The optimum reaction conditions for affording maximum percentage of grafting have been established in the case of grafting of acrylonitrile (AN) onto Na-PCMGG (DS¯=0.497) using ceric ammonium nitrate (CAN) as a redox initiator, in an aqueous medium, by successively varying reaction conditions such as concentrations of nitric acid, ceric ammonium nitrate, monomer (AN) as well as reaction time, temperature and amount of substrate. The influence of these reaction conditions on the grafting yields have been discussed. The overall activation energy of grafting has been calculated. The IR-spectroscopic, thermal (TGA/DSC) and scanning electron microscopic (SEM) techniques have been used for the characterization of the graft copolymer.