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Abstract:The development of Insensitive Munitions (IM) has been progressing for over three decades. Ever since the highly publicized US Navy aircraft carrier accidents in the 1960s to 1980s, there has been a growing recognition of the value of IM. Reminders of the need for IM have been provided all too often in the form of accidents, such as experienced by the US Army at Camp Doha and the prevalence of attacks on military installations around the world.The process for developing IM has improved over the years as technology for mitigating the consequences of accidental initiation has emerged. Early IM developments were based upon replacement of the traditional TNT-based explosives, with their high vulnerability, with reduced vulnerability PBXs. This led to significant improvements, such as that observed with the replacement of H-6 with PBXN-109 in the US Navy Mk82 GP bomb. From the early 1990s, the use of a complete systems approach was highlighted as the optimum method to achieve IM compliance while maintaining or enhancing operational performance. The use of a systems approach has resulted in the fielding of a number of munition systems with significant IM properties.The challenge for the future is to continue the development and fielding of improved performance IM munitions with limited funding for research and the high cost of introducing new ingredients into energetic formulations.A key development to allow continued progress to occur is the introduction of improved versions of current explosive ingredients. The attention focused in the past few years on forms of RDX with reduced shock sensitivity has highlighted the possibility of improving well-known materials. In the near future, the application of materials technology may provide improved versions of other important crystalline energetic materials currently in production or advanced development, including HMX, NTO, CL-20 and ADN and help advance the development of further explosive ingredients such as FOX-7 and LLM-105.Advances in the development and application of computer modeling must be made if we are to move forward from our current reliance on a limited number of canonical tests that are held to be representative of the hazards likely to be encountered. The availability of verified and validated models describing the response of energetic materials to various thermal and mechanical threats will enable us to perform parametric studies on systems. This will allow us to estimate their response to hazards that are characteristic of the specific environment experienced by that system, and so to tailor the materials and packaging to minimize risk and maximize performance.

Abstract:In order to improve the desensitizing efficiency of TATB on HMX, HMX/TATB composites were prepared by in-stiu coating and mixing method respectively. The composite was characterized by SEM, DSC and sensitivity test. Compared with the sample prepared by mixing method, the sample prepared by in-stiu coating with the same TATB content has a better coverage, a higher decomposition temperature of HMX and lower mechanical sensitivity. The impact sensitivity and friction sensitivity of HMX/TATB compounds with 10% TATB prepared by in-stiu coating is 24%, 0% respectively.

Abstract:ε-HNIW coated with melamine-formaldehyde resin was prepared by in-situcondensatesation polymerization from ε-HNIW as the core material , melamine and formaline as wall materials. The coated ε-HNIW was characterized on structure, morphologies, thermal properties and impact sensitivity. It showed that ε-HNIW was well-coated and the sensitivity was reduced as the H₅₀ increased by 10.3 cm. The optimum reaction conditions are as follows: the mole ratio of melamine to formaldehyde was 1∶2.5, and the pH of preparing prepolymer and in-situcondensatesation step are respectively 8-9 and 4-5, the temperature of in-situcondensatesation step is 70 ℃.

Abstract:The waterborne polyurethane (WPU) emulsions were synthesized with toluene diisocyanates (TDI), poly(propylene glycol) (PPG), dimethylolpropionic acid (DMPA) and 1,4-butanediol (BDO) under acetone reflux，and characterized by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and particle size distribution measurements. It shows that the particle size distribution of emulsion is 0.2-2.3 μm, the waterborne polyurethane resin degraded obviously at 263 ℃ and 379 ℃ attributes to the degradation of hard segment and soft segment respectively, which is an endothermic course. The scanning electron microscopy (SEM) images and FT-Raman spectra reveal that CL-20 is successfully coated by waterborne polyurethane. The impact sensitivity experimental results indicate that the characteristic height H₅₀ of CL-20 coated by WPU is increased by 40 percent.

Abstract:High-nitrogen energetic compound 3,6-diamino-1,2,4,5- tetrazine-1,4-dioxide (DATZO₂) was synthesized from 3,6-bis(3,5-dimethylpyrazol-1-yl)-1,2-dihydro-1,2,4,5- tetrazine (BDT) by a two-step reaction sequence, with an overall yield of 46.8% at the 30 g scale. 3,6-bis(3,5-dimethylpyrazol-1-yl)-1,2,4,5- tetrazine (BT), which is an important synthesis intermediate, was obtained by using oxygen as oxidizer without N_xO_y. A series of synthesis and recrystallization methods was developed to yield different particle sizes and morphologies, and their sensitivity were tested. The thermal decomposition of DATZO₂ was investigated, kinetic parametes of decomposition and mechanism functions were obtained.

Abstract:Starting from tetraacetyldibenzy-lhexaazaisowurtzitane (TADBIW), tetraacetylhexaazaisowurtzitane（TAIW）was synthesized via catalytic hydrigenolysis debenzylation using palladium compound as catalyst. Tetraacetyl-bis- (4-chlorobenzoyl)hexaazaisowurtzitane (TABIW) was synthesized through reaction of the condensation of TAIW and 4-chlorobenzoyl chloride. Finally the title compound tetranitro-bis(3,5-dinitro-4-chloroben- zoyl)hexaazaisowurtzitane (TNBIW) was obtained by the nitration of TABIW with oleum（w(SO₃)=20%）/ fuming nitric acid （w(HNO₃) =98%）at 90 ℃ for 4 h. The melting point of TNBIW is 242-244 ℃, and its yield is 57.2%（based on the numbers of TADB）. The structures of TNBIW and its two intermediates were (TABIW, TAIW） determined by IR, 1HNMR, MS and elemental analysis.

Abstract:γ- Hexanitrohexaazaisowurtzitane (HNIW) was obtained with the yield of more than 88% and the purity of larger than 99.4% by nitration of tetraacetydiformylhexaazaisowurtzitane (TADFIW) in 82.48%-88.89% nitric acid. The results show that the optimal concentration of nitric acid is 86.66% as the yield is 94.0% and the purity is 99.51%. The main impurity pentanitromonoacetylhexaazaisowurtzitane （PNMAIW）in HNIW prepared by this method was seperated and characterized, that is different from the main impurity pentanitromonoformylhexaazaisowurtzitane （PNMFIW）in HNIW from nitration of TADFIW in the mixture of nitric acid and sulfuric acid. It shows that nitration mechanisms in those nitrating environments are different.

Abstract:The synthesis of the 4,5-nitroimidazole with yield of 89.4% was described: the disulfuric imidazole salt obtained from the neutralization of imidazole with concentrated sulfuric acid, was nitrated by mixture of sulfuric acid (20%) and nitric acid (98%) under condition of N₂, and then reacted with nitric acid (98%) at 90-95 ℃ for 5-5.5 h. The conditions for later reaction with nitric acid was discussed at same time. And the results show that the optimal are the molar ratio of nitric acid to imidazole is 1.6∶1, reaction temperature 90-95 ℃, and reaction time 5-5.5 h.

Abstract:The synthesis of 3,6-diguandine-1,2,4,5-tetrazine(BDT) and its salts were described from triaminoguanidine nitrate and 2,4-pentanedione after condensation, oxidation and neutralization. Their structures were confirmed by IR, HMR, DSC. Taking CH₃COOH-NaNO₂ as oxidizer, CH₃COOH as reactive medium, BDT was obtained with the yield of 85% at room temperature . This improvement reduces the cost of synthesis, raises the yield, facilitates experimental operation.

Abstract:The 1-(p-dimethylaminophenyl)pentazole was synthesized at low temperature with sodium azide and p-dimethyldiazonium which was synthesized by coupling sodium nitrite with p-dimethylphenylenediamine dihydrochloride in aqueous media. Its structure was characterized by ¹H NMR at -20 ℃.The stability of 1-(p-dimethylaminophenyl)pentazole in solvent at different temperatures was further analyzed by ¹H NMR with a dynamic heating process from -50 ℃ to 25 ℃. It is concluded that the stability is less stable in solvent, and it decomposes almost at 25 ℃ for several minutes. According to the results of the ¹H NMR analysis, the reaction mechanism of decomposition and synthesis of arylpentazole, which was put forward by Bulter et al, are confirmed.

Abstract:Taking aminosulfonic acid as starting material, ADN was obtained by the process of neutralization, nitration, ammonolysis, and purification. The structure was characterized by IR, UV and elemental analysis. The effects of the nitration reaction temperature and time on the yield were investigated. ADN was seperated and purified by the absorption of charcoal, and relative conditions were studied, such as the weight of charcoal,the speed of washing,the terminal point of washing and the method of desorption. The purity of ADN reaches to 99.8% without recrystallization with yield of 50%.

Abstract:The paper is focused on 2,4,6,4′,6′,2″,4″,6″-octanitro［1,1′,3′,1″］-terphenyl (ONT), 2,2′,2″,4,4′,4″,6,6′,6″-nonanitro［1,1′,3′,1″］-terphenyl (NONA), 2,4,6-tris(2,4,6-trinitrophenyl)-1,3,5-triazine (TPT), N,N-bis(2,4-dinitrophenyl)-2,4,6-trinitroaniline (NTFA), 2,2′,4,4′,6,6′-hexanitrobiphenyl (HNB), 1,3-dinitrobenzene (1,3-DNB) and 1,3,5-trinitrobenzene (TNB). The initiation reactivity of these substances has been studied by means of the data obtained from non-isothermal differential thermal analysis (DTA), their ignition temperatures, impact sensitivity, the data obtained from the Russian manometric method and the detonation characteristics. For comparison, also the data published about 2,2′,2″,2,4,4′,4″,4,6,6′,6″,6-dodecanitro-［1,3′,1′,1″］quaterphenyl (DODECA) have been included. The paper specifies and discusses the relationships between the results of various methods used, inclusive of the forms of modified Evans-Polanyi-Semenov relationship. It has been stated that the technologically most attractive substances, out of those studied, can be ordered in the sequence ONT-TPT-NONA-NTFA according to their increasing thermal reactivity.

Abstract:The synthesis, culture of crystal and single-crystal X-ray crystallography of a new kind of polynitrostilbene ［1,4-di(2,4,6-trinitro-styryl)benzene, TNT-TTD］, which was synthesized through Knoevenagel Condensation by using piperidine as a base catalyst were reported. The crystal belongs to the Triclinic system with space group P-1.The compound was characterized by using FT-IR, ¹H NMR, ¹³C NMR and MS spectroscopy techniques. Density functional theory (DFT) B3LYP was employed to optimize structure and calculate frequencies of TNT-TTD. The calculated geometrical parameters were close to the corresponding experiments ones. The thermal decomposition of the title compound was investigated by DSC and TG-DTG methods at heating rate 10 ℃·min^-1. The melting point and initial decomposed temperature of TNT-TTD is 302 ℃ and 311 ℃. The results indicate that TNT-TTD has high heat resistant ability.

Abstract:The single crystal of 3,4-bis (nitrofurazano) furoxan (BNFF) was obtained using acetone as solvent. Its molecular structure was characterized by elemental analysis, IR, MS, ¹³C NMR and single-crystal X-ray diffraction. The results indicate that BNFF crystal belongs to orthorhombic, space group P212121 with a=0.6794 (3) nm, b=1.0755 (5) nm, c=1.5137 (4) nm, V=1.1060 (7) nm³, M_r=312.14, Z=4, D_x=1.874 g·cm^-3 ,D_c=1.875 g·cm^-3, F(000)=624, μ(MoKα)=0.176 mm^-1, R₁=0.0757, wR₂=0.1206. Three 5-membered furazan rings of BNFF molecule are planar and the dihedral angles between them are 62.16 (0.29)° and 25.67 (0.36)°

Abstract:The azotetrazolate high-nitrogen energetic materials is a kind of energetic materials that reported widely. The new two-step synthesis method of some azotetrazolate nonmetallic salts was introduced, including guanidinium, aminoguanidinium, diaminoguanidinium, and triaminoguanidinium etc. The physical, chemical properties and explosive performance of production and ammonium salt, hydrazium salt were also studied. It shows that these materials have high heat of formation, large gas production, good thermal stablity and high reaction heat, and they may have possible applications as gas generants, low signature propellants, low-smoke or non-smoke pyrotechnics and high performance explosives.

Abstract:Thermal decomposition behaviors and thermal properties of diaminoazofurazan (DAAzF) and diaminoazoxyfurazan (DAAF) were studied by DSC with heating rate 2.5 ℃·min^-1, 5 ℃·min^-1, 10 ℃·min^-1 and 20 ℃·min^-1, TG /DTG at heating rate 10 ℃·min^-1, VST and thermal explosion test. The values of average activation energy of DAAzF and DAAF calculated by kissenger′s equation and Ozawa′s equation are 333.3 kJ·mol^-1, 219.3 kJ·mol^-1 with pre-exponential factors (lnA) 67.535 s^-1 and 49.230 s^-1 respectively. Thermal stability parameters of DAAzF and DAAF are shown respectively : VST: 0.26 mL·g^-1/100 ℃/48 h, 1.95 mL·g^-1/100 ℃/48 h; Loss of weight：0.08%/100 ℃/48 h, 0.47%/100 ℃/48 h; thermal explosion temperatures for 5 and 1000 seconds delay are 375 ℃ and 279.5 ℃ for DAAzF, 220 ℃ and 222.5 ℃ for DAAF respectively. These results make clear that DAAzF and DAAF have good thermal stability and the thermal stability of DAAzF is superior to that of DAAF. Sensitivity tests indicated that DAAzF and DAAF are insensitive to impact , friction and electrostatic spark. Average particle size diameters of DAAzF and DAAF were less than 10 μm analysed by LS Laser Particle Size Analyzer.

Abstract:In-situ FTIR was employed to study the characteristics of thermal decomposition of TEX in the process of tempaerature programming. The thermal decomposition mechanism was deduced.The first step of TEX thermal decomposition was denitration, and the evolutaed gases were mainly NO₂, N₂O, HCN, NO,CO and aldehyde group-containing products.

Abstract:The surface energy of FOX-7 and the soaking effect of fluoropolymer FOX-7 were studied in comparison with TATB by using the contact angles and Young-Good-Girifalco-Fowkes(YGGF) equation.The calculation results show the interfacial energy and interaction of FOX-7 with fluoropolymer are close to that of TATB. Fluoropolymers have good soaking effect on FOX-7 and TATB, and the effect on TATB is better than that on FOX-7. FOX-7 has strong alkalescence that offers electron easily on the acid-base interaction. The particle of FOX-7 with two fluoropolymers (F₂₆₀₃ and F₂₆₄₂) were studied by SEM as well. The results show the soaking of FOX-7/F₂₆₀₃ is much better than that of FOX-7/F₂₆₄₂ on particle scale,however,it can be expected that the fluoropolymer can make the almost same effect on FOX-7 and TATB on the whole.

Abstract:γ-Hexanitrohexaazaisowurtzitane(HNIW) with different contents of pentanitromonoacetylhexaazaisowurtzitane (PNMAIW) was prepared, and crystallized to ε-HNIW in ethyl acetate/trichloromethane system. Results show that the content of PNMAIW decreases by less than 1% through crystallization, and affects the time of crystallization.

Abstract:The impurity N,N′-dibenzyl-oxalmide in 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazateracycle［5.5.0.0^5,9.0^3,11］dodecanes (HBIW) prepared by glyoxal and benzylamines was separated by column chromatography and identified by FTIR,¹HNMR, MS and elemental analysis. Futhermore, N,N′-dibenzyl-oxalamide was synthesized with benzylamines and oxalyl chloride,and identified by spectrometric analysis which verified that the impurity was the N,N′-dibenzyl-oxalamide.

Abstract:Method of acid- alkali titration is traditional analysis method. It is typical of manipulation easy, little error and excellent accuracy. In this paper, by using the method of acid-alkali titration, the acid number for ε-hexanitrohexaazaisowurtane（HNIW）obtained in two system（nitric acid and ethyl acetate and chloroform) was determination respectively. Different conditions were determined. For ε-HNIW prepared in nitric acid system, titration conditions are 5-6 g HNIW with 80 mL acetone as solvent and neutral red-methylene blue as indicator. For ε-HNIW prepared in EtOAc-CHCl3 system, conditions are 5-6 g HNIW with 50 mL acetone as solvent and resorcin blue as indicator.

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