Preparation and characterization of water-soluble N-alkylated chitosan

N-Alkylated chitosan derivative was synthesized by Michael addition reaction of chitosan and hydroxyethylacryl. The chemical structure and physical properties of the chitosan derivatives were characterized by FT-IR, 1H NMR, XRD and DSC techniques. The 1H NMR results indicated that the degree of substitution (DS) was from 0.18 to 1.2. The chitosan derivatives exhibited an excellent solubility in distilled water. XRD analysis showed that the derivatives were amorphous. DSC results demonstrated that thermal stability of the derivatives was lower than that of chitosan and it decomposed around 226 °C for hydroxyethylacryl-CS with DS higher than 1.05. The lysozyme enzymatic degradation results revealed that the chitosan derivatives had the ability to enzymatic degradation and the initial degradation rate of the chitosan derivatives was dependent on its molecular weight. The antimicrobial activity of the chitosan derivatives was decreased compared with that of chitosan, but it still had the ability of antimicrobial.