The Modification of Wool Fabric by Certain Organic Sorbates

Abstract

Organic sorbates, chiefly sulfate and sulfonate derivatives, when adsorbed by wool from aqueous solution decreased the amount of water the fabric would absorb subse quently. The thermodynamic parameters for the adsorption of one of the sorbates have been obtained and compared with those for other protein/detergent systems. The over all change in standard entropy of adsorption is positive ; the interpretation of this is that dye adsorption is accompanied by water desorption, leading to an increase in entropy. As the amount of sorbate incorporated into the wool increases, the amount of water desorbed increases. The sorbate is not readily desorbed when the treated fabric is sub sequently exposed to water and, hence, the change in entropy for the sorption of water by the treated fabric will be different from the corresponding change for the untreated fabric. This factor should be considered in discussion of the regain of treated fabric. It was not possible to compare the water-sorption properties of all the treated fabrics on the basis of the molar concentration of the additive. Where comparisons could be made, it was evident that those additives containing the highest percentage of alkyl chain per molecule produced the greatest lowering of regain in the hydration region of the sorption isotherm and, therefore, presumably the greatest decrease in the polar nature of the wool. It is suggested that the decrease in saturation regain of the treated fabrics is analogous to the precipitation of water-insoluble anionic detergent/protein complexes.