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2010
Conference Paper
Titel
Influence of application of energy on the effectiveness of chemical additives in suspension preparation
Abstract
The production of nanoparticles can follow two routes: the bottom-up synthesis and the top-down production via milling of a coarse powder in a ball mill. The possible reduction ratio of the particle size during grinding strongly depends on the stabilisation of the particles in the slip to prevent agglomeration. In-depth knowledge of the interactions between the powder and the additives is needed to control the production of nanosized powders through milling and to adjust the characteristics of the slip in a defined manner. It has to be considered that the interactions between powder and additives and the stabilizing effect of the dispersing agents can significantly change during the milling process in comparison with the interactions within the slip before the reduction of the particle size. Results of changing interactions of a boehmite powder in water with commercially available dispersing agents based on polyacrylic acid as a function of the application of energy are presented. Measurements of the surface charge of the particles and simultaneous analyses of the viscosity of the slip and the adsorption behavior of the additives enable a direct detection of the changing interactions. The reasons for the varying interactions and the therewith connected loss of stabilization are discussed and the feasibility of milling of the boehmite powder in a ball mill is presented.