Strategy for spray coating of highly porous and light weighting particles using spouted bed technology

In this thesis an in-depth experimental study of the spray coating of light weighting and mesoporous organic aerogels was carried out. The main goal of this study was to design a stable core-shell particle system with a uniform coating layer without changing the initial particle structure. Further, the applied coating layer provides many beneficial improvements and additional properties for the aerogel particles, like an enhanced mechanical stability or a protection against moisture during storage.

To design the structured core-shell particles with unaffected porous structure and uniform coating layer, series of experiments was conducted. The coating process with beeswax and ethanol based shellac solutions was performed at two levels using acoustic levitation and spouted bed set ups. At single particle level the basic influences on particle structure were captured. During coating at multiple particle level, which was performed in spouted bed, the results were validated. The optimum coating process parameters were identified. A uniform and stable core-shell particle system was designed. No change of initial porous particle structure was observed.