Journal of Colloid and Interface Science, Vol.206, No.2, 558-568, 1998
Evaluation of the structure and acid-base properties of bulk wood by FT-Raman spectroscopy
The structure of pine wood (Pinus silvestris L.) has been analyzed by FT-Raman spectroscopy, taking birch wood and the wood components cellulose, hemicellulose (xylan), and lignin as well as previously characterized wood resins as references. The acid-base properties of hulk pine wood were evaluated by comparing the spectra recorded before and after the treatment with various solvents. After the treatment with the probe liquids having only a Lifshitz-van der Waals (LW) component, it was found that the LW interactions in pine wood take place without changing the main structure. After treatment with Lewis acid-base active probe liquids, the spectra indicate that, e.g., the intense peak located at similar to 2936 cm(-1) (CH2 stretch) seems to disappear, suggesting that this peak may be related to Lewis acidity. In addition, after treatment with a Lewis acid, it was found that the intense peak located at similar to 1657 cm(-1) (C=C) is shifted, relating to Lewis basicity. With the ratio similar to 2936/ similar to 1657 cm(-1) as a measure of the acid-base properties of bulk wood, a value of about 2.00 indicates that the bulk pine wood is largely acidic. The pH determined supports the evaluation made by FT-Raman spectroscopy,