The Effect of Twist Angle on the Modulus in Worsted and Semi-Worsted Staple Yarns

Abstract

This paper is concerned with the prediction of the tensile properties of worsted (spun wholly from combed wool in which the fibres are reasonably parallel) and semi-worsted (in which combing operation is skipped) yarns spun from 100% Wool, Polyester, Nylon, Viscose and Acrylic fibres. In the review of the literature, the work done by various researchers on continuous filament yams is highlighted. In the experimental work, it was found that the reported equations for modelling the behaviours of continuous filament yams were useful for predicting the behaviour of staple yarns, i.e., those spun from fibres of limited lengths. Although the published theoretical work did not fit the practical case exactly, the equations relating yam and fibre moduli gave acceptable values for staple yarns once an appropriate correction factor was introduced