Microstructure of chemically modified wood using X-ray computedtomography scanning in relation to wetting properties
(English)Manuscript (preprint) (Other academic)
X-ray computed tomography was utilized to visualize and quantify the 2D and 3D microstructure of acetylated and furfurylated southern yellow pine (SYP) and maple samples. The total porosity and the porosity of different anatomical components, the cell wall thickness and the maximum opening of tracheid lumens were evaluated. The wetting properties (swelling and capillary uptake) were related to these microstructural characteristics. Our data show significant changes in the wood structure for furfurylated sapwood samples, including a change in tracheid shape and filling of tracheids by furan polymer. In contrast, no such changes were noted for acetylated samples at the resolution of the measurement (0.8 μm). The images obtained for furfurylated maple samples demonstrated that all ray cells and some vessel elements were filled with furan polymer while the fibres largely remained unchanged. Furfurylation significantly decreased the porosity of the sample, and this was observed in both earlywood and latewood regions in southern yellow pine softwood samples. In contrast, the total porosity of this softwood sample was hardly affected by acetylation. These findings are in line with wetting results demonstrating that furfurylation reduces both swelling and capillary uptake in contrast to acetylation which reduces mostly swelling. Cell wall thickness measurements revealed a significant increase after chemical modification especially at higher levels of furfurylation.
acetylation, cell wall thickness, furfurylation, hardwood, microstructure, porosity, softwood, tracheid, wettability, sub-micron X-ray Computed Tomography
Research subject Chemistry
IdentifiersURN: urn:nbn:se:kth:diva-175874OAI: oai:DiVA.org:kth-175874DiVA: diva2:863047
QS 20152015-10-232015-10-232015-10-29Bibliographically approved