Methylmethacrylate (MMA) + acrylamide (AAm), MMA + acrylonitrile (AN), and MMA + acrylic acid (AA) binary vinyl monomer mixtures were graft copolymerization onto acetylated Saccharum spontaneum L, was carried out and maximum graft yield (185.6 %) was found with MMA + AAm binary mixture. Synthesized graft co-polymers were characterized with FT-IR spectrophotometry, scanning electron microscopy (SEM), thermal analysis TGA/DTA/DTG, and X-ray diffraction (XRD) techniques. Thermal stability of Ss-g-poly(MMA + AAm) was found to be more than that of natural, acetylated S. spontaneum fiber and other graft copolymers. Although on grafting, percentage crystallinity and crystallinity index were found to decrease but graft copolymers were found to exhibit more moisture, chemical, and thermal resistance. Also, it can be observed that the surface of the grafted fibers is highly rough in comparison with the ungrafted fiber. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121:2060-2071, 2011