Urushi as a Green Component for Thermally Curable Colloidal Lignin Particles and Hydrophobic Coatings

Colloidal lignin nanoparticles are promising buildingblocks forsustainable functional materials. However, their instability in organicsolvents and aqueous alkali limits their applicability. Current stabilizationmethods require nonrenewable and toxic reagents or tedious workupprocedures. Here we show a method to prepare hybrid nanoparticlesusing only natural components. Urushi, a form of black oriental lacquer,and lignin are coaggregated to form hybrid particles, with Urushiacting as a sustainable component that stabilizes the particles viahydration barrier effect and thermally triggered internal cross-linking.The weight fractions of the two components can be adjusted to achievethe desired level of stabilization. Hybrid particles with Urushi content>25 wt % undergo interparticle cross-linking that produces multifunctionalhydrophobic protective coatings that improve the water resistanceof wood. This approach provides a sustainable and efficient methodfor stabilizing lignin nanoparticles and opens up neoteric possibilitiesfor the development of lignin-based advanced functional materials.

Automated summary

We have successfully prepared hybrid nanoparticles by coaggregating urushi, a form of black oriental lacquer, and lignin as natural components. Urushi acts as a sustainable component that stabilizes the particles through hydration barrier effect and thermally triggered internal cross-linking. The weight fractions of the two components can be adjusted to achieve the desired level of stabilization. Hybrid particles with Urushi content >25 wt% undergo interparticle cross-linking, producing multifunctional hydrophobic protective coatings that improve the water resistance of wood. This approach provides a sustainable and efficient method for stabilizing lignin nanoparticles and opens up new possibilities for the development of lignin-based advanced functional materials.