The Sorption Behavior of Cystine-Modified Wool

Abstract

The sorption behavior of wool fibers with a reduced cystine content has been studied, using water and formic acid as sorbates. Reduction alone causes little change of the sorption behavior but reduction followed by alkylation of the sulfhydryl groups causes changes depending on the extent of reduction and the alkylation procedure.

The water absorption isotherm of the alkylated wool is less than the corresponding isotherm of unmodified wool until near-saturation humidities where the water content becomes higher for the alkylated samples. For absorption at high humidities the uptake curves of reduced and methylated samples show large overshoots of water content above the equilibrium water content. For samples alkylated with alkyl dihalides such that new cross-links are formed, the rate of uptake is less than for unmodified wool, but at saturation the water content is between that of unmodified wool and reduced and methylated wool. The conversion of cystine to lanthionine in wool also leads to increased water contents at high humidities. The changes in sorption behavior of the modified wools are more marked when formic acid vapor is the sorbate.