Processing of Natural and Regenerated Cellulosic Fiber Blended Yarns: Defining a Novel Yarn Quality Index (YQI) and Fiber Interaction Framework

Abstract

The growing demand for sustainable textile materials has increased interest in the utilization of natural and regenerated cellulosic fibers in blended yarn structures. In this study, ring-spun yarns produced from Tencel, Modal, Viscose, Bamboo, Cotton, and their binary blends were evaluated in terms of yarn tenacity, imperfection index (IPI), and coefficient of mass variation (CVm). A novel Yarn Quality Index (YQI), incorporating yarn strength and regularity characteristics (IPI and CVm), was proposed to provide an integrated assessment of yarn performance. Synergy and fiber-impact heatmaps, fiber interaction network analysis, and sensitivity analysis were further employed to investigate blend behavior and fiber compatibility. The results showed that pure Tencel exhibited the highest tenacity (27.38 cN/tex) and a very low IPI (15.6), resulting in the highest YQI (14.61), while Cotton exhibited the highest IPI (137) and the lowest YQI (1.03). Among the blends, Tencel exhibited the highest tenacity, whereas several Tencel-containing blends achieved YQI values statistically comparable with other intermediate-performing yarn systems. One-way ANOVA confirmed significant effects of yarn type on tenacity, IPI, CVm, and YQI (p < 0.001), with Tukey–Kramer analysis identifying distinct groups of statistically comparable yarn systems. Synergy analysis showed that most blends exhibited neutral or negative synergy relative to expected performance, indicating that superior parent-fiber properties do not necessarily translate into positive blend interactions. Fiber-impact analysis revealed that Cotton:Tencel and Cotton:Modal produced the greatest improvements relative to pure Cotton, demonstrating the potential of highly uniform regenerated fibers to compensate for the poorer regularity of Cotton. Sensitivity analysis identified IPI as the dominant contributor to YQI variation (72.2%), followed by tenacity (22.4%) and CVm (5.4%). Overall, the proposed YQI, combined with statistical and fiber-interaction analyses, provides an integrated framework for evaluating blended yarn quality and highlights the importance of controlling yarn imperfections and optimizing fiber compatibility in the development of high-performance cellulosic yarns.