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The Effect of Detonator Shell Materials on Detonation Calorimetry Results

Němec Ondřej, Musil Tomáš, Künzel Martin

Central European Journal of Energetic Materials

2020

Vol. 17, no. 4

552--565

Detonation calorimetry is a method for the determination of the heat released by the detonation of an explosive charge. Compared to classical combustion calorimetry, detonation calorimetry requires an inert atmosphere, a large sample mass and a detonator for its initiation. This detonator releases some energy for which the results must be corrected. Four types of detonator have been tested in the calorimeter alone and also in combination with explosive charges of PETN. It was found that the aluminium shell of the detonator considerably increases the apparent heat of detonation of the PETN samples in a vacuum, while the presence of combustible (polymeric) components has the opposite effect. Pressurization of the calorimetric vessel with nitrogen gas only partially suppresses these effects. The preferred technique is to use copper or glass confinement in a high pressure inert atmosphere.

Bomb Calorimetric Correlation Study between Chemical Structure and Enthalpy of Formation for a Linear Energetic Polyphosphazene

Bellamy A. J., Contini A. E., Golding P.

Central European Journal of Energetic Materials

2013

Vol. 10, no. 1

3--15

Energetic polyphosphazenes constitute a novel class of insensitive binders which potentially outperform conventional carbon-based systems in terms of their energy-densities and glass transition temperatures. To facilitate the calculation of energetic performance for these materials, we report here on the use of bomb calorimetry to determine the standard enthalpies of combustion (ΔcH°) and formation (ΔfH°) of 2,2,2-trifuoroethan-1-oxy-/2,3-dinitratopropan-1-oxy-polyphosphazene (I) as the proportion of (energetic) 2,3-dinitratopropan-1-oxy substituents (% Energetic Substitution, % ES) is varied between 31% and 78%. Similar data is presented for the parent polymer bis(2,2,2-trifuoroethan-1-oxy)-polyphosphazene (II) (% ES = 0). ΔcH° was found to vary between -2275 kJ·mol-11for the parent polymer II (% ES = 0) and -3415 kJ·mol-1 for I with % ES = 78. The corresponding values for ΔfH° were -3184 kJ·mol-1 and -1566 kJ·mol-1. These data indicate that, as expected, the polymer heats of formation become more favourable – with respect to the energetic performance of the polymer – as the percentage of energetic side chain functionalities (% ES) increases.