Multifunctional integration of renewable raw material-based waterborne polyurethanes: Schiff base dynamic bond-mediated self-healing and UV resistance enhancement mechanisms

Biomass-derived vanillin and ethylenediamine were used as raw materials to synthesize Schiff base chain extenders, which were then incorporated into waterborne polyurethane (WPU) systems to fabricate a series of multifunctional composite films (VWPUs) with tunable Schiff base contents. Research results indicate that all VWPU films exhibit excellent mechanical properties, self-healing capabilities, significant UV resistance, and moderate thermal stability. Among them, the VWPU-2 film demonstrated the best repair effect. Benefiting from the dynamic reversible nature of the Schiff base bond (C=N), the material achieved noticeable healing of surface scratches after 2 h of static storage at 60 °C. After 6 h of repair, the mechanical property self-healing efficiency reached 93.5%. Furthermore, the aromatic ring and phenolic hydroxyl structure in vanillin molecules enhance the polyurethane film's absorption capacity in the 280–400 nm wavelength range, resulting in reduced UV transmittance. This study provides a novel and sustainable design approach for constructing multifunctional water-based polyurethanes with both self-healing and UV resistance, where Schiff base dynamic bonds and vanillin-derived functional groups synergistically realize self-healing and UV resistance, opening new avenues for the development of high-performance, eco-friendly polymer materials. Graphical The alternative text for this image may have been generated using AI.