Seyed Ahmad Ayati Najafabadi - Biomaterials Group, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran Iran,
Hengameh Honarkar - Polyurethane and Advanced Polymers Department, Faculty of Science, Iran Polymer and Petrochemical Institute, Tehran, Iran
Majid Moghadam - Catalysis Divisions, Department of Chemistry, University of Isfahan, Isfahan, Iran
Valiollah Mirkhani - Catalysis Divisions, Department of Chemistry, University of Isfahan, Isfahan, Iran

In this study, molecular weight of chitosan was reduced by using ultraviolet (UV)-irradiation (wavelength=254 nm) and hydrogen peroxide (H2O2), simultaneously. The efficiency of the depolymerization was demonstrated by determination of viscosity-average molecular weight. Moreover, the structure of the depolymerized chitosan was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Nuclear magnetic resonance (1H NMR) and UV–visible (UV-Vis) spectroscopy. The FTIR and 1H NMR studies demonstrated the breakage of 1,4-β-D-glucoside bonds of chitosan. XRD quantitative analysis also showed that crystalline structure of the chitosan changed during depolymerization. The results showed that combined UV-irradiation/H2O2 method was significantly efficient for preparing low molecular weight chitosan and could be applied in scale-up production of the depolymerized chitosan

Ultraviolet Irradiation- H2O2- Depolymerization- Chitosan- Oligosaccharide