No abstract

This paper examines the influence of various parameters such as delivery speed, nozzle pressures, and yarn count on the properties of vortex yarns produced using a Murata vortex spinning system. The results indicated that the delivery speed, nozzle pressure, and yarn count are all significant parameters for yarn evenness, imperfections, hairiness and tensile properties. Our findings show that increasing the delivery speed increases the hairiness and decreases the number of neps, and the tensile properties of vortex yarns. When the nozzle pressure increases, yarn unevenness, the number of thick places, the neps values, and the tensile properties of vortex yarns increases but the hairiness values of vortex yarns decreases. In general, the physical, the hairiness, and the tensile properties of coarser vortex yarns are better than finer yarns.

The electromagnetic shielding effectiveness (SE) of various weft-knitted fabrics made of hybrid yarns is investigated by considering the anisotropy of the structures, which has not been analyzed in previous studies. The anechoic chamber with aperture method at different polarizations of electromagnetic waves within the frequency range of 30 MHz and 9.93 GHz is used to determine the SE of knitted fabrics manufactured on a circular weft knitting machine from siro-spun and siro core-spun yarns without and with a metal core. The results show that SE depends on the orientation of the fibers within the structure regarding the direction of the electrical field in addition to parameters such as metal content, loop length and frequency; these results can be used to outline the basic points in determining a knit structure with desired SE.

The present research focused on the effects of spandex and yarn count parameters on the properties of elastic core-spun vortex yarns. The experiment and test results indicated that the various properties of elastic core-spun vortex yarns were significantly affected by spandex and yarn count. Coarser yarns showed lower unevenness, imperfection and breaking elongation values than finer yarns. Core-spun vortex yarns containing spandex showed lower tenacity and higher breaking elongation values than vortex spun yarns. The liveliness of spandex affected the hairiness properties of core-spun vortex yarns. The number of fibers in the cross section and the liveliness of spandex must be evaluated together during the manufacturing process of elastic core-spun vortex yarns.

Murata vortex spinning system is based on the air jet spinning system. The vast majority of previous works deal with the properties of vortex spun (VS) yarn and the spinning system. In this study, we investigated knitted fabrics from VS yarn in comparison with fabrics from ring (RS), compact (CS) and open-end rotor (OES) spun yarns made from viscose. The effect of yarn spinning system on dimensional and physical properties of knitted fabrics was explained with specific attention to fabrics from VS yarn. Shrinkage of fabrics from VS yarn has the lowest at widthwise direction, while having the highest at lengthwise direction. It is shown that the order of fabric spirality and twist liveliness for yarns from different spinning systems are quite similar. However, relation between loop shape factor and angle of spirality is inconsistent. Angle of spirality of fabrics from VS yarn is higher than fabrics from OES yarn, but lower than that of others. The bursting strength of fabrics from VS yarn is lower than that of those from RS and CS yarns and higher than that of those from OES yarn. From this study, it is also evident that fabrics from VS yarn have the lowest pilling tendency and highest resistance to abrasion.