New insights into kinetics of PETN decomposition from the product and reactant point of view: An investigation with mass spectrometry and differential scanning calorimetry

Pentaerythritol tetranitrate (PETN) is a benchmark organic energetic material and is used in both military and industrial applications. Accurate kinetic parameters for the decomposition of energetic materials are required to predict the hazards, thermal, cook-off and properties of PETN. Kinetic parameters of PETN decomposition have been previously reported in wide range of values. We are attempting to find new insights on the kinetics of PETN decomposition by studying kinetics of gas evolution and heat released from the reaction. Gas evolution kinetics is studied by a mass spectrometer coupled with a thermogravimetric analyzer (TGA-MS) and heat released in the reaction with a deferential scanning calorimeter (DSC) in open and closed pan. PETN single crystals are used as the samples. The activation energy of decomposition is obtained as a function of extent of reaction by the isoconversional kinetic analysis. The activation energy for the generation of NO2 (m/z = 46) in PETN decomposition is consistent with the bond energy of RO-NO2 in nitrate esters. The activation energy for the overall PETN decomposition is similar to that of the generation of NO2. The effect of confinement on the decomposition kinetics in TGA-MS and DSC, are also discussed in this work. This investigation shows that activation energy for PETN decomposition is in the range of 170-176 kJ/mol. (C) 2015 Elsevier B.V. All rights reserved.