Chemical extractives of the tropical wood Wallaba are natural anti-swelling agents

International audienceWallaba (Eperua falcata) is a tropical wood which is known to have naturally low swelling characteristics. Samples of wallaba heartwood were subjected to differential solvent extraction. Wood pieces that were extracted with methanol experienced significantly higher swelling after rehydration from oven dry to 96% relative humidity in comparison to non-extracted samples and samples extracted with other solvents. Methanol soluble wallaba heartwood extract was purified by high pressure liquid chromatography and the compounds present were characterised by nuclear magnetic resonance spectroscopy. Methanol extract was found to contain a very high relative proportion of polar compounds which are proposed to bind to the polymeric cell wall by multiple hydrogen bonds restricting the association of water and therefore acting as natural anti-swelling agents