Particle properties and crystalline structure of ADN-Prills

The application of ammonium dinitramide (ADN) for solid propellants made important steps on its way into a successful future over the last decade. Next to synthesis and propellant formulation the particle technology plays a key role in the development of ADN containing propellants. Especially the properties of spherical ADN particles, so-called ADN-prills, generated from dispersed melting droplets from spray- or emulsion- processes are of major interest. By temperature resolved X-ray diffraction measurements new insights about temperature depending crystalline structures inside of ADN-prills could be gained. Anisotropic crystal properties could be detected at certain temperature ranges between ambient temperature and the melting point of ADN at 93°C. Due to the unexpected material properties of molten ADN droplets surprising correlations between process parameters, particle size, crystal structure, thermal stability and mechanical stability was found. The results of these interdisciplinary investigations are reported in DOI: 10.1002/prep.201800328 [1].