Effect of extractives on vibrational properties and shrinkage of African Padauk (Pterocarpus soyauxii Taub.)
Résumé
Vibrational properties (specific dynamic Young's modulus E'/r and damping coefficient tand) of wood are of special importance for several parts of musical instruments. But, concerning tand, little is known about the inter-specific variability. This last parameter can be partly explained by microfibril angles (as for E'/r), and in some cases by an additional effect of some extractives. The effect of some extractives has also been observed on dimensional stability, this factor being also relevant for musical instruments making. We studied the effect of extractives on tand, and on moisture related properties, of African Padauk, taking into account different radial locations in the trunk, from sapwood to inner heartwood. Removal of extractives provoked a marked increase in both damping and shrinkage of heartwood. Further experiments are conducted in order to find a first typology of the effects of extractives on lowering/rising the damping and/or the shrinkage.