Agricultural waste Ipomoea batatas leaves for low-temperature dyeing and functional finishing of polyester fabrics

The increasing focus on eco-friendly textiles and cleaner production manufacturing techniques have made nat- ural pigments for coloring and enhancing the functionality of textiles become a popular trend. This research aimed to extract plant pigment from bio-waste Ipomoea batatas leaves and utilize it for dyeing and functional decoration of polyester fabric at low temperature. The study optimized the parameters for pigment extraction and fabric dyeing and also investigated the stability of the pigment solution. The finding indicated that strong acids and bases, intense light, high temperatures, and oxidants have a greater impact on pigment stability. Observation and analysis using SEM, bio-optical microscope, FTIR, and UV-vis-NIR absorption spectroscopy revealed that chlorophyll pigment entered into the interior of polyester molecular chains through hydrophobic end intercalation and was retained by the physical forces, enabling low-temperature coloring and functional finishing of polyester fabrics. As a result, the polyester fabrics dyed with natural pigment exhibited excellent resistance to rubbing, washing, saliva, and perspiration (rated at level 4 or higher), except for the average light fastness (only grade 4). Additionally, the dyed polyester fabrics demonstrated outstanding UV resistance (UPF of 33.57 for raw polyester and 120.77 for pre-mordant dyed polyester) and antibacterial properties (raw polyester agar plates showed bacterial growth, while the colored polyester agar plates had almost no bacterial growth). Even after 10 wash cycles, the dyed polyester fabrics maintained their UV protection and antibacterial properties. This research is expected to provide a new approach to the valuable utilization of agricultural residues in the textile industry.