Effect of Dimethyl Sulfoxide on Chemical and Physical Properties of Wool

Abstract

A study was made of the chemical reactivity of wool in dimethyl sulfoxide (DMSO) as well as the effect of DMSO and related aprotic solvents on the physical properties of wool. Some functional groups in wool, especially amino groups of lysine and imidazole groups of histidine, are readily modified in DMSO in the presence of triethylamine by activated vinyl compounds (e.g., acrylonitrile and (di)vinyl sulfone). Treatment with vinyl sulfone increases the resistance of wool to oxidation by peracetic acid, suggesting that new cross links are present. Also studied were (a) the relative reactivities in aqueous, aqueous-DMSO, and DMSO media; (b) the supercontraction of wool and densification of felts by DMSO; (c) the effect of heating wool in DMSO on amino acid composition; and (d) stress relaxation of hair, including sulfhydryl- disulfide interchange. Our studies suggest that DMSO is a useful medium in which to modify wool with various reagents. In some applications, DMSO has advantages over water.