In this article, the morphological transformation in Hibiscus sabdariffa stem fiber through graft copolymerization with effective ethyl acrylate (EA) and its binary vinyl monomeric mixtures using ceric ammonium nitrate-nitric acid initiator system has been reported. Different reaction parameters such as temperature, time, initiator concentration, monomer concentration, and pH were optimized to obtain the maximum graft yield (117.3%). The optimized reaction parameters were then used to screen the additive effect of EA with n-butyl acrylate (BA), acrylic acid (AA), and 4-vinyl pyridine (4-VP) in binary vinyl monomer mixtures on percentage grafting, properties, and the behavior of the fiber. The graft copolymers were characterized by FTIR, SEM, XRD, TGA, and DTA techniques and evaluated for physico-chemical changes. With increase in the P(g) a significant physico-chemico-thermal resistance, miscibility in organic solvents, hydrophobicity were found to increase, whereas crystallinity, crystallinity index, dye-uptake, and hydrophylicity decreased, however, the cellulose form I remained unchanged. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1650-1657, 2012