This paper presents an analysis of the observed combustion behavior of AN mixtures with different additives, fuels, and energetic materials. It has been determined on the basis of flame structure investigation by fine tungsten-rhenium thermocouples that the surface temperature of AN is controlled by the dissociation reaction of the salt occurring at the surface. Results obtained have indicated that the leading reaction of combustion of AN doped with additives proceeds in the condensed phase up to pressures of 20 -30 MPa. A reason for the inability of pure AN to burn is suggested and the role of additives in the combustion mechanism is discussed.

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Experiments concerning the ballistic characterization of several nanoaluminum (nAl) powders are reported. Most studies were performed with laboratory composite solid rocket propellants based on ammonium perchlorate as oxidizer and hydroxyl-terminated polybutadiene as inert binder. The ultimate objective is to understand the flame structure of differently metallized formulations and improve their specific impulse efficiency by mitigating the twophase losses. Ballistic results confirm, for increasing nAl mass fraction or decreasing nAl size, higher steady burning rates with essentially the same pressure sensitivity and reduced average size of condensed combustion products. However, aggregation and agglomeration phenomena near the burning surface appear noticeably different for microaluminum ( Al) and nAl powders. By contrasting the associated flame structures, a particle-laden flame zone with a sensibly reduced particle size is disclosed in the case of nAl. Propellant microstructure is considered the main controlling factor. A way to predict the incipient agglomerate size for Al propellants is proposed and verified by testing several additional ammonium perchlorate/hydroxyl-terminated polybutadiene/aluminum formulations of industrial manufacture

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A new family of energetic compounds, nitropyrazoles bearing a trinitromethyl moiety at the nitrogen atom of the heterocycle, was designed. The desirable high-energy dense oxidizers 3,4-dinitro- and 3,5-dinitro-1-(trinitromethyl)pyrazoles were synthesized in good yields by destructive nitration of the corresponding 1-acetonylpyrazoles. All of the prepared compounds were fully characterized by multinuclear NMR and IR spectroscopy, as well as by elemental analysis. Single-crystal X-ray diffraction studies show remarkably high density. Impact sensitivity tests and thermal stability measurements were also performed. All of the pyrazoles possess positive calculated heats of formation and exhibit promising energetic performance that is the range of 1,3,5-trinitroperhydro-1,3,5-triazine and pentaerythritol tetranitrate. The new pyrazoles exhibit positive oxygen balance and are promising candidates for new environmentally benign energetic materials.

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Thermal decomposition of melted 3,4‐bis(3‐nitrofurazan‐4‐yl)furoxan (DNTF) in isothermal conditions was studied. The burning rates of DNTF were measured in the pressure interval of 0.1–15 MPa. The thermal stability of DNTF was found to be close to the stability of HMX, while the burning rate of DNTF was close to the burning rate of CL‐20. The thermocouple measurements in the combustion wave of DNTF showed that combustion of DNTF was controlled by the gas‐phase mechanism. The DNTF vapor pressure was determined from thermocouple measurements and agreed well with data obtained at low temperatures under isothermal conditions.

Burning rate characteristics of the low-sensitivity explosive 5nitro-1,2,4-triazol-3-one (NTO) have been investigated in the pressure interval of 0.1 -40 MPa. The temperature distribution in the combustion wave of NTO has been measured at pressures of 0.4 -2.1 MPa. Based on burning rate and thermocouple measurements, rate constants of NTO decomposition in the molten layer at 370 -425 8C have been derived from a condensed-phase combustion model (k ¼ 8.08 · 10 13 · exp(À 19420/T) s À1 . NTO vapor pressure above the liquid (ln P ¼ À 9914.4/T þ 14.82) and solid phases (ln P ¼ À 12984.4/T þ 20.48) has been calculated. Decomposition rates of NTO at low temperatures have been defined more exactly and it has been shown that in the interval of 180 -230 8C the decomposition of solid NTO is described by the following expression: k ¼ 2.9 · 10 12 · exp(À 20680/T). Taking into account the vapor pressure data obtained, the decomposition of NTO in the gas phase at 240 -250 8C has been studied. Decomposition rate constants in the gaseous phase have been found to be comparable with rate constants in the solid state. Therefore, a partial decomposition in the gas cannot substantially increase the total rate. High values of the activation energy for solid-state decomposition of NTO are not likely to be connected with a submelting effect, because decomposition occurs at temperatures well below the melting point. It has been suggested that the abnormally high activation energy in the interval of 230 -270 8C is a consequence of peculiarities of the NTO transitional process rather than strong bonds in the molecule. In this area, the NTO molecule undergoes isomerization into the aci-form, followed by C3-N2 heterocyclic bond rupture. Both processes depend on temperature, resulting in an abnormally high value of the observed activation energy.