A bio-based waterborne polyurethane with high toughness, superior wear resistance, and water resistance enabled by sorbitol monooleate

Waterborne polyurethanes (WPUs) have recently attracted enormous attentions in extensive industrial applications because of their sustainability and low toxicity. However, due to the use of water as the dispersion medium and abundant hydrophilic moieties of the molecular skeleton, waterborne polyurethanes always suffer from poor mechanical properties and inferior water resistance. In this work, dehydrated sorbitan monooleate (SP), a bio-derived renewable polyol, is introduced into the waterborne polyurethane skeleton to modulate the contents of the traditional trifunctional polyol of trimethylolpropane (TMP). Due to the rigid furan ring and the fatty side chain in the SP, the SP-modulated waterborne polyurethanes (WPU-SP) exhibit simultaneous excellent mechanical properties, high toughness, flexibility, and versatility, with the maximum tensile strength of WPU-SP reaching 39.19 MPa, and the film is capable of lifting weights over 25,000 times its own weight without fracture. Additionally, compared to the traditional waterborne polyurethane extended with TMP, the wear resistance and the water resistance of WPU-SP are significantly improved, as the decreases in wear rate and water absorption rate of WPU-SP are up to 59 % and 45 %, respectively. Benefiting from these unique properties, the WPU-SP shows excellent performance in anticorrosion and exceptional applicability for soft leather materials, in which the corrosion prevention efficiency can reach over 95 % and the wear index can be reduced to within 10 mg as a protective coating. This study represents a facile and effective approach for developing high-performance sustainable waterborne polyurethane materials through the incorporation of SP into polymer networks.