The adsorption of water-soluble cationic poly(urethane-urea-amine) acetate (PUUA) on colloidal silica as aqueous dispersion was studied. The results indicated that the conformation of the PUUA chains was in stretched conformation in dilute solution, and the average molecular size was smaller than the diameter of silica particles. The adsorption of PUUA onto the colloidal silica was attributed to van der Waals' and hydrogen bonding forces. The adsorption isotherms revealed that, after stable adsorption on the surface of silica particle, the adsorption amount of PUUA linearly increased, moreover, there was not an ultimate saturated adsorption. The apparent adsorption was linearly, by the same slope, decreased with increase of the colloidal silica size, falling of the surface charges of silica, and increase of the amount of sodium acetate added. Furthermore, the adsorption was ascended with increasing molecular weight of PUUA, and the adsorption of the large molecules was prior to the small molecules of PUUA. The electrostatic attraction was the predominant effect on the adsorption of the PUUA from water onto the colloidal silica. The apparent viscosity of the dispersion was decreased by the adsorption of the PUUA-E onto the colloidal silica. The sensitivity of the dispersions showed pseudoplastic flow, while the protection of the dispersions displayed dilatancy.

Key words: POLYURETHANE, AMINES, NANOPHASE MATERIALS, SILICON OXIDE, SOL, ADSORPTION, VISCOSITY