Cellulose Graft Copolymers

Graft copolymerization reactions of fibrous cellulose with vinyl monomers were initiated at free radical sites formed on the cellulose molecule by interaction with high-energy radiation, by reaction with Ce4+ ions in acidic solution, or by H abstraction by ·OH radicals fromed by reaction of Fe2+ ions with HLOz in aqueous solution. The effects of experimental conditions on the nature, half-lives, location of these free radical sites on the cellulose molecule, and on the copolymerization reactions were studied by the use of electron spin resonance spectroscopy. The molecular weights of the grafted polymers varied over a range from about 3 × 104 to 1 × 106. The distributions of the grafted polymers within the fibrous cellulosic structure were determined. Some of the changes in physical properties of the cellulose graft copolymers, as compared with cellulose, were decreased permanent set, development of thermoplasticity, decreased stiffness, increased rot resistance, and increased abrasion resistance.