Alpha-lipoic acid inspired cationic waterborne polyurethane/chitosan-modified cotton fabrics with enhanced dyeability and antioxidant properties

The development of multifunctional cotton composites combining waterproof, wrinkle-resistant, anti-ultraviolet, antioxidant properties, along with good dyeability, is highly attractive for expanding their application in protective textiles. In the work, a composite cotton fabric (cWPU/CS/LA@C) was prepared via knife-coating process, using cationic waterborne polyurethane (cWPU) and chitosan (CS) as matrices, with alpha-lipoic acid (LA) serving as both the active ingredient and crosslinking agent. The mechanical properties of cWPU/CS/LA@C were significantly improved, showing a tensile strength of 58.74 MPa and an elastic modulus of 446.46 MPa. Additionally, it exhibited high hydrophobicity, excellent wrinkle resistance, good antioxidant activity and satisfactory low-temperature dyeability. Compared to the untreated cotton fabric, higher color depth (K/S) values were achieved for the modified cotton fabrics dyed with curcumin and reactive red KN-B at 30 °C and 60 °C, respectively. Meanwhile, the adsorption behavior of two dyes on modified cotton under these dyeing conditions followed the pseudo-first-order kinetic model. Furthermore, the color fastness of cWPU/CS/LA@C fabric remained at a high level even after 15 washing cycles. This research provides a simple feasible approach for preparation of multifunctional cotton composite materials and broadens their applications in technical and healthcare textile fields.