Influence of interfacial properties of styrene/butadiene latex on the interaction with poly(vinyl alcohol) in aqueous media

The interfacial properties of styrene/butadiene latex were found to play a substantial role in its interaction with partially hydrolysed polyvinyl acetate (PVOH/Ac) in aqueous solutions. In particular, the level of carboxylation of the latex particles governs the adsorption process. A slightly hydrophobic PVOH/Ac is weakly adsorbed onto medium carboxylated latex at low equilibrium concentrations, whereas a multilayer adsorption occurs at high polymer concentrations, closely resembling the incipient phase separation already observed in the case of PVOH/Ac-polystyrene latex systems. The adsorption mechanism for the monolayer formation is suggested to be of entropic origin, driven by the hydrophobic interactions between the latex surface and especially the acetate groups of the PVOH/Ac chain. Increasing the hydrophilic character of the latex surface through pre-adsorbed sodium dodecylbenzene sulphonate or non-ionic fatty alcohol ethoxylate surfactants did not significantly affect the association behavior between PVOH/Ac and the latex surface. In addition to the importance of the interfacial properties of the latex particles, it has been shown that an increased degree of hydrolysis of the PVOH/Ac macromolecule also leads to an appreciable reduction in its affinity for the styrene/butadiene latex interface.