摘要:

AbstractIt has been demonstrated that addition of small amounts of the newly developed neutral polymeric bonding agents (NPBA's) to energetic propellants such as HMX/PEG/NG composites causes strong filler reinforcement. The mechanism of this reinforcement occurs through interfacial effects, and not because of an overall increase in the crosslink density of the binder. It has been demonstrated directly that the NPBA's have a favorable relative affinity for HMX and concentrate at the solid surface during mixing. All the experimental evidence supports the theory that highly crosslinked polymeric shells form around the HMX particles and chemically bond to the binder matrix during the cure, thus causing an increase in the initial modulus. Furthermore, these shells appear to eliminate the weak, soft layers around the particles, and hence filler reinforcement persists up to much higher elongation than without addition of NPBA. Based on the filler reinforcement observed, the simple one‐step procedure of incorporating our NPBA is almost as effective as the more costly process of precoating the particle

ISSN:0721-3115    

DOI:10.1002/prep.19920170202

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe paper describes an analysis on the energy and pressure exponents of composite modified double‐base (CMDB) propellants. The evaluation of the energy was conducted by means of a thermodynami‐ cal program. Propellant burning rates were determined by the strand burner method. In the AP‐based composition, the energy is enhanced and the pressure exponent reduced with increasing AP content. When AP is partially or entirely replaced by the nitramines HMX or RDX, Isp is improved, and the pressure exponent is inevitably increased. A mixture of lead salicylate or lead o‐amino benzoate and copper 2,4‐ or 3,5‐dihydroxy benzoate produces a remarkable effect on the burning nature of the CMDB propellant. It was noted that the pressure exponent decreases from 0.66 to 0.48 with lead and copper salts added at 3.0% in AP‐Al, 0.82 to 0.60 at 2.0% in RDX‐Al and 0.72 to 0.54 at 2.5% in RDX‐AP‐Al composi

ISSN:0721-3115    

DOI:10.1002/prep.19920170203

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractMolecular properties of benzene nitro derivatives were investigated by using semi‐empirical MO calculations. As the results, the molecular structures and the rotational barrier of the nitro group calculated by AM1 showed a good agreement with the experimental values. The heats of formation in gaseous and condensed phases were obtained by considering isodesmic reactions. By this procedure, the heat of formation of hexanitrobenzene in solid phase was calculated to be +22.7 kcal/mol. The detonation parameters were also calculated by using four equations of state. The predicted detonation velocities showed a good agreement with the experimental value

ISSN:0721-3115    

DOI:10.1002/prep.19920170204

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA model relating the combustion characteristics, particularly the regression rate, to the fuel properties in a solid fuel ramjet (SFRJ), is presented. The analysis is based on inspecting the different phenomena (e.g., chemical kinetics and heat transfer) involved in the fuel decomposition process in order to determine the rate controlling steps, and modeling the important mechanisms. Model predictions were compared to experimental findings for four polymeric fuels, showing excellent qualitative agreement in classifying different fuels, as well as good quantitative predictions of the fuel regression rates. The model can serve as a useful tool for the selection of appropriate fuels, as well as for preliminary design of the engine and mission profile prior to static firings of the final SFRJ prototype.

ISSN:0721-3115    

DOI:10.1002/prep.19920170205

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA critical diameter exists for both high velocity (HVD) and low velocity detonation (LVD). No relationship exists between these two diameters, however they are both dependent upon the temperature, confinement, contaminants, type of detonation and, most importantly, geometry. In cylindrical geometry, the critical diameter is determined by go/no go tests which are relatively expensive and time consuming. In this respect, there is a need for a method by which the critical diameter can be determined quickly and reliably.A relatively simple procedure which can also be performed in the field is proposed in this article where the critical diameter is determined in principle by a single test through the application of conical geometry. However, on account of “overdrive”, the values always fall below those obtained by cylindrical geometry. Metal plating is proposed as a method of indication. The results are then compared simultaneously by optical and electrical measurements. The temperature dependence of the critical diameter of the HVD of pure nitromethane was also demonstrated by conical geometry and was compared to the values of cylindrical geometry.The method was originally proposed as a joint US/German effort between Dr. Mallory of NSWC, China Lake, and Dr. Leiber of BICT. Since Dr. Mallory has recently passed away, the question is therefore open as to whether or not this test can be approved internationa

ISSN:0721-3115    

DOI:10.1002/prep.19920170206

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractMetal complexes having the potential to modify the burn rate of rocket propellants are described. These are the diaminoglyoxime (DAG) complexes: Co(DAG–H)2·DAG, Cu(DAG–H)2·DAG, Ni(DAG–H)2and Pd(DAG–H)2. The thermal decomposition was characterized by DSC, TGA and IR spectroscopy at a heating rate of 5°C/min, and by fast thermolysis/FTIR spectroscopy at 100–250°C/s. The M(DAG–H)2complexes are more thermally stable than M(DAG–H)2·DAG. However, all of the compounds produce highly thermally stable residues which would be expected to retard the heat and mass transfer at a burning surface. The residues most closely resemble coordination complexes of the metal and polymeric cyclic azine compounds. The crystal and molecular structure of the previously unreported complex Ni(DAG–

ISSN:0721-3115    

DOI:10.1002/prep.19920170207

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractDamages caused by a large, accidental explosion in Henderson, NV, were surveyed and interpreted for their estimated causative airblast overpressures. Results were widely scattered by uncertainty in structural (primarily window glass) response as well as weather effects, but the total pattern of estimated overpressures versus distances generally agrees with a 1‐kt NE assumption for the airburst source strength. This is duplicated by a 227‐Mg HE surface burst. Since approximately 1.36‐Gg AP were destroyed in the area of the largest single explosion, an HE explosive equivalence for ammonium per‐chlorate appears to be about 1/6. Considering the yield‐scaled response of overpressures to yield, there is no significant difference with an independent yield estimate of 454‐Mg HE, made from close‐in blast effects on relatively ideal struct

ISSN:0721-3115    

DOI:10.1002/prep.19920170208

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19920170209

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19920170201

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY