Pullulan modification via poly(N-vinylimidazole) grafting

Abstract

A new cationic pullulan derivative was obtained via graft copolymerization of N-vinylimidazole (NVI). Grafting of poly(N-vinylimidazole) (PNVI) onto pullulan has been achieved in aqueous medium using ammonium persulphate (APS) as the initiator. The effect of monomer concentration, pullulan concentration, initiator concentration, time and temperature on the grafting yield has been investigated. The highest grafting yield (513%) of pullulan-graft-PNVI was obtained using 0.016 M pullulan, 0.66 M NVI, 0.18 M APS at 40 degrees C in aqueous solution for 3 h under nitrogen atmosphere. Water-soluble products were obtained which were further characterized by FTIR, elemental, TGA, SEC and H-1 NMR analyses. Pullulan-graft-PNVI gave soluble and insoluble complexes in aqueous acidic medium with tripolyphosphate and citrate ions due to its cationic nature. (C) 2018 Elsevier B.V. All rights reserved.