Lignin-modified high-performance waterborne polyurethane with enhanced UV, corrosion, and weather resistance for marine coatings

The incorporation of lignin into waterborne polyurethane (WPU) networks for the preparation of high-performance, multifunctional protective coatings represents a highly attractive yet challenging research direction. This study employed a highly reactive soluble modified lignin (MOLA) as a polyol and incorporated it into the main chain of a WPU polymer network. A series of bio-based waterborne polyurethanes (CLWPU–CO x ) with tailored molecular architecture was synthesized and found to exhibit corrosion resistance, UV blocking, UV-aging resistance, self-cleaning behavior, weather resistance, biodegradability, and non-biotoxicity. The influence of MOLA content on the chemical structure and properties of CLWPU–CO x was systematically investigated, and quantitative structure–property relationships between the MOLA loading ratio and material properties were established. The results indicated that MOLA simultaneously served as both a chemical and physical crosslinking site, thereby regulating the microphase separation of WPU. The resulting uniform internal structure and high crosslinking density endowed CLWPU–CO x with excellent hydrophobicity, water vapor barrier properties, gas barrier properties, and long-term outdoor durability, confirming its considerable potential for marine anti-corrosion protective coating applications. Download: Download high-res image (158KB) Download: Download full-size image