The Structure of Chitin and Chitosan,

摘要

Chitin is the basic structural material in the exoskeletons of arthropods (crab,shrimp,lobster and most insects),and it also occurs in certain fungi. Chemically,the material is a poly-N-acetylglucosamine,and it is related to cellulose,differing from the latter in having an aminoacetyl group, CH3COHN-,substituted for one of the hydroxyl groups. Chitosan is a partially deacetylated chitin and differs from the latter in being quite soluble in dilute acids;chitin is virtually insoluble and is only decomposed slowly by certain enzymes. Chitosan is a polyelectrolyte and has considerable potential as a chelating agent for minerals,organic materials,and food products. It is also a good film former,and has been shown to impart wet strength to paper. Two pilot plants are now producing chitin and chitosan with the expectation that significant utilization will occur as these materials become available in commercial quantities. This report describes the research done to determine whether the structure of chitin and chitosan is dependent on the type of crustacean used as a source of raw material. Also investigated is the structure as well as the mechanical and electrical properties of amorphous chitosan films.