Characterization of Graft Polymers

Abstract

Since the earliest recorded attempts to modify rubber by the polymerization of monomers dissolved in rubber considerable work has been directed toward the preparation and characterization of copolymers other than those with random distribution based on the reactivity ratios of the two components. Block polymers consisting of A and B chains coupled to form a linear molecule have been reported by many investigators including Melville and coworkers and Woodward and Smets. Woodward and Smets used the different solubilities in selected solvents and their mixtures to separate block copolymers of styrene-methyl methacrylate and vinyl acetate-styrene from the two homo-polymers with which they occurred. Solution properties of the isolated materials were then investigated. This technique for isolation and characterization has been used with graft polymers in which branches containing all A are attached to a “backbone” of B units. Claesen and Smets prepared and separated vinyl acetate-polymethyl methacrylate and vinyl chloride-polymethyl methacrylate graft polymers from the homopolymer mixture by solubility differences and reported on the osmotic and viscometric behavior of the graft materials. Other investigators have studied conditions and techniques for preparing graft copolymers while attempting partial characterization of the materials produced by using solubility differences for isolation and the usual methods for property studies.