
 Possibilities for compositional tailoring of Norway spruce (Picea abies
 L. Karst.) wood using a hydrophobic oil impregnation process

ZusammenfassungImpregnation with hydrophobic oils offers non-toxic options for preserving Norway spruce (Picea abies L. Karst) wood that could potentially be used to tailor the properties
 of wood products, especially those used in exposed conditions. The objective of this study was to quantify
 the effects of the water-filled porosity and density of Norway spruce wood and treatments (applied to set
 the wood’s water contents at desired test levels) prior to impregnation with the linseed oil derivative
 Linogard by the Linotech process on its oil retention. Retention of oil differed significantly between
 tissue types. Dried specimens always retained less oil than corresponding undried or rewetted specimens.
 Furthermore, water-filled porosity and density had significant effects on oil retention levels within tissue
 types, allowing linear regression equations to be developed that gave good predictions of oil retention
 parameters for different tissues, with R2 values ranging from 0.66 for mature
 heartwood to 0.85 for mature sapwood. Thus there is scope to use hydrophobic oil impregnation processes
 for producing compositionally tailored wood materials with specified properties.

Tall oil/water – emulsions as water repellents for Scots pine sapwood
Abstract Like classic wood preservatives, many water repellents have the drawback of being detrimental to the environment. Hence interest in environment-friendly, even biodegradable, substances has increased. Natural oils (e.g. tall oil, linseed oil) appear to be capable of preventing water uptake by wood. However, in order to achieve total sapwood penetration, the amount of oil needed is high. The aim of this study was to investigate the water repellent efficiency of crude tall oil and crude tall oil water emulsions (oil-in-water and water-in-oil emulsions), and the possibilities of reducing the amount of oil needed with the emulsion technique. Scots pine sapwood samples were impregnated with tall oil formulations. The levels of water absorption and the degree of water repellent efficiency were determined with cyclical wetting and drying tests. The results showed that tall oil treatments reduce the water uptake of pine sapwood. With tall oil emulsion treatments almost equal water repellent efficiencies were reached as with pure tall oil, even when the oil retentions were considerably lower. The total amount of oil required could be halved. The emulsion technique is a potential method of decreasing the amount of oil needed in order to protect wood from water uptake. Zusammenfassung Wie viele klassische Holzschutzmittel haben auch viele Hydrophobierungsmittel den Nachteil, dass sie umweltschädlich sind. Deshalb ist das Interesse an umweltfreundlichen, insbesondere biologisch abbaubaren, Mitteln gestiegen. Natürliche Öle (wie z.B. Tallöl, Leinöl) haben grundsätzlich eine hydrophobierende Wirkung. Um jedoch eine vollständige Imprägnierung des Splintholzes zu erreichen, ist eine grosse Ölmenge erforderlich. Ziel dieser Arbeit war es, die hydrophobierende Wirkung von Tallöl sowie von Tallöl-Wasseremulsionen (Öl-in-Wasser- und Wasser-in-Öl-Emulsionen) zu untersuchen sowie festzustellen, in welchem Umfang die benötigte Ölmenge durch das Emulgieren reduziert werden kann. Kiefernsplintholzproben wurden mit Tallölgemischen imprägniert. Der Grad der Wasseraufnahme und der Hydrophobierungsgrad wurden mittels zyklischer Befeuchtungs- und Trocknungsversuche bestimmt. Die Ergebnisse zeigten, dass eine Behandlung mit Tallöl die Wasseraufnahme von Kiefernsplintholz reduziert. Behandlungen mit Tallölemulsionen erbrachten annähernd die gleiche Wasser abweisende Wirkung wie solche mit reinem Tallöl, obwohl dabei die eingebrachte Ölmenge deutlich niedriger war. Die erforderliche Ölmenge konnte auf die Hälfte reduziert werden. Die Emulsionstechnik ist eine potenzielle Methode um die Ölmenge, die zum Feuchteschutz von Holz benötigt wird, zu reduzieren.
Water Repellent Efficiency of Organic Solvent Extractives from Aleppo Pine Leaves and Bark Applied to Wood
Summary Natural wax-like materials were extracted from leaves and bark of Aleppo pine (Pinus halepensis Mill.) by using toluene as organic solvent. Experimental water repellent formulations (WRFs) were prepared using 10% gum rosin as the resin constituent and 0%, 1% and 2% paraffin wax, pine needle/bark extracts or mixtures of paraffin wax and needle/bark extracts in proportion 1 : 1 as hydrophobic substance. All experimental WRFs applied to small, cross-sectional wood specimens of Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.). Wood specimens were impregnated by a simple immersion technique and the water repellent effectiveness (WRE) was assessed by using tangential swelling data. Toluene soluble extracts from needles and bark applied to wood provided hydrophobic properties to pine and beech wood specimens but to a lesser degree when compared to paraffin wax. Bark extracts appeared to be stronger hydrophobic materials than needle extracts. Both needle and bark extracts can be successful substitutes for paraffin wax in WRFs up to 50 %. The degree of protection provided by WRFs and the differences between treatments were smaller in pine heartwood and beech sapwood than in pine sapwood.