Thermal analysis explosives

Reactivity (instability) information Acceleration rate calorimetry Differential thermal analysis (DTA) Impact test Thermal stability Lead block test Explosion propagation with detonation Drop weight test Thermal decomposition test Influence test Self-acceleration temperature Card gap test (under confinement) JANAE Critical diameter Pyrophoricity... 

Mixtures of aluminium powder with liquid chlorine, dinitrogen tetraoxide or tetran-itromethane are detonable explosives, but not as powerful as aluminium-liquid oxygen mixtures, some of which exceed TNT in effect by a factor of 3 to 4 [1], Mixtures of the powdered metal and various bromates may explode on impact, heating or friction. Iodates and chlorates act similarly [2], Detonation properties of gelled slurries of aluminium powder in aqueous nitrate or perchlorate salt solutions have been studied [3], Reactions of aluminium powder with potassium chlorate or potassium perchlorate have been studied by thermal analysis [4],... 

The title compound (with 66.5% nitrogen content) is prepared by condensing formylhydrazine (2 mols, with elimination of 2H2O) by heating to 170°C. Dining a pilot production run in a 500 1 reactor, an explosion destroyed the vessel. The heat of decomposition of the compound was determined by thermal analysis as 1.5 kJ/g, with an energy of activation of 91 kJ/mol. 

The nitrate containing 0.1% of ammonium chloride decomposes vigorously below 175°C [1], Presence of 0.1% of calcium chloride or iron(III) chloride in the nitrate lowers its initiation temperature sufficiently to give violent or explosive decomposition. Thermal analysis plots for aluminium chloride, calcium chloride and iron(III) chloride are given [2],... 

Great care must be exercised in the thermal analysis of certain sulfoxide complexes. Complexes of the type [Md SOl XX], (X = C104, N03, etc.) are known to be highly explosive on heating to elevated temperatures indeed, sulfoxide complexes with explosive properties equal to TNT and nitroglycerine have been reported in the patent literature (148,149). 

J.C. Oxley, The Thermal Stabihty of Explosives Chapter 8 in Handbook of Thermal Analysis and Calorimetry Applications to Inorganic and Miscellaneous Materials Volume 2 , P.K. Gallagher and M.E. Brown, eds, Elsevier p. 349—369. Elsevier Amsterdam. 

Collectively, the thermal analysis techniques can be used to compare different batches of gunpowder and its constituents or to make more fundamental studies of, for example, the stability of the explosive under various physical or chemical conditions. 

Differential thermal analysis (DTA) has provided a wealth of information regarding the thermal behavior of pure solids as well as solid mixtures [10]. Melting points, boiling points, transitions from one crystalline form to another, and decomposition temperatures can be obtained for pure materials. Reaction temperatures can be determined for mixtures, such as ignition temperatures for pyrotechnic and explosive compositions. 

The research papers which originated in the last couple of years in different countries in this field indicate that ED and Er are not generally reported and there is an emphasis on the study of comprehensive thermal behavior of explosives as a function of temperature or time by means of different thermal analytical techniques. Most commonly used methods of thermal analysis are differential thermal analysis (DTA), thermogravimetric analysis (TGA) or thermogravimetry and differential scanning calorimetry (DSC). 

Thermal Analysis Thermal analysis consists of a group of techniques where a physical property of an explosive is measured as a function of programmed temperature and the most common complementary techniques are listed in Table 3.5. 

Differential Thermal Analysis of Explosives, Propellants Pyrotechnics. Differential Thermal Analysis (DTA) involves measuring the temp difference between an inert ref compd... 

E.E. Mason, "Application of Derivative Differential Thermal Analysis to Military High Explosives . NAVWEPS Rept 6996... 

Thermal Analysis of Explosives and Propellants under Controlled Atmospheres , AnalChem 33, 1451-53(1961) 9) R-N. 

Rogers, "The Simple Microscale Differential Thermal Analysis of Explosives , MicrochemJ 5, 91-99(1961) 10) E.E. Mason... 

The common methods of investigating the kinetics of explosive reactions are differential thermal analysis, thermogravimetric analysis and differential scanning calorimetry. 

DSC is often used for the study of equilibria, heat capacities and kinetics of explosive reactions in the absence of phase changes, whereas DTA combined with TGA is mainly used for thermal analysis. 

Crude material prepared in glass on 3 g mol scale was distilled uneventfully at 40°C/ 0.067 mbar from a bath at 70—80°C. A 30 mol batch prepared in a glass-lined vessel with a stainless steel thermo-probe (and later found to contain 15 ppm of iron) decomposed very violently during distillation at 75°C/13 mbar from a bath at 130°C. Thermal analysis showed that the stability of the methyl (and ethyl) ester was very sensitive to traces of heavy metals (iron, copper, chromium, etc.) and was greatly reduced. Addition of traces of hydrated iron(II) sulfate led to explosive decomposition at 25°C. 

Substances which explode by a weak impact (called highly sensitive substances) can be identified by a screening test like the drop ball test Whether deflagration occurs easily can be checked by an ignitability test Another screening test to examine the ease of occurrence of a reaction relies on the determination of the temperature at which decomposition is initiated by thermal analysis on micro-samples. This quantifies the ease of initiating a thermal explosion. 

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