The Role of Spiral Structure in Untreated and Treated Cottons

Abstract

The untwisting of the spiral structure was observed as load was applied to the cotton fiber. Reversals are shown to be a vital structural feature which affects the twisting. A reversing spirality represents an idealized structure for obtaining optimum strength, elongation, and elastic recovery from the straight-chain molecules of cellulose. Friction between growth layers and fibrils in such a structure is suggested as a possible cause for permanent set, low intrinsic strength of highly oriented cotton, and the weak points near their reversals. The spiral structure persists through mercerization even though tension is applied; however, the X-ray angle is reduced appreciably. The high alignment achieved by resin treatment of cotton while under tension causes a reduction in elongation and increase in strength from that of slack treatment. The high alignment in cotton resin-treated with tension persists through washing with a detergent in water. Differences between properties of cotton are reduced but not eliminated by mercerization and resin treatment.