Persulfate Degradation of Wool

Abstract

Degradation and discoloration of wool by persulfate in aqueous solution are greater at pH 1.6 than at pH 4.6. The main damage is believed to be due to attack by hy droxyl-free radicals resulting from decomposition of persulfate, since little damage can be attributed to hydrolytic action. Amino acid analyses on untreated and on degraded wool show significant attack of cystine, methionine, arginine, histidine, proline, tyrosine, and possibly phenylalanine. Evidence for non-hydrolytic cleavage of the protein chain and attack of terminal amino acids is presented. N,N-Dimethylacetamide greatly moderates the action of persulfate on wool, probably through preferential reaction with hydroxyl radicals. Polyacrylamide on wool gives no protection against persulfate, but poly-N,N-dimethylacrylamide gives some protection.