Sustainable Strategy for Promoting the Color Strength and Dimensional Stability of Polylactic Acid Fabrics

In the realm of environmental protection and sustainable development, polylactic acid (PLA) materials have garnered significant attention due to their biodegradability. Moreover, PLA is more widely used in the clothing and home textile industries. However, the application of PLA in the textile industry is constrained by hydrolysis issues during conventional aqueous dyeing processes. This paper investigates a waterless dyeing technique utilizing linear silicone (LS) as a nonaqueous dyeing medium. Because PLA fibers are dyed in a nonaqueous environment, the breaking strength of PLA fabrics in the LS waterless dyeing system increased by 4% to 10%, and the breaking elongation improved by 7% to 20% at dyeing temperatures of 110 and 120 °C. However, it showed a reduction of 23.4% at 120 °C in water-bathed dyeing. The LS waterless dyeing system facilitates high-temperature dyeing of PLA fibers, ensuring that the fibers remain intact at temperatures below 140 °C. In contrast, when subjected to traditional water bath dyeing at 120 °C, the fibers exhibit significant breakage. The hydrolysis concerns are mitigated in the LS waterless dyeing bath, resulting in enhanced thermal stability and mechanical properties compared to that in fibers dyed in a conventional water-bathed dyeing system. At equivalent temperatures, the K/S value of dyed PLA fabric can be improved when a small dosage of acetic acid is employed in a waterless dyeing bath, while color fastness to washing, rubbing, and light remain uninfluenced. The selected dyeing medium can be recycled and reused, which not only significantly improves the resource utilization efficiency of the dyeing process but also effectively reduces the generation and emission of waste. This study provides a promising approach for waterless dyeing of PLA fiber, facilitating their practical application and marking an important milestone toward sustainability in the textile industry.