Influence of degree of N-butyrylation on critical concentration of N-butyrylated chitosan/dichloroacetic acid liquid crystalline solution

N-butyrylated chitosan with various degree of N-butyrylation (DB) were prep ared by mixing completely deacetylated chitosan and butyric anhydride in mi ld condition without serious degradation and O-substitution. A standard cur ve to measure DB was obtained by plotting the infrared absorbance ratio of A(1560)/A(2880) against the known DB (from 0%similar to 99%) of eight speci mens. The influence of DB on the critical concentration C* of N-butyrylated chitosan/dichloroacetic acid solutions required to form mesophase was inve stigated by optical method. A maximum C* value appeared at medium DB. The e ffect was explained by the disordering of chain with medium composition rat io of the copolymer of glucosamine and N-butyryl glucosamine.