Synthesis of waterborne multi-branched sulfonated lignin-based amphiphilic polyurethane and its application in fabric coatings

Textiles often subjected to a variety of challenging environments during outdoor use. To improve the performance and lifespan of textiles, this study presents the development of a flexible fabric coating based on waterborne multi-branched sulfonated lignin-based amphiphilic polyurethane. The coating incorporates a specially designed perfluorinated alcohol chain extender, along with choline phosphate glycol and biomass material lignin as additional chain extenders integrated into the polyurethane side chains. The introduction of polyethylene glycol with varying molecular weights was conducted to explore how polymerization degree of the hydrophilic soft segment in polyurethane influences the coating's waterproof and moisture-permeable properties. The findings indicated that incorporating polyethylene glycol-1000 as the soft segment could effectively balance the hydrophobic and breathable moisture-permeable properties of the coating. The effect of sulfonated lignin content on the UV resistance of the coating was further investigated. At a sulfonated lignin content reached 6 wt%, the coated fabric demonstrated exceptional UV shielding capabilities. Moreover, due to the amphoteric ionic side chain and terminated sulfonated lignin of polyurethane, the fabric coating exhibited excellent antibacterial properties, with an inhibition rate exceeding 99.9 % against Staphylococcus aureus and Escherichia coli . This fabric coating is suitable for use in outdoor clothing, protective gear, outdoor tents, and other fields.