Grafting of acrylic monomers onto cotton fabric using an activated cellulose thiocarbonate-azobisisobutyronitrile redox system

The feasibility of a cellulose thiocarbonate-azobisisobutyronitrile (AIBN) initiation system to induce graft copolymerization of methyl methacrylate (MMA) and other acrylic monomers onto cotton fabric was investigated. Other acrylic monomers were acrylic acid, acrylonitrile, and methyl acrylate. The initiation system under investigation was highly activated in the presence of a metal-ion reductant or a metal-ion oxidant in the polymerization medium. A number of variables in the grafting reaction were studied, including AIBN concentration, pH of the polymerization medium, nature of substrate, monomer concentration, duration and temperature of polymerization, and composition of the solvent/water polymerization medium. The solvents used were methanol, isopropanol, 1,4-dioxane, cyclohexane, benzene, dimethyl formamide, and dimethyl sulfoxide. There were optimal concentrations of AIBN (5 mmol/L), MMA (8%), Fe2+ (0.1 mmol/L), Mn2+ (8 mmol/L), and Fe2+ (2 mmol/L). A polymerization medium of pH 2 and temperature of 70degreesC constituted the optimal conditions for grafting. The methanol/water mixture constituted the most favorable reaction medium for grafting MMA onto cotton fabric by using the Fe2+-cellulose thiocarbonate-AIBN redox system. MMA was superior to other monomers for grafting. The unmodified cotton cellulose showed very little tendency to be grafted with MMA compared with the chemically modified cellulosic substrate. A tentative mechanism for the grafting reaction was proposed. (C) 2003 Wiley Periodicals, Inc.