Search

Water repellents, as environmentally-friendly treatments, are gaining popularity as non-biocidal solutions for wood protection. Drying oils, in addition to waxes and organosilicon compounds, are one of the most important water repellents for wood. Tung oil has so far been proven to be one of the best performing oils for wood protection. However, tung oil, similarly as other oils, does not penetrate deeply into wood, due to its high viscosity. In order to improve the penetration of oil into wood, a vacuum-pressure procedure has to be applied. The species used in this study are important in Central Europe: sweet chestnut heartwood ( Castanea sativa ), European larch heartwood ( Larix decidua ), Scots pine heartwood and sapwood ( Pinus sylvestris ) and Norway spruce ( Picea abies ). Oil uptake depends on the applied impregnation method and on the wood species used. Retention of tung oil was higher after an impregnation process than with the immersion procedure. Magnetic resonance imaging (MRI) was applied to elucidate the influence of wood species on oil penetration and distribution in wood after treatment. High spatial resolution MR imaging is highly sensitive to changes of liquids in wood and is therefore also very appropriate for monitoring oil penetration. Furthermore, with a good signal to noise ratio of MR images, the method can also discern among specimens with different patterns of oil distribution, as well as between areas of early-wood and late-wood. [ABSTRACT FROM AUTHOR]

Sweet chestnut ( Castanea sativa ) heartwood is one of the most durable European commercial wood species. Various aspects that could potentially influence the durability were studied in the present research: presence of extractives, ring width and weathering. The properties of wood that had been in outdoor use for 35 years were also examined. The results indicate that ring width and weathering (outdoor use) did not influence the durability. None of the fungi used were able to degrade sweet chestnut heartwood in a modified EN 113 experiment. After extraction with methanol or water, specimens lost between 11% and 15% of total mass by leaching of extractives. However, extraction only slightly decreased the durability of the leached wood. This indicates that other components (in addition to water and methanol soluble extractives) could be responsible for durability. Furthermore, analysis of 35-year-old wood showed that not all relevant properties of the old sweet chestnut wood deteriorated within the mentioned time frame. This proves that old sweet chestnut hardwood can potentially be reused for a variety of applications. [ABSTRACT FROM AUTHOR]