Hygroexpansion in Wood

Skaar, Christen

doi:10.1007/978-3-642-73683-4_4

Cited by 30 publications

(28 citation statements)

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“…The amount of bound water in wood, and therefore the extent of swelling is controlled by thermodynamics [65]. A steady-state amount of bound water is reached when the bound water chemical potential is in equilibrium with the free water chemical potential.…”

Section: Molecular Scalementioning

confidence: 99%

“…Given that ray cell walls are thicker than earlywood longitudinal cells, they concluded that the presence of ray cells could restrain radial swelling in the earlywood. The variation in the swelling along the tangential and radial directions has also been attributed to differences in the cell composition along the parallel and perpendicular directions of the S 2 cell wall layer, differences in the MFA, as well as the influence of the middle lamella [21,23,65,106]. Although there is no consensus, it is recognized that differences between tangential and radial swelling are related to the cell wall structure and the arrangement of the cells.…”

Section: Cellular Structurementioning

confidence: 99%

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Wood Moisture-Induced Swelling at the Cellular Scale—Ab Intra

Arzola-Villegas

Lakes

Plaza

et al. 2019

Forests

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Wood, a complex hierarchical material, continues to be widely used as a resource to meet humankind’s material needs, in addition to providing inspiration for the development of new biomimetic materials. However, for wood to meet its full potential, researchers must overcome the challenge of understanding its fundamental moisture-related properties across its many levels of hierarchy spanning from the molecular scale up to the bulk wood level. In this perspective, a review of recent research on wood moisture-induced swelling and shrinking is presented from the molecular level to the cellular scale. Numerous aspects of swelling and shrinking in wood remain poorly understood, sub-cellular phenomena in particular, because it can be difficult to study them experimentally. Here, we discuss recent research endeavors at each of the relevant length scales, including the molecular, cellulose elementary fibril, secondary cell wall layer nanostructure, cell wall, cell, and cellular levels. At each length scale, we provide a discussion on the current knowledge and suggestions for future research. The potential impacts of moisture-induced swelling pressures on experimental observations of swelling and shrinking in wood at different length scales are also recognized and discussed.

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Section: Molecular Scalementioning

confidence: 99%

Section: Cellular Structurementioning

confidence: 99%

Wood Moisture-Induced Swelling at the Cellular Scale—Ab Intra

Arzola-Villegas

Lakes

Plaza

et al. 2019

Forests

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“…Wood shrinks or swells in response to changes in MC and this property has been extensively modeled and experimentally tested (Vintila 1939;Pentoney 1953;Erickson 1955;Browne 1957;Boutelje 1962;Kelsey 1963;Barrett et al 1972;Boyd 1974;Quirk 1984;Skaar 1988;Pang 2002;Pfeil, unpublished results). Change in dimension is influenced by several factors, such as specific gravity, temperature, extractives, solvent type, moisture cycles, chemical treatment, anatomical orientation, wood type, and specimen size.…”

Section: Background Dimensional Stability Of Ew and Lwmentioning

confidence: 94%

“…Change in dimension is influenced by several factors, such as specific gravity, temperature, extractives, solvent type, moisture cycles, chemical treatment, anatomical orientation, wood type, and specimen size. Longitudinal shrinkage is an order of magnitude lower than radial or tangential shrinkage, presumably because of the orientation of the cellulose microfibrils in the cell walls (Kelsey 1963; Barrett et al 1972;Skaar 1988;McAlister and Clark III 1992;Pang 2002). Previous work on tangential and radial shrinkage in isolated EW and LW is summarized in Table 1.…”

Section: Background Dimensional Stability Of Ew and Lwmentioning

confidence: 96%

Influence of chemical treatments on moisture-induced dimensional change and elastic modulus of earlywood and latewood

et al. 2010

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To better understand the performance of bonded, coated, and modified wood, knowledge of how these processes alter the dimensional change and mechanical properties of wood at a given moisture content (MC) are important. These localized influences on earlywood (EW) and latewood (LW) properties are not well understood. In the present study, the influence of chemical treatments by hydroxymethylated resorcinol (HMR) and acetylation on moisture-induced dimensional change and longitudinal modulus of elasticity (MOE) of isolated EW and LW specimens of Loblolly pine (Pinus taeda L.) was evaluated. The dimensional change was not altered by the HMR treatment, whereas acetylation lowered it by ;50% in EW and LW in both radial and tangential directions. The MOE was not influenced by the two chemical treatments tested. Based on results of swelling, shrinkage, and MOE it can be concluded that chemical treatment does not modify EW selectively compared with LW neither in radial nor in tangential orientation.

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“…Kemampuan penggunaan suhu tinggi ini dalam mempercepat proses pengeringan didukung oleh beberapa hasil penelitian (Kollmann, 1961;Cech dan Huffman, 1971;Huffman, 1972;Rhatigan et al, 2003). Suhu yang tinggi, khususnya yang mencapai diatas titik didih air, akan membentuk uap yang mampu untuk mempercepat pergerakan air sepanjang serat (Stamm dan Raleigh, 1967;Skaar, 1988 et al, 1983). Hal yang perlu dipertimbangkan juga adalah sejauh mana suhu yang digunakan akan mempengaruhi penurunan sifat mekanika kayu tersebut (Gerhards, 1979;Sehlstedt-Persson, 1995;Fruhwald, 2007 (Chudnoff, 1972;Simpson, 1987;dan Listyanto et al, 2013).…”

Section: Intisariunclassified

Kualitas Pengeringan Kayu Mahoni pada Berbagai Variasi Kerapatan Incising dengan Dua Skedul Pengeringan Suhu tinggi

Listyanto

Rahman

Swargarini

2016

Jurnal Ilmu Kehutanan

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Tujuan dari penelitian ini adalah untuk mengetahui pengaruh interaksi variasi kerapatan incising dan dua skedul pengeringan terhadap kecepatan dan cacat-cacat pengeringan kayu mahoni, serta mengetahui pengaruh variasi kerapatan incising terhadap kekuatan lengkung statik kayu mahoni yang telah dikeringkan. Tiga pohon mahoni (Swietenia mahagony) berdiameter 300-350 mm ditebang dan selanjutnya dibelah dan dibuat menjadi balok dengan ukuran 60 mm × 100 mm dengan panjang 500 mm untuk dijadikan sampel pengeringan. Di antara masing-masing bagian tersebut, dibuat sampel ukuran 20 mm × 20 mm × 25 mm, yang digunakan untuk penentu kadar air awal dan distribusinya. Sampel pengeringan selanjutnya dibagi menjadi 5 variasi kerapatan incising, yaitu 0 lubang/m2 (tanpa incising), 1000 lubang/m2, 2000 lubang/m2, 3000 lubang/m2, dan 4000 lubang/m2. Setiap variasi kerapatan incising selanjutnya akan dikeringkan dengan 2 skedul pengeringan, yaitu suhu pengeringan 100°C sampai tercapai kadar air akhir 12% dan suhu 60°C pada 8 jam pertama dan selanjutnya dilanjutkan 100°C, sampai tercapai kadar air akhir 12%. Paramater yang diamati adalah kecepatan pengeringan, cacat retak permukaan, dan distribusi kadar air akhir. Hasil analisis menunjukkan bahwa kerapatan incising 3000-4000 lubang/m2 memberikan pengaruh yang cukup nyata di dalam mempercepat proses pengeringan dan distribusi kadar air akhir. Skedul pengeringan dan variasi kerapatan incising tidak berpengaruh pada retak permukaan. Pra perlakuan incising sampai batas 4000 lubang/m2 ini dapat diterapkan untuk mempercepat proses pengeringan dengan penurunan nilai modulus elastisitas dan modulus patah yang tidak berbeda nyata.Kata kunci: incising, pengeringan suhu tinggi, mahoni, lengkung statik, skedul pengeringan AbstractThe aims of this research were to investigate the effects of interaction between incising densities and two drying schedules on drying rate and defects as well as to examine the effect of incising densities on static bending characteristics of dried mahogany. Tree mahogany (Swietenia mahogany) trees with the diameter of 300-350 mm were cut and sawn into columns with the dimension of 60 mm ×100 mm × 500 mm. Each column was cut into five parts with the length of 500 mm. A small sample with the dimension of 20 mm × 20 mm × 25 mm were taken in between drying sample to measure moisture content. Five incising densities, which were 0 holes/m2 (unincised), 1000 holes/m2, 2000 holes/m2, 3000 holes/m2 and holes/m2, were applied to the drying sample. Samples were dried with two different drying schedules until the moisture content of 12%. Drying rate, defects, and moisture distribution were measured to evaluate the drying quality. Static bending test was applied to examine the strength properties. The results showed that incising densities of 3000-4000 holes/m2 could significantly improve drying rate and final moisture content distribution. There was no significants defects due to the variation of incising densities and drying schedules. No significant decrease of modulus of elasticity and modulus of rupture among five incising densities was found in this research.

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Hygroexpansion in Wood

Cited by 30 publications

References 0 publications

Wood Moisture-Induced Swelling at the Cellular Scale—Ab Intra

Wood Moisture-Induced Swelling at the Cellular Scale—Ab Intra

Influence of chemical treatments on moisture-induced dimensional change and elastic modulus of earlywood and latewood

Kualitas Pengeringan Kayu Mahoni pada Berbagai Variasi Kerapatan Incising dengan Dua Skedul Pengeringan Suhu tinggi

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