Biodegradation Characteristics of Chitin and Chitosan Films

This research focused on the development of recyclable materials by using chitin and chitosan obtained from shells of crab, shrimp and lobster. The fabrication of chitin and chitosan films was investigated is terms of their mechanical properties and biodegradation. The tensile strength of chitin films was 30-40% lower than that of chitosan films, but the crystallinity of chitin film was much higher than that of chitosan films. The crystallinity and orientation of crystallites were hardly affected by the four kinds of solvent chosen to cast chitosan films, but a detailed analysis revealed that the cast film prepared with acetic acid provided slightly lower crystallinity than others. The degradation rate of chitin films by Sphingobacterium multivorum, a kind of decomposition bacteria separated from soil, was higher in comparison with the chitosan films. The degradation rate of chitosan samples prepared with acetic acid was the highest, followed in order by the films prepared with propoinic acid, formic acid and butyric acid. SEM observation revealed that the degradation of chitosan films was followed by exfoliation of chitosan fibrils from the film surface. (Received September 12, 2005; Accepted in revised form October 21, 2005)