Methylmethacrylate (MMA) and octadecyl acrylate (OA) were grafted to poly(methythydrosiloxane) (PMHS) by hydrosilylation, respectively, with hexachloroplatinic acid as catalyst, and the former was further hydrolyzed to prepare methacrylic acid (MAA)-graft-PMHS under the alkaline condition. Through orthogonal experiment, main factors affecting the graft reaction between OA and PMHS were discussed and arranged in a decreasing order according to their abilities of the effect on the hydrosilylation of OA with PMHS: catalyst dosage, reaction temperature, reaction time, material ratio, and solvent dosage. It was found that the hydrosilylation of OA with PMHS was easier to that of MMA with PNIHS. Under optimal conditions, the grafting ratios of MMA with PMHS and CA with PMHS reached about 90 and 95%, respectively. FTIR and H-1 NMR spectra indicated that the hydrosilylation reactions followed the Markovnikov's rule and played a strong preference toward beta-1,2-addition. The test of contact angle indicated that surface energy of a system was mainly dependent on the polar groups. The surface energy of OA-graft-PMHS (35.07 mN/m) was similar to those of PNIHS (35.62 mN/m) and polyoctadecyl acrylate (36.57 mN/m), and lower than that of MAA-graft-PMHS (43.50 mN/m). (C) 2007 Wiley Periodicals, Inc.