Set and Release of Set in Wool Fibers: Release at 20°C

Abstract

Unreduced and reduced wool fibers were set in water at 80°C and 20°C, respectively. Both types were released at 20°C in water or hydrochloric acid solution. Often, length recovery was still continuing after release for many days. Length recovery was more rapid in the HCl solution. This indicates that disulfide/sulphydryl interchange is not an important rate-controlling process in recovery under the conditions specified. In agreement with previous work, it was found that the stress at the instant of release must have fallen below a, "critical" value if here is to be a residual set at times greater than one minute, after release. The "critical" stress is lower for reduced wool than for unreduced Wool. The forces aiding and opposing recovery are discussed, as well as changes in conformation accompanying set and recovery. Finally, the data are con sidered in terms of series-zone models for wool.