Modification of Sodium Salt of Partially Carboxymethylated Guar Gum by Graft Copolymerization with Methyl Acrylate

Abstract

Grafting of methyl acrylate onto sodium salt of partially carboxymethylated guar gum (backbone) was carried out using ceric ammonium nitrate as a redox initiator in an aqueous medium. The reaction variables including concentrations of initiator, nitric acid, monomer and amount of the backbone as well as time and temperature were varied for establishing the optimized reaction conditions for grafting. The influence of these reaction parameters on the grafting yields and the rates of polymerization, graft copolymerization and homopolymerization was also studied and the results were discussed. The kinetic scheme of free radical graft copolymerization was proposed and the experimental results were found to agree very well with the proposed kinetic scheme. The graft copolymer sample was characterized by IR-spectroscopic, thermal and scanning electron microscopic techniques.