Multifunctional bio-based waterborne polyurethane with excellent transparency, strength, abrasion resistance, and antimicrobial properties

Coatings are widely used as protective and decorative layers on various substrates. However, the use of large quantities of solvent-based coatings can lead to environmental pollution. Although waterborne coatings are eco-friendly owing to their low toxicity and low emission of volatile organic compounds, the main raw materials for fabricating waterborne polyurethane are derived from unsustainable petroleum resources. In this study, a series of bio-based waterborne polyurethanes (BWPUs) were synthesised using bio-based poly(trimethylene ether) glycol (PO3G) to reduce dependence on petrochemical resources. The structures and performances of the prepared BWPUs were systematically characterised. The results showed that WPUs exhibit obvious microphase separation and possess excellent mechanical properties, high transparency, wear resistance, and antimicrobial properties, which can be controlled by adjusting the equivalent ratio of the isocyanate component to that of the hydroxyl component. This study provides new ideas for designing BWPUs with excellent properties, limiting the dependence on petrochemical resources.