Surface Reconstruction and Low-Temperature Dyeing Performances of a Poly(Lactic Acid) Filament Pretreated with a Choline Chloride and Oxalic Acid Deep Eutectic Solvent

Poly(lactic acid) (PLA) is considered the best candidate biobased material alternative to petroleum-based polyethylene terephthalate due to its renewability and biodegradability. However, the crucial dyeing issue of PLA filament limits its applications in the textile industry. Herein, a green deep eutectic solvent (DES) consisting of choline chloride and oxalic acid was employed for the surface reconstruction of the PLA filament. Owing to the synergistic contribution effect of physical etching and chemical modification from the DES, the surface roughness and chemical activity of the PLA filament improved significantly, thereby conferring potent low-temperature dyeing performances. The DES-modified PLA filament can achieve K/S value and dye uptake at 90 °C commensurate to those of the PLA filament at 110 °C with no decay on the dry and wet rubbing fastness. This work demonstrates a promising approach for the low-temperature dyeing of PLA filaments, enabling the practical applications of PLA filaments.