The esterification and dyeing properties of raw wool fibers

The reaction of raw wool fibers (RWFs) with methanol, ethanol and n-propanol catalyzed by HCl has been found to modify carboxyl side chains. The effect of esterification of wool on its behavior toward acid dye has been studied. Esterified wool fibers (EWFs) showed an increase in acid dye affinity, and dyed esterified wool shows an increase in dye fastness to washing. The process of esterification with alcohols/hydrogen chloride caused some modification of carboxyl and other groups. The surface modification of wool fibers was determined by FTIR, modification rate of carboxyl groups and the acid dye distribution of RWFs and EWFs with various alcohols was evaluated by Datacolor.