Polyacrylamide and Poly N,N-Dimethylacrylamide Grafted Hydroxyethyl Starch: Efficient Biodegradable Flocculants

摘要

Synthesis of Hydroxyethyl Starch grafted Polyacrylamide (HES-g-PAM) and Poly N,N-dimethyl-acrylamide (HES-g-PDMA) is carried out by Ce~(+4) in water medium. The reaction conditions for maximum grafting is optimized by varying the reaction variables, including the concentration of monomers, ceric ammonium nitrate (CAN), Hydroxyethyl Starch, reaction time and temperature. The grafted copolymers are characterized by FTIR spectroscopy, NMR (both ~1H and ~(13)C) spectroscopy, Molecular weight determination and Molecular weight distribution by using Gel Permeable Chromatography (GPC), Thermal Analysis (TGA), SEM, XRD studies. Biodegradation of the graft copolymers is carried out by enzyme hydrolysis. Flocculation performances of the graft copolymers are evaluated in 1.0 wt% coal suspensions. A comparative study of the flocculation performances of HES-g-PDMA and HES-g-PAM was also made. It shows that the flocculation performance of HES-g-PDMA is better than that of HES-g-PAM. HES-g-PDMA performs best when compared with other commercial flocculants in the same suspension.