Solvothermal synthesis is an important technology to prepare the inorganic matter. In this investigation, xylenewater-thermal reaction of polypropylene (PP), styrene (St), and maleic anhydride (MAH) under pressure was carried out to prepare grafting polymers. Infrared (IR) spectra and NMR spectra confirmed that MAH and St were successfully grafted onto the PP backbones. Through differential scanning calorimetry (DSC) and X-ray analysis, it was found that the crystallinity of grafting polymers decreased due to the formation of side chains. Response surface methodology (RSM) was applied to investigate the influence of various factors on the grafting percentage. The predicted results coincided well with the experimental values at optimum reaction conditions; therefore, the response model was adequate to reflect the expected optimization. (c) 2011 Wiley Periodicals, Inc. Adv Polym Techn 32: 109117, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20242