Membrane Emulsification Preparation of ADN/PVA Composite Particles Exhibiting Excellent Thermal Properties and Anti-Hygroscopicity.

Ammonium dinitramide (ADN) is a high-energy green oxidizer with significant potential for use in solid propellants; however, its practical application is restricted by its strong hygroscopicity and low safety. In this study, morphology control and surface coating were simultaneously addressed by preparing ADN/PVA composite particles with different PVA contents by membrane emulsification. At a PVA content of 5%, the ADN/PVA composite microspheres exhibited favorable morphology and a high degree of sphericity, with no phase transition induced and the crystal structure well preserved. DSC results showed that the initial decomposition temperature of ADN/PVA increased by 21.88-26.50 °C compared to that of raw ADN, and the exothermic peak became narrower, indicating that the energy release of ADN was more concentrated and its thermal stability was significantly improved. Meanwhile, the impact sensitivity and friction sensitivity were reduced by 33.33% and 16.67%, respectively, relative to raw ADN, and the moisture absorption rate was reduced by 87.92%. Therefore, the ADN/PVA composite particles prepared by membrane emulsification exhibit excellent thermal stability and anti-hygroscopicity.