Potential reuse of HMX separated from decommissioned propellants: crystallization and characterization of low-sensitivity HMX

Abstract

ABSTRACT Herein, in order to increase the purity and improve the performance of HMX crude products (Raw HMX) isolated from decommissioned propellants, a new method to obtain submicron levels using the solvent-anti-solvent process was proposed. Two different morphologies of HMX, regular prismatic vs. spherical-like, were obtained by means of two solvents (DMSO, DMF). Polyethylene glycol-200 (PEG-200) was used to improve the morphology and dispersion of crystals at low saturation and low crystallization temperatures. Various rates of addition of anti-solvent (water) were studied to prevent HMX crystalline transition and effectively increase purity. Furthermore, the aging process was applied to further modify the crystals with controlled particle size distribution The purity of the samples was tested by High Performance Liquid Chromatography (HPLC) spectroscopy, and the purity of the crystallized samples was improved from 95.53% in Raw HMX to over 99%. The thermal decomposition properties were investigated by differential scanning calorimetry (DSC) and the kinetic parameters of the thermal decomposition reaction of the materials were calculated using the Kissinger and Ozawa method. The samples were also tested for impact and friction sensitivity, which was reduced compared to both Raw HMX and industrial HMX, demonstrating that this type of modified HMX recovered from decommissioned propellants is fully reusable.