Preparation of O-carboxymethyl chitosans and their effect on color yield of acid dyes on silk

O-Carboxymethyl chitosans with a low degree of substitution (DS) and a high degree of deacetylation (DD) were prepared directly from chitin and characterized by using H-1-NMR, C-13-NMR, and elemental analysis methods. In our study, O-carboxymethyl chitosans could increase the color yield of Acid Red 44 and Acid Green 25 on silk fabrics without lowering the corresponding washing fastness property. (C) 2003 Wiley Periodicals, Inc.