Synthesis of Grafted Locust Bean Gum Using Vinyl Monomer and Studies of Physicochemical Properties and Acute Toxicity

Objective: The objective of the work was to synthesize polyacrylamide (PAAm) grafted locust bean gum (LBG) via conventional method using ceric ammonium nitrate (CAN) as free radical initiator to improve flocculation efficiency. Method: The effects of concentration of CAN, acrylamide (AAm), LBG, reaction time, and temperature on grafting were studied to determine the grafting percentage and grafting efficiency. The synthesized graft copolymers have been characterized by Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The swelling of graft copolymer was measured in different solutions with pH values ranging from 1 to 12. Viscosity of the polymer solutions were carried out with an Oswald viscometer. Flocculation efficacy of the graft copolymer was studied in kaolin suspension. The acute oral toxicity study of graft polymer was evaluated as per OECD guide line. Results: The graft copolymer shows swelling-deswelling behavior in buffer solutions with pH 2.0 and 9.0. The intrinsic viscosity of LBG improved significantly on grafting of polyacrylamide chains. Grafted copolymer gives better performance by showing lower turbidity than LBG. No mortality of the animal was observed during 14 days after treatment with graft copolymer. Conclusion: Among the grafted LBG, the graft copolymers showing higher intrinsic viscosity were the most efficient flocculent.