Graft copolymerization of acrylamide onto xanthan gum

The graft copolymerization of acrylamide onto xanthan gum initiated by the Fe2+/BrO3- redox system in aqueous medium was studied gravimetrically under a nitrogen atmosphere. The effect of Fe2+,:BrO3-, H+, acrylamide and xanth an gum on graft copolymerization was studied by determining the grafting pa rameters, i.e. grafting ratio, efficiency, conversion and add on. Homopolym er too has been separated out. An increase in grafting parameters was obser ved with increase in ferrous ion concentration (4 x 10(-3) mol dm(-3) to 5. 0 x 10-3 mol dm-3) while with increasing bromate ion concentration, graftin g ratio, efficiency, add on and conversion were found to decrease. It was o bserved that grafting takes place efficiently when acrylamide concentration and temperature were 4.0 x 10(-3) mol dm-3 and 35 degreesC, respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.