Surface Protection of Wood with Metal Acetylacetonates

Abstract

Metal acetylacetonates are coordination complexes of metal ions and the acetylacetonate anion with diverse uses including catalysts, cross-linking agents and adhesion promotors. Some metal acetylacetonates can photostabilize polymers whereas others are photocatalysts. We hypothesize that the ability of metal acetylacetonates to photostabilize wood will vary depending on the metal in the coordination complex. We test this hypothesis by treating yellow cedar veneers with different acetylacetonates (Co, Cr, Fe, Mn, Ni, and Ti), exposing veneers to natural weathering in Australia, and measuring changes in properties of treated veneers. The most effective treatments were also tested on yellow cedar panels exposed to the weather in Vancouver, Canada. Nickel, manganese, and titanium acetylacetonates were able to restrict weight and tensile strength losses and delignification of wood veneers during natural weathering. Titanium acetylacetonate was as effective as a reactive UV absorber at reducing the greying of panels exposed to 6 months of natural weathering, and both titanium and manganese acetylacetonates reduced the photo-discoloration of panels finished with a polyurethane coating. We conclude that the effectiveness of metal acetylacetonates at photostabilizing wood varies depending on the metal in the coordination complex, and titanium and manganese acetylacetonate show promise as photoprotective primers for wood.

Surface characterization and paint bonding quality on chemically and thermally modified short rotation teak wood

“…In order to prevent wood photodegradation, chemical protection can be applied, such as chemical modification (Evans et al 2002; Hill 2006) and treatment with inorganic compounds particularly hexavalent chromium compounds (Evans et al 1992; Baysal et al 2004; Zhu and Evans 2021). Modified wood is generally more resistant to weathering than unmodified wood.…”

“…On the other hand, UV absorbers can also improve the photostability of wood (Grelier et al 1997; Kiguchi and Evans 1998). Titanium acetylacetonate is as effective as an organic benzophenone UV absorber at protecting yellow cedar panels from weathering, and both titanium and manganese acetylacetonates reduced photo-discoloration of panels finished with a polyurethane coating (Zhu and Evans 2021).…”

Studies of the Photoprotection of Radiata Pine Wood Using Photocatalytic Nanoparticles

“…Hence, there has been significant interest in the development of treatments to photostabilize wood and also on the evaluation of the photoprotective effects of wood modification or treatment of wood with biocidal preservatives [3,[6][7][8]. Surface treatments that are the most effective at improving the performance of coatings are transition metal compounds that photostabilize lignin [6,[9][10][11], organic UV absorbers and hindered amine light stabilizers [6,12,13], and reflectors and pigments [14,15]. More recently, there has been significant interest in inorganic nanoparticles (NPs) as photoprotective treatments for wood surfaces [16].…”