Effect of Particle Size of AP and Catalyst on the Thermal Decomposition of Ammonium Perchlorate

Abstract

Analytical investigations on thermal decomposition behavior of course, fine and ultrafine ammonium perchlorate (AP) with and without catalyst were carried out by thermogravimetric and by differential thermal analysis.The low temperature decomposition (LTD) and high temperature decomposition (HTD) reactions and kinetic parameters for the two stages were computed using three non-mechanistic kinetic equations. With decrease in particle size of AP, the percentage mass loss in LTD decreases, but the overall reactivity increases. The variation of both activation energy (E) and pre-exponential factor (A) with particle size and catalyst impose difficulty in correlating the calculated E values with the observed enhancement in reaction rate due to decrease of particle size and catalyst. The E values calculated after normalizing the A values by kinetic compensation correction follows the expected trends. The catalytic activity of copper chromite was found higher than iron oxide in all fractions of AP decomposition behaviour.