[en] A sodium salt of a modified lignosulfonate at different percentages was added to a porcelain stoneware suspension and the effects on the rheological properties of slips and on the mechanical properties of prepared samples were investigated. As the presence of sulfonates groups can change the stability of dispersion, a rheological characterisation was necessary to find the critical concentration to obtain well dispersed suspensions and high MOR values. The suspensions stability was tested by oscillatory measurements and the increase of elastic modulus in the suspension corresponded to a MOR and to Youngs modulus increase as well. Finally, to explain the results obtained by the mechanical characterisation of the prepared samples, a model drawing on the composite materials experience, is suggested. (Author) 7 refs.