Enhanced performance of water-based wood coatings using KH-550-modified nano-silica: a sustainable approach for multifunctional surface protection

The incorporation of nano-silica into polyurethane coatings can enhance wear resistance and reduce surface gloss. However, silica can form agglomerates and affect the improvement of coating properties, it is necessary to modify the surface of the nano-silica. Anhydrous ethanol was used as the dispersant and the γ-aminopropyltriethoxysilane (KH-550) was used as the surface modifier to enhance particle dispersion. To evaluate coating performance, the nano-silica was mixed into the polyurethane coating both before and after modification, then evenly hand-brushed onto the beech wood surface. The results show that the coating’s gloss steadily stabilizes and performs well overall when modified nano-silica is added. At the optimal nano-silica loading of 2.0%, the coating exhibited comprehensive performance enhancements, including improved gloss (Perpendicular grain gloss 32.2 ± 1.9 GU at 60°, parallel grain gloss 48.6 ± 2.1 GU at 60°), enhanced abrasion resistance (Class 1), superior adhesion (Class 1), increased hardness (from HB to 3H), and excellent cold liquid resistance, while maintaining minimal color deviation (ΔE < 1.5). The incorporation of modified nano-silica in polyurethane coatings demonstrates significant functional enhancements, modified coatings can enhance the coating performance of wood, thereby extending its service life, and having a certain significant protective influence on wood.