Mutual Radiation Grafting of Styrene onto Cellulose Acetate

A study of the gamma -ray-induced mutual grafting of styrene onto cellulose acetate (combined acetic acid, 52.8%) showed that cellulose acetate enhances the rate of polymerization of styrene. Dilution of the monomer with benzene accelerates the polymerization, with a maximum effect occurring at 60 mole% styrene. Grafting efficiency increases as monomer concentration increases also with increasing total dose for benzene solution, but decreases for acetone and dimethyl formamide solutions. Graft copolymer was separated from both homopolymers by alternating repeated extractions with benzene and acetone as solvents. Molecular weights of polystyrene formed in different regions in the reaction system used were quite different from one another. They increased in the following order of polymerization sites: surrounding monomer solution phase < monomer solution inside the cellulose acetate film < grafting layer. Isolated graft copolymer was much richer in the styrene component, and soluble in tetrahydrofuran, dioxane, and dimethyl formamide, but insoluble in both benzene and acetone. Polystyrene grafted on acetyl groups and that on the rest of glucose units of the stock polymer were isolated, respectively, but alkali saponification and by acetolysis of the cellulose backbone. The grafted amounts of the respective products were not very different from each other. Apparently, grafting did not take place predominantly on a specific part of the backbone polymer chain. (BBB)