Synthesis and characterization of chitosan‐ g ‐methacrylic acid and studies of its additional physicochemical properties, such as swelling, metal‐ion sorption, and flocculation behavior

The aim of this study was to examine the synthesis of a graft copolymer of chitosan and methacrylic acid (MAA) by free‐radical polymerization with a potassium peroxymonosulfate/cyclohexanone (CY) redox system in an inert atmosphere. The optimum reaction conditions affording maximum grafting ratio (% G ), grafting efficiency (% E ), add on (% A ), and conversion (% C ) were determined. The grafting parameters were found to increase with increasing concentration of MAA up to 24 × 10 −2 mol/dm 3 , but thereafter, these parameters decreased. With increasing concentration of peroxymonosulfate from 0.6 × 10 −2 to 1.2 × 10 −2 mol/dm 3 , % G , % A , and % E increased continuously. All of these grafting parameters increased with increasing concentration of CY up to 1.2 × 10 −2 mol/dm 3 , but beyond this concentration, the grafting parameters decreased. With various concentrations of chitosan from 0.6 to 1.4 g/dm 3 , the maximum % G , % A , and % E were obtained at 1.4 g/dm 3 . % G , % A , and % C decreased continuously with various concentrations of hydrogen ions from 2 × 10 −3 to 6 × 10 −3 mol/dm 3 . The grafting parameters increased with increasing temperature up to 35°C, but thereafter, these parameters decreased. With increasing time period of reaction from 60 to 180 min, % G , % A , and % E increased up to 120 min, but thereafter, these parameters decreased. The graft copolymer was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009