THE USE OF CHITOSAN ON HYDROGEN-PEROXIDE PRETREATED WOOL

Since chlorination is known to produce substantial pollution with adso rbable organo halogens (AOX) in textile wastewater, shrink resist trea tments like the widely used chlorine/Hercosett process are no longer e nvironmentally acceptable. The current trends towards the use of natur al products have led to using polymers of natural origin such as chito san as a substitute for synthetic polymers in wool finishing given its properties of biodegradability, bioactivity, and biocompatibility. Th e application of chitosan to wool in a zero-AOX aqueous treatment to i mprove shrink-resistance and dyeing properties was investigated. To en hance chitosan sorption, wool was subjected to hydrogen peroxide treat ment prior to the chitosan treatment either under alkaline or acidic c onditions. A staining technique was used to assess the presence and di stribution of chitosan on wool. The alkaline hydrogen peroxide pretrea tment promoted the diffusion of chitosan into the wool fiber leading t o shrink-resist properties. To determine the influence of treatment co nditions on the dyeing behavior, a low temperature (60C) was used. Dye d chitosan-treated wool, pretreated with hydrogen peroxide either at a lkaline or acid pH, showed high values of exhaustion and fixation.