RAFT mediated grafting of poly(t-butyl acrylate) onto the surface of a commercial poly(ethylene-co-propylene), Elpro, has been carried out using initiation by Co-60 gamma-radiation at 298 and 273 K. The polymerizations were in bulk monomer and using the RAFT agent 1-phenylethyl phenyldithioacetate. The rates of homopolymerization and grafting were found to decrease with increasing RAFT agent concentration, indicating that both polymerization processes involve participation of the RAFT agent. There was good agreement between the predicted and experimental molecular weights of the homopolymer that had a narrow polydispersity. The poly (t-butyl acrylate) grafts were hydrolyzed by trifluoroacetic acid to form poly(acrylic acid) grafts, which could either be further functionalized or used to control the surface polarity of the Elpro. ATR-FTIR spectroscopy was used to characterize the grafts and Raman spectroscopy was used to assess the depth of the grafts. The water contact angle for the Elpro surface grafted with poly(acrylic acid) was found to be linearly dependent on the amount of the graft present. The living nature of the grafted chains was demonstrated by the addition of a second block of polystyrene. (c) 2006 Wiley Periodicals, Inc.