Synthesis, Characterization, and Swelling Studies of Gum Arabic–Grafted Methacrylic Acid Polymeric Network

Abstract

Gum arabic–based copolymer has been synthesized by free radical polymerization of methacrylic acid (MAA) onto gum arabic in the presence of potassium persulfate (KPS). Hexamethylene tetramine (HMTA) was used to give the copolymer a three-dimensional cross-linked structure. The reaction has been carried out under vacuum in order to prevent hindrance caused by air in the reaction. Various reaction parameters like reaction time, temperature, pH, KPS concentration, MAA concentration, HMTA concentration, vacuum, and amount of solvent have been optimized to achieve maximum percentage grafting. The characterization was carried out using FT-IR, SEM, and TGA/DTA/DTG techniques, which confirmed the grafting of MAA onto gum arabic. Various swelling studies have been carried out with the copolymer at room temperature, at elevated temperatures, in different salt solutions, and in different pH media. The results showed that MAA concentration, temperature, and pH affect the percentage swelling of graft copolymer to a reasonable extent. The copolymer swelled in different salt solutions but to a lesser extent than in distilled water.