X-ray scattering and microtomography study on the structural changes of never-dried silver birch, European aspen and hybrid aspen during drying
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Kirsi Leppänen
,
Ingela Bjurhager
Abstract
The impact of drying on the structure of the never-dried hardwood cell wall was studied at nanometer level by means of wide- and small-angle X-ray scattering (WAXS, SAXS), and at micrometer level by X-ray microtomography (μCT). Never-dried silver birch, European aspen and hybrid aspen samples were measured by WAXS in situ during drying in air. The samples included juvenile and mature wood, as well as normal and tension wood to allow comparison of the effects of different matrix compositions and microfibril angles. The deformations of cellulose crystallites and amorphous components of the cell wall were detected as changes in the cellulose reflections 200 and 004 and amorphous halo in the WAXS patterns. Especially, the width of the reflection 004, corresponding to the cellulose chain direction, increased due to drying in all the samples, indicating an increase of strain and disorder of the chains. Also, the cellulose unit cell shrank 0.2–0.3% during drying in this direction in all the samples except in hybrid aspen tension wood. According to the SAXS results of silver birch, the distance between micro-fibrils decreased during drying. It was detected by μCT that the mean cross-sectional maximum width of the parenchymatous rays decreased from that of never-dried to air-dried birch by roughly 16%.
©2011 by Walter de Gruyter Berlin Boston
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- Meetings
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Articles in the same Issue
- Original Papers
- Fundamental understanding of pulp property development under different thermomechanical pulp refining conditions as observed by a new Simons’ staining method and SEM observation of the ultrastructure of fibre surfaces
- Enhancing dewatering of thermo-mechanical pulp (TMP) based papermaking through enzymatic treatment
- Mechanisms of TMP peroxide bleaching using Mg-based alkalis
- Properties of wood chips for thermomechanical pulp (TMP) production as a function of spout angle
- Determination of local material properties of OSB sample by coupling advanced imaging techniques and morphology-based FEM simulation
- Combined bound water and water vapour diffusion of Norway spruce and European beech in and between the principal anatomical directions
- Oxygen plasma-treated enzymatic hydrolysis lignin as a natural binder for manufacturing biocomposites
- Influence of the adhesive formulation on the mechanical properties and bonding performance of polyurethane prepolymers
- Characterizing perpendicular-to-grain compression (C⊥) behavior in wood construction
- Predicting the strength of Populus spp. clones using artificial neural networks and ε-regression support vector machines (ε-rSVM)
- X-ray scattering and microtomography study on the structural changes of never-dried silver birch, European aspen and hybrid aspen during drying
- Equilibrium moisture content (EMC) in Norway spruce during the first and second desorptions
- Fungal degradation of bamboo samples
- qPCR as a tool to study basidiomycete colonization in wooden field stakes
- Meetings
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