Chemical structure of cellulose‐styrene graft copolymers

Abstract

AbstractAt first polyvinyl alcohol was used as a model for cellulose, and the grafting of styrene and methyl methacrylate was carried out in a heterogeneous system by use of mutual irradiation, preirradiation, and catalytic method. In all cases trichloroethylene or carbon tetrachloride was added to the reaction mixture to shorten the branches. True graft copolymers were isolated by vigorous alternate extraction of unreacted PVAL and homo‐PST (or‐PMMA), and hydroxyl groups in the copolymers were completely acetylated to carry out osmotic measurements. Molecular weights of the separated chains and the mother polymers were also determined by osmometry. It was shown that the graft copolymer has only one mother PVAL molecule and one graft branch regardless of the grafting methods employed. In the case of cellulose, high tenacity rayon was used as a substrate. The reaction product was acetylated, and the extraction of homo‐PST and unreacted cellulose (in the form of triacetate) was carried out with benzene (at 80°C) and CH2 Cl2 ‐MeOH (1:1, at room temp.), respectively. In this case also, it was shown that the graft copolymer molecule consisted of one graft branch and one mother cellulose molecule.