The Torsional Properties of Single Wool Fibers

Abstract

An apparatus is described for the direct measurement of torque-twist relationships for single wool fibers. Calculation of the rigidity of a dry fiber (0% relative humidity) agrees with results obtained by Speakman, who used a torsion pendulum technique. However, this latter technique is shown to give an underestimation of the rigidity of the fiber at 100% relative humidity. This discrepancy is explained as being due to the hyperbolic relationship between the torque and twist of a single fiber. Measure ments were also carried out on the torque relaxation of a single fiber, both wet and dry. at fixed values of twist. All the results obtained are consistent with a molecular model in which the matrix consists of a cross-linked polymer held together by a network of hydrogen bonds.