RDX和NGU对叠氮硝胺发射药动态燃烧稳定性的影响

以30 mm高压模拟炮为试验平台,以单基发射药为参照,研究了3种典型叠氮硝胺(DIANP)发射药的动态燃烧稳定性,分析了配方组成对DIANP发射药起始燃烧特征、膛内压力上升过程及膛内压力波动的影响,探讨了DIANP发射药配方组成与其起始燃烧特征、膛内压力上升特点和压力波强度的相互关系。结果表明,在DIANP发射药配方中添加质量分数30%的固体组分黑索今(RDX)或硝基胍(NGU),发射药膛内动态燃烧稳定性增加,膛压-时间曲线波动减小,膛压从30 MPa增至50 MPa所需的时间分别增加了92%和78%,起始负压差从－40.7 MPa降低至－4.44 MPa和－10.66 MPa。在DIANP发射药体系引入高含量的固体组分RDX或NGU,由于低压下RDX分解前熔融吸热,而NGU火药燃烧表面存在坚实熔融层,均可有效减小DIANP发射药起始燃气的生成速率,降低发射装药起始燃气生成猛度,缓减起始阶段膛内压力的上升,提高药床起始燃烧一致性,减小膛内压力波强度。     

改性双基推进剂制备中硝化甘油的连续加料与计量技术

为了实现改性双基推进剂制备过程中硝化甘油的安全输送和精确计量,利用乳化喷射器、直管质量流量计及数据处理器(PLC)对硝化甘油(NG)与水的混合液进行了连续加料与计量试验研究。利用Fluent模拟软件对NG的乳化喷液过程进行模拟分析,得到最佳的乳化喷射器结构参数为:喉管直径14.33 mm,喉管长度60.03mm,喉嘴距12.00 mm;在此结构参数下进行模拟分析得到:乳化喷射器出口处NG最大体积分数小于30%,且所占节点比率小于0.05,说明NG与水混合均匀,确保了NG安全连续输送。研究了质量流量计在不同管道压力下对计量精度的影响,当管道压力为0.25~0.31 MPa时,能满足质量流量计的检测要求,计量误差≤1.0%,能满足改性双基推进剂连续制备的工艺要求。     

1，3-二叠氮乙酰氧基-2，2-二叠氮甲基丙烷（PEAA）的结构、性能与热分解机理的理论研究磁

1,3-二叠氮乙酰氧基-2,2-二叠氮甲基丙烷（PEAA）是一种玻璃态转化温度低而含氮量高的叠氮化物,具有作为含能增塑剂的潜在应用价值。文中采用密度泛函理论研究了其分子结构和红外光谱,预测了热力学函数、生成焓、爆轰性能和比冲;采用分子力学方法预测了其晶体结构和晶体密度;计算了多种可能的热解引发键的键解离能。结果表明,PEAA的热分解始于乙酰氧基上叠氮基的N—N键断裂,该过程经氢转移过渡态完成并放出氮气和热量,所需活化能约162kJ／mol。与已有实际应用的叠氮增塑剂DATH（1,7-二叠氮基-2,4,6-三硝基-2,4,6-三氮杂庚烷）相比,PEAA的热稳定性更好。还考察了PEAA对硝胺改性双基推进剂能量性能的影响,发现无论用PEAA替代其中的NG还是RDX均使体系的能量输出和比冲增大,但体系的爆速和爆压略有降低。     

Molecular dynamics study of binding energies, mechanical properties, and detonation performances of bicyclo-HMX-based PBXs

To investigate the effect of polymer binders on the monoexplosive, molecular dynamics simulations were performed to study the binding energies, mechanical properties, and detonation performances of the bicyclo-HMX-based polymer-bonded explosives (PBXs). The results show that the binding energies on different crystalline surfaces of bicyclo-HMX decrease in the order of (010)>(100)>(001). On each crystalline surface, binding properties of different polymers with the same chain segment are different from each other, while those of the polymers in the same content decrease in the sequence of PVDF>F(2311)>F(2314) approximately PCTFE. The mechanical properties of a dozen of model systems (elastic coefficients, various moduli, Cauchy pressure, and Poisson's ratio) have been obtained. It is found that mechanical properties are effectively improved by adding small amounts of fluorine polymers, and the overall effect of fluorine polymers on three crystalline surfaces of bicyclo-HMX changes in the order of (010)>(001) approximately (100). In comparison with the base explosive, detonation performances of the PBXs decrease slightly, but they are still superior to TNT. These suggestions may be useful for the formulation design of bicyclo-HMX-based PBXs.     

Procedures for the production of gun propellants by use of different extruders

This report discusses the use of gun propellants produced by different types of extruders. These extruders are different to each other with respect to their construction, screw configuration and mode of operation.For the production of propellants by solvent processes, we preferred twin-screw extruders operating either in the synchronous mode or the countercurrent mode. The results of this process consist of extruded strands possessing a high density and an excellent surface, especially for single-base propellants produced by use of the countercurrent operating twin-screw extruder.The sychronous twin-screw extruder is mainly applied to the processing of triple-base propellants with a high content of nitroquanidine, such as e.g. M 30.The development of brittleness at low temperature is significantly improved as a result of the manufacturing technique employed.A planetary roller extruder, a four-screw extruder and a synchronously operating, twin-screw extruder are discussed with reference to the production of gun propellant without the use of solvent. A report is given on the advantages and properties of these extruders as regards optimal plastification of water-wet fibrous NC/NG mix. A method of producing propellant chips, which can be subjected to further processing by the selected extruder or a twin-roll unit, is also described. The ballistic properties of the resulting products are superior to those obtained by standard manufacturing processes.     

含发射药震源药柱研制

研制含单基药、双基药的高爆速震源药柱,并对其制造工艺进行了研究.讨论该震源药柱高爆速产生的机理,研究了炸药的配比、炸药的密度对震源药柱性能的影响,测试了震源药柱的各项性能指标.结果表明,该震源药柱制造工艺简单、密度高,各项性能优于国标高爆速震源药柱指标.为处理废弃发射药、充分利用废弃高含能材料开辟了一条新的途径.     

Development of a deterred propellant for a large caliber weapon system

There is a continuing need to increase the velocity and associated terminal performance of kinetic energy ammunition as tougher armor targets are encountered. Application of a deterrent, or burning rate reducer, into the surface of standard propellants, together with appropriate changes in geometry and loading density, has been suggested as a means of increasing velocity by as much as ten percent. The attainment of such a desirable performance gain is critically dependent on the deterrent's satisfying certain requirements: (1) chemical compatability with the base propellant, (2) sufficient penetration of the base propellant, (3) diffusion stability of the deterred region over an extended time, (4) ignitability of the deterred layer, (5) sufficient decrease in burning rate. Unfortunately, there exists only a minuscule data base on the way deterrents behave when applied to various base propellants. The deterred propellants used in small arms and anti-aircraft guns were developed by a cut-and-try technique, and the sort of data required for rational design of large caliber weapons systems, e.g. burning rates in the deterred region, is extremely scarce. Since we lack an appropriate data base we have used thermochemical calculations and burning rate estimates to identify promising deterrent/base propellant combinations. The burning rate estimates were based on empirical fits to available closed bomb and strand burner tests with small arms propellants. Several promising deterrent systems are presented, including five candidates which exhibit a decrease in burning rate with no decrease in propellant energy. On the basis of these theoretical predictions, an experimental deterrent coating and analysis study has been initiated at Radford Army Ammunition Plant.     

高固含量改性双基推进剂流变性能的影响因素

为了了解含RDX的高固含量改性双基(CMDB)推进剂的流变性能,采用转矩流变仪研究了螺杆转速、机体温度、口模直径、口模长径比以及RDX含量对CMDB推进剂(代料或实料)流变性能的影响。结果表明:CMDB推进剂代料表观黏度会随着螺杆转速的增加、药浆温度的升高、口模长径比的增大而减小,随口模直径的增加而小幅度增加;CMDB推进剂表观黏度随RDX含量增加而减小,且随着螺杆转速的增加,表观黏度降低趋势更加明显。     

The effect of nitrate esters on the thermal decomposition mechanism of GAP

Thermal gravimetric analysis (TG), differential thermal analysis (DTA), and in situ Fourier Transform Infra-Red spectrometer (FTIR) experiments were used to investigate the thermal decomposition mechanism of glycidyl azide polymer (GAP) crosslinked by using the curing agent isocyanate compound N-100 and the different ratios of plasticized-cured GAP/NG/BTTN, which are of potential interest for the development of high performance energetic propellants. The results of TG show the thermal decomposition temperature of GAP shifted to lower temperatures in the presence of NG/BTTN. The decomposition peak temperatures of cured GAP/NG/BTTN (1:1:1), cured GAP/NG/BTTN (1:0.5:0.5) and cured GAP/NG/BTTN (1:0.25:0.25) decrease by approximately 20 degrees C, 33 degrees C and 39 degrees C compared with cured GAP, respectively. This indicates that plasticizers NG/BTTN have good acceleration effects on the decomposition of cured GAP, especially for low content of NG/BTTN. At the same time, the results of DTA show that the decomposition heat of cured GAP/NG/BTTN is larger than that of cured GAP. In situ FTIR results show NG/BTTN not only accelerate the decomposition of -N3 groups and characteristic urethane links [Formula: see text], but also accelerate the decomposition of C-O-C groups.     

Molecular dynamics study of the structures and properties of RDX/GAP propellant

Molecular dynamics simulations have been performed to investigate well-known energetic material cyclotrimethylene trinitramine (RDX) crystal, glycidyl azide polymer (GAP) and RDX/GAP propellant. The results show that the binding energies on different crystalline surface of RDX change in the order of (0 1 0) > (1 0 0) > (0 0 1). The interactions between RDX and GAP have been analyzed by means of pair correlation functions. The mechanical properties of RDX/GAP propellant, i.e., elastic coefficients, modulus, Cauchy pressure, and Poisson's ratio, etc., have been obtained. It is found that mechanical properties are effectively improved by adding some amounts of GAP polymer, and the overall effect of GAP on three crystalline surfaces of RDX changes in the order of (1 0 0) > (0 1 0) > (0 0 1). The energetic properties of RDX/GAP propellant have also been calculated and the results show that compared with the pure RDX crystal, the standard theoretical specific impulse (I(sp)) of RDX/GAP propellant decrease, but they are still superior to those of double base propellant.     

HFZ炸药性能特征

通过显微镜观察了HFZ炸药及炸药组分各种不同粒度的表面状态,采用TG分析了炸药组分分解规律,高速摄影观察了HFZ炸药（Ф32mm,密度1．0g／cm^2）的爆炸过程。由单基药、氧化剂及助剂组成的HFZ炸药中,单基药颗粒在炸药中是起敏化作用,当受热、冲击等外界作用时,细小的颗粒、粗的颗粒外层先分解,反应放出的热和生成物对周围介质扰动,粗的单基药颗粒内层及氧化剂颗粒发生反应,炸药稳定爆轰。     

Molecular dynamics simulations of RDX and RDX-based plastic-bonded explosives

Molecular dynamics simulations have been performed to investigate well-known energetic material cyclotrimethylene trinitramine (RDX) crystal and RDX-based plastic-bonded explosives (PBXs) with four typical fluorine-polymers, polyvinylidenedifluoride (PVDF), polychlorotri-fluoroethylene (PCTFE), fluorine rubber (F(2311)), and fluorine resin (F(2314)). The elastic coefficients, mechanical properties, binding energies, and detonation performances are obtained for the RDX crystal and RDX-based PBXs. The results indicate that the mechanical properties of RDX can be effectively improved by blending with a small amount of fluorine polymers and the overall effect of fluorine polymers on the mechanical properties of the PBXs along three crystalline surfaces is (001)>(010) approximately (100) and PVDF is regarded to best improve the mechanical properties of the PBXs on three surfaces. The order of the improvement in the ductibility made by the fluorine polymers on different surfaces is (001) approximately (010)>(100). The average binding energies between different RDX crystalline surfaces and different polymer binders are obtained, and the sequence of the binding energies of the PBXs with the four fluorine polymers on the three different surfaces is varied. Among the polymer binders, PVDF is considered as best one for RDX-based PBXs. The detonation performances of the PBXs decrease in comparison with the pure crystal but are superior to those of TNT.     

Energetic residues from field disposal of gun propellants

Military training with howitzers and mortars produces excess propellant that is burned on the training range and can result in point sources containing high concentrations of unreacted propellant constituents. Propellants contain energetic compounds such as nitroglycerin (NG) and 2,4-dinitrotoluene (2,4-DNT), both of which are found at firing positions and propellant disposal areas. To quantify the mass of residue remaining from the field-expedient disposal of propellants, two mortar propellants and one howitzer propellant were burned under different field conditions. These conditions included burning on a snow pack, at the bottom of a snow pit, and in a pan surrounded by snow for the mortar propellants and on dry and wet sand for the howitzer propellant. For the mortar propellant, the energetics (NG) remaining after burning in the bowl, on frozen ground, and on snow were 0.21%, 5.2% and 18%, respectively. For the howitzer propellant, the difference in energetics (2,4-DNT) remaining after disposal on wet and dry sand was <0.1%, with the overall residue rate of around 1%, similar to that for the mortar propellant burned in an open container. These tests demonstrate that environmental factors, especially in winter, can play a significant role in the effectiveness of field-expedient disposal of propellants.     

Impact fracture behaviour of double-base gun propellants

Impact fracture properties of three nitrocellulose—nitroglycerine gun propellants have been measured in a three-point bend mode at moderate impact rates with an instrumented drop-weight impact tester. Dynamic moduli and loss tangents were measured over the temperature range −100 to +120° C, and three transitions were identified. A transition at about −30° C was found to increase the low-temperature fracture toughness of the higher nitroglycerine content propellants. The fracture data were analysed in terms of plane stress and plane strain fracture modes using a simplified model. It was found that the fracture toughness in zones undergoing plastic deformation under plane stress conditions was approximately twice that in zones under plane strain conditions. The plastic zone radii were greater than 0.3 mm at 20° C, falling to about 0.1 mm at −45° C. Strain energy release rates were calculated from fracture load and modulus, and from fracture energy. Good agreement was obtained between the two methods.     

叠氮硝胺发射药与赛璐珞药盒长储稳定性研究

为研究叠氮硝胺发射药与赛璐珞药盒的长储稳定性，采用差示扫描量热法(DSC)和真空安定性法(VST)研究分析了叠氮硝胺发射药与赛璐珞片的化学相容性，采用GJB736.8—1990火工品试验71 ℃试验法研究分析了叠氮硝胺发射药与赛璐珞药盒之间的组分迁移性。DSC试验表明，叠氮硝胺发射药与赛璐珞片混合体系的热分解峰温降低，降低值为0.5 ℃，混合体系相容；VST试验表明，混合体系净增放气量R为0.3 mL/g，混合体系相容；71 ℃试验法储存26 d后，叠氮硝胺发射药中的增塑剂（DIANP、NG）质量分数由39.82%降低到33.67%，药盒中增塑剂（DIANP、NG）质量分数由0增加到33.89%，发射药与药盒之间存在增塑剂的迁移。叠氮硝胺发射药与赛璐珞药盒化学相容性良好，但物理安定性差，存在增塑剂的迁移，加速老化10 d后，体系浓度达到平衡。     

Nanodiamonds of static and detonation syntheses and prospects for their applications

Basic physical, physicomechanical and physicochemical characteristics of diamond nanopowders of detonation and static syntheses and carbon composites on their base have been discussed. It has been shown that the above properties depend on the composition of the initial raw material, thermobaric conditions of the synthesis of nanopowders, and the methods of their recovery from the synthesis products. The applications, for which nanodiamonds hold the greatest promise, have been listed.     

The effect of fillers on chloropolyester blend CPB 4 and inhibition of double-base propellants

A direct bonding inhibition system based on chloropolyester blend CPB 4 has recently been developed for inhibition of double-base rocket propellants. The effect of alumina trihydrate (Al₂O₃ · 3H₂O) and antimony trioxide (Sb₂O₃) on various properties of CPB 4 has been studied, such as effect on gel time, exotherm peak temperature, tensile strength, per cent elongation, water absorption, nitroglycerine absorption, heat resistance, and flame retardant characteristics. The data on flame retardance and other characteristics indicate that CPB 4 with 30% Al₂O₃ · 3H₂O and CPB 4 with 20% Sb₂O₃ are suitable for inhibition of double-base propellants. The double-base propellant sustainers (containing 2-NDPA) have been inhibited with CPB 4 containing 30% Al₂O₃ · 3H₂O and CPB 4 containing 20% Sb₂O₃ separately (without the application of any barrier coating), and statically fired at ambient, sub-zero (after conditioning at ?40°C for 18 h) and high (after conditioning at +50°C for 18 h) temperatures. The pressure—time profiles were found to be smooth and flat in all cases, indicating that the pressure level was the same throughout the combustion duration, inferring the suitability of these systems for inhibition of double-base propellants without the application of any barrier coating.     

Core protein-nucleic acid interactions in hepatitis C virus as revealed by Raman and circular dichroism spectroscopy

Molecular interactions required for hepatitis C virus (HCV) assembly are not well known and are poorly understood. The 5' untranslated region (5'UTR) of the RNA genome is highly conserved and has extensive secondary structure, and the highly basic core protein is rich in arginine residues. Using Raman and circular dichroism (CD) spectroscopies, specific interactions have been demonstrated here between the 5'UTR sequence and the core protein that may be important for the specific encapsidation of the viral genome during HCV replication. These interactions can be described as follows: (1) hydrogen bonding of arginine with unpaired guanine and/or with wobble GU base pairs, and arginine-phosphate electrostatic contacts; (2) although the percentage of base pairs in the A-form is maintained in 5'UTR, the HCVc-120 protein is beta-sheet and beta-helix enriched upon formation of protein-5'UTR macromolecular assemblies; (3) protein-5'UTR interactions resulting in protein alpha-helix formation involve guanine bases in duplex segments. The mentioned interactions may represent novel targets for antiviral strategies against this important virus.     

Optical,structural and electrical properties of polyaniline systems doped with C60 and small gap C60 fullerenes

In this work two systems consisting on polyaniline (Pani) doped with simple and small gap C₆₀ fullerenes have been prepared and characterized. Composites with different doping amounts of 1,2,4 and 8 wt% have been analyzed in order to evaluate their structure together with their optical and electrical properties and the effect of fullerene type and amount on them. The shift and change of shape in Fourier transform infrared spectroscopy (FTIR) bands and solid ¹³C NMR spectroscopy signals showed the presence of interactions between matrix and fullerenes by electron density transfer among them. Optical properties have also been analyzed in terms of ultraviolet (UV) spectroscopy. The blue shift of several bands confirmed the charge transfer. Obtained structures have been analyzed by optical microscopy (OM) showing the different way in which both types of fullerenes have been incorporated into the polymer chains. Finally, conductivity has been measured by the four probe technique, relating obtained values with the structure of the composite and the different degree of crystallinity of simple and small gap fullerenes.     

Computation of interface interactions and mechanical properties of HMX-based PBX with Estane 5703 from atomic simulation

Atomic simulation was applied to investigate the interface interactions and mechanical properties of β-octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX)-based polymer-bonded explosive (PBX) with Estane 5703. The interface structure of HMX (100) crystal surface with Estane 5703 was analyzed using pair correlation function (PCF), and the interfacial binding energies between them were calculated. It is shown that there exist hydrogen bonds and electrostatic interactions on the interface. By calculating and comparing the bonds lengths and distributions for possible initial bonds fractured in detonation, it is known that the interactions do not affect the stability of the PBX. Moreover, the elastic constants for HMX and the HMX-based PBX were computed using static elastic constants analysis method, and the engineering moduli and Poisson ratios were derived by Reuss average. Based on the value of Cauchy pressure, it is indicated that the ductibility of crystalline HMX can be effectively improved by blending the polymer in small amount. The relevancy to shockwave stability for this PBX in detonation was discussed finally.