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Introduction/purpose: Gunpowder is a type of explosive material (EM), a mixture of chemical compounds capable of releasing their potential energy in a very fast exothermic chemical reaction. This paper investigates the single base gunpowder samples. Methods: Microcalorimetry (MC), or heat flow calorimetry (HFC), is the only modern method that monitors the direct cause of autoignition - the rate of heat release, which is a key factor for gunpowder storage explosive safety. It is based on high-sensitivity calorimeters which allow monitoring of chemical reactions at low speeds. The microcalorimeter "TAM III" was used and the method given by the NATO standard STANAG 4582. A very reliable result was obtained on the chemical stability of the observed single base gunpowder samples, as well as an assessment of its behavior in the next 10 years. Results: The thermal activity of gunpowder depends on several factors, the most important of which are: chemical composition, size and shape of the gunpowder grain, the degree of decomposition of the gunpowder, storage conditions, etc. Namely, it is a much more exact and consistent indicator of the chemical stability of gunpowder compared to the critical diameter. Conclusion: The MC method should be used both for monitoring the chemical stability of gunpowder during storage and for the prediction of the service life of gunpowder.

Introduction/purpose: Gunpowder is a type of explosive material (EM), a mixture of chemical compounds capable of releasing their potential energy in a very fast exothermic chemical reaction. This paper investigates the single base gunpowder samples. Methods: Microcalorimetry (MC), or heat flow calorimetry (HFC), is the only modern method that monitors the direct cause of autoignition - the rate of heat release, which is a key factor for gunpowder storage explosive safety. It is based on high-sensitivity calorimeters which allow monitoring of chemical reactions at low speeds. The microcalorimeter "TAM III" was used and the method given by the NATO standard STANAG 4582. A very reliable result was obtained on the chemical stability of the observed single base gunpowder samples, as well as an assessment of its behavior in the next 10 years. Results: The thermal activity of gunpowder depends on several factors, the most important of which are: chemical composition, size and shape of the gunpowder grain, the degree of decomposition of the gunpowder, storage conditions, etc. Namely, it is a much more exact and consistent indicator of the chemical stability of gunpowder compared to the critical diameter. Conclusion: The MC method should be used both for monitoring the chemical stability of gunpowder during storage and for the prediction of the service life of gunpowder. [ABSTRACT FROM AUTHOR]

The most reliable way of chemical stability assessment and the lifetime prediction of nitrocellulose (NC) gunpowder (GP) by measuring of the stabilizer contents is to monitor the consumption of the stabilizer with time, under storage conditions. Due to the limited time available for testing of reliable lifetime prediction the various methods based on the artificially aging process (which simulates the natural aging of GP) has been developed. The aim is to reach equivalent aging in much shorter time then at ambient temperature under naturally storage conditions. The present article describes the results of comparative analysis of the lifetime prediction of naturally and artificially aged different series of NC-40 powder at ambient temperature 25oC. It is showed that empirical value of activation energy of 80 kJ/mol can be used for extrapolation of the reaction rate constant of the stabilizer consumption in the naturally aged NC-40 powder from average annual temperature 15oC in KB-1 collection (conditions of continental climate) to an ambient temperature of 25oC. The lifetime of naturally aged NC-40 powder calculated in this way is in accordance with the lifetime of artificially aged GPs calculated at ambient temperature 25oC, according to worldwide used standard AOP-48 Ed. 2. The lifetime of the naturally aged NC-40 powder calculated in this way is in accordance with the lifetime which was calculated by Van't Hoff extrapolation method, too.