多磷酸法由DPT制备HMX研究

本法采用新型硝化剂ＨＮＯ３－Ｐ２Ｏ５－ＮＨ４ＮＯ３硝解ＤＰＴ制备ＨＭＸ，并用日立６３５型高效液相色谱肖解混合物ＨＭＸ／ＲＤＸ中的ＨＭＸ含量，测定ＨＭＸ得率。实验结果表明：本法制得的ＨＭＸ得率大于６０％，已接近用醋酐法由ＤＰＴ制备ＨＭＸ的得率，这是非醋酐法制备ＨＭＸ取得的新进展。     

Dependence of the Mechanical Sensitivity on the Fractal Characteristics of Octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine Particles

Three fabrication methods were used to synthesize HMX powders with different particle sizes and microscopic morphologies. All as‐prepared samples were characterized by laser granularity measurements and scanning electron microscopy (SEM). The mechanical sensitivity and thermal stability of the different HMX powders were characterized using mechanical sensitivity tests and differential scanning calorimetry (DSC). Size distribution data and SEM images were used to find the size fractal dimension (D) and surface fractal dimension (D_s) of HMX samples, which were calculated by the least‐squares method and fractal image processing software (FIPS), respectively. The parameters D and D_s quantize two important properties of HMX particles, namely the complexity of the particle size distribution and the irregularity of the particle surface, which affect the thermal conductivity of the particle group if it is exposed to stimuli such as impact, friction or heating. The fractal dimensions reveal the dependence of the mechanical sensitivity of HMX on the powder size, size distribution and microscopic morphology. The results indicate that the proportion of fine particles in HMX powder increases as the D value increases, which causes decreased impact sensitivity. This occurs because hot spot formation leading to an explosion is more difficult because of the improved thermal conductivity of the particle group. Similarly, the surface roughness of HMX particles increases with an increase in D_s, causing an increase in friction sensitivity because of the excessive accumulation of frictional heat. In addition, thermal analysis results indicate that the maximum thermal decomposition rate of HMX decreases with increasing D and D_s.     

还原型锡酸铅粒度对Al/HMX/CMDB推进剂燃烧性能及安定性的影响

为研究还原型锡酸铅粒度对Al/HMX/CMDB推进剂燃烧性能及安定性的影响,采用干筛法筛选6种不同粒度的还原型锡酸铅,制备了含不同粒度还原型锡酸铅体系的推进剂;通过燃速靶线试验、甲基紫试验与热加速老化试验得到推进剂的燃速、压强指数、甲基紫变色时间和贮存寿命。结果表明,随还原型锡酸铅粒径由7.0μm减至2.5μm,Pb²⁺及SnO₂的催化活性逐渐增大,活化中心愈多,该体系推进剂在15~20MPa范围内的燃速逐渐增加,压强指数由0.30减至0.17;同时还原型锡酸铅粒度的减小加速了该体系推进剂的自催化作用,造成其安定性下降,当还原型锡酸铅的粒径为2.5~3.5μm时,推进剂的安定性显著降低。     

Explosive characteristics of aluminized HMX-based nanocomposites

The explosive characteristics of HMX compositions doped with 15% Al (by weight) were studied experimentally. The detonation velocity, pressure and temperature profiles, the velocity of endwise acceleration of plates, and the heat of explosion of dense pressed samples were measured. The results were compared for compositions based on mechanical mixtures of initial micron-size particles of HMX with aluminum powders of various sizes and for nanocomposites. The addition of nanoaluminum reduces the detonation velocity to a greater degree than the addition of micron-size aluminum. The mechanical mixtures have close detonation velocities, whereas in composites containing different types of nanoaluminum, they differ by almost 200 m/sec. For all compositions, except for the most homogeneous nanocomposite, two-peak pressure profiles are observed. For charges of a composite and a mechanical mixture with nanoaluminum of the same type, the second peak pressures almost coincide but are reached in different times. At the same time, the peak pressure increases with decreasing aluminum particle size. The temperature profiles agree qualitatively with the pressure profiles. The velocity of endwise acceleration of plates depends linearly on the activity of the aluminum powder used. Nanocomposites and mechanical mixtures containing the same aluminum powder have close heats of explosion. Nanoaluminum is almost completely oxidized during calorimeter bomb tests, and the major factor determining the heat of explosion of the compositions with nanoaluminum is also the content of active metal in the aluminum powder. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 85–100, March–April, 2008.     

Structures and Properties Prediction of HMX/TATB Co‐Crystal

In this study, a new co‐crystal explosive of 1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocane (HMX)/1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB) (molar ratio 1 : 1) was designed based on crystal engineering. The crystal structure was predicted using the polymorph predictor (PP) method. The main properties of co‐crystal consisting of mechanical properties, stability, and interaction formats were simulated through molecular dynamics methods. Simulated results indicate that the crystal structure of the HMX/TATB co‐crystal may belong to the P , P2₁2₁2₁ or P2₁/c space group. The calculations of the binding energy and the analysis for radial distribution function show that the two components are connected through electrostatic hydrogen bonding and strong van der Waals interactions. The new co‐crystal has better mechanical properties with the moduli systematically decreased. With the appearance of the new crystal, the trigger bond N NO₂ has little change.     

添加剂对HMX重结晶晶体形貌的影响

通过模拟计算与试验相结合的方法,研究了添加剂乙酰胺、丙烯酰胺、乙胺水溶液对重结晶HMX晶体形貌控制的影响.结果表明,3种添加剂对HMX重结晶晶体形貌影响的大小顺序为:乙酰胺＞丙烯酰胺＞乙胺,乙酰胺使晶体偏离球形化,丙烯酰胺具有使晶体向着球形化发展的趋势,由于乙胺与HMX晶面的附着能较小,乙胺对HMX重结晶晶体形貌改变不...     

AIL-N2O5-HNO3体系中硝解DADN制备HMX

在酸性离子液体(AIL)催化下利用N2Os硝解DADN制备了HMX.考察了离子液体用量、反应时间、物料配比、不同离子液体对硝解反应的影响,在优化条件下进行了对比试验.结果表明,在所用的21种AIL中,[Et3NH]TsO具有最好的催化效果,HMX的纯度为99％,收率可达到95.6％,离子液体可以通过简单的萃取后回收使用...     

Smokeless GAP‐RDX Composite Rocket Propellants Containing Diaminodinitroethylene (FOX‐7)

Composite rocket propellants prepared from nitramine fillers (RDX or HMX), glycidyl azide polymer (GAP) binder and energetic plasticizers are potential substitutes for smokeless double‐base propellants in some rocket motors. In this work, we report GAP‐RDX propellants, wherein the nitramine filler has been partly or wholly replaced by 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7). These smokeless propellants, containing 60% energetic solids and 15% N‐butyl‐2‐nitratoethylnitramine (BuNENA) energetic plasticizer, exhibited markedly reduced shock sensitivity with increasing content of FOX‐7. Conversely, addition of FOX‐7 reduced the thermochemical performance of the propellants, and samples without nitramine underwent unsteady combustion at lower pressures (no burn rate catalyst was added). The mechanical characteristics were quite modest for all propellant samples, and binder‐filler interactions improved slightly with increasing content of FOX‐7. Overall, FOX‐7 remains an attractive, but less than ideal, substitute for nitramines in smokeless GAP propellants.     

RDX和HMX单晶的压痕断裂韧性

使用纳米压痕仪在HMX、RDX单晶表面进行压痕实验,并用不同压痕方程计算了单晶的断裂韧性.计算得到HMX晶体(010)面与RDX晶体(020)、(210)面间断裂韧性分别力0.092543、0.097387、0.10072 MPa·m1/2.结果表明,实验单晶的KIC值遵循Palmqvist系裂纹系统shetty方程,...     

HMX废酸转晶工艺研究

为降低醋酐法生产ＨＭＸ成本,将废酸转晶法改为一次升降温操作可获得熔点高于２７３℃,酸度低于０．０２％,转晶率高于９０％的ＨＭＸ,减少了废醋酸损失并回收了ＲＤＸ。改进后的废酸转晶法与我国现行混合溶剂转晶法比,生产成本降低２０％－２５％,超过文献记载水平。