Ultrastructural X-ray scattering studies of tropical and temperate hardwoods used as tonewoods

Abstract

The structure of hardwoods representing eight tropical and five temperate species was characterized from the atomistic level up to the cellular level using X-ray scattering, X-ray microtomography and light microscopy. The species were chosen for this study based on their popularity as tonewoods. The ultrastructure of wood cell walls, including crystallite size, orientation and close-range order of cellulose microfibrils were determined by small- and wide-angle X-ray scattering (SAXS, WAXS). The SAXS patterns were interpreted by using an analytical model of cylinders packed in a hexagonal close-range order with paracrystalline distortion. The values for the cylinder diameters given by this model were compared to the average crystallite widths obtained by WAXS using the Scherrer equation. In six out of 26 samples, all of these representing tropical species used especially in fretboard parts of electric guitars, large differences between these two sizes were obtained. The WAXS and microscopy results of these samples corresponded to tension wood structures. These comparisons and interpretations of SAXS results have not been previously presented for any tropical hardwoods, especially related to those containing tension wood tissue. The importance of the ultrastructural characterization was highlighted in this study in the case of tropical hardwood samples.

The 24-chain core-shell nanostructure of wood cellulose microfibrils in seed plants

“…Previous studies have misconceived the use of wood SAXS patterns to model the whole CMF, and the chosen model of infinitely long cylinders was also oversimplified. This resulted in CMF diameter estimates that were too small to fit 18 chains 25,[36][37][38] . We showed by Porod analysis that SAXS patterns may be used to model the CMF core zone, not the whole CMF (SI Fig.…”

Influence of Natural Aging on the Moisture Sorption Behaviour of Wooden Structural Components

“…With this technique, up to 23 wood samples can be evaluated simultaneously under the same environmental conditions, thus providing increased accuracy and facilitating comparisons [ 25 ]. Furthermore, various chemical techniques are available for assessing the degradation of wooden artefacts, including wet chemistry [ 1 , 26 ], infrared (IR) spectroscopy [ 27 , 28 , 29 ], near-infrared (NIR) spectroscopy [ 30 , 31 ], Raman spectroscopy [ 27 , 32 ], nuclear magnetic resonance (NMR) spectroscopy [ 27 , 33 , 34 ], gas chromatography–mass spectrometry (GC-MS) [ 27 , 35 , 36 ], direct analysis in real time mass spectrometry (DART-MS) [ 37 , 38 ], and X-ray techniques [ 27 , 39 , 40 ]. IR spectroscopy, which is among the most popular methods for determining the chemical structures of wood, can provide information about the disappearance or generation of various functional groups or chemical bonds based on peak position, shape, and intensity [ 28 ].…”