POLY(N-VINYL-2-PYRROLIDONE) MONOALKYL XANTHATES .1. ADSORPTION AND CHEMICAL-REACTION

The interaction of poly(N-vinyl-2-pyrrolidone) (PVP) with Potassium monoalkyl xanthates was studied by UV-vis spectrophotometry and ultrafiltration measurements. A simple association model was applied in order to describe the results. Some characteristics of the association process were analyzed. The findings suggest the presence of a more complex process than one simple association or chemical reaction process. We have supposed that the absorption obtained corresponds to the adsorption of the product. From the second-order rate constant values of the chemical reaction, we have calculated the activation free energy DELTAG(double dagger) for the reaction of each xanthate studied with PVP and its variation with the number of carbon atoms in the alkyl chain. The different contributions to DELTAG(double dagger) values are discussed in terms of the one specific ionic interaction between -OCSS- and one positive active center in the polymer chain and one hydrophobic association with the backbone of the PVP.