A Study on the Structural and Tensile Behaviour of Tasar and Eri Spun Silk Yarns

This study investigates the structural and tensile characteristics of spun silk yarns produced from two wild silk varieties—Tasar (Antheraea mylitta) and Eri (Samia ricini)—with the objective of evaluating their performance and inter- parameter relationships. Given the growing demand for sustainable and eco-friendly textiles, a detailed analysis of yarn geometry and mechanical Behaviour was undertaken to better understand the suitability of these fibers for high-value applications. Spun yarns of 60 Nm count were prepared from degummed pierced Tasar and cut Eri cocoons using standardized cotton system spinning techniques. A range of parameters, including linear density, yarn diameter, twist per meter, surface twist angle, contraction and retraction factors, and tensile properties (count strength product, single yarn tenacity, and elongation), were systematically evaluated.The results revealed that Eri yarns exhibited more consistent structural properties and superior tensile performance compared to Tasar yarns, with lower variability across key parameters. Tasar yarns demonstrated higher twist levels and contraction values, contributing to greater compactness but lower mechanical strength. Statistical analysis confirmed significant differences between the two yarn types, with correlation studies highlighting strong positive associations among CSP, tenacity, and elongation, while twist negatively influenced tensile Behaviour. These findings underscore the critical influence of fiber morphology and yarn structure on the mechanical properties of wild silk yarns. The study offers valuable insights for process optimization, quality enhancement, and the expanded application of Tasar and Eri yarns in sustainable textile development.