Thesis Details

Thesis Title: Effect of short fiber content, fiber tenacity, staple length, and micronaire on the quality of 100 percent cotton air-jet spun yarn
Thesis Author: Mark Kametches
Abstract: The Murata air-jet spinning system, first introduced at the ATME exhibition in 1982, offers higher production rates and more economical operations as compared to ring and open-end systems. While the primary end products of air-jet spinning are synthetic and synthetic blend yarns in a wide range of counts from Ne20 to Ne8-, much research has been directed towards improving the quality of 100% cotton air-jet spun yarns. Because of the low elongation and variation in natural fiber properties relative to man-made fibers, cotton is less suitable for acting as wrapper fibers. This thesis is designed to evaluate the effect of fiber tenacity, length, micronaire, and percent short fiber content, and the interaction therein, on 100% cotton air-jet spun yarn. Preliminary studies have shown that high fiber tenacity, greater fiber length, low micronaire, and minimal short fiber content each contribute to improved quality in cotton air-jet yarns. The experimental design, consisting of twenty-four conditions, was established based on these findings. Each condition represents a different combination of the cotton fiber properties. Using finisher sliver short fiber content, the designated fiber properties, and yarn quality data, the statistical interactions and regression coefficients were calculated. The yarn was also sized and tested on the Sulzer-Ruti Webtester for abrasion resistance. Investigative results of the thesis are as follows: 1. Short fiber content was found to have the most significant effect on yarn quality. An increase in short fiber content resulted in lower yarn strength, higher Uster CV's, increased hairiness, and increased thicks, thins, and Classimat long thick places. 2. Yarns spun from higher tenacity fibers were determined to have increased yarn strength, lower Uster CV's, and fewer thicks and neps. 3. Longer fibers shown to produce yarns having lower Uster CV's, fewer Classimat minors, and fewer thins, thicks, and neps. 4. Lower micronaire values were associated with yarns having higher yarn strength, fewer things, and decreased hairiness. 5. Although combed conditions were of higher quality than carded conditions within similar fiber groupings, proper fiber selection for carded Pima yarns produced yarns of equal quality to combed Prema and Pima/DPL-90 blend yarns.