Natural fiber composites have been prepared by grafting hydrophobic monomer methyl methacrylate (MMA) onto chemically modified rice straw (RS) using complex initiating system [CuSO4/glycine/ammonium persulfate (APS)] in an aqueous medium with and without the additive, sodium silicate (SS). The chemically modified RS, RS-g-PNIMA, and RS-g-PMMA/SS composite have been characterized by FTAR, and their morphology was studied by scanning electron microscopy (SEM). The thermal behavior and tensile properties of the samples have been studied, and the flame retardant proper-ties have also been evaluated by limiting oxygen index (LOI) test and cone calorimetry. The biodegradation and water absorbency have been carried out for its ecofriendly nature and better commercialization. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113:3710-3715, 2009