Novel Biodegradable Flocculating Agents Prepared by Grafting Polyacrylamide to Konjac

Grafting copolymers of polyacrylamide (PAM) with Konjac gum (KGM) have been synthesized using ceric-ion-induced initiation technique. The copolymers were characterized using several instrumental techniques, including infrared (IR) spectroscopy, elementary analysis, scanning electron microscopy (SEM), size exclusion chromatography (SEC) analysis, and intrinsic viscosity to confirm the success of grafting. The flocculation performance of graft copolymers was characterized by two methods. One was to study the relationship between the flocculants doses in kaolin Suspension and the Supernatant transmittance, and the other is to examine the time dependence of sediment height of kaolin suspensions. It was found that the graft copolymer is better than KGM and pure PAM. Biodegradation behavior was testified by monitoring the decay of relative viscosities, and approved by KGM ether bonds breaking in IR spectra and the molecule weight reduction in SEC analysis. The results indicate that the grafted KGM copolymers have improved both, flocculation performance and better biodegradable properties than the unmodified parent KGM and pure PAM. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 2527-2536, 2009