Synthesis and characterization of graft copolymer of sodium alginate and poly(itaconic acid) by the redox system

In this study, grafting of itaconic acid (IA) onto sodium alginate (NaAlg) using cerium(IV) ammonium nitrate/nitric acid (CAN/HNO₃) as redox system was carried out by free radical polymerization. The structures of the grafted copolymers (NaAlg-g-PIA) were characterized by ATR-FTIR spectroscopy, NMR spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The reaction conditions for maximum grafting were optimized by varying the reaction time, temperature, percentage of sodium alginate, monomer, initiator, and nitric acid concentrations. The optimum reaction conditions were obtained with reaction time of 5 h, reaction temperature of 30 °C, IA concentration of 0.92 M, CAN concentration of 1.368 × 10^?1 M, HNO₃ concentration of 0.094 M and percentage of NaAlg 0.5 g/dL. The solubility test of NaAlg-g-PIA was also investigated using solvents. The results indicate that prepared graft copolymer was non-soluble in the various solvents, while it was soluble only in saturated solution of NaOH and promising as an adsorbent.