The effect of pressure on nanomorphology in kaolinite under wet and dry conditions. Correlation with other kaolinite properties.

Kaolin morphology has particular importance in paper filling and coating. Besides particle size distribution and shape, aspect ratio and aggregate structure have a dominant importance on the rheological behaviour of kaolin slurries, and in other properties such as opacity, gloss, printability and brightness. The objectives of this investigation were to evaluate the changes produced by isostatic pressure on nanomorphology of kaolins and to determine the effect of the presence or absence of water during these experiments. Nanomorphology was evaluated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). These results were correlated with the variations on kaolinite structural order by X-ray diffraction (XRD), particle size distribution, surface area (BET method) and pore total volume determined from N2-adsorption.