Imine-containing Self-healing Waterborne Polyurethane Elastomeric Coating Derived from Bio-based Polyester Polyol

The development of sustainable polyurethane (PU) materials is crucial for minimizing the environmental impact of conventional solvent-based PUs. This study presents a novel approach to synthesizing and characterizing an imine-containing self-healing waterborne polyurethane (WPU) coating derived from bio-based polyester polyol. The process involves the synthesis of an imine-containing diol (IM-diol) from terephthalaldehyde and ethanolamine, followed by the creation of a series of bio-based dynamic bond-containing WPU using bio-based polyester polyol, IM-diol, isophorone diisocyanate (IPDI), and other additives. The imine dynamic bonds within the WPU exhibit excellent self-healing, reprocessability, and degradability. The mechanical and thermal properties of the synthesized bio-based WPU materials were characterized. Dynamic light scattering (DLS) results showed excellent stability in the prepared imine-containing WPU particles. Scratched WPUs exhibited practical self-healing ability at 80 degrees C after 30 min. The reprocessed imine-containing WPU grains fully recovered their mechanical properties (healing efficiency of 95%) for the first time. Thermogravimetric analysis (TGA) revealed that the thermal decomposition temperature of the synthesized imine-containing WPU exceeds 230 degrees C, indicating high thermal stability and potential for high-temperature applications. This study provides a promising method to produce a bio-based WPU elastomer with robust self-healing subjected to a dynamic exchange reaction under mild conditions. The findings suggest promising applications for bio-based WPUs in various fields, including coatings and adhesives, highlighting their potential for sustainable solutions in industries that require robust performance. The outstanding properties of the synthesized materials inspire confidence in their potential for various applications and the exploration of new uses that meet both performance and sustainability criteria.