Penetration of Alkaline Solutions into Wool Fibers Determined by Changes in the Rigidity Modulus

An apparatus is described for determination of the torsional rigidity and rigidity modulus of textile fibers. The apparatus is a modification of the torsion pendulum and is especially suitable for determination of changes in torsional moduli, e.g., after some treatment. Tests have been made on wool fibers subjected to treatments with either potassium hydroxide in ethanol or sodium hydroxide in butanol kerosene. In the first case the rigidity modulus decreased about 10% on account of the treatment, while no change occurred in the second case. The rigidity modulus is a much more sensitive indicator of changes in the outer parts of the fiber than is Young's modulus.