Elasticity of wool as related to its chemical structure

Abstract

Wool protein, like other fibrous proteins. is composed of long, fle xible molecular chains. This flexibility appears to be the basis of the "long-range" elasticity of wool fibers. The wool fiber is distinguished from othu textile fibers by the presence of covalent disulfide cross-links between these main chains. Rupture of these links by chemical means decreases the strength of the fiber without necessarily affecting the elastic recovery. Rebuilding the covalent linkages largely restores the original properties of the fiber. Wool appears to be analogous to rubber in several r espects. Thus the stress-strain, solubility, and swelling characteristics are greatly influenced by the extent of cross-linking in the two materials.