Acetate starch/sodium alginate dual-polysaccharide eco-friendly size network on polyester/cotton yarns

The development of starch-based environmentally friendly sizes is crucial for the sustainable development of the textile industry. However, a single modified starch cannot meet the sizing requirements of blended yarns. The mechanical blending of acetate starch (AS) and sodium alginate (SA) is prone to phase separation and difficult to form a stable network structure. In this paper, different ratios of AS/SA composite size were prepared using ultrasonic blending, and the effects of different size formulations on the properties of sized film, sizing solution and sized yarn were investigated through multiple tests. The blending mechanism was elucidated combination with molecular dynamics simulations. The results indicated that: the size with a mass ratio AS/SA of 7:3 has the best performance. Compared to pure AS, it has demonstrated a 36.2% increase in the adhesion force, 43.7% reduction in the hairiness index, 26.04% improvement in yarn breaking strength, 101.61% increase in abrasion ratio, and 15.2% decrease in sizing add-on, achieving "enhanced performance with reduced sizing add-on". At this ratio, the carboxylate (-COO^-) of SA and the hydroxyl (-OH) of AS formed a strong hydrogen-bond network, while, Na⁺ constructs stable ionic channels through charge shielding to suppress electrostatic repulsion of -COO^-.