HETEROGENEOUS MOLECULAR AGGREGATION AND FRACTAL STRUCTURE IN CHITOSAN ACETIC-ACID SYSTEMS

The influence of deacetylation degree on heterogeneous molecular aggregation has been investigated for chitosan solution in 2 wt % acetic acid aqueous solution using rheological and small-angle x-ray scattering (SAXS) methods. Three samples of chitosan, which were designated CS62, CS79, and CS96, were used, and the deacetylation degrees of these samples were 0.62, 0.79 and 0.96, respectively. Rheological properties show that the systems of CS62 and CS96 are homogeneous, and the system of CS79 has a certain heterogeneous structure with a long-time relaxation mechanism. According to the SAXS measurement, the heterogeneous system has a fractal structure and the fractal dimension is about 1.3.