvinyl alcohol can be used as antistatic agent.

Abstract:In order to develope a device that could disrupt explosive components quickly and easily, a special shaped charge structure was studied. AUTODYN two-dimensional program was used to simulate the forming progress of water jet. The speed of water jet with different thicknesses of explosive was obtained. The results show that that the device can generate a water jet. The water jet tip velocity and average velocity increase with thickness of explosive. And, when the thickness of explosive range from 4 to 6 mm, the water jet tip velocity ranges from 861 to 1282 m·s^-1 and the average water jet velocity range form 393 to 571 m·s^-1. The water jet can disrupt explosive objects safely at this velocity range in theory.

Abstract:In order to study the multimode penetrators with the same shaped charge, the numerical simulation of the forming process of the explosively formed projectile (EFP) with fins which was formed by a grooved torus in front of the liner, was carried out by the Arbitrary Lagrange-Euler(ALE) method using LS-DYNA. Results indicate that the charge structure can form EFP with eight fins, and the length-diameter ratio of EFP with fins is 2.75 times of that of EFP and it velocity increases by 15 percent.

Abstract:Oxidation of ammonium perchlorate (AP) was used to remove organic templates of ordered mesoporous materials at relatively low temperature (100 ℃). SBA-15 prepared by using triblock copolymers P123 as a template was chosen as an example to demonstrate the AP-HNO₃ treatment method. The resultant template-free product (N-SBA-15) had a larger pore size (10.4 nm) and volume (1.40 cm³·g^-1) compared to the calcined sample (6.5 nm and 1.03 cm³·g^-1). The IR spectrums show that N-SBA-15 has a high concentration of surface silanol groups. No framework shrinkage is observed based on XRD results. TEM images show that N-SBA-15 has a highly ordered two-dimensional hexagonal structure (p6mm). Moreover, N-SBA-15 shows almost no micropore volumes. Therefore, high quality N-SBA-15 can easily be obtained under mild conditions. This strategy can also be extended to prepare other template-free mesoporous silicas, such as those with space groups of Fm3m, Im3m, and Ia3d.

Abstract:In order to evaluate the combustion efficiency of Al powder in Al-H₂O reaction, the reaction of Al powder with particle size of 50 nm, 2 μm, 13 μm and 29 μm and H₂O was studied from electrochemistry. An evaluated system to characterize the Al-H₂O reaction with parameters including corrosion potential, corrosion current density and corrosion potential temperature coefficient was initially established by polarization curves of Al-H₂O reaction at different temperatures. The experimental data were fitted and analyzed to discuss the behaviours of Al-H₂O reaction affected by particle size and temperature. The electrochemical thermodynamics of Al-H₂O reaction was studied by Faraday′s law and Gibbs-Helmholtz equation. Results show that with the reduction of particle size of Al powder, the corrosion potential (E_corr) of Al-H₂O reaction decreases and the Al-H₂O reaction easily takes place. The decrease rate of E_corr is relatively significant when the particle size is less than 2μm. The combustion efficiency of Al powder with 50 nm is 90.6% in Al-H₂O system, which is much higher than that of Al powder with 2μm at 25 ℃ (66.7%).

Abstract:Emulsion explosive is widely applied for its safety and environmentally friendly and stable characteristics, but the rock breaking efficiency of the emulsion explosive is not ideal for its low explosion power. In order to improve the detonation characteristics of the traditional emulsion explosives, hydrogen storage material was put into it. Through underwater explosion experiment and emulsion explosives Brisance experiment, the energy output characteristics of different emulsion explosives were studied. Results of selected detonation parameters for prepared compositions of explosive materials with hydrogen storage materials are presented. For comparative purposes, the paper also presents analogous results for conventional emulsion explosives which sensitized by glass microspheres, hydrogen storage material MgH₂ and TiH₂ are both have good improvement on the explosive power, and respectively increase remarkable on decay time and overpressure of the shock wave. Before the detonation reaction, hydrogen storage material MgH₂ and TiH₂ were hydrolyzed to create H₂, then small bubbles were distributed uniformly in the emulsion matrix, at last the emulsion matrix was sensitized. H₂ was energetic material and participated in the detonation reaction, so the total energy output increased. Compared with emulsion explosives sensitized by microspheres, shockwave energy of emulsion explosives sensitized by MgH₂ increased32%, and shockwave decay time of emulsion explosives sensitized by TiH₂ increased 42%.

Abstract:A new method to synthesize 3, 3′-diamino-4, 4′-azoxyfurazan (DAOAF) which used 3, 4-diaminofurazan as raw material and 3-amino-4-formylaminofurazan or 3, 4-diformylaminofurazan as intermediate was introduced. 3-amino-4-formylaminofurazan or 3, 4-diformylaminofurazan was oxygenating by 30% H₂O₂ in solvent of 1, 4-dioxane. After refluxing for 4 h, DAOAF was obtainded with yield 97% or 89%. The product was characterized by ¹H NMR, ¹³C NMR, IR and EI.

Abstract:2-(2′, 4′, 6′-trinitro)phenylamino-4-nitroimidazole was obtained by condensation of 2-amino-4-nitroimidazole with 2, 4, 6-trinitrochlorobenzene in yield of 30.9%. Its structure was characterized by ¹H NMR, MS and IR. And differential scanning calorimetry (DSC) was used to study the thermal behavior of 2-(2′, 4′, 6′-trinitro)phenylamino-4-nitroimidazole. The decomposition temperature was 285.92 ℃.

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