Synthesis and characterization of kitosan graft copolymers

Chitosan and chitosan derivatives are green biopolymers that have unlimited usage areas and are of great importance due to their distinctive features. In this study, chitosan graft copolymers; Chitosan was synthesized by Schiff base synthesis reactions, carboxylation reactions and graft modification reactions. First, the synthesis of schiff bases of chitosan, the synthesis of 4-hydroxybenzaldehyde-chitosan was carried out by two different methods with acid and base catalysts. In addition, graft copolymers of 2,3,4-trihydroxybenzaldehyde-chitosan, indole-3-carboxaldehyde-chitosan and 1-naphthaldehyde-chitosan were synthesized. The synthesis of chitosan carboxyl derivatives was carried out with three different methods, with 2-chlorosodium acetate 1) catalyzed by NaOH at room temperature 2) grinding at 120 °C in solid phase and 3) in ethylene glycol at 120 °C catalyzed by sulfanilic acid. The synthesis of terephthalaldehyde-chitosan graft copolymers was carried out with two different methods as base-catalyzed and acid-catalyzed. In addition, a cinnamoyl chloride-chitosan graft copolymer was synthesized. The structures of the synthesized chitosan graft copolymers were characterized using scanning electron microscopy (SEM), UV-vis. absorption, fluorescence emission and FT-IR spectroscopy techniques.