Abstract
This research studies the effect of extension increase percent of bare Lycra yarns during loop formation on the geometrical, physical and mechanical properties of plain jersey fabrics. Samples with 100% cotton yarns, Lycra yarns in alternating courses (half plating) and Lycra yarns in every course (full plating) were produced on a circular knitting machine. The two latter cases were produced at five different levels of Lycra extension. Thermal setting was carried out without any traverse tension during finishing, thus evaluating the full effect of Lycra extension. Results show a sharp increase in the courses density rather than the wales density. Fabric thickness and weight per unit area also increased, and air permeability in the case of the half and full plating fabrics decreased considerably. The breaking load and extension also increased, while the initial elasticity modulus decreased with an increase in abrasion resistance in the case of full plating. A comparison between half and full plating methods contributes to improving fabric quality by determining optimal Lycra percentage.