Combustion Synthesis of La 0.8Sr 0.2MnO 3 and Its Effect on HMX Thermal Decomposition

Abstract

Perovskite-type La 0.8Sr 0.2MnO 3 was prepared by stearic acid gel combustion method. The obtained powders were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scaning electron micrograph (SEM) and X-ray photoelectron spectroscopy (XPS) techniques. The catalytic activity of La 0.8Sr 0.2MnO 3 was investigated on thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) by thermal gravity-differential scanning calorimetry (TG-DSC) techniques. The experimental results show that La 0.8Sr 0.2MnO 3 is an effective catalyst for HMX thermal decomposition. The surface-adsorbed species such as H 2O, OH − and adsorbed oxygen (O ad) could result in an advance in the onset temperature of HMX thermal decomposition. The mixture system of Mn 3+ and Mn 4+ ions and lattice oxygen could play key roles for the increase of the decomposition heat of HMX because these exothermic reactions could be catalyzed by La 0.8Sr 0.2MnO 3 between CO and NO x (from the thermal decomposition of HMX) and the oxidation reaction of CO. According to the previous researches and our results, perovskite-type La 0.8Sr 0.2MnO 3 may be used as a novel catalyst or modifier for nitrate ester plasticized polyether (NEPE) propellant.