REVERSIBLE WATER-SWELLABLE CHITIN GEL

A novel, reversible, water-swellable chitin gel has been produced by t he carboxymethylation of a dry chitin film. The property of this mater ial is that unlike carboxymethyl-chitin, it takes up water but is not soluble and retains a degree of rigidity even when wet. The degree of swelling depends on the reaction conditions and alkali (sodium or pota ssium hydroxide) used as a co-reactant during the carboxymethylation. Upon drying, the gel returns to its dry film form. This water uptake a nd loss is cyclic, which is a desirable property in certain applicatio ns and is a tremendous advantage in the handling of this material. (C) 1997 John Wiley & Sons, Inc.