Novel azide polymer/NC/RDX composite microspheres: low sensitivity and excellent thermal stability

The high sensitivity of nitramine explosives limits their wide application, and an effective way to reduce the sensitivity is to coat them. In this study, four types of azide polymers (GAP, GAPA, GAPE, GAP-ETPE) and nitrocellulose (NC) were selected as the coating materials to coat RDX by the solvent evaporation method. The morphology, structure, dimensions and coating quality of the composite microspheres were investigated by SEM, laser particle size measurement, XRD, XPS and FT-IR. The results indicated that uniformly coated RDX composite microspheres with high sphericity and uniform particle size distribution were prepared. In addition, the thermal stability of the composite microspheres was further analyzed by DSC. The results showed that the critical temperature of thermal explosion (Tb) and self-accelerated decomposition temperature (TSADT) of the azide polymer/NC/RDX composite microspheres were increased from 211.92°C and 198.49°C to 218.82°C and 206.19°C, respectively. In addition, mechanical sensitivity tests showed that the friction sensitivity and impact sensitivity of the composite microspheres were reduced by 24% ~36% and 35% ~58%, respectively.Therefore, this work demonstrates the beneficial effects of azide polymers and NC as coating materials for nitramine explosives and provides a reference for the desensitization research of nitramine explosives.