Abstract

This study successfully synthesised a polysiloxane modified waterborne polyurethane (SiWPU) emulsion using double-ended hydroxypropyl silicone oil (HP-PDMS) as the silicon-modified monomer for waterborne polyurethane (WPU). Citric acid-modified chitosan (CAMC) was prepared via the acylation reaction of citric acid with chitosan. Layer-by-layer assembly technology produced a CAMC/SiWPU leather finishing agent. FTIR and XPS analyses confirmed the successful incorporation of the organic silicon monomer into the WPU chain segments. FTIR and SEM characterisation demonstrated that citric acid successfully modified chitosan. Analysis results confirm that the silicon monomer has been successfully incorporated into the WPU segments, and chitosan has also been successfully modified by citric acid. Performance testing indicates that the latex film exhibits an excellent water contact angle of 121.95°, demonstrating outstanding hydrophobicity. Leather samples (test specimen diameter 5mm) treated with the CAMC/SiWPU emulsion exhibited a bacterial inhibition zone diameter of approximately 15mm against E. coli, demonstrating good antibacterial properties. Furthermore, the incorporation of CAMC and silicon monomer significantly improved the tensile strength, softness, rubbing fastness and yellowing resistance of the leather samples.