Poly(lactic Acid)/Cesium Tungsten Bronze Fibers with Good Dyeability and High Photothermal Conversion Performance

Green and sustainable photothermal fibers are gaining significant attention for their role as high-performance thermal insulators in personal thermal management applications. Conventional photothermal fibers, such as carbon and zirconium carbide, are limited by their black or dark gray appearance, which restricts their aesthetics and fashion in textile design. To address this limitation, the present study employs eco-friendly poly(lactic acid) (PLA) as the biopolymer matrix and integrates cesium tungsten bronze (CsxWO3), known for its excellent visible light transmittance and significant near-infrared shielding capabilities, as the functional component for photothermal conversion. Leveraging melt spinning technology, this research explores for producing PLA fibers with high photothermal conversion efficiency and dyeability. The impacts of the CsxWO3 content on the rheological behavior, crystallization, mechanical characteristics, dyeability, and photothermal conversion performance of PLA were explored with the goal of providing a scientific foundation for the development of color-diversified photothermal conversion fibers. The findings show that incorporating CsxWO3 at levels below 0.8 wt % does not compromise the thermal stability of the PLA melt. Moreover, the addition of CsxWO3 notably promotes the perfection of the PLA crystalline structure, which is beneficial for maintaining the excellent mechanical properties of the PLA/CsxWO3 fibers. The fibers exhibit a tensile tenacity of about 4.3 cN/dtex and an elongation at break of around 26%, aligning with the performance criteria for modern textile processing. Additionally, the PLA/CsxWO3 fibers demonstrate remarkable photothermal conversion capabilities. At a CsxWO3 concentration of 0.4 wt %, the fabric temperature increases by 20 °C under an irradiance of 600 W/m2 after a mere 10 min of irradiation, surpassing the temperature rise of the pure PLA fabric by 9.9 °C. The dyeing performance of these fibers rivals that of pure PLA, enabling a wide range of vibrant color applications.