Metallic nano-particles for the protection of wood
During the study, the effects of various nano-particle types and sizes on color, wettability, and surface chemistry of radiata pine (Pinus radiata) sapwood samples were investigated over 6 weeks of outdoor exposure. Specimens were treated with 0.2% wt/wt water dispersions of zinc oxide (ZnO), titanium dioxide (TiO2), aluminum oxide (Al2O3), silica dioxide (SiO2), cerium dioxide (CeO2), and iron oxide (Fe2O3), and four nano-sizes of Fe2O3.
No reduction of wettability
The nano-particles protected wood from photo-discolouration to differing degrees with iron oxide providing the most effective and consistent protection. Smaller alpha Fe2O3 nano-particles provided better UV protection. However, the nano-particles did not reduce the wettability of wood after UV exposure nor were they able to completely prevent lignin degradation. Zinc oxide nano-particles provided some cellulose and hemicellulose protection during UV exposure. Iron oxide nano-particles exhibited some potential for limiting degradation, but the differences were small and not significant from untreated controls. The results suggest that combinations of zinc and iron oxide might be useful for UV protection, and further trials are planned with these mixtures.
The study has been published in Journal of Coatings Technology and Research, Volume 19, September 2022.