Karaya Gum (KG) has been modified by graft copolymerization with 3,3- dimethyl acrylic acid in aqueous media initiating by diode laser (532 nm) or by cerium(IV) ammonium nitrate. The optimum reaction conditions to afford maximum and efficient graft copolymerization initiated by laser were 60 minutes laser irradiation time, 0.5 g of KG and 0.20 g of 3,3-dimethyl acrylic acid, whereas, those initiated by cerium(IV) ammonium nitrate (CAN) where 3 h of the reaction, 0.5 g of KG, 0.20 g of 3,3-dimethyl acrylic acid at 30 °C. The grafting ratio and homopolymer have been determined for both. The percentages of graft efficiency and of graft yield were 36% and 90%, respectively, using laser beam and were 26% and 76%, respectively, using CAN. The graft copolymers were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscope (SEM) which proved a successful production of KG-g-3,3-dimethyl acrylic acid. The laser irradiation was found to be effective and green tool for producing KG-g-3,3-dimethyl acrylic acid (graft polymer).
