Thesis Details

Thesis Title: The Influence of Blending Different Growth Area Cottons on the Quality of Waste, Yarns, and Knit Fabrics
Thesis Author: Michael P. Sasser
Abstract: This thesis examines the possibility of substituting Memphis growth area cottons for more expensive California cottons. It has been found that, with all properties being as alike as possible, California cottons can be replaced with Memphis cottons to greatly reduce raw material costs. To accomplish this, five different blends were used. These ranged from 100% Memphis area to 100% California, in 25% increments. This was done for both 4.1 and 4.5 micronaire cottons. These blends were then combed under two different conditions. Half of the conditions was combed at a fixed percentage of 15%, and the other half was combed at a fixed machine setting. This allowed the noil percentage removed to fluctuate from condition to condition. After combing, this material was spun into a 22/1 yarn on ring, open-end and air jet spinning machines. The first objective was to determine the influence of the various blends on cleaning, carding, and combing wastes. Based on actual weights taken from each of these cleaners, it was determined that the percentage of Memphis area cotton in the blend had no effect on the total amount of waste removed. From MTM and AL-101 tests of waste samples, it was determined that blend had no effect on the amount of lint or non-lint content of the blends, and the fiber length properties were not affected. It was found, however, that as the micronaire fineness increased from 4.1 to 4.5 the amount of waste removed increased significantly. It was also found that as the micronaire was increased, the mean and upper half mean fiber length of the waste increased. This may mean less fiber damage is occurring during cleaning because the 4.5 micronaire cottons are easier to open. The second objective was to determine the influence of these blends on various yarn properties. It was determined that as the amount of California cotton in the blend increased, the number of Uster neps increased significantly for the ring and open-end yarns. No other properties were affected by the blend. The micronaire did influence the single-end strength and the level of Uster neps. It was also seen that the ring and open-end yarns were significantly stronger than the air jet yarn, and the ring and air jet yarns had significantly fewer imperfections than the open-end. The third objective of this thesis was to evaluate the appearance of the greige and dyed knit fabrics created from these yarns. When these fabrics were dyed, depth of shade values were measured with the Colorimeter. It was found that the shade was affected by the blend, micronaire, and spinning system. As the amount of California cotton increased, and as the micronaire increased, the fabrics fabrics dyed darker. It was determined however, that even though these differences were measurable by instrument and statistically existed, few showed any actual visual differences. In conclusion, it can be said that with all other properties alike, Memphis area cottons can be a suitable sUbstitute for more expensive California cotton. Data indicate that Memphis area and California cottons of the same grade can be cleaned to the same degree with no adverse affects to the length properties. When this stock is combed, yarns of comparable quality can be spun. At the time of this writing, replacing California cotton with Memphis area cotton, can save about ten cents per pound in raw material costs.