Recovery Process in Stretched Wool Fibers

Abstract

The recovery process in stretched wool fibers at different strain levels ranging from 5% to 40% was investigated at room conditions for a long time, up to one year, and in water. The recovery process in stretched wool fibers is quite slow at room conditions; thus this slow recovery process causes quite high remaining deformation on the wool. The recovery process in the strain (ϵ) and logarithm time (log t) coordinates has a linear dependence in the wide time range that allows estimating the required time for a complete recovery. In contrast to the rather slow recovery process at room conditions, a complete recovery in water at room temperature was observed within approximately 30 s. Structural changes during the recovery processes at room conditions and in water were analyzed by an FTIR/ATR method. The influences of water content and new formations of hydrogen bonds in the recovery processes were examined. Slow recovery at room conditions was associated with the reorganization of the hydrogen bonds between microfibrills and matrix which results in formation of a new and rather stable structure. The absorption of water by the matrix phase causes the disruption of the strong hydrogen bonds holding the stretched form of the fiber and leads to a rapid recovery.