A novel strategy for improving the affinity of corn starch sizing agents to polyester/cotton yarns via incorporation of ionic liquid

Abstract Starch is a renewable sizing agent, but lacks affinity for synthetic fibers. In this study, an ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([Bmim]BF 4 ), was incorporated into thermoplastic starch (TPS) to create a composite size for blended yarns. [Bmim]BF 4 disrupted the hydrogen‐bonded crystalline structure of starch, reducing its crystallinity. Compared with pure TPS, the optimized composite film containing 5 wt% [Bmim]BF 4 exhibited a 72.4% increase in tensile strength and a 66.8% increase in elongation at break, along with greater hydrophobicity and paste viscosity stability. When applied to yarns, this composite size significantly improved abrasion resistance and achieved an 87.1% reduction in hairiness, outperforming pure TPS due to enhanced interfacial adhesion. Moreover, the composite offers lower cost and superior hairiness control compared with synthetic sizing agents like poly(vinyl alcohol), positioning it as a promising eco‐friendly alternative for textile sizing. © 2026 Society of Chemical Industry.