Study on Complex Dyeing of Bio-based Polyamide 11 Fibers in Ethanol

Polyamide 11 (PA11) is a novel type of 100% bio-based and renewable fiber which can not achieve good dyeing results for conventional water bath dyeing techniques due to its smooth surface and long carbon chain hydrophobic structure. Furthermore, conventional dyeing processes typically involve extensive use of water and chemical reagents, driving up production costs and exerting serious ecological damage. The development of a new dyeing method suitable for bio-based PA11 fibers is crucial for sustainable development in the textile industry. In this study, we present a novel method for achieving effective dyeing of bio-based PA11 fibers using only dyes, calcium chloride (CaCl 2 ), and recyclable ethanol (EtOH), eliminating the necessity for additional chemical reagents. The dyeing process operates at a reduced temperature (80 ℃) and bypasses the pre-treatment stage for PA11. Compared to the traditional aqueous dyeing, the novel method significantly enhances dye uptake (> 98%) and color depth (K/S value) of PA11, while maintaining comparable color fastness ( ≧ grades 3–4), and acceptable mechanical properties. In addition, the new dyeing method has minimal impacts on the structure and performance of bio-based PA11 fibers. This is of great significance for the development and application of bio-based PA11 in the field of chemical fibers. Graphical abstract