Solid State Grafting Copolymerization of Acrylamide onto Poly(vinyl alcohol) Initiated by Redox System

A solid state grafting copolymerization of acrylamide (AM) onto poly(vinyl alcohol) (PVA) was conducted with ammonium persulfate and sodium bisulfite redox system as initiators. Before the reaction the PVA powder and required amount of AM were mixed evenly, and sprayed with water to swell the PVA powder and to dissolve AM. Then the swollen PVA powder was sprayed with the redox solution, and the reaction temperature was controlled at a temperature between 30 degrees C and 80 degrees C for 120 min. The grafting percentage and efficiency were determined as functions of monomer/PVA ratio, initiator concentration and reaction temperature. The structure and performance of the graft copolymers were confirmed by FTIR-ATR, XRD, C-13 NMR, and thermogravimetric analysis, together with mechanical property and apparent viscosity measurements. It has been confirmed that grafting copolymerization of AM onto PVA initiated by this redox system occurred with higher grafting percentage and efficiency in the solid state. The thermal stability and water-solubility of grafted PVA were found to be better than those of unmodified PVA. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39938.