Solubility as a Criterion of Cross-Linking in Wool

Abstract

Three commonly used solubility tests have been applied to wools treated with various mono- and bifunctional active esters. Treatment with the bifunctional esters invariably leads to large reductions in solubility. Those monofunctional esters which introduce bulky groups into wool also decrease its solubility. However, bifunctional reagents reduce the solubility to a greater extent than monofunctional reagents of similar size, particularly with the performic acid-ammonia and urea-thioglycollate tests. The urea- bisulfite test, on the other hand, is so sensitive in detecting chemical modification that it differentiates poorly between the introduction of bulky groups and cross links. Whereas none of these tests can be used to prove the presence of cross links unequivocally, the former two can be used, in conjunction with other tests, as a qualitative criterion of cross-linking.