Abstract
A study on the dyeing behavior of an acid dye on extended and unstretched wool fibers was made in connection with the structural transformation of the fibers. It was observed that in a pH range between 4 and 6 remarkable differences in dye uptake for extended and unstretched fibers were obvious and the extended fibers adsorbed a larger amount of the dye compared to unstretched fibers do at the same pH. It was suggested that this result was attributable to changes of dissociation constant(s) and/or micro-environment of dissociative groups of wool fiber. Furthermore, the amount of dye uptake increased with increasing the extent of extension up to 50% and the amount of dye uptake reached a constant value at extensions beyond 50%. It was recognized that these dyeing behaviors were correlated with the structural transformation of wool fiber from α- to β-form.
