Nanostructural deformation of high-stiffness spruce wood under tension

Thomas, L. H., Altaner, C. M., Forsyth, V. T., Mossou, E., Kennedy, C. J., Martel, A. and Jarvis, M. C. (2021) Nanostructural deformation of high-stiffness spruce wood under tension. Scientific Reports, 11, 453. (doi: 10.1038/s41598-020-79676-2) (PMID:33432070) (PMCID:PMC7801420)

Abstract

Conifer wood is an exceptionally stiff and strong material when its cellulose microfibrils are well aligned. However, it is not well understood how the polymer components cellulose, hemicelluloses and lignin co-operate to resist tensile stress in wood. From X-ray scattering, neutron scattering and spectroscopic data, collected under tension and processed by novel methods, the ordered, disordered and hemicellulose-coated cellulose components comprising each microfibril were shown to stretch together and demonstrated concerted, viscous stress relaxation facilitated by water. Different cellulose microfibrils did not all stretch to the same degree. Attempts were made to distinguish between microfibrils showing large and small elongation but these domains were shown to be similar with respect to orientation, crystalline disorder, hydration and the presence of bound xylan. These observations are consistent with a major stress transfer process between microfibrils being shear at interfaces in direct, hydrogen-bonded contact, as demonstrated by small-angle neutron scattering. If stress were transmitted between microfibrils by bridging hemicelluloses these might have been expected to show divergent stretching and relaxation behaviour, which was not observed. However lignin and hemicellulosic glucomannans may contribute to stress transfer on a larger length scale between microfibril bundles (macrofibrils).

• Item Type: Articles
• Additional Information: The authors thank ILL, Grenoble for a grant (beamtime award 9-13-300) and Rigaku UK Ltd for the gift of a diffractometer. We also thank John Archer (ILL) who designed and constructed the tensile testing apparatus used for WANS and SANS. VTF acknowledges the award of grant GR/R47950/01 which funded the refurbishment of the D19 diffractometer at the ILL.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Jarvis, Dr Michael and Altaner, Dr Clemens and Thomas, Dr Lynne
• Authors: Thomas, L. H., Altaner, C. M., Forsyth, V. T., Mossou, E., Kennedy, C. J., Martel, A., and Jarvis, M. C.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Scientific Reports
• Publisher: Nature Research
• ISSN: 2045-2322
• ISSN (Online): 2045-2322
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Scientific Reports 11: 453
• Publisher Policy: Reproduced under a Creative Commons License