Measurement of the uptake of linseed oil in pine by the use of an X-ray microdensitometry technique

Pine sapwood (Pinus sylvestris) was impregnated with linseed oil to three l evels of uptake. The distribution of the penetrant was found by taking micr odensity measurements of an impregnated sample and then using an ethanol ex traction procedure to remove the linseed oil. A second set of X-ray measure ments at identical locations in the same sample allowed the linseed oil to be indirectly mapped. An uneven distribution of linseed oil in the specimen s with the lowest uptake (25% increase in weight) was seen as sharp gradien ts in the densitometry curves. With increased filling by the linseed oil, t hese gradients were gradually smoothed. Microstructural changes in specimen s with high uptake were revealed using scanning electron microscopy. Throug h a combination of X-ray microdensitometry investigation and changes observ ed in the wood's mechanical properties and morphology, it was concluded tha t liquid flow during impregnation results in significant damage to the cell structure.