During the last decades, wood modification became of greater research interest especially for substitution of harmful and toxic wood preservatives such as CCA. However, modification processes and modification agents can lead to high costs during the process resulting in expensive products. The future target is to reduce production costs and to obtain an effective wood preservative at the same time. In this study 6 formulations of epoxidised linseed oil and 5 formulations of methyltriethoxysilanes were investigated. These formulations differ in respect to their process parameters, retentions of the impregnation agents and various additives in order to improve durability of the impregnated material. Since these products are intended to be applied in outdoor use, a 20 months outdoor weathering test on the test field in Uppsala (SE) was accomplished on the specimens. Check propagation, blue stain infestation, colour change, and moisture content were measured regularly to assess the outdoor performance in respect to the various formulations of the impregnation agents. The obtained results can serve as indication for the viability of the treatments. Specimens impregnated with low retentions of epoxidised linseed oil show a similar performance regarding check propagation and moisture uptake as specimens with higher retentions. No significant difference between these specimens was found for colour change which is mainly caused by blue stain fungi on the surface. In opposite, specimens treated with methyltriethoxysilane exhibited no consistent water uptake and check propagation in respect to the retentions realized. However, according to penetration depth of blue stain fungi a dependence of fungicide additives and process parameters were found.
Keywords: epoxidised linseed oil, methyltriethoxysilane, natural weathering, wood modification
Authors
Franke T.
Eberswalde University for Sustainable Development , Faculty of Wood Engineering, Eberswalde, Germany
Terziev N.
Swedish University of Agricultural Sciences, Department of Forest Products, Uppsala, Sweden
Panov D.
University of Tartu, Institute of Chemistry, Department Nature and Technology, Tartu, Estonia
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