Dynamically Formed Hydrous Zirconium (IV) Oxide-Polyelectrolyte Membranes. VI. Effect of Copolymer Composition on the Stability of Poly (Acrylic Acid-Covinyl Acetate) and Poly (Acrylic Acid-Covinyl Alcohol) Membranes
A series of poly (acrylic acid-covinyl acetate) (I) copolymers were synthesized. Selected copolymers were hydrolyzed fully to give the corresponding poly (acrylic acid-covinyl alcohol) (II) copolymers. One of the (I) copolymers was partially hydrolyzed to yield two poly (acrylic acid-covinyl acetate-covinyl alcohol) (III) terpolymers. The ability of (I), (II) and (III) to interact with zirconium ions in an acidic medium was investigated. Hydrous zirconium (IV) oxide-(I), and -(II) dynamic membranes were formed. The stabilities of these membranes were compared in terms of the copolymer composition of the relevant polyelectrolytes. An attempt was made to correlate the ability of the polymers to interact with zirconium with the stability of the membrane. The (II) copolymer membranes were more stable than the (I) copolymers, and there was no direct correlation between the ability of the polyelectrolytes to interact with zirconium and the membrane stability. It is thought that membrane stability is a combination of the polyelectrolyte's ability to interact with zirconium and its solubility in water at neutral pH. The (II) copolymers had higher zirconium uptake capabilities than the corresponding (I) copolymers had. Tests on the (III) terpolymers showed that the zirconium uptake capability of the terpolymer increased as the degree of hydrolysis increased. © 1989.