Viscoelastic properties of green wood across the grain measured by harmonic tests in the range 0–95°C: Hardwood vs. softwood and normal wood vs. reaction wood
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Vincent Placet
Abstract
The viscoelastic properties of wood have been investigated with a dynamic mechanical analyser specifically developed for wooden materials, the WAVET device. Measurements were carried out on four wood species in the temperature range 0–100°C at frequencies varying between 5 mHz and 10 Hz. Wood samples were tested under water-saturated conditions in the radial and tangential directions. As expected, the radial direction always revealed a higher storage modulus than the tangential direction. Great differences were also observed in the loss factor. The tanδ peak and internal friction were higher in the tangential than in the radial direction. This behaviour is attributed to the fact that anatomical elements act as a function of the direction. The viscoelastic behaviour of reaction wood differs from that of normal or opposite wood. Compression wood of spruce, which has a higher lignin content, is denser and stiffer in transverse directions than normal wood, and has a lower softening temperature (Tg). In tension wood, the G-layer is weakly attached to the rest of the wall layers. This may explain why the storage modulus and softening temperature of tension wood are lower than those for opposite wood. We also demonstrate that the time-temperature equivalence fits only around the transition region, i.e., between Tg and Tg+30°C. Apart from these regions, the response of wood reflects the combined effects of all its constitutive polymers, so that the equivalence is no longer valid.
©2007 by Walter de Gruyter Berlin New York
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- Study of the phenolic compounds formed during pretreatment of sugarcane bagasse by wet oxidation and steam explosion
- Determination of the accessible hydroxyl groups in heat-treated Styrax tonkinensis (Pierre) Craib ex Hartwich wood by hydrogen-deuterium exchange and 2H NMR spectroscopy
- Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
- Synthesis of light-colored rosin glycerol ester
- Studies on fluorescence of cellulosics
- Fluorescence spectroscopy for chromophore studies on bleached kraft pulps
- Influence of surface structure on wetting of coated offset papers
- Fundamental study of the interaction of Ti atoms with spruce surfaces
- Surface analysis of groundwood paper treated by diffuse coplanar surface barrier discharge (DCSBD) type atmospheric plasma in air and in nitrogen
- Ultrastructural aspects of fibre development during the stone groundwood process: New insights into derived pulp properties
- Stabilization of peracetic acid with aspartic acid diethoxy succinate (AES)
- Stabilization of H2O2 in the presence of Fe(II) and Mn(II) impurities under alkaline conditions
- Viscoelastic properties of green wood across the grain measured by harmonic tests in the range 0–95°C: Hardwood vs. softwood and normal wood vs. reaction wood
- Thermoforming of wood veneer composite sheets
- A revised multi-Fickian moisture transport model to describe non-Fickian effects in wood
- Novel experimental approach for longitudinal-radial stiffness characterisation of clear wood by a single test
- Fracture characterisation of yew (Taxus baccata L.) and spruce (Picea abies [L.] Karst.) in the radial-tangential and tangential-radial crack propagation system by a micro wedge splitting test
- Determination of Young's modulus and shear modulus by means of deflection curves for wood beams obtained in static bending tests
- Insecticidal activity of essential oil from Chamaecyparis formosensis Matsum
- Knotwood as a window to the indirect measurement of the decay resistance of Scots pine heartwood
- Field assessment of wood stake decomposition in forest soil
Articles in the same Issue
- Meetings
- Chemical composition of 36 Brazilian Amazon forest wood species
- Characterization of non-cellulosic glucans in Eucalyptus globulus Labill. wood and kraft pulp
- Study of the phenolic compounds formed during pretreatment of sugarcane bagasse by wet oxidation and steam explosion
- Determination of the accessible hydroxyl groups in heat-treated Styrax tonkinensis (Pierre) Craib ex Hartwich wood by hydrogen-deuterium exchange and 2H NMR spectroscopy
- Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
- Synthesis of light-colored rosin glycerol ester
- Studies on fluorescence of cellulosics
- Fluorescence spectroscopy for chromophore studies on bleached kraft pulps
- Influence of surface structure on wetting of coated offset papers
- Fundamental study of the interaction of Ti atoms with spruce surfaces
- Surface analysis of groundwood paper treated by diffuse coplanar surface barrier discharge (DCSBD) type atmospheric plasma in air and in nitrogen
- Ultrastructural aspects of fibre development during the stone groundwood process: New insights into derived pulp properties
- Stabilization of peracetic acid with aspartic acid diethoxy succinate (AES)
- Stabilization of H2O2 in the presence of Fe(II) and Mn(II) impurities under alkaline conditions
- Viscoelastic properties of green wood across the grain measured by harmonic tests in the range 0–95°C: Hardwood vs. softwood and normal wood vs. reaction wood
- Thermoforming of wood veneer composite sheets
- A revised multi-Fickian moisture transport model to describe non-Fickian effects in wood
- Novel experimental approach for longitudinal-radial stiffness characterisation of clear wood by a single test
- Fracture characterisation of yew (Taxus baccata L.) and spruce (Picea abies [L.] Karst.) in the radial-tangential and tangential-radial crack propagation system by a micro wedge splitting test
- Determination of Young's modulus and shear modulus by means of deflection curves for wood beams obtained in static bending tests
- Insecticidal activity of essential oil from Chamaecyparis formosensis Matsum
- Knotwood as a window to the indirect measurement of the decay resistance of Scots pine heartwood
- Field assessment of wood stake decomposition in forest soil
