EFFECTS OF BOLAFORM ELECTROLYTES ON THE INTERACTION BETWEEN A WATER-SOLUBLE POLYMER AND SULFONATED MONOAZO DYES .1.

The interaction between sulphonated monoazo dyes and poly( vinylpyrrolidone) in the presence of bolaform electrolytes with two quaternized amino groups was investigated by means of visible absorption spectrum measurements. The first binding constants of the dyes with poly(vinylpyrrolidone), determined by neglecting the binding of the dyes with the bolaform electrolytes, were much larger than those in the absence of the bolaform electrolytes. However, interaction between the dyes and the bolaform electrolytes in aqueous solutions was found, so that the above assumption was not fulfilled Therefore, the first binding constants of the dye/bolaform electrolyte complexes with poly(vinylpyrrolidone) were determined by using the equation based on the equilibria in the trinary systems containing the dyes, the bolaform electrolytes and poly(vinylpyrrolidone). The first binding constants of the complexes with poly(vinylpyrrolidone) were larger than those of the dyes, which suggests that the bolaform electrolytes enhance the affinity of the dyes for the polymer through the formation of dye/bolaform electrolyte complexes.