Thesis Details

Thesis Title: The effects of yarn conditioning on yarn properties of both ring spun and open end 100% cotton and cotton/polyester yarns and the resultant weaving
Thesis Author: John Whisonant
Abstract: Because of the tremendous productivity and speed, air-jet weaving machines are becoming more evident in today's textile world. However, these increased speeds place greater stresses on filling and warp yarns. The process of conditioning yarn offers one possible method for enhancing yarn performance on today's high speed weaving machines. This research was conducted to determine the effects of yarn conditioning on yarn properties, weaving stop levels, and dye uptake performance. Four types of yarns were used in this research. They were: 13.5/1 100% cotton and cotton/polyester ring spun, 11.0/1 100% cotton open-end, and 12.0/1 cotton/polyester open-end yarn. Also, a 40.0/1 100% cotton ring spun yarn was used for warp yarn. The yarns were conditioned on two types of conditioners. One conditioner used a indirect steam system and the other used a direct steam system. Two temperature levels of 50-55 degrees Celsius and 75-80 degrees Celsius were used in both types of conditioners. The conditioned yarns were tested for single-end strength, single-end elongation, elasticity, torque (liveliness), and hairiness. Also, unconditioned yarns of the same type were tested to provide a baseline for comparison. This research also examined how yarn conditioning effects slashing parameters. The 40.0/1 100% cotton ring spun yarns were slashed and tested for size pickup, encapsulation, penetration, and tensile properties. Finally, the yarns used for warp and filling were knitted into socks and then dyed. The purpose of this was to determine the effect of yarn conditioning on dye uptake and delta E properties. The 13.5/1 100% cotton ring spun yarns and the 12/1 cotton/polyester open-end yarns were woven as filling on air-jet weaving machines. The warp yarns were also woven on airjet machinery. All weaving trials used a plain oxford weave. The yarn tests results revealed that yarn conditioning did not affect strength, elongation, or elasticity. There were some instances when yarn conditioning increased yarn hairiness, especially for ring spun yarns. One of the most consistent findings of this research was that conditioning yarn on either system at either temperature level, significantly reduced yarn liveliness. Results indicated that the indirect steam system, operated at a 75-80 degrees Celsius temperature level, exhibited the most reduction in yarn liveliness. The filling stop trials indicated that conditioned yarns wove at a lower stop level than unconditioned yarn. However, only yarns conditioned on the indirect steam system, at 75-80 degrees Celsius, wove significantly better at the 95 % confidence level. This research also showed that filling stop levels with ring spun yarn are affected to a greater degree than open end yarns. Slashing procedures were kept consistent throughout the trial. Yarn conditioning did not affect any of the slashing parameters tested. Because of this, the conditioned warp yarns did not weave at a lower warp stop level. The dye uptake trials revealed that conditioned yarns absorb less dye than unconditioned yarn. The difference in dye uptake was great enough to result in visible differences, as indicated by the Delta E values. There were also dye uptake differences between type of conditioner and temperature used. The 100% cotton yarns exhibited the greatest differences in dye uptake. This is contributed to changes in the crystallinity of the cotton fiber when the heat and moisture of yarn conditioning are applied.