Changes of the main physical and technological properties of talc due to mechanical strain

A commercial talc was treated by planetary ball milling to evaluate the changes of the main physical and technological properties due to induced progressive mechanical stress. Firstly, a high orientation of talc platelets was obtained, secondly a progressive structural disorder of the talc and finally a re-aggregation of the particles during prolonged grinding was observed. Delamination during the initial and intermediate stages cannot be excluded. Mechanical grinding reduced the particles size and increased the specific surface area leading to enhanced absorption and cation exchange capacity during the initial and intermediate stages of grinding. The reduced lightness and brightness for prolonged grinding were attributed to the agglomeration of the particles. The mechanical treatment does not induce significant amorphization, thus preserving the main properties of talc even after prolonged grinding. (C) 2008 Elsevier B.V. All rights reserved.