Preparation of chitosan and its miscibility studies with gelatin using viscosity, ultrasonic and refractive index

Chitosan was prepared from chitin by deacetylation using hot alkali (50% NaOH), and the DD (Degree of Deacetylation) was determined using FTIR spectroscopic method. The prepared chitosan was dissolved in buffer solution (0.2 M sodium acetate and 0.1 N acetic acid) and blended with modified natural polymer gelatin in solution. The miscibility of chitosan/gelatin blend in buffer solution was investigated by viscosity, ultrasonic and refractive index method at 30 and 50 C. Using viscosity data, the interaction parameter gamma and alpha, based on Chee and Sun et al. approaches were determined. The values indicated that the blend is immiscible in all proportion. The variation of ultrasonic and adiabatic compressibility with blend composition also supports the Sun et al. approach. This was further confirmed by refractive index method. The variation of temperature has no effect on miscibility of the chitosan/gelatin blend. (c) 2006 Elsevier Ltd. All rights reserved.