Dilute Solution Properties of Ionomers Obtained from Eudragit-S

Eudragit-S is an anionic copolymer of methylmethacrylate and methacrylic acid (MMA/MAA) in which the ratio of the free carboxyl groups to the ester groups is 1:2. (i.e. 33.3 % methacrylic acid). Coating lacquers obtained from granulated Eudragits are used in pharmacy for medical purposes. In this work, dilute solution behaviours of the copolymer and its Ba2+ ionomers were studied in dioxane and acetone. The data obtained by reduced viscosities and the mean-squared dipole moment methods were in agreement with the hypothesis that nonpolar solvents weakly solvate the polymer chains. The mean-squared dipole moment measurements is an efficient method for interpreting the solution behaviour of ionomers.