Metal acetylacetonates are coordination complexes of metal ions and the acetylacetonate anion. They have diverse uses as catalysts, cross-linking and curing agents and adhesion promotors. Some metal acetylacetonates can photostabilise polymers whereas others are photocatalysts. We hypothesise that the ability of metal acetylacetonates to photostabilise wood will vary depending on the metal in the coordination complex. We treated yellow cedar veneers with different acetylacetonates (Co, Cr, Fe, Mn, Ni, and Ti) and exposed the veneers to natural weathering in Australia for 20 days. The weight losses, erosion, tensile strength, colour, surface microstructure and chemistry of the treated veneers after weathering were compared with those of the controls (untreated and treated with DMF). Nickel, manganese, titanium and iron acetylacetonates were more effective than cobalt acetylacetonate at photostabilising wood, based on the different measures we used to assess the degradation of weathered veneers. Iron and nickel acetylacetonate were more effective at photostabilising lignin in weathered veneers than the other metal acetylacetonates possibly because they were able to complex lignin. Further research is needed to test this hypothesis. Our findings support our hypothesis and accord with a previous study that showed that titanium acetylacetonate could photostabilise radiata pine veneers.

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