Synthesis and thermal characterization of xylan-graft-polyacrylonitrile

► Grafting polyacrylonitrile onto xylan via ceric ion initiated polymerization. ► Ceric solutions prepared with perchloric acid or nitric acid and optimum conditions were determined for both ceric solutions and characterizations were performed. ► Perchloric acid employed polymerizations realized at milder temperatures than nitric acid employed reactions. ► Oxidation of xylan was observed for both reactions, but it was higher when perchloric acid was used. ► Molecular weight and conversion ratio were controlled by acid type and thermal behaviors of the copolymers were greatly affected by molecular weight and acid type. In this study emulsion polymerization of acrylonitrile using xylan from agricultural waste material (corn cob) and cerium ammonium nitrate was investigated in terms of catalyst acid. Stock ceric solutions were prepared using either nitric or perchloric acid as catalyst. Optimum conditions were determined using different parameters such as reaction time, temperature, and component concentrations. Nitric acid catalyzed reactions resulted in maximum conversion ratio (96%) at 50°C, 1h where ceric ion, acrylonitrile, xylan, and catalyst concentrations were 21.7mmoll−1, 0.5moll−1, 0.2% (w/v), and 0.1moll−1, respectively. However, 83% conversion was obtained with perchloric acid catalysis at 27°C, 1h where concentrations were 5.4mmoll−1, 0.8moll−1, 0.5% (w/v), and 0.2moll−1, respectively. Copolymer synthesis using perchloric acid was realized at milder conditions than using nitric acid. Thermal analyses of obtained polymers were conducted to characterize copolymers. Results showed that calculated activation energy, maximum degradation temperature, and heat of thermal decomposition changed relying mainly on molecular weight.