Thesis Details

Thesis Title: An investigation of the impact of yarn Delta T values and weave structure on the tear strength of 100% polyester rotor yarn fabric
Thesis Author: Suzanne Perry
Abstract: Since the presentation of the first rotor spinning machine in the 1960's, rotor yam has securely established itself in the marketplace. The lower cost of rotor yam has made it a viable option for many end uses. However, the low tear strength of fabric woven from rotor yam has prevented the substitution of rotor yam for ring yam in many industrial end uses. Rotor yam does not transform its yam strength into fabric tear strength as efficiently as ring yam. If a rotor yam can be constructed that is more like ring yam, then the resulting tear strength might improve. 1 Unlike ring yam, rotor yam cannot be opened completely by untwisting due to its wrapper fibers and nonuniform twist. Thus, for rotor yam, there is a difference between the measured twist and the theoretical twist determined by the spinning setup. The difference between measured twist and theoretical twist in a spun yam is quantified by the twist difference, delta T. The delta T for ring yam is approximately zero, but the delta T for rotor yam can be considerably higher. If rotor yam can be constructed with a lower delta T, then perhaps the fabric will have higher tear strength. In this research, the impact of several fiber and rotor spinning parameters on delta T was evaluated. Yams were then woven into fabrics to evaluate the impact of each yam's structural changes on fabric tear strength. The results of this study are summarized below. Delta T was impacted by fiber finish film strength, rotor diameter, and rotor surface speed. There appeared to be no causal relationship between delta T and tear strength. The high film strength finish yielded better tear strength than the standard film strength finish. The twill weave pattern had consistently better tear strength than the plain weave pattern, and the conversion of yarn strength into tear strength was enhanced by the twill weave. Ring yarns were generally more efficient than rotor yarns at converting yarn strength into tear strength. The exception was in the warp tear direction where little or no difference existed between ring and rotor conversions.