Adsorption of some linear copolymers onto kaolin particles in concentrated suspensions

Polyelectrolytes are commonly used as dispersants to stabilise highly concentrated ceramic dispersions. The ability of such polymeric additives to stabilise these suspensions is determined to a large extent by the electrical charge of the adsorbed polyelectrolyte. In this study, we investigated the adsorption onto kaolin suspension of various polyelectrolytes containing different electrical charge. The stability of these kaolin dispersions after addition of different polyelectrolyte additives was correlated with the adsorption isotherm, the zeta potential and the rheological properties. The adsorption isotherms were evaluated by the Langmuir model, and the electrokinetic properties of the kaolin particles were analyzed. A rheological test was performed to determine the deflocculating power of these polyelectrolytes. Their ability of these polymers to stabilise kaolin suspensions was found to be dependent on the content and the structure of the functional groups in the macromolecular chain.