Graft copolymer (chitosan-g-N-vinyl formamide):: Synthesis and study of its properties like swelling, metal ion uptake and flocculation

A graft copolymer of chitosan and N-vinyl formamide has been synthesized by free radical polymerization using bromate/cyclohexanone redox in an inert atmosphere. The grafting ratio, add on, and efficiency increase continuously with increase in concentration of N-vinyl formamide from 9 x 10(-2) mol dm(-3) to 41 x 10(-2) mol dm(-3), bromate ion from 0.4 x 10(-2) mol dm(-3) to 2.4 x 10(-2) mol dm(-3) and chitosan from 0.6 g dm(-3) to 1.4 g dm(-3). Grafting parameters decrease with increase in concentration of hydrogen ion from 2 x 10(-3) mol dm(-3) to 10 x 10(-3) mol dm(-3). Experimental results also show that these parameters i.e. grafting ratio, add on, and efficiency increase with increase in cyclohexanone concentration from 0.4 x 10(-2) mol dm(-3) to 1.2 x 10(-2) mol dm(-3), but beyond this cited range, these parameters decrease. Maximum grafting i.e. 189.5% has been found at 120 min and 40 degrees C. The swelling, metal ion sorption and flocculation capability have been studied, respectively. The flocculation capability of chitosan and chitosan-g-N-vinyl formamide in both coking and non-coking coals has been studied for the treatment of coal mine waste water. The graft copolymer has been characterized by Infra red (IR) spectroscopy and thermogravimetric analysis. (C) 2008 Elsevier Ltd. All rights reserved.