Surfactant Interactions in Polyvinyl Acetate and Poly (vinyl acetate—butyl acrylate) Latexes

Abstract

Types of surfactant interactions encountered in polyvinyl acetate and poly (vinyl acetate-acrylate) latexes are: (1) simple saturation adsorption at the latex/water interface, (2) adsorption and penetration into the latex particle leading to the formation of solubilized polyelectrolyte type polymer-surfactant complex, and (3) grafting to the polymer chains, especially with non-ionic surfactants. In this paper, the effects of molecular weight and structure of anionic surfactants on their interactions with model vinyl acrylic latexes are considered. It is shown that anionic surfactants having fairly low molecular weight and perhaps simple structure readily penetrate into the latex core causing new adsoption sites to open up. Such a process seems to result in a linear C-type adsorption isotherm and solubilization of the latex. On the other hand, higher molecular weight and bulkier anionic surfactants seem to show a saturation type adsorption isotherm without any solubilization of the latex. It is also shown that the adsorption of non-ionic surfactants at a vinyl acrylic latex/water interface that exhibit a saturation type isotherm can be related to the polarity of the polymer surface, in agreement with earlier sufactant adsorption studies.