Abstract:For synthesis of 2,4-dinitroimidazole(2,4-DNI) from the rearrangement of 1,4-dinitroimidazole(1,4-DNI),microwave heating instead of conventional heating can improve yield of the product and shorten the reaction time from 4~50 h to 10 min. The authors investigated the effects of microwave power for heating,reaction time,solvent type and concentration of 1,4-DNI in chlorobenzene on the yield of 2,4-DNI. Based on this investigation the optimal rearrangement conditions would be as follows: microwave power: 375 W, heating time: 10 min,solvent: chlorobenzene,concentration of 1,4-DNI: 10%. Under the conditions listed above,the yield of resulting 2,4-DNI can be up to 95% with a melting point of 265-268 ℃(decomposition).

Abstract:A single crystal of energetic compound 4-amino-1,2,4-triazolium picrate (4-ATPA) was cultured from methanol solvent at 25 ℃. The compound crystallized in the orthorhombic system, is space group Pcnb with a=9.177(4)， b=13.279(6)，c=19.855(6) ?, V=2419.5(16) ? 3, Dc=1.720 g·cm-3, Z＝8, μ(MoKα)=0.152 mm-1 and F（000）=1280. Of the 2580 total reflections, 2194 were unique(Rint=0.0048). The final R=0.0588 and wR=0.1370 for 2194 observed reflections with I>2σ(I). Single X-ray diffraction reveals that the structure is composed of 4-amino-1,2,4-triazolium cation and picric anion.

Abstract:3,4-Diphenylfuroxan and four no-reported compounds 3,4-bis(pyridine-2′-yl)furoxan, 3,4-bis(pyridine-3′-yl)furoxan, 3,4-bis(pyridine-4′-yl)furoxan and 3,4-bis(pyrazine-2′-yl)furoxan were self-designed and synthesized using chloride oxime-based compounds as starting materials and the synthetic method of dimerization reaction of cyanide oxidation. The structures of target compounds were characterized by IR, NMR, MS and elemental analysis. The effects of different substituents, different catalysts,reaction temperature on the synthesis of furoxan derivatives using dimerization reaction were preliminarily investigated. Results show that the electron withdrawing ability of substituents is stronger,the structure of cyanide oxidation is more easily generated,and the yields of target products are higher. The inorganic weak base(for example Na2CO3, KHCO3) is usually chosen as catalyst. The reaction temperature is usually controlled at 2-10 ℃. Under the optimal conditions, the yields of target compounds are 64.7%, 71.3%, 70.0%, 71.1% and 75.6%, respectively.

Abstract:2-Methyl-2-nitro-1,3-diazidopropane (NMPA) can be used as a low-molecular plasticizer of propellants and as an ingredient of gas generators. NMPA was mentioned in literatures,but its detailed synthesis procedures were not reported. The authors synthesized NMPA via a self-designing process that consists of three steps, i.e. condensation, sulfonation and azido-substitution,using nitroethane and formaldehyde as starting materials. The factors affecting the NMPA′s yield,including reaction temperature,time and media for azido-substitution,were investigated. Based on this investigation,the optimal reaction conditions were determined: T=93~95 ℃,t=30 h,medium DMSO,which made NMPA′s yield (based on nitroethane) up to 71.5% and purity of 99%. The structure of the resulting product was identified by IR, NMR and element analysis. Some properties of NMPA were measured as follows: ρ 1.28 g·cm-3,Tg(DSC) -51.5 ℃,Tp(DSC) 234 ℃,impact sensitivity 34 cm,friction sensitivity 32%.

Abstract:Substituted diphenyl ethers (SDE) belong to an important fine chemical intermediates which can be synthesized via Williamson reactions. Room-temperature ionic liquid (RIL) as solvent could realize clean procedure of SDE′s synthesis. The authors prepared a RIL of 1-butyl-3-methyl imidazolium hexafluorophosphate (BMIMPF6), and synthesized a series of SDEs from substituted nitrobenze and phenol via Williamson reaction by use of BMIMPF6 as green solvent and K2CO3 as catalyst. Some factors affecting the etherification,such as temperature,time and catalysts etc,were studied,and the relatively optimal reaction conditions were worked out: molar ratio of reaction material/catalyst=1/1(molar),T=100 ℃,t=1 h. Under the above procedures the yield of resulting SDEs could be 70%-93%, and the structural confirmation was done by 1H NMR, 13C NMR and MS. One additional point should be emphasized that the RIL could be reused at least 5 times without noticeably deteriorating SDE′s yield and purity. This is beneficial to environmental protection.

Abstract:The new nanosolid superacid catalyst TiO2/SO42- was prepared by sol-gel method, and samples were characterized by acid base titration,XRD and TEM. Results show that the superfine solid TiO2/SO42- is nanocrystal with good dispersibility and its average size is 27 nm. With the catalyst TiO2/SO42-, 2,4,N-trinitroanilinoacetic acid(TNAA) was synthesized from chlorobenzene and glycine with yield of 71.6%. The optimum conditions are 0.2 mol chlorobenzene,and 0.7 g catalyst,and 0.07 mol glycine,and 0.08 mol nitric acid,and reaction time of 3 hours,and reaction temperature of 45 ℃. When calcined at 600 ℃,the activity of regeneration catalyst is restored mostly after regenerated eight times.

Abstract:Using emulsion double metal cyanide (EDMC) complex instead of Lewis acids etc as catalyst the hydroxyl terminated polyepichlorohydrin (PECH) with high relative molecular mass（MW） and narrow distribution was synthesized by ring-opening polymerization of epichlorohydrin (ECH). The PECH obtained can be used to prepare energetic azide binders with top quality. The key factors influencing the ECH′s polymerization were studied,including initiators,addition method of monomer,dosage of catalysts,and reaction time. Results show that the functionality of PECH varies as types of initiators. The increase of catalyst dosage and the rise of reaction temperature result in higher MW of PECH. To add the monomer droprise continuosly could be helpful to improve the polymerization. The yield of PECH reaches more than 95% on the conditions listed below: bisphenol A as initiator, catalyst dosage of 0.05% (based on resulting PECH mass),reaction temperature of 128 ℃. The MW of PECH can be adjusted by varying the molar ratio of monomer to initiator. The functionality of the synthesized PECH was calculated based on f= (OH value/MW)/56100 and found to be of 2-3. The PECH structure was identified by FTIR, 1H NMR, and GPC.

Abstract:Two new heat-resistant explosives of 1-picryl-3-amino-5-nitro-1,2,4-triazole(TNTA-TNB) and 4-picryl-3,5-dinitro-1,2,4-triazole (DNT-TNB) were synthesized via condensation of 3-amino-5-nitro-1,2,4-triazole (ANTA) (or ammonium 3,5-dinitro-1,2,4-triazole (ADNT)) with 2,4,6-trinitrochlorobenzene. The condensation mechanism was explored and discussed. The effects of some key reaction conditions,such as media,temperature,time and catalysts,on condensation were investigated. The explosive synthesis was carried out at 70 ℃,8 h in DMF and NaF as catalyst. IR, NMR and elemental analysis confirmed the synthesized compound structures. In addition,we imroved the synthetic process of 2,4,6-tris(3-amino-5-nitro-1,2,4-triazole-1-yl)-1,3,5-triazine by means of direct reaction of ANTA with 2,4,6-trichloro-1,3,5-triazine omitting the preparation of ANTA-Na and without using phase transfer catalyst,lowering the production cost,simplifing the procedure,and improving the reaction safety.

Abstract:Nitrate ester explosives were synthesized in chip based micro reactor. When alcohol and nitric-sulfuric mixed acid are mixed in the micro reactor, the yield of triethylene glycoldinitrate (TEGN) is 86.39%,and the yield of diethylene glycol dinitrate is 90.60%. The effects of the ratio between nitration agent and raw material, and the effect of liquid hourly space velocity (LHSV) on the reaction were studied. The results show that when the ratio of acid/alcohol is low, the yield of nitrate explosives decreases with the increase of LHSV, however, when the mole ratio of acid/alcohol increased for a certain, the yield of the product did not change significantly with the decrease of LHSV. And the optimal mole ratio of nitric acid/alcohol for diethyleneglycol is 5, and for triethylene glycol is 4.

Abstract:The thermal behaviors of CL-20 mixed with three binders ((NC+NG),PET and PBT) at 160-200 ℃ were investigated by NBK LAWA gasometric measuring system. The thermal behaviors were described from the changes of evolved gases and decomposition kinetics. Results show that the apparent activation energies of CL-20 and its mixed systems with (NC+NG),PET and PBT are 176.68，176.31，136.12 and 127.0 kJ·mol-1, respectively. There is less influence of (NC+NG) binder on the decomposition rate and the apparent activation energy of CL-20. The heterogeneous gas/condensed phase reactions between gas products from CL-20 initial decomposition and PET or PBT decrease appear activation energies and increase obviously decomposition rates for CL-20/PET and CL-20/PBT systems. While the mechanism functions of CL-20 decomposition in the three systems are not changed by (NC+NG), PET and PBT.

Abstract:The density,binding energy and radical distribution function of HTPB/plasticizers blends and binder hydroxyl-terminated polybutadiene (HTPB),and plasticizer dioctyl sebacate (DOS),dioctyl adipate (DOA),dibutyl phthalate (DBP),dioctylphthalate (DOP) were calculated by molecular dynamics simulation (MD) for evaluating compatibility of HTPB and plasticizers. The results show that Δδ value of pure substance,the density added value,binding energy and radical distribution function value,the compatibility of HTPB and plasticizers can be obtained,and the order of compatibility are as follows: HTPB/DOS>HTPB/DOA>HTPB/DOP>HTPB/DBP.

Abstract:The compatibility of two double-base propellants (SB-1 and SB-2) and priming composition (WX-percussion composition) was studied by differential scanning calorimeter (DSC) and vacuum stability test (VST). The DSC results show that in the mixed systems WX-percussion composition/SB-1 and WX-percussion composition/SB-2,thermal decomposition peak temperatures of WX-percussion composition is increased by 8.8 ℃ and 7.4 ℃, respectively. Then,it can be considered that the two mixture systems are compatible. It is found in VST method that the net increment values of released gases for the two mixture systems are less than 0.6 mL·g-1 and the two systems are judged to be compatible. The peak temperature rise on DSC for WX-percussion composition in the two mixture systems was analyzed and discussed by the “topochemistry” principle,and it is proposed that the processes of thermal decomposition are inhibited by azido nitramine(DA) and nitroglycerine(NG) gases from their evaporation and (or) gasification.

Abstract:Three-impulse-at-one-spot thruster is a device which initiates three igniters by logic igniting circuit, and achieves trajectory correction for various flight vehicles. The effects of different main charge amounts, thickness of sealing film and combustion chamber volume on sympathetic ignition of the igniters were analyzed. Results show that output performance improves by increasing main charge amount while sympathetic ignition taking place after excessive charge,so 175-200 mg charge amount is suggested. The sympathetic ignition is effectively prevented by increasing thickness of sealing film while excessive thickness brings too much energy loss, so 0.3 mm thickness of sealing film is suggested. The sympathetic ignition is effectively prevented by increasing combustion chamber volume while too large volume will result in excessive whole dimension, so 3.7 mL chamber volume is suggested.

Abstract:In order to discuss the effect of combustion heat of the products on acoustic radiation characteristics, the underwater combustion for different thermite contents of pyrotechnic compositions were studied with underwater acoustics system. Results show that acoustic energy can be increased significantly by adding the proper content of the thermite, and the optimal thermite content is 25%. Fifteen gram pyrotechnic composition with thermite content of 25% can produce the sound pressure level as high as 158.8 dB, and the acoustic frequency is mainly 0~5 kHz,then the acoustic energy decreases with the increasing of thermite content.

Abstract:Estimation of 100p% firing level is very important in reliability design, qualification and evaluation for pyrotechnics. A number of methods which include the up and down method, the Langlie method, the Wu method,the Neyer method and the optimal stochastic approximation method have been developed for a long time. These methods were compared under the normal and logistic sensitivity distribution by using Monte Carlo technique. The appropriate application range for each method was given by considering deviations. The optimal stochastic approximation method is suggested for p=0.5 and the Neyer method is suggested for p=0.99-0.999.

Abstract:The loading process was analyzed to improve performance of delay electric detonator withstanding a high acceleration impact. The consolidating and buffering structures, and delaying technology withstanding impact were also studied. The design of stress distribution, firing, auxiliary ignition, consolidating design of delay element,annular gas storage space structure design were adopted. Thereby, high impact loading test was carried out. Results show that the value withstanding acceleration of the above design structures is higher than 1×105 g and the delay performance is also improved.

Abstract:The law of the burning rates of B/CuO delay compositions at ambient temperature from -50 ℃ to 70 ℃,and with the boron contents increasing from 8.3% to 20% were studied. Results show that when the boron content is 8.3%, the B/CuO delay compositions are misfired, and the burning rates increase with increasing of boron contents from 11% to 20%. When the boron contents are from 14% to 18%, the burning rates almost keep the same value. With the increasing of ambient temperature, the burning rate also has a little increase. Least square method was used to simulate the burning rates, and a burning rate formulation of B/CuO delay compositions was put forward.

Abstract:The plasma sensitivities of different kinds of primary explosives were studied. The voltage-time curves,current-time curves and light-time curves were obtained. The data were analyzed by using D-optimization method. Results show that lead styphnate (LTNR)，nickel hydrazine azide （NHA） and B/Pb3O4 are ignited by the SCB heat; lead picrate,lead azide,nickel hydrazine nitrate(NHN) and barium styphnate are ignited by the SCB plasma. The order of plasma sensitivity is: lead picrate>lead azide>barium styphnate>nickel hydrazine nitrate.

Abstract:The technology of the booster preparation including particle size distribution and content of the main explosive PETN, mixing and casting temperatures of the PETN and carrier explosive were studied. A new high energy booster was prepared in the study and was initiated by 3.6 g·m-1 detonating cord. Its density is greater than 1.60 g·cm-3，detonation velocity is greater than 7000 m·s-1. It could breakdown 25 mm thick low carbon steel plate. Temperature test and under water pressure test results show that it meets the requirements.

Abstract:The effects of thermoplastic polyurethane elastomer (TPUE) on mechanical,energy and combustion performance of triethylene glycol dinatrate (TEGN) propellants were studied. Results show that TPUE improves the mechanical properties,especially the impact resistance at low temperature (-40 ℃). When TPUE content is about 1%-3%,the impact strength at -40 ℃ increases by more than 60%. With the increase of TPUE,the propellant force (f) decreases gradually,and the co-volume (α) and pressure exponent (n) increase a little. When TPUE is 3%，f,α and n is changed to 2%,1.4% and 5.3% respectively.

Abstract:The friction properties of two types of polymer bonded explosive(PBX) coded P1,P2 and two coatings named C1,C2 were tested by the universal testing machine based friction system and the nano-indenter respectively. The results of friction properties obtained by the two methods are correlative. The friction coefficient of C1 coating is the highest among the four materials and the C2 coating is more close to P1 and P2. The friction test for four materials which were in the aging enviroment of 60 ℃ 80%RH have beend conducted. Results show that only the C1 coating′s friction becomes much higher among the four materials.

Abstract:Effects of the varieties and contents of nitrocellulose（NC）ball,particle sizes of ammonium perchlorate（AP）,contents of AP and RDX on the mechanical properties of casting high energy composite modified double-base (CMDB) propellant,were studied. Results show that,the tensile strength and elongation at +20 ℃ and +50 ℃ of the CMDB propellant decrease significantly with the decreasing of NC (12.0%N) content. Appropriate content of NC(13.0%N) and NC(12.6%N ) balls in CMDB propellant can enhance the tensile strength of CMDB propellant. But NC(13.0N%) ball is not helpful to the improvement of tensile elongation of the propellant,while NC(12.6%N) ball is beneficial to the improvement of the propellant elongation. At the same time,appropriate content of DB ball composed of NC(12.0%N) and NG in the propellant will improve the tensile strength and the elongation of the propellant. Particle sizes of AP have influences on the mechanical properties of the propellant. AP with smaller particle size is helpful to improve the tensile strength of the propellant, while AP with bigger granularity is conducive to the improvement of the propellant elongation. When RDX content in CMDB propellant increases gradually，the tensile strength of CMDB propellant at +20 ℃ and +50 ℃ firstly increases and then decreases,while the elongation at +20 ℃ and +50 ℃ firstly decreases and then increases.

Abstract:Multiple channels data collecting instrument has been used to investigate the temperature distribution of melt-cast explosive during the cooling process under various cooling conditions. The most valuable inflexion point of the temperature curve was obtained during the cooling process, especially at the moment when the phase transformation occured. Through the analysis of the experiment data, the mechanism of the phase transformation and that several temperatures of the phase transformation of melt-cast explosive were obtained. Phase transformation temperatures tend to decline along with the increase of the content of melt-cast explosive. Phase transformation temperatures are 76-77 ℃,which are both under the TNT melting point.

Abstract:Three heat-resistant composite explosives (ANPyO(F2311), ANPyO(F2603), ANPyO(F2311:F2603=1:1)) composed of 2,6-diamino-3,5-dinitropyridine-1-oxide (ANPyO), polymer binders and plasticizer were prepared. The performance tests were conducted by measuring the heat resistance, formability, sensitivity, explosion energy and penetration power. Results show that three ANPyO-based heat-resistant composite explosives have better heat resistance and processability,which indicates that three composite explosives can be used in the temperature range of 200-250 ℃,and the mechanical sensitivities of three composite explosives are vicinal and lower than that of ANPyO individual explosive,and the minimum values of impact and friction sensitivity are about 10% and 24%, respectively. The detonation velocity and breaking armour of three composites explosive are higher than that of PYX-based composite explosive, and detonation velocity is increased by about 400 m·s-1, and depth of breaking armour is increased by about 30 mm.

Abstract:The explicit pictures of bubble oscillation at free field and water jet formed during bubble and boundary interaction at underwater explosion was captured by APX-RS digital high-speed camera with the frame rate of camera of 6000 s-1 by using Xe lamp. The wall of the water tank was equipped with a layer of acoustic-impedance materials,and the bubble oscillation was not influenced by shock waves reflected from the wall of water tank. The experimental data obtained by high speed camera agree with the experimental results of 8 kg test pound.

Abstract:The combustion characteristics of the high-energy smokeless modified double-base propellant (HESMDB) at 10-43 MPa was studied. Results show that the burning rate of HESMDB increases with pressure enhancement. There is an inflexion point in the combustion curve of HESMDB propellant at 25 MPa, and then the burning rate of HESMDB increases rapidly. The effects of combustion catalyst is obvious on HESMDB at 10-25 MPa, and lessened at 25-43 MPa. NI-Pb/NI-Cu/CB enhances the burning rate of HESMDB 75.16% at 10 MPa.

Abstract:To study the relationship between the burning rate and the characteristic value of combustion wave,the combustion wave structure of double-base propellant with low burning rate and low flame temperature were obtained by using the technology of imbedded minimized thermal couples into propellant,and the experimental data were calculated and the characteristic value of combustion wave,the surface temperature,the dark zone thickness,the temperature grades of condensed phase and gas phase fizz zone, were obtained. Burning rate of propellants without catalysts increases with the surface temperature increasing，and the surface temperature of propellants with catalysts is higher than that of propellants without catalysts. Flame temperature enhances with increase in pressure, and there is not necessary relationship between flame temperature and burning rate. Results show: the relationship between the burning rate of the said double-base propellant with low burning rate and low flame temperature and the characteristic value of combustion wave is rather complex,and there are linear and non-linear relationships when combustion performance changes. The reason is that combustion wave structure is changed with catalysts.

Abstract:In recent years, much attention was paid to new energetic binders used in high-energy solid propellants,which were synthesized from ring opening of oxirane and oxetane with different energetic groups. The relationships between the different energetic groups and physical and chemical properties，such as densities,heats of formation,melting point and mechanical properties,were reviewed. Finally, the possibility of this type of energetic binders used in PBX explosives was discussed by comparing their strongpoint and disadvantages.

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