Alkali treatment of cotton yarns with ultrasonic bath

In this study, the effects of ultrasound on the conventional mercerization treatment of cotton yarns were investigated. The yarns were treated in slack and under tension conditions with sodium hydroxide at various times (5 and 10 min) and temperatures (0, 20, 40 and 60℃) with and without the presence of ultrasound waves. The microstructure of samples were analyzed under characteristic absorbance at peaks with wave number 665, 713, 897, 982, 1032, 1165, 1206, 1236, 1282, 1319, 2900 and 3343 cm –1 . Hydrogen-bonding intensity (HBI) was measured by A 4000–2995 :A 1337 , and crystallinity index (CI) was calculated by the absorbance ratios A1431:A987 and A1263:A1200, using the method of Jayme and Knolle. Moreover, tensile breaking load and elongation at break of samples were determined. Results showed that mercerizing cotton yarns in the presence of ultrasound waves in slack and under tension conditions led to an increase in the amount of cellulose II cotton, up to 71% and 61%, respectively. In comparison with the conventional method, it improved breaking load for both slack and with tension mercerized samples, and also increased elongation at break. However, there was no significant difference in elongation break values of mercerized samples with tension.