Studies on the properties of alkali-treated jute-modacrylic flyer-spun yarns

Jute and jute-modacrylic yarns of various blend ratios have been prepared and treated with different concentrations of NaOH (5% -22% w/w). It is observed that this treatment results in axial shrinkage and weight loss of the yarns. The axial shrinkage increases with the increase in NaOH concentration up to 18% whereas the weight loss increases with the increase in NaOH conc. up to 22%. Even though the tenacity and modulus of yarns decrease substantially on alkali treatment, the work of rupture increases after treatment which is mainly due to the increase in breaking elongation. Statistical analysis shows that the modulus of different strain levels and tenacity values are positively and significantly correlated with the packing fraction values of the yarns. Blending of modacrylic fibre with jute does not show any appreciable improvement in bulk property of yarn. However, the whiteness index and mean gray value of alkali-treated blended yarns confirm the improvement in appearance of the yarns due to the preferential migration of modacrylic fibres on the surface of the yarn.