Abstract:

Chitosans with two different degrees of deacetylation (DD) were used separately prepare different concentrations
of chitosan solutions by using different concentrations (V/V) of acetic acid solutions as dispersing agent and different
concentrations (m/V) of sorbitol as plasticizer. We examined the effect of acetic acid, sorbitol and chitosan concentration on
the pH and conductivity of chitosan solutions, and illustrated the roles of ionic polymerizations in chitosan film formation.
The rheological properties of chitosan film-forming solutions were studied and the effect of sorbitol on the properties of
chitosan film-forming solutions and the formed films was analyzed. Results showed that sticky solution was formed by
combination of ions from sorbitol, acetic acid and chitosan. Chitosan film-forming solutions with and without sorbitol as
plasticizer were both pseudoplastic fluid, and sorbitol presented a good compatibility with the two kinds of deacetylated
chitosan that could form uniform and continuous films, resulting in a shift in the endothermic and exothermic peak
temperatures of chitosan films and presenting certain influence on their thermal stability.

Key words: chitosan, solution properties, chitosan film, thermal stability