Changes in Physical Properties of Hot Mercerized Ring and Open-end Spun Cotton Yarns

The effects of hot mercerization on open-end and ring spun yarns in slack and under tension conditions were compared. It was found that hot mercerizing at optimum temperature had different effects on cotton yarns of different structures. The results indicated more pronounced effect of treatment temperature on physical properties of ring yarn, while the mercerized open-end spun yarns showed higher dye uptake and tensile strength compared to the ring spun yarns. The degree of mercerization of ring and open-end spun yarns was obtained by measuring the barium activity number. X-ray and infrared spectroscopic analyses (the ratio of alpha(1372) cm-1/alpha(2900 cm-1)) were used to measure the crystallinity of cotton yarns mercerized at various temperatures. Results showed that mercerization treatments lead to a decrease in cellulose crystallinity as assessed by determining the increase of the reactivity of cellulose towards dye sorption. The decrease in crystallinity was varied with experimental conditions. It was also revealed that the higher the mercerizing temperature, the more shrinkage occurred on both yarns, where ring spun yarns have shown higher shrinkage.