Rheology of ceramic suspensions in aqueous polysaccharide matrices

Several polysaccharides exhibit weak gel properties when dissolved in aqueous phases and, hence, they can be profitably used to prepare aqueous matrices suitable to host disperse phases and to improve the stability and workability of the dispersions. Such an application is particularly interesting in the ceramic field, where high concentration levels of the disperse phase must be reached. In the present paper the rheological properties of concentrated dispersions of ceramic powders (alumina and calcium carbonate) in aqueous polysaccharide matrices (welan and rhamsan) are examined under flow conditions as well as in the linear viscoelastic regime. The comparison with the corresponding properties of aqueous suspensions and polysaccharide matrices highlights the beneficial effects of the polymer addition. The results obtained can be considered paradigmatic of the advantages deriving from the usage of such polymers for the rheological and stability properties of many other disperse systems.