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Thermal decomposition of energetic materials is accompanied by generation of heat, and under certain conditions may lead to the well-known phenomenon of the self-ignition (or thermal explosion). Therefore, it is of great concern of explosive community to predict whether or not a specimen of energetic material will ignite or not under given conditions (defined primarily by a specimen mass and shape,...
Thermal stability of twenty-five polynitro arenes has been examined by means of non-isothermal differential thermal analysis (DTA), and it was expressed as an onset of thermal decomposition, TD. Electronic charges, qN, at nitrogen atoms of the polynitro arene molecules were calculated by means of the ab initio DFT B3LYP/6-31G** method. The relationship was confirmed between the onsets TD and squares...
By using DFT method, changing the six parameters of TATB cell and calculating the total energy corresponding to different volume ratio, this paper concludes that TATB crystal can only extend irreversibly along the c-axis when heated because the point of experiment is unstable thermodynamically and the ratio of non-reversible expansion must be about 2.6-3.7 per cent theoretically.
The paper reports physical and chemical characterisation of commercial preparations of iron powder and their solid-state reactivity with potassium chlorate(VII). The samples of the commercial products were subjected to: granulometric analysis, SEM observations, low-temperature adsorption and desorption of nitrogen, surface area determination by BET, XRD study of the phase composition and TPR. Iron(II)...
In this paper, the results of researches on crystallization of insensitive high explosives were described. 3-Nitro-1,2,4-triazol-5-one (NTO) and nitroguanidine (NQ) were selected. The laboratory methods of preparation were presented. The influence of different solvents and other parameters on crystallization process was investigated. The results of the particle size distribution in the crystals obtained...
The research on gaseous detonation has recently become a very important issue, mainly due to safety reasons in connexion with increasing importance of gaseous fuels. To simulate detonation, the Direct Monte-Carlo Simulation technique has been used. This technique is known to be a very powerful tool for solving complex flow problems. Simple model of molecular collisions, making it possible to increase...
The paper presents physicochemical characterization of components of the reaction mixture of iron powder and polycrystalline KClO4. Reactivity of the studied substrates was tested in the solid-state reaction. Research has been done to determine the effect of the grain shape and degree of crystallization of substrates on their selected thermochemical properties. Taking into regard amount of the generated...
Development of condensed energetic systems, especially photosensitive primary explosives for the systems of laser initiation is one of the foremost fields of application of energetic materials. There have been synthesized and investigated a coordination complex of mercury(II) chlorate(VII) with 5-hydrazinotetrazole as ligand (compound (I)) as a potential photosensitive primary explosive. This complex...
The paper presents an analysis of observable combustion instability of energetic materials with condensed phase leading reaction. The Zeldovich's and Novozhilov's criteria have been calculated by an example of two dinitramide salts, ADN and HMDADN, having a condensed- phase combustion mechanism. It is suggested an explanation of combustion instability observed.
Demilitarized energetic materials such as explosives and propellants are a useful source of energy for civilian applications. The excess of military explosives and propellants can be reused as components in commercial explosives. The influence of double base propellants (DBP) on detonation characteristics of ANFO and emulsion explosives was investigated. Some physical characteristics of emulsion matrix...
The plastic explosive Hardex-70, employed during the research work, has caused serious changes in microstructural and functional properties of Hadfield cast steel. A complex investigation has been carried out on this material concerning the mechanism of its strengthening by explosion energy. It has been found that the strengthening of Hadfield cast steel caused by a detonation wave of great energy...
Dimethylnitramine (DMN) is usually investigated as a model compound for nitramine explosives. In the present study, the reaction of DMN with NO2 molecule and two possible initial channels of unimolecular decomposition of DMN in gas-phase (N-N bond scission and direct HONO elimination) were studied. Critical points on the potential energy surfaces (PES) of all reactions were optimized using the B3LYP...
The article deals with measurement of velocities of detonation in special charges constructed with an inner channel. The detonation course of these charges was investigated by measuring the velocities of detonation. The abnormalities found in the detonation course were interpreted as a consequence of the channel effect. For better understanding of the problem, the operation of channel effect was also...
Oxidation of hexanitrobibenzyl to hexanitrostilbene using oxygen has been shown to produce 4-hydroxy-2,2',4',6,6'-pentanitrostilbene as a major by-product. The single crystal structure of this new product is reported.
The crystal quality and the internal microstructure of crystals have a great influence on the sensitivity of energetic materials. Besides, the particle size and the particle size distribution are of great importance to the processing technology of energetic materials. Particle properties can especially be influenced by applying different crystallization techniques, such as cooling crystallization,...
Computational investigation including molecular structure, crystal density, heat of formation, relative specific impulse, heat of detonation, detonation velocity and pressure on dinitrofurazanfuroxan (DNTF) was performed by quantum chemistry (density functional theory and Beck 3LYP hybrid density functional with 6-31G (d, p) basis set), molecular mechanics (Dreiding forcefield) and Monte Carlo methods...
Reaction of vicarious nucleophilic substitution (VNS) of hydrogen was applied for preparation of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) in a twostep process. Using this approach 3-amino-2,4,6'2'4 6' -hexanitrostilbene (MNHNS) and new 2,6-bis(3-amino-2,4,6-trinitrophenyl)-3,5-dinitropyridine (DAPYX) were obtained.
The energetic plasticizer glycidyl azide polymer (GAP) is used for new types of rocket propellants which are formulated with the objective of achieving higher burning rates. The reaction profiles for several possible initial steps in the decomposition of mixtures of the nitramines octahydro-1,3,5,7-tetranitro-1,3,5,7- tetrazacyclooctane (HMX), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and hexanitrohexaazaisowurtzitane...
The energetic plasticizer glycidyl azide polymer (GAP) is used for new types of rocket propellants which are formulated with the objective of achieving higher burning rates. While the homolytic fission of an N-NO2 bond, which we discussed previously, is energetically favored as the initial decomposition step, experiments show that the decomposition of mixtures of the nitramines octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane...
The paper deals with possible applications of the connection of liquid chromatography with atmospheric pressure chemical ionization (APCI) mass spectrometry (Agilent 1100 series LS-MSD system) and gas chromatography with electron capture detector (GC-ECD) in the analysis of some common available or improvised explosives. The analysis of selected types of individual explosives, 2,4,6-trinitrotoluene...
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