News Coatings Technologies
Bio-based phloretin enables robust, self-healing and UV-resistant waterborne polyurethanes
A novel bio-based crosslinker enhances waterborne polyurethane coatings, providing strong mechanical properties, efficient self-healing, UV protection and corrosion resistance, particularly beneficial for leather finishing.
Self-healing coatings promise longer service life but often struggle to maintain high mechanical strength. A team led by Ruixue Zhai has now presented an innovative waterborne polyurethane (WPU) that combines robustness and healing capability by using the bio-based crosslinker phloretin (PRT).
The dual network of reversible phenol–carbamate covalent bonds and hydrogen-bonded interactions gave the optimised film (WPUP-2) a tensile strength of 46.51 MPa, an elongation at break of 1,263 % and a toughness of 173.96 MJ/m³. After thermal activation, it achieved 98 % self-healing efficiency and showed shape-memory behaviour. Recycling via thermal pressing further increased tensile strength to 57.84 MPa.
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Multifunctional performance for leather finishing
Phloretin also enhanced UV and corrosion resistance by effectively shielding against 365 nm UV light. When applied to leather, the coating significantly improved durability and usability, pointing to a promising route for sustainable smart coatings.
Source: Zhai, R. et al. Multifunctional waterborne polyurethane coating constructed by phloretin: Integrating high robustness, self-healing, UV resistance, and anticorrosion, applied to leather finish. Prog. Org. Coat. 207, 109430 (2025).
