Showing papers in "Journal of Energetic Materials in 1996"
TL;DR: In this article, the role of additives in the combustion process of ammonium perchlorate was reviewed and it was found that additives influence the low temperature decomposition of AP, its ignition temperature and burning rate.
Abstract: This paper reviews the role of additives in the combustion process of ammonium perchlorate. These additives are found to influence the low temperature decomposition of AP, its ignition temperature and burning rate. Transition metal oxides and various other compounds like chromates, halides, carbonates and perchlorates are well known decomposition catalysts. Admixture of these compounds is found to change the pattern and products of decomposition. The mechanism of decomposition is explained on activation energy obtained from thermal data. The activation energy of ammonium perchlorate is attributed to transfer of electron from perchlorate ion to ammonium ion and the role of catalyst is to accelerate this proccess. A complex is formed with metal ion C104 − and NH4 + radical which stabilizes the electron transfer process.
21 citations
TL;DR: In this article, a combustible cartridge case was studied by changing the percentage of ingredients namely; nitrocellulose (NC), nitroguanidine (NiGu), cellulosic fibres, dibutylphthalate (DBP) and diphenylamine (DPA).
Abstract: The formulation of combustible cartridge case was studied by changing the percentage of ingredients namely; nitrocellulose (NC), nitroguanidine (NiGu), cellulosic fibres, dibutylphthalate (DBP) and diphenylamine (DPA). A composition containing around 55% nitrocellulose & balance cellulosic fibers and nitroguanidine along with 3.5 parts dibutylphthalate & 1 part of diphenylamine was found compatible with triple base multi-tubular propellant, besides having reasonably good mechanical and ballistic properties.
18 citations
TL;DR: In this article, the effects of synthesis, grinding, and static loads on the extent of microstrain and defect development in CL-20 particles were quantitatively determined as frequency versus halfwidth of rocking curves.
Abstract: Microstrains and defects are introduced during synthesis and crystal-growth stages of energetic particles and increase during processing stages such as grinding, mixing, and extrusion. The detection and quantification of these microstrains and defects in a given particle population is a difficult task that requires highly sensitive techniques. In this study a novel X-ray diffraction technique (XAPS) based on simultaneous rocking-curve analysis of individual particles was successfully applied to CL-20 powders. The effects of synthesis, grinding, and static loads on the extent of microstrain and defect development in CL-20 particles were quantitatively determined as frequency versus half-width of rocking curves. The greater half-width values observed for the samples subjected to grinding and static loads indicated greater microstrain and defect density in comparison to the as-received samples of CL-20. It may be possible to relate the findings of such analysis to combustion calculations for energet...
15 citations
TL;DR: A wide-angle x-ray diffraction technique developed earlier by the authors to characterize the degree of mixing in concentrated suspensions is applied to the quantitative characterization of the distributive mixing achieved in extruded LOVA grains, to demonstrate the applicability of the technique towards total quality assessment of energetic grains.
Abstract: A wide-angle x-ray diffraction technique developed earlier by the authors to characterize the degree of mixing in concentrated suspensions is applied to the quantitative characterization of the distributive mixing achieved in extruded LOVA grains, to demonstrate the applicability of the technique towards total quality assessment of energetic grains. The samples included LOVA grains which were either processed in a batch mixer and ram extruded or processed and extruded using co-rotating twin screw extrusion.
14 citations
TL;DR: Burning characteristics and sensitivities to the ballistic shock were investigated for BAMO/NMMO composite propellants oxidized with HMX, AP, and AN, and the highest sensitivity was observed for HMX-based propellants as mentioned in this paper.
Abstract: Burning characteristics and sensitivities to the ballistic shock were investigated for BAMO/NMMO composite propellants oxidized with HMX, AP, and AN. Tests of card gap, fragment impact (FI), electrostatic discharge (ESD), and bullet impact were conducted to evaluate their sensitivities. AP-based propellants showed plateau burning characteristics. Combined catalysts, such as lead compounds with carbon black, and copper chromite with an organic iron compound, were effective in burn rate augmentation. The use of additives and the replacement of oxidizer had little effect on the sensitivity to the shock wave. The highest sensitivity was observed for HMX-based propellants. An organic iron compound increased the sensitivities to FI and ESD. It is suspected that thermal decomposition reactions played an important role in the reaction mechanisms in FI and ESD tests.
7 citations
TL;DR: In this article, transferable insensitive explosive (TIE) formulations based on the solid high explosive, triaminotrinitrobenzene (TATB), and the liquid explosive, bis(2-fluoro-2,2-dinitroethyl) formal (FEFO), are measured by wedge test, embedded particle velocity gauge and embedded manganin pressure gauge techniques and calculated using the Ignition and Growth reactive flow model.
Abstract: The shock initiation properties of transferable insensitive explosive (TIE) formulations based on the solid high explosive, triaminotrinitrobenzene (TATB), and the liquid explosive, bis(2-fluoro-2,2-dinitroethyl) formal (FEFO), are measured by wedge test, embedded particle velocity gauge and embedded manganin pressure gauge techniques and calculated using the Ignition and Growth reactive flow model. These extrudable formulations are demonstrated to be slightly more shock sensitive than the TATB/inert binder explosive, LX-17. However, the TIE formulations are much less sensitive than HMX-based explosives and still qualify as insensitive explosives in safety and hazard tests. The wedge tests showed a very steep dependence of run distance to detonation on the input shock pressure. Embedded gauge and reactive flow modeling results imply that shock initiation begins when a small amount of the solid TATB decomposes rapidly enough to heat the surrounding FEFO to decomposition temperature. The FEFO then ...
5 citations
TL;DR: In this paper, the use of urea as a De-NOx agent in solid gun propellants was investigated and it was found that urea is thermally stable up to a temperature of 130 deg C, and is compatible with nitrocellulose-based formulations.
Abstract: : In an attempt to eliminate nitrogen oxides (NOx's) from the combustion and pyrolysis products of solid propellants, an investigation into the use of 'De-NOx' agents was performed. The agents selected were all compounds that thermally decompose to generate amines; participation of amines in the thermal De-NOx process results in the reduction of nitrogen oxides to nitrogen. Of all the compounds screened, it was found that urea was the best suited for use as a De-N0x agent in solid gun propellants. Use of - resulted in a significant decrease in NOx production. Furthermore, urea is thermally stable up to a temperature of 130 deg C, and is compatible with nitrocellulose-based formulations. Compared to neat JA2 (a double-base propellant), a JA2/urea formulation containing 10 weight-percent urea generates 60% less NOx. Calculations indicate that the incorporation of 4% urea results in a 200 K decrease in flame temperature, and a decrease in impetus and velocity of approximately 4% and 2%, respectively.
5 citations
TL;DR: In this paper, a method has been developed to analyze ammonium dinitrimide, a new energetic material, as well as other anionic impurities in it using ion chromatography with UV detection.
Abstract: A method has been developed to analyze ammonium dinitrimide, a new energetic material, as well as other anionic impurities in it. This method employs ion chromatography with UV detection. Analysis of ADN samples could be done in under 20 minutes employing this method. Analysis of pure samples as well as aged samples was accomplished.
5 citations
TL;DR: In this paper, the authors used micellar electrokinetic capillary chromatography (MECC) for analysis of TNAZ, 1,3,3-trinitroazetidine, and CL-20, hexanitrohexaazaisowurtzitane.
Abstract: Recently two new explosives, TNAZ, 1,3,3-trinitroazetidine, and CL-20, hexanitrohexaazaisowurtzitane, have attracted interest as possible replacements for or inclusion in various military propellants and explosives. Analysis of these two compounds as well as 12 other nitramine and nitroaromatic explosives could be accomplished by capillary electrophoresis using the technique of MECC, micellar electrokinetic capillary chromatography. Analysis times of less than 10 minutes could be done using this method. Increased sensitivity for some explosives could be accomplished, as well, by using UV detection at 185nm rather than 254nm which is typically used.
4 citations
TL;DR: In this paper, safety hazards of a non-azide propellant containing azodicarbonamide (ADCA), potassium perchlorate (KCIO 4), and other additives were evaluated using various test methods to determine impact and shock sensitivity, ignition sensitivity, heat sensitivity, propagation of explosion and burning, and violence of burning.
Abstract: Safety hazards of a non-azide propellant containing azodicarbonamide(ADCA), potassium perchlorate(KCIO 4) and other additives were evaluated using various test methods to determine impact and shock sensitivity, ignition sensitivity, heat sensitivity, propagation of explosion and burning, and violence of burning. With BAM 50/60 tube test, the new propellant, both in the form of dry powder and granule, was detonated, while when wetted with 10% water, it did not propagate detonation, and the addition of 15% water permitted no ignition. In the form of dry pellets BAM test resulted in no propagation of detonation but propagating deflagration. On the other hand, the pellets, when tested with 30 mm diameter PVC tube, neither detonated nor deflagrated by initiation with a no.6 detonator on the ground. From these test results a wet process is recommended espeially for blending raw materials and for granulating the mixed composition.
2 citations
TL;DR: In this article, a method has been developed to analyze ammonium dinitrimide (ADN), a new energetic material, as well as other anionic impurities in it, employing capillary ion electrophoresis with UV detection.
Abstract: A method has been developed to analyze ammonium dinitrimide (ADN), a new energetic material, as well as other anionic impurities in it. This method employs capillary ion electrophoresis with UV detection. Analysis of ADN samples could be done in under 5.5 minutes employing this method. Analysis of pure samples as well as aged samples was accomplished.
TL;DR: In this paper, the formation and composition of the nucleant material has been investigated by thermal methods using mixtures of HNS and TNT, with composition in the range 0.5%, the normal casting level, to 50% w/w HNS to TNT.
Abstract: Hexanitrostilbene (HNS), is added to trinitrotoluene (TNT), in order to improve the grain structure of cast munitions. The formation and composition of the nucleant material has been investigated by thermal methods using mixtures of HNS and TNT, with composition in the range 0.5%, the normal casting level, to 50% w/w HNS to TNT. These were cycled between ambient and upper temperatures in the range 160 to 235°C. Endotherms in the DSC traces, due to nucleant decomposition, have been observed in situ without the need for separation and purification. DSC enthalpy measurements, before and after thermal decomposition, were used to determine the composition of separated nucleant. Nucleant regeneration after decomposition, was investigated by thermal methods. Nucleant could not be recrystallised from solvents. Results have been interpreted on the basis of the formation of a, solid solution of TNT in HNS, rather than a complex of formula TNT2HNS.
TL;DR: In this paper, the sensitivity of hexanitrostilbene to flyer plate impact in the temperature range-65 C to 65 C has been investigated and it was found that as temperature decreases the mean firing energy of the flyer plate gradually increases.
Abstract: The sensitivity of hexanitrostilbene to flyer plate impact in the temperature range-65 C to 65 C has been investigated. It was found that as temperature decreases the mean firing energy of the flyer plate gradually increases. The increased energy requirement is attributable to the reduction in the shock sensitivity of the high surface area hexanitrostilbene acceptor explosive. The explosive response was found to depend on the viability of the hot spots formed and on a temperature dependent reaction rate. The electrical performance of a small flyer plate generator appears to have been unaffected over the temperature range.
TL;DR: In this article, the head-to-tail pattern of intermolecular hydrogen bonding favors the antiparallel packing of the molecular assemblies and close packing, and the geometry of the C-H linkage alpha to the NO2 group is discussed in connecting to molecular stability.
Abstract: In crystal structures of nitrobenzenes, intramolecular hydrogen bonding increases the molecule's stability, planarity and packing coefficient. The head-to-tail pattern of intermolecular hydrogen bonding favours the antiparallel packing of the molecular assemblies and close packing. The geometry of the C-H linkage alpha to the NO2 group is discussed in connecting to the molecular stability. The relation between the crystal density and hydrogen bonding is discussed.
TL;DR: Based on 79 crystal structures of nitrobenzenes, the geometry of the benzene ring and the conformation of the nitro group were examined in this paper, where the packing energy was calculated and consistent well with experimental value.
Abstract: Based on 79 crystal structures of nitrobenzenes, the geometry of the benzene ring and the conformation of the nitro group were examined. The bond lengths and the endocyclic angles in the nearly planar benzene ring vary considerably, with the latter being well correlated to the electronic properties of the subtituents. Packing energy was calculated and consistent well with experimental value.
TL;DR: In this article, experimental data on the dependence of velocity of detonation on charge diameter, V(d), of unconfined cylindrical charges of the underwater explosives, PBXW-115 (Aust), PBXN-111 and Composition H-6, and of Composition B, the explosive charge fill offered by Nordic Defence Industries for the Danish Mine Disposal Charge, Damdic, are given.
Abstract: : Experimental data on the dependence of velocity of detonation on charge diameter, V(d), of unconfined cylindrical charges of the underwater explosives, PBXW-115 (Aust), PBXN-111 and Composition H-6, and of Composition B, the explosive charge fill offered by Nordic Defence Industries for the Danish Mine Disposal Charge, Damdic, are given. These data are analysed in terms of the previously-reported empirical relationship between the V(d), the detonation velocity at infinite charge diameter (D*) and the reaction zone length parameter, (a*).