Compatibility and thermal decomposition mechanism of nitrocellulose/Cr₂O₃ nanoparticles studied using DSC and TG-FTIR

Abstract

Nano metal oxides are common combustion catalysts for enhancing the burning rate of solid propellants. Cr₂O₃ nanoparticles (NPs) are efficient combustion catalysts for the pyrolysis of energetic components. In this study, Cr₂O₃ NPs were synthesized <i>via</i> a modified sol-gel method and further used for studying the thermal decomposition of nitrocellulose (NC). Differential scanning calorimetry (DSC) and thermogravimetry-Fourier-transform infrared spectroscopy (TG-FTIR) analyses indicate that the Cr₂O₃ NPs can be safely used with NC and the mechanism of the reaction between Cr₂O₃/NC and pure NC follows the Avrami-Erofeev equation: <i>f</i>(<i>α</i>) = 3(1 - <i>α</i>)[-ln(1 - <i>α</i>)]^1/3/2. The peak temperature and activation energy (<i>E</i> _a) for the thermal decomposition of Cr₂O₃/NC are lower than those of pure NC. NO₂ was detected at a lower temperature after NC was mixed with Cr₂O₃ NPs; this indicated the catalytically accelerated bond cleavage of NC by Cr₂O₃ NPs.