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Abstract:An energetic tetraaza macrocyclic compound, tetrafurazano[3, 4-c:3′′, 4′′-g: 3′′′, 4′′′-k:3′′′′′, 4′′′′′-o] furoxano[3′, 4′-c:3′′′′, 4′′′′-m][1, 2, 9, 10]tetraazacyclohexadeoctylene(TFFA)was synthesized by oxidation reaction from 3, 4-bis(4′-aminofurazano-3′-yl)furoxan(DATF) and trichloroisocyanuric acid as starting materials with a yield of 52.3%.Its structure was characterized by ¹H NMR, ¹³C NMR, FT-IR, MS and elemental analysis. The reaction mechanism of DATF oxidation by trichloroisocyanuric acid was preliminarily discussed. The thermal behavior of TFFA was studied by DSC and TG-DTG. The structure of TFFA was optimized by B3LYP method with 6-31G^** basis set. On the basis of vibrational analysis, the relationship between the thermodynamics properties and temperatures was obtained. The detonation properties of TFFA were predicted by Kamlet-Jacobs formula. Results show that thermal decomposition peak temperature of TFFA is at 215.2 ℃, which demonstrates that TFFA possesses good thermal stability and the density, detonation velocity, detonation pressure and explosion heat are 1.86 g·cm^-3, 8775 m·s^-1, 38.92 GPa and 7015 kJ·kg^-1, respectively.

Abstract:The method of in situ X-ray powder diffraction (in-situ XRD) was used to investigate the effect of additives such as HTPB(hydroxyl-terminated polybutadiene), TDI(toluene-2, 4-diisocyanate), DOS(dioctyl sebacate), T-12(dibutyltin dilaurate), AP(ammonium perchorate) and Al(Aluminum powder) on the polymorphic transformation of hexanitro-hexaazatetracyclo-dodecane(ε-CL-20). Results show that, under heating condition, the preliminary polymorphic transformation temperature of ε-CL-20 changes by adding the additives. The crystal of CL-20 is coated to some degree by HTPB and TDI. As an adhesive catalyst, T-12 accelerates coating combined with HTPB and TDI. But in above two cases the transformation of ε→γ is inhibited. DOS enhances the transformation of ε→γ mixed with CL-20. In addition, AP/CL-20 and Al/CL-20 are both solid-solid mixing, which has little effect on the polymorphic transformation of ε-CL-20. Moreover, while heated at 70 ℃ for 60 h, the polymorph of ε-CL-20 in all the composite systems is not changed.

Abstract:Cyclopentadiene was prepared from its dimeric form by pyrolysis at 200 ℃. By using cyclopentadiene and 1, 4-benzoquinone as starting materials, pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane was synthesized with total yield 51.6% via Diels-Alder, [2+2]photo-cycloaddition and Huang-Minlong reduction. The products were characterized by ¹H NMR, ¹³C NMR, IR spectra and MS. The optimal conditions of Diels-Alder and [2+2]photo-cycloaddition were discussed and confirmed. The optimum conditions for Diels-Alder reaction are: the reaction temperature of dropwise is -11 ℃, the reaction time 3 h. The best condition of [2+2]photo-cycloaddition are as following: the acetone as solvent, the raw materials concentration is 2 g·125mL^-1 and the reaction time 23 h.

Abstract:The intermediate 1,4-formaldehyde-2,3,5,6-tetrahydroxy-piperazine (DFTHP) was prepared by the reaction of formamide and glyoxal condensed in alkaline condition, then it was condensed and nitrified in the system of heteropolyacid/pure nitric acid to obtain 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diaza-tetracyclo dodecane (TEX). TEX was characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy, and the mechanism of the reaction was also discussed. H₃[P(W₃O₁₀)₄] was proved to be the favorable heteropolyacid catalyst, the optimum processing conditions were determined as: mass ratio m(DFTHP)/m(urea)=1:0.25, the dosage of H₃[P(W₃O₁₀)₄] 1 g, adding the reactants at 50 ℃, reaction temperature 65 ℃ and reaction time 40 min, with the yield of TEX 44.7%.

Abstract:5, 6-Di(trinitroethylamino)furazano[3,4-b]pyrazine(DNFP) was synthesized from 5, 6-dihydroxyfura-zano[3,4-b]pyrazine by four steps reactions including chlorination, amination, N-hydroxymethyl and condensation reaction in a yield of 31%. And its structure was determined by IR, ¹H NMR, ¹³C NMR and elemental analysis. The reaction condition and mechanism of DNFP were studied. The heat of formation of DNFP was calculated by DFT/B3LYP methods, and other detonation performances of DNFP were predicted by Kamlet-Jacobs formula. Results show that its heat of detonation is 6714 J·g^-1, detonation velocity 8.91 km·s^-1, and detonation pressure 36 GPa.

Abstract:The intermolecular interactions between γ-aminopropyltrianolsilane (KH5501) and TATB were theoretically studied using the density functional theory LDA/PW method and the three optimized geometries of the mixture of KH5501and TATB were obtained. By analyses of bond length and bond angles of TATB before and after mixing with KH5501, It is found that the coupling agent KH5501 changes the structure of TATB in two was: the bond length of C—NO₂ bond is shortened, and accordingly, the impact sensitivty decreases. In another side the planar structure of TATB is destroyed and accordingly, the molecular polarity of TATB is enhanced. The analyses of the frontier orbits of TATB show that, the interaction between KH5501 and TATB, make the gaps of frontier orbits become narrower, thereby the thermostability as well as the photostability of TATB is debased, and the reaction activity of TATB is enhanced. Through the comparation of the calculation results between three optimized geometries, the results indicate that the bond length of N—O bond of TATB all get longer, particularly, the Ⅳ geometry gets longest. Although the electron transfer between TATB and KH5501 occur, the Ⅳ geometry transfers largest. Meanwhile, compared with other geometries, there is the largest energy of the molecular interaction in Ⅳ geometry. For mentioned above reasons, it is concluded that the Ⅳ geometry is of the largest stability among the three geometries, and the main bonding between TATB and KH5501 in IV geometry is the hydrogen bond interactions formed between the hydrogen atom in the hydroxide of KH5501 and the oxygen atom in the nitric of TATB. It is the hydrogen bond interactions, formed between the hydrogen atom in the hydroxide of KH5501 and the oxygen atom in the nitric of TATB, that improve the binding and the interfacial properties of TATB, which is consistent with the experimental results.

Abstract:Multi-walled carbon nanotubes (MWCNTs)/fluoropolymer (F2314) composites were prepared via a melt blending process The influences of MWCNTs content on the viscoelastic properties (dynamic mechanical behavior and three-point bending creep properties of MWCNTs/F2314) were explored using dynamic mechanical analysis (DMA) method. The results show that with increasing the MWCNTs content, the storage modulus (E′) of MWCNTs/F2314 composites increases, the glass transition temperature (T_g) and peak value of loss factor (tanδ_max) decrease. The creep strain and constant creep strain rate of MWCNTs/F2314 composites distinctly decrease due to the presence of MWCNTs. At 80 ℃/0.1 MPa, when the MWCNTs content(mass fraction) increases from 2% to 20%, the creep strain and constant creep strain rate of MWCNTs/F2314 composites decrease by 87.6% and 84.7%, respectively. Burger four-element mechanical model can be used to simulate the creep behaviors of MWCNTs/F2314 composites and obtain the constitutive equations of creep curves.

Abstract:Nanoporous silicon powder was prepared by chemical etching method using silicon powder with purity of over 99% and particle size of smaller than 20 μm as raw material and HF, HNO₃, distilled water and sodium nitrite as the etching medium The nanoporous silicon powder were characterized by scanning electron microscope(SEM), specific surface tester and Fourier transform infrared spectrum(FTIR). The porous silicon (PSi)/sodium perchlorate composite materials were prepared and their combustion test was performed. Results show that the main factor affecting the pore-size distribution is nitric acid concentration in the etching system. The etching time is the key factor increasing the specific surface area of nanoporous silicon powder. The best etching conditions are nitric acid concentration of 5.2% and etching time of 120 min. The prepared nanoporous silicon powder is nanoporous materials, whose surface is covered by large amounts of Si-H bonds and the surface area is up to 58.2264 m²·g^-1 . The prepared PSi/sodium perchlorate can combust violently, accompanied with deflagration phenomenon and can be used as green ignition reagent or combustion agent.

Abstract:The porous nickel hydrazine nitrate(NHN) was obtained by in-situ liquid-solid reaction of ammonium salt, hydrazine hydrate and porous nickel under constant temperature in half-closed environment. The detonation velocities of NHN with different mass increase rate were measured using optical fiber time measurement method. Results show detonation velocity is maximum(about 2300 m·s^-1) when the mass increase rate ranges from 35% to 40%. The optimum reaction condition to obtain NHN with high detonation velocity was investigated by orthogonal test. It is found when the concentration of hydrazine hydrate is 0.256 mol·L^-1, and the concentration of ammonium nitrate 0.192 mol·L^-1, and reaction temperature 65 ℃ and pH 9, the detonation velocity of NHN reaches up to 2357-2499 m·s^-1.

Abstract:The changes in appearance, structure integrality, mass /volume change rate, mechanical sensitivity, mechanical performance and launch safety of casted RDX-based polymer bonded explosive(PBX) with time during aging were studied by an accelerated aging test with temperature cycle from -55 ℃ to 71 ℃. The aging test at 65, 75, 85, 95 ℃, and SEM and DMA study of aging samples were carried out. Results show that after 25 temperature cycles aging test, there is no visible fissure and pores in PBX, and the structural integrity does not change, and the mass/volume change rate is less than 1%. The impact sensitivity increases to 16%. The explosion does not occur under the impact conditions of drop weight of 400 kg and drop height of 3 m. The compressive strength increases, and the compression ratio decreases, and the mechanical properties of the PBX deteriorate obviously. The compressive strength increases by 47.5% and compression ratio decreases by 9.8% after aging 252 d at 65 ℃. With the aging time extended, the dynamic mechanical loss peak(tanδ) of β relaxation decreases, the crossing degree of polymer network increases and polymer combine with filling material tightly, showing that crossing reaction of post curing is one of the reason about mechanical properties deterioration.

Abstract:In order to evaluate damage power of thermo-baric warhead, the oxygen consumption of one thermo-baric warhead was studied by static experiment. The real-time variety graph of oxygen concentration-time was obtained. The energy releasing efficiency and damage power were evaluated by duration of oxygen consumption and quantity. Results show that the energy releasing efficiency and damage power of thermo-baric warhead are 1.13 and 1.55 times higher than that of plastic bonded explosive warhead, respectively. The assessment results are consistent with those evaluated using parameters of by shock wave and temperature.

Abstract:To acquire the failure mode and failure mechanism of semiconductor bridge (SCB) initiator in the process of long-term storage, the changes in resistance and appearance of SCB electrode plugs before and after storage in various environment stress were studied by accelerated life test, resistance test and scan electron microscope test. Results show that a single temperature (71 ℃) stress does not cause the corrosion of SCB electrode plugs and accretion of resistance. Temperature and humidity (80 ℃, RH=95%) stress can cause slow corrosion of leading wire of SCB electrode plugs and resistance adding slightly. Under the temperature and humidity(80 ℃, RH=95%) stress, SCB electrode plugs with salt water after storage appear serious corrosion phenomenon. A conclusion of accelerating the corrosion of SCB electrode plugs by chlorine ion and corrosion degree of judging the soldering joints by resistance size of SCB electrode plugs is obtained. Namely the greater the resistance of SCB electrode plug, the deeper the corrosion degree of bridge or soldering joints

Abstract:In laser-driven flyer technology, the efficiency of laser and the velocity of flyers can be improved by the using of multi-flyers. In order to obtain the influence of each layer in multi-flyer with different materials and thickness on the velocity of flyers, multi-flyers with different parameters were prepared by Ti, C, Al₂O₃ and Al. The multi-flyers were driven by Neodymium-Yttrium-Aluminium Garnet-Laser laser system in the energy range between 200 mJ and 300 mJ. The velocity of multi-flyers were tested by Photonic Doppler Velocimetry (PDV). Results show that the velocity of multi-flyers with absorption layer (0.15 μm, Ti) increases 110% compared to single flyer, and the velocity of multi-flyer with insulation layer(0.3 μm, Al) and ablation layer(1.0 μm, Al₂O₃) increases 41% compared to single flyer. Energy utilization and accelerate distance of different multi-flyers were analyzed. It indicates that the velocity of laser-driven multi-flyers can reach 90% of maximum velocity at 0.02 μs, and reach a maximum at 0.08 μs.

Abstract:Since the split Hopkinson pressure bar (SHPB) test can not describe the effect problem on pyrotechnics using acceleration, an equivalent equation of bullet speed and acceleration of SHPB test was obtained using results of SCB pyrotechnics from by air cannon and SHPB tests, such as axial strain, time to reaction, chip firing energy etc and taking that the acceleration of air cannon test is equivalent to the bullet speed of the SHPB test. An overload acceleration mechanics simulation test method of pyrotechnics for SHPB test is established finally.

Abstract:A flat-sheet style and micro-scale explosive train of loaded HMX-base lead explosive JO-9C(Ⅲ)in a thin sheet to form strip-shaped lead explosive instead of columned lead explosive was designed. Micro-scale electric detonator and booster in two terminals of explosive train, whose axes are upright with surface of strip-shaped lead explosive, were used as input and output of explosive train, and the detonation transfer route which includes two right-angle was formed finally. The detonation transfer performances of explosive train with strip-shaped lead explosive with the thickness of 1.8 mm and 0.8 mm under different temperature (high temperature, low temperature, room temperature)conditions were studied and compared. Results show the detonation of the explosive train with double right-angle route composed of micro-scale electric detonator, booster and strip-shaped lead explosive with the thickness of 0.8 mm can transfer step by step. The higher the temperature of explosive train, the greater the destructivity to the restrictions after action.

Abstract:With the characteristics of high speed, long rang, small vulnerability, better bullet carrying ability, strong defense penetration ability and large damage capacity, the tactical ballistic missile (Tactical Ballistic Missile, TBM) has become a serious threat to the world′s nations. Thus, it is of great importance to develop the anti-TBM warhead technology. The research on the anti TBM warhead technology was reviewed from the aspects of the fragment warhead, KE-rod (kinetic energy rod) warhead, controllable lethal element warhead, jettison warhead, kinetic energy interceptor and lethality enhancer device. It is suggested that the anti-TBM warhead composite technology, comprehensive damage efficiencies and multi-hurt technology shall be enhanced in the future.

Abstract:Diguanidinium 3, 3′-bis(nitramino)-4, 4′-azofurazanate (G₂DNAAF) was synthesized with total yield of 64% using 3, 4-diaminofurazan (DAF)as starting materials. The structure of G₂DNAAF was characterized by NMR, IR, elemental analysis and single crystal X-ray diffraction analysis. The thermal stability was analyzed by the differential scanning calorimetry (DSC) method. Furthermore, the enthalpy of formation and detonation parameters were calculated theoretically. Results show that the crystal of G₂DNAAF belongs to monoclinic system, space group P2(1)/n with a=5.226(2) Å, b=12.686(5) Å, c=11.944(5) Å, α=90°, β=92.896(7)°, γ=90°, V=790.8(5) ų, Z=2, D_c=1.698 g·cm^-3, μ= 0.148 mm^-1, F(000)=416. The decomposition temperature of G₂DNAAF is 259.0 ℃. The enthalpy of formation is 588.27 kJ·mol^-1, and the detonation velocity and detonation pressure are 7.839 km·s^-1 and 26.81 GPa, respectively.

Abstract:Three-dimension (3D) mesoscopic structure features of polymer bonded explosives (PBXs) pressed by unidirectional and bidirectional warm die compaction (UWDC and BWDC) and isostatic warm soft compaction (IWSC) methods with the modeling granules of TATB were nondestructively studied by X-ray micro-tomography (X-μCT) technique. Results show that the initial fine crack and some residual pores are existed in the PBXs pressed by unidirectional and bidirectional compaction methods. The scale range of initial mesoscopic damage is from hundred microns to millimeter. At the same temperature (85 ℃)and pressure (90 MPa), the initial mesoscopic damage can be produced by UWDC and BWDC methods, but this damage can avoid by IWSC method.

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