Pretreatment dependence of mechanical and surface properties of cotton ring- and OE rotor-spun yarns

The variations in the mechanical and surface properties of cotton ringand OE rotor-spun yarns on exposure to different chemicals during wet processing have been studied. It is observed that the structure and yarn twist are the dominant parameters in determining the accessibility of chemicals during wet processing. The most distinct outcome of alkaline scouring of cotton yarns, in comparison to enzyme scoured ones, is the resulting yarn characteristics, i.e. more tensile strength, no change in breaking extension, more dye pick-up, more residual shrinkage, and more resistance to abrasion. Dramatic increase in residual shrinkage and dye uptake and decrease in abrasion resistance of alkaline scoured yarns after hydrogen peroxide bleaching are consistent with the effect of twist on the yarn during bleaching. The enzyme softening is effective in reducing the hairiness of the bleached yarn. While the absorbency change due to enzyme softening is small, the reduction in tenacity, abrasion resistance and hairiness is relatively large. Interestingly, however, there is no apparent change in the breaking extension and residual shrinkage of hydrogen peroxide bleached yarns.