The grafting of polyacrylamide to polypropylene was realized with supercritical carbon dioxide as a substrate-swelling agent and monomer/initiator carrier. The effects of supercritical carbon dioxide assisted impregnation and graft polymerization conditions on the grafting ratio were studied. The original polypropylene and grafting products were characterized with infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. (c) 2006 Wiley Periodicals, Inc.