Graft copolymerization of methyl methacrylate onto rice husk

Graft copolymerization of methyl methacrylate (MMA) onto Rice Husk (RH) was synthesized with a fiber length less than 45 μm. The graft copolymerization was carried out under a nitrogen atmosphere by a free radical initiation in aqueous medium. Hydrogen peroxide and ferrous ions were used as a redox initiator/cocatalyst system. The PMMA homopolymer that formed during the reaction was removed from the grafted copolymers by soak with acetone for 24hr. The percentage of grafting was found to be dependent on the amount of monomer; temperature and amount of hydrogen peroxide were investigated. The optimum conditions for amount of monomer, reaction temperature and amount of hydrogen peroxide were 46.94mmol, 50oC and 5.88mmol, respectively. The highest percentages of grafting and grafting efficiency were 10.8% and 77%, respectively, under optimum condition. After removal of homopolymer, the graft copolymerization (grafted fiber) was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. The presence peak around 1666 cm-1 in the FTIR of the graft RH provides strong evidence of present MMA in the RH fibers. SEM reveals that the surface of the original RH fiber become rough and contained grooves and the surface of the fiber was homogenously covered by PMMA after graft copolymerization