Polymer cosolvent systems. 8. PMMA/CCl₄/(ISO)amyl acetate. Study by laser light scattering and viscometry

Two new non-symmetrical cosolvent mixtures for PMMA are reported in this work. Unperturbed dimensions, Mark-Houwink-Sakurada constants, second virial coefficients and preferential sorption coefficients have been determined for both systems at 298K using as experimental techniques viscometry and laser light scattering. The results indicate that both mixtures (CCl₄/(iso)amyl acetate) are poor cosolvents for atactic PMMA, the mixture formed by amyl acetate being a better cosolvent than the mixture formed by isoamyl acetate. In both systems no inversion in solvation was found: the acetate is preferentially adsorbed on PMMA over the whole composition range. In order to predict the experimental preferential sorption coefficients the Read equation has been used, obtaining the polymer liquid interaction parameters X_ij. by means of the Blanks-Prausnitz criterion.