Effects of Tension on the Swelling of Cotton Fibers

Abstract

Changes in the cross-sectional area and circularity of cotton fibers tensioned in water and other media have been measured microscopically. It was found that the area increased significantly over that brought about by water-swelling alone. Fibers tensioned in bundle form at 0.45 g./grex for 1 hr. in water showed an average increase of 98% in area compared to dry untensioned fibers, and an increase in circularity (axis ratio) of 57%. These increases were not retained on drying, even when tension on the fibers was maintained. Immersion without tension in urea solution, ethylamine, or sodium hydroxide of mercerizing strength, followed by removal of the reagent and drying, in each case produced increases in area and circularity over those of the untreated fibers. Tensioning at 0.45 g./grex during im mersion in these reagents increased the circularity, but decreased the area with respect to the untensioned fibers. The elongation of fiber bundles tensioned in the various media was measured. The sodium hydroxide solution produced the greatest elongation.