STRUCTURE AND SORPTION BEHAVIOR OF WATER VAPOR AND DYE OF DESCALED WOOL FIBERS

Abstract

In order to clarify the function of the cuticle and the cortex of Merino wool fiber, descaling treatments were applied to the fiber in dehydrated n-propyl and n-butyl alcohol solutions of potassium hydroxide and the procedure of the descaling was followed by optical and scanning electron (SEM) microscope. Tensile strength of the treated fibers was measured and their sulfur contents were determined.The fiber ends fractured by stretching were observed by SEM. The sorption behavior of water vapor and an acid dye, Orange II, was investigated. The results obtained are summarized as follows;(1) The n-propyl alcohol solution of KOH permeates into wool fibers much faster than n-butyl alcohol solution.(2) Descaled wool fibers were obtained without any damage of the cortical segments by the treatment with the n-butyl alcohol solution under gentle agitation.(3) Young's moduli of the descaled wool fibers are comparable to that of the untreated fiber.(4) By the treatment of fibers with the n-butyl alcohol solution of 10% (initial conc.) KOH, cracks almost perpendicular to the fiber axis were formed on the surface-region of the paracortex and the fiber was broken at the position of the crack during the stretching.(5) The cuticle becomes the barrier of the diffusion of water vapor and the acid dye in the early stage of the sorption, while in the prolonged stage, the cell membrane complex in the cortex becomes probably the source of the barrier.