Low-temperature combustion of energetic materials in filled polymer systems

Abstract

In systems filled by inert additives, combustion of cellulose nitrate (CN) proceeds in a flameless low-temperature regime with a low linear burning rate. At a standard temperature, the exponent in the low of CN combustion in ballasted mixtures with inert additives in the pressure range of 0.1 to 10 MPa is several times lower than that of pure cellulose nitrate and amounts to 0.23. The qualitative and quantitative composition of gaseous products of flameless CN conversion is found. It is noted that this composition approximately corresponds to data available in the literature for the products of thermal decomposition of cellulose nitrate at comparatively low temperatures. Based on this fact and on a weak dependence of the CN burning rate on pressure in ballasted systems, the process under these conditions is assumed to be controlled by conversion of the energetic component predominantly in the condensed phase. In the case of a composite consisting of cellulose nitrate, silicon carbide, and polymer binder, for samples 10-25 mm in diameter, armoring exerts practically no effect on combustion parameters. Combustion of the same mixture with smaller diameters of non-armored samples is unstable. The presence of a liner establishes a clearly expressed critical combustion diameter in the examined systems.

Spatial forms of a combustion wave in energetic heterogeneous systems

“…These results can be used to explain the reasons of local fluctuations in the temperature and burning rate of energetic materials [15] and somewhat unusual forms of the dependences of the low-temperature combustion parameters of ballasted energetic systems [16].…”

Self-Propagation Low Temperature Flameless Combustion Synthesis of Ni and Al Nanoparticles: Time-Resolved XRD Study

“…Among these are the absence of open flame and glowing areas, relatively low reaction temperatures (260-500°C) and burning rate (0.02-0.5 mm/s) at normal conditions. The process also produces large amounts of condensed products and vapors formed upon incomplete decomposition of the energy-rich compounds and pyrolysis of ballasting polymer compounds [2]. In contrast to closely related process of self-propagating high-temperature synthesis (SHS) [3], in present case the process of wave propagation is entirely sustained by the energy released upon thermal decomposition of the energy-rich compounds.…”

“…Frontal flameless combustion of energy-rich compounds, such as cellulose nitrates (CN), cyclotrimethylenetrinitramine, cyclotetramethylenetetranitramine, N,N-diethanolnitramine etc., dispersed in ballasted polymer systems is known to exhibit a number of specific features [1,2]. Among these are the absence of open flame and glowing areas, relatively low reaction temperatures (260-500°C) and burning rate (0.02-0.5 mm/s) at normal conditions.…”

Formation of nanosized particles of nickel and silver in a wave of flameless combustion of cellulose nitrate in ballasted systems

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Wave transformation of systems consisting of energy rich solid compounds (cellulose nitrates, cyclotrimethylenetrinitramine (RDX), cyclotetrame thylenetetranitramine (HMX), N,N diethanolnitra mine dinitrate, and other similar compounds) dis persed in a medium of inorganic and organic ballasting components differs significantly from the combustion of the same energy rich compounds in individual form [1][2][3][4]. Unlike the classical self propagating high tem perature synthesis [5], the wave process in this case is driven by the heat released by the decomposition of the energy rich component.

It was shown [1, 2, 4] that variation of the initial conditions (pressure and temperature) of the process, and also the nature and ratio of the energy rich and ballasting components enables one to control the physicochemical parameters of the wave and the com positions and properties of the condensed transforma tion products, which, in some cases, can be of interest as materials for various functional purposes.

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“…Wave transformation of systems consisting of energy rich solid compounds (cellulose nitrates, cyclotrimethylenetrinitramine (RDX), cyclotetrame thylenetetranitramine (HMX), N,N diethanolnitra mine dinitrate, and other similar compounds) dis persed in a medium of inorganic and organic ballasting components differs significantly from the combustion of the same energy rich compounds in individual form [1][2][3][4]. Unlike the classical self propagating high tem perature synthesis [5], the wave process in this case is driven by the heat released by the decomposition of the energy rich component.…”