POLYMER-CONTAINING DISPERSIONS OF KAOLINITE IN BINARY SOLVENT

A study has been made of the stability and rheological properties of polymer-containing dispersions of kaolin in a binary solvent, in relation to the solvent composition; acid-base interactions were taken into account in this study. The efficiency of stabilization of polymethyl methacrylate (PMMA) dispersions in an acidic solvent (chloroform) is higher than in a basic solvent (acetone), and mixtures of the two solvents give intermediate efficiencies. Specific features of the behavior of PMMA and clay dispersions in a 6:1 mixture of chloroform and acetone have been determined; these features are manifested in higher values of the intrinsic and Newtonian viscosity, and also in minimum adsorption of PMMA. The introduction of a basic solvent into the PPMA/kaolin/chloroform system (15% by weight) weakens the coagulation structure, an effect analogous to that of cationic surfactants. The simultaneous presence of acetone and a cationic surfactant gives a superadditive suppression of structurization in this system and an increase in its stability.