Abstract:In order to explore formulation design theory and methods for high energy insensitive polymer bonded explosives(PBXs), the general mathematical model of multi-objective nonlinear optimization design for high energy insensitive PBX formulations was proposed, based on the investigation of structure-property relationship for PBXs. The empirical functions of sensitivities versus compositions of TATB/HMX-based PBX formulations were acquired from experimental data. And a specific mathematical model for HMX/TATB based PBXs was set up accordingly, using the cylinder specific kinetic energy function, impact sensitivity function and shock sensitivity function as multiple objective functions, with the energy level, sensitivity level and the content bounds as constraint conditions. Ten PBX compositions of 8 energy levels were designed and their energies as well as sensitivities were predicted according to the specific mathematical model. Four of the 10 compositions were selected to be tested. As a result, the error of the prediction values for energies and shock sensitivities according to the design model deviates within 5% and 6% respectively, while the prediction values of impact sensitivities are in the same level with experimental results.

Abstract:Based on the blast field test results of 1 kg thermobaric explosive, the method of grey correlation analysis was used to investigate the influence rule of 5 raw materials and their contents on blast performances. The results show that the reduced order of the positive correlative factors investigated to the overpressure at 3 m from the explosion center is: high explosive RDX, fine particles of ammonium perchlorate(AP); and with the overpressure at 9 m is: fine particles of aluminum powder Al(Ⅱ), coarse particles of aluminum powder Al(Ⅰ) and coarse particles of amonium perchlorate(AP). It indicates that high explosive RDX and fine particles of AP are in favor of the overpressure at 3 m, but weaken the overpressure at 9 m. Whereas the aluminum powder with two particles size and the coarse particles of AP have the inverse influence on overpressure at both distances.

Abstract:3, 4-Diaminofurazan was prepared from 3, 4-diaminoglyoxime by two new methods. Supported solid alkali or micelle was used as catalysts in the reaction first time. When the reaction catalyzed by supported solid alkali, the optimal conditions are: 150 ℃, 3, 4-diaminoglyoxime:supported solid alkali:H₂O(mass)=1:3.5:12.5, 4 h. Under those conditions, the yield could be improved to 91.2%. The temperature, pressure and catalyst amount are lower and yield is higher than the reaction catalyzed by KOH. Moreover, the catalyst can be reused at least five times without decreasing of catalyst activity. Then, 3, 4-diaminofurazan synthesis catalyzed by micelle was explored. Anionic and cationic surfactants both possessed well catalytic activity when the mass ratio of surfactant and 3, 4-diaminoglyoxime was 0.02. On the condition of 110 ℃, DAG:KOH:H₂O:sodium dodecyl benzene sulfonate(mass)=1:1.3:7.1:0.02, when the reaction time was 10 h, the yield was 46.0%. Compared with the reaction without catalyzed by micelle, the cite reaction could react at lower temperature and pressure.

Abstract:In order to reduce the sensitivity of hexanitrohexaazaisowurtzitane (HNIW), the waterborne polyurethane grafted styrene and acrylonitrile copolymer (WPU-g-SAN) were synthesized from isophorone diisocyanate (IPDI), 2-hydroxyethyl methacrylate (HEMA), styrene (S) and acrylonitrile (AN) as raw materials by seeded emulsion polymerization in situ. The cast films obtained from WPU-g-SAN were characterized by Fourier transform infrared (FTIR), wide-angle X-ray diffraction (WAXD), nuclear magnetic resonance (¹H NMR) and dynamic mechanical analysis (DMA). The results showed that the title copolymer was amorphous and exhibited a certain degree of phase separation. HNIW and HNIW coated with the WPU-g-SAN were examined by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The impact sensitivity was tested by method of GJB772A-1997. The experimental results indicated that the characteristic height H₅₀ of HNIW coated with WPU-g-SAN increases from 13.6 cm to 28.5 cm.

Abstract:The end surface of the principal propellant exists regressive burning in large caliber gun. The p-l curve of projectile can be perfected as the regressive burning eliminated. Hereon, different fire retardant amounts epoxy resin composites(ERC) were studied. On the basis of tests of mechanical properties, thermal expansion properties, curing properties of these ERC and open-pore-ratio of coated 25/37 nitroguanidine propellant by ERC, the relationships between the open-pore-ratio and the properties of ERC were analyzed. Results show 99% open-pore-ratio can be achieved when the mass formula of ERC is as follow: 60% resin(E₄₄ epoxy resin:650 polyamide=4:3), 40% mixed fire retardant(quartz powder:TiO₂=1:2), added 10% diluting agent(alcohol:acetone=1:1).

Abstract:The nitrocellulose(NC) nano-fibers were prepared by means of electrostatic spinning. The composition of spinning solvent systems used in the preparation was determined with optimized condition. Results show that the nitrocellulose nano-fibers with diameter of 80 nm can be obtained when the mixed liquid composed of acetone and ethanol is in the volume ratio of 1:1, and spinning voltage14 kV, spinning concentration 9%, spinning fluid flow 0.1 mL·h^-1 and received distance 22 cm. The electrostatic spinning does not change the molecular chain structure of nitrocellulose. The decomposition heat of nitrocellulose nano-fibers is 1835.80 J·g^-1 which is higher than that of traditional nitrocellulose.

Abstract:The energetic copolyether of 3-nitratomethyl-3-methyloxetane and tetrahydrofuran was synthesized using boron trifluoride etherate (BF₃·Et₂O) and 1, 4-butanediol as an initiator system for the cationic ring-opening polymerization. The effects of reaction conditions were discussed, and the molecular weight could be controlled. The copolymer was characterized by IR, ¹H NMR and ¹³C NMR respectively. Meanwhile, the differential scanning calorimetry (DSC) show that the glass transition temperature of copolymer is -55.3 ℃, the peak temperature of decomposition is 214.1 ℃.

Abstract:Thermal decomposition and kinetics of 1-methyl-2, 4, 5-trinitroimidazole(MTNI) were studied by using TG-DTG, TG-FITR, TG-MS and RCFT-IR in situ thermolysis cell or fast thermolysis probe with rapid-scan Fourier transform infrared spectroscopy(thermolysis/RSFT-IR and fast thermolysis/RSFT-IR) methods, respectively. Results show that the exothermic decomposition process can be derived into two steps: the rupture of the O—NO bond and ring breaking. The main products of thermal decomposition detected by TG-MS method were NO₂, CO, CO₂ and H₂O. On the basis of experimental results, the thermal decomposition mechanism of MTNI is outlined.

Abstract:The thermal decomposition and combustion performance of homogeneous azidonitramine gun propellant composed of nitrocellulose, azidonitramine and nitroglycerine(DA3), azidonitramine gun propellant composed of 85 mass % of DA3 and 15 mass % of RDX(DAR15) and azidonitramine gun propellant composed of 75 mass % of DA3 and 25 mass % of RDX(DAR25) were studied by high-pressure DSC (PDSC) and a closed-bomb. The results show that the DSC curves of DAR15 and DAR25 consist of two exothermic peaks, whereas DA3 gives only one exothermic peak. The first exothermic peaks at 210 ℃ is due to the thermal decomposition of DA3. The second exothermic peaks at 236 ℃ is caused by the decomposition of RDX. With increasing the RDX content, the first exothermic quantity decreases, and the second exothermic quantity increases. In comparison with DA3, the burning rate pressure exponent of DAR15 and DAR25 increases over the pressure range from 40 MPa to 120 MPa and decreases over the pressure range from 120 MPa to the pressure corresponding with maximum dp/dt (p_dpm). RDX makes the initial burning rate and combustion gas generation brisance of DAR15 and DAR25 decrease, and their burning progressivity increases.

Abstract:The thermal decomposition behaviors of AP and AP/Catocene were studied by DSC and TG analysis, and the activation energy E_a1, E_a2, E_a3 and the pre-exponential factor lgA₁, lgA₂, lgA₃ were calculated by Ozawa and Kissinger method. In results of DSC, there is a additional exothermic peaks at 180 ℃ with Catocene which belongs to the decompostion of Catocene. GFP makes the values of E for low and high temperature decomposition reaction of AP decrease 13.2 kJ·mol^-1 and 7.1 kJ·mol^-1, respectively. The most probable mechanism functions of the thermal decomposition reaction of AP and AP/catocene were determined based on Satava-Sestak method. The mechanism of accelerating effects was discussed.

Abstract:The combustion properties and thermal behaviors of energetic thermoplastic elastomer (ETPE) gun propellant and RGD7 nitramine gun propellant were studied by the closed bomb test, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results show that in comparison with RGD7 nitramine gun propellant, the ETPE gun propellant has lower burning rate, longer burning time and the burning rate pressure exponent larger than 1, whereas the pressure exponent of RGD7 nitramine gun propellant is less than 1. For RGD7 nitramine gun propellant, the endothermic melting peak of RDX at 204.8 ℃ in the propellant is inconspicuous and the exothermic decomposition peak of RDX at 240 ℃ is lag behind the exothermic decomposition peak at 194 ℃ of the NC/NG, where as the thermal decomposition temperature at 263 ℃ of poly(BAMO/AMMO) in ETPE gun propellant is higher than the thermal decomposition temperature at 240 ℃ of RDX. The different combustion properties of two gun propellants are caused by the different thermal behaviour of main compounds in the propellants.

Abstract:The effects of density and impact intensity on combustion properties of energetic thermoplastic elastomer(ETPE) gun propellants were studied by closed bomb test, high pressure flameout set, scanning electron microscopy (SEM) and physicochemical property test. The results show when the actual density of ETPE gun propellant (BAMO/AMMO based) is 84% more than that of theoretical density, with increase of the density, the burning rate, burning-rate coefficients and pressure exponent of ETPE gun propellants reduce. There is a adverse correlation between the impact intensity and the burning rate and pressure exponent of ETPE gun propellants.

Abstract:The signal of voltage, current and light required to ignite the common and superfine lead azide (LA) were studied by semiconductor bridge (SCB). Results show that the appearance time of light is shorter than the end time of the second peak, but for the common LA, it is opposite. With increasing the ignition voltage, the duration time of the second peak and appearance time of light for two kinds of samples are short. The ignition data of the two kinds of LA obtained by D-optimization show that the minimum firing voltage of superfine LA is about 50% less than that of the common LA.

Abstract:A Gibbs free energy method improved via initiating initial values by computer with random direction method was presented to calculate the equilibrium composition of combustion products. The factors of solving initial number and interval selection affecting the random direction method were discussed. Combustion products of hydrazine and oxygen obtained by improved and original Gibbs free energy methods are same. The advances of improved arithmetic are simple, convergent and initial value matched a constraint condition completely which is generated by computer.

Abstract:To investigate the effects of loading methods in Brazilian Test on tensile strength for the PBX, traditional Brazilian Test, arc Brazilian Test and rubber-cushion Brazilian Test were conducted for PBX specimens, and the corresponding tension strengths was 3.57 MPa, 5.22 MPa and 5.48 MPa respectively. Compared with the tension strength of 5.5 MPa by standard tensile test, the rubber-cushion Brazilian test shows same result. The load-displacement curves of the traditional Brazilian test and the arc Brazilian test were invalid, but the load-displacement curve of rubber-cushion Brazilian test was valid. Small cracks appear at loading contact zones besides the leading cracks through samples by the traditional Brazilian test and the arc Brazilian test, but there was only one diametrical crack by the rubber-cushion Brazilian test. It indicates that the rubber-cushion Brazilian test estabilished by this work is better to measure the tensile strength of the PBX than the other Brazilian test methods.

Abstract:The isopressing charging technology with multi-runner device of logical network initiator was studied according to the structural features of small diameter, large aspect ratio, multi-corners of the high viscousity of PETN based putty explosives. The charging process conditions were determined accordingly i.e, pressure is 80 MPa and dwell time is 30 min. The influences of different groove dimensions (0.3 mm×0.3 mm~2.0 mm×2.0 mm) and different corner turning (108°~160°) on detonation velocity were investigated. The minimum groove size and the maximum cokner for propagation of explosion were investigated. The physical and chemical uniformity and wave synchronization for isopressing charging were also studied by experiments. The results show that the least groove dimension is 0.3 mm×0.3 mm, and the biggest degree of corner turning is 150°. The range of charge density is 1.504~1.507 g·cm^-3, and the charge composition deviation is 0.34%~0.56%, and the dispersion of the wave synchronization is between the 0.03~0.05 μs.

Abstract:In order to study the feasibility of ballistic projectile method used in the power test of non-capsensitivity industrial explosive, ballistic projectile tests using 200 g emulsion matrix, ammonium nitrate and fuel oil mixture (ANFO) explosive and heavy ANFO explosive as samples and 100 g TNT and 2^# rock powdery emulsion explosive as primers were conducted. Results show that this method is hardly affected by the power of primer and has good accuracy and reliability. Moreover, the sensitivity of the ballistic projectile method to the change of the components of non-capsensitivity industrial explosive was verified by adding aluminite powder into the emulsion matrix samples, and the results show the ballistic projectile method has high sensitivity to the change of the components of non-capsensitivity industrial explosives.

Abstract:In order to destroy the waste tear bomb safely and effectively and obtain the optimal parameter of burning destory for tear bomb. Minimum free energy method is adopted to calculate the equilibrium products of combustion from the combustion of the tear bomb at diffierent temperatures and excess air rate. Though it, the way of destroying waste tear gas in incinerator is proved to be feasible. In this paper, the variable concentration of the correlative resultant of the gas is analyzed, the proper temperature is 1047 K and excess air rate is 1.6 which are required by the safe and eddective incineration of the tear bomb.

Abstract:The uncracked porous silicon (PS) membrane which was fabricated by electrochemical etching technic was used to create nanoenergetic materials (nEMs) in experiments. The average diameter of pores was 4.3 nm, and the thickness of PS membrane was over 100 μm. The surface of PS membrane was modified by suitable coupling agents (KH550, KH560 and KH570). The infra-red spectrum (IR spectrum) of samples was tested by FTIR technology. The experimental results show that the coupling agents can remove the handing bonds on the surface of PS membrane by translating unstable bond of Si—H to much more stable chemical bond Si—OR. And KH550 and KH570 were more suitable to remove the handing bonds than KH560.

Abstract:In order to investigate the afterburning effects of aluminized explosives, the explosives of AⅨ-Ⅱand JAL were studied, and a double-layer test device filled with different gases and designed for enhancing the afterburning effects of under-oxidized explosives was used. The explosion energy outputs of the charges in the test device filled with oxygen, air, and nitrogen under different pressures were studied by underwater explosion test method. The shock wave energy, bubble energy and total energy were calculated respectively, and a method for calculating the energy of afterburning effect was introduced. The experimental results show that these experiments have excellent parallelism, the underwater explosion parameters are the same when they are at the same distance from the center of explosion, at the same depth and different directions, and the shock wave peak pressures accord with explosion similarity laws in the measuring range. This test device can enhance the afterburning effect of aluminized explosive significantly, in the studied range, the energy released by afterburning effect reaches the maximum value of 78% of the detonation heat. The underwater explosion method combined with the designed test device can measure the afterburning effect of aluminized explosives.

Abstract:Based on the comprehensive analysis of literatures about energetic thin films, it is concluded that the technology and process of preparation for metal-composite energetic film, energetic semiconductor bridge(SCB) and nano-porous silicon/oxidant composite films are compatible with one of preparation on the micro-electro-mechanical systems(MEMS) devices. In addition, through representation about the methods of fabrication and energy output characteristic on three kinds of energetic thin films mentioned above, it is considered that initiating explosive device for MEMS can unfold a critical way for development of technology on initiators and pyrotechnics.

Abstract:Ionic liquids have been investigated widely in recent years for their unique properties, including near zero vapor pressures and solubility controled by chioce of cation and anion. Application of ionic liquid in nitration of aromatic compound for syntheses of energetic material is reviewed. Strongly hydrogen bonded explosives such as TATB purified by re-precipitation of the ionic liquids are introduced here. Application progress of energetic ionic liquids in hypergolic fuels of bipropellants and as TNT replacement for melt-castable explosives are also reviewed.

Abstract:The crystal structure, thermal stability, and properties of all polymorphs (including α-, β-, γ-, ε-and ζ-) of CL-20 were introduced. Recrystallization method of CL-20 including solvent-non-solvent method and solvent evaporation method, and the polymorphic transformation of CL-20 in solution were summarized. Considering that ε-CL-20 has the most application value and cannot be prepared directly. It is still necessary to be recrystallized but the polymorph of CL-20 would transform to others in this process which could cause the polymorph purity of ε-CL-20 decreasing, and then affecting the explosive performance of CL-20. The factors affecting the polymorphic transformation of CL-20, such as solvent and temperature were discussed. According to the Ostwald′s rule, the polymorphic transformation of CL-20 in solvent could be explained from the aspects of kinetics and thermodynamics. The deficiency of current research was depicted and the preparation way of ε-CL-20 with high purity through controlling the polymorphic transformation path and optimizing the recrystallization conditions were proposed.

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