Graft copolymers of cellulose and vinylic ketones. I. Preparation of poly(methyl vinyl ketone)–cotton cellulose copolymers

The graft copolymerization reaction of methyl vinyl ketone from several solvents with fibrous cotton cellulose, preirradiated to a dosage of 5.2 × 10¹⁹ eV/g with γ-radiation from ⁶⁰Co, was investigated. Solvents included water, methanol, N,N-dimethyl formamide, and several combinations of these solvents. From water a maximum yield of copolymer product was obtained after 2 hr at 25°C. The addition of methanol to aqueous solutions of methyl vinyl ketone, in all concentrations, inhibited the graft copolymerization reaction. The addition of a small amount of N,N-dimethylformamide to aqueous solutions of the monomer increased the rate of the copolymerization reaction; however, the addition of large amounts of N,N-dimethylformamide to these solutions also inhibited the reaction. From solutions of methanol or N,N-dimethylformamide and monomer, little or no copolymerization of monomer with irradiated cellulose occurred. The copolymer products exhibited a strong infrared absorption band at 5.85 μ which is characteristic of the ? C?O group of the grafted poly(methyl vinyl ketone). Fibrous copolymer yarns exhibited increased yarn number and decreased breaking strength and average stiffness, as compared with unmodified cotton yarns.