Nanomilling of organic compounds in stirred media mills

• Applicants: Professor Dr.-Ing. Arno Kwade; Professor Dr.-Ing. Wolfgang Peukert
• Subject Area: Mechanical Process Engineering
• Term: from 2013 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 238114850

Objective of this research project are in-depth investigations of the fracture behavior of organic crystals during stirred media milling. Moreover, the impact of formulation and process parameters on product characteristics and grinding limit will be investigated in detail. Building on the main results of the first funding period, the research shall be focused on the complex interplay of particle breakage, agglomeration, precipitation as well as ripening phenomena, which occur in parallel during media milling of organic crystals. Investigations concerning the influence of solubility on product formation as well as complex stability issues of the strongly hydrophic organic compounds are part of the study. Furthermore, the detailed characterization of the solid state and microstructure, respectively, of the organic crystal coupled to liquid phase analysis will gain a deeper understanding of the production of organic particles during media milling. Furthermore, fundamental mechanisms affecting the grinding limit of organic particles shall be identified and investigated in great detail. Based on the main results of the first and second funding period, the stress model for the description and optimization of grinding processes of inorganic materials in stirred media mills will be extended with regard to organic crystals. In addition, a strategy to minimize grinding media wear will be devolved to improve the product quality. Hence, the second funding period comprises the following essential aspects:- Distinction between particle fracture and precipitation as well as ripening effects during media milling to gain a deeper understanding of the mechanical production of organic particles.- Distinction between surface and volume effects during wet grinding of organic crystals.- Characterization and in-depth understanding of the complex interplay of organic crystal, stabilization additives and liquid medium as well as their impact on product characteristics.- Identification of the limiting mechanisms regarding the grinding limit of organic particles.- Development of a strategy to minimize abrasion and characterization of the interactions between wear, product particles and formulation.

• DFG Programme: Research Grants
• Co-Investigators: Professorin Dr.-Ing. Sandra Breitung-Faes; Dr. Cornelia Damm