The influence of shear forces on clay modification with oppositely chargedpolyelectrolytes

The interaction between the oppositely charged polymers poly(dimethyldially lammonium chloride) (PDADMAC) and poly(maleic acid-co-styrene) in the prese nce of clay can be used for strong surface modification. Different methods were applied for characterizing each step of the reaction and the propertie s of the modified material. By characterizing the formation of the pure pol yelectrolyte complex in solution as well as the three component system (two polyelectrolytes in presence of clay) with polyelectrolyte titration and c omparing these results with the total carbon content, it was shown that a s ignificant quantity of a soluble, Positively charged polyelectrolyte comple x is formed in the system. The strong cationic surface charge is obtained b y precipitation of this complex on clay It was found that the conditions of reaction (type of stirrer, time) strongly influence the particle propertie s like particle size and adsorption behavior/surface charge. The higher sur face charge and the greater diameter of particles was obtained with an anch or stirrer, whereas the formation of larger particles and the precipitation of the complex is prevented by the stronger shear forces of the leaf stirr er.