Anatomical properties and process parameters affecting blister/blow formation in densified European aspen and downy birch sapwood boards by thermo-hygro-mechanical compression

Ahmed, Sheikh Ali; Morén, Tom; Hagman, Olle; Cloutier, Alain; Fang, Carol; Elustondo, Diego

doi:10.1007/s10853-013-7679-9

Cited by 24 publications

(20 citation statements)

References 17 publications

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“…Similar results were found in earlier studies by Blomberg and Persson (2004). Ahmed et al (2013) reported that the compression deformation was affected by anatomical features of the wood, such as the cell wall thickness and cell cavity size. The thinner the cell wall is, or the bigger the cell lumen of wood is, the more the cell is deformed.…”

Section: Compression Ratio and Thickness Swellingsupporting

confidence: 91%

“…Altogether, the morphology properties of the HP-compressed samples was consistent with previous studies concerning the morphology of optimized thermal compression (Navi and Girardet 2000;Kutuar et al 2009;Ahmed et al 2013;Laine et al 2016). The results confirmed that HP processing is a less destructive compression method for wood.…”

Section: Scanning Electron Microscopy Analysissupporting

confidence: 90%

“…This might have been caused by the destruction of the wood structure during HP treatment. Previous microscopic studies have shown that the compression process caused a substantial number of cracks and fractures in the cell wall of densified wood, especially at a high-compression ratio (Bucur et al 2000;Blomberg et al 2006;Ahmed et al 2013;Budak et al 2016). These cell deformation defects have a negative impact on mechanical properties of densified wood.…”

Section: Effects Of Hp On Mechanical Propertiesmentioning

confidence: 97%

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Effects of High-Pressure Treatment on Poplar Wood: Density Profile, Mechanical Properties, Strength Potential Index, and Microstructure

Yu¹,

Zhang²,

Zhu³

et al. 2017

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The density profile, mechanical properties, strength potential index, and microstructure changes of hybrid poplar were investigated before and after high-pressure (HP) treatments. The results of density profile indicated that a high uniform density distribution was developed inside the pressurized wood samples. The mechanical properties results showed that the HP treatments significantly increased (P < 0.05) the modulus of elasticity (MOE), the modulus of rupture (MOR), and the Brinell hardness (BH) of the densified wood at selected conditions. Of all the wood samples, the compressed wood at 150 MPa condition possessed the highest density and strength properties. Considering the variation in strength properties along with density, it can be concluded that the compression destruction degree of HP treatment was comparable with that caused by optimized thermal compression technique based on the strength potential index results. The integrity of wood cells presented in scanning electron microscopy results demonstrated the compression of wood cell wall achieved by HP treatment without causing any fractures, which further indicated that HP treatment is a less destructive compression technology. Based on this research, HP treatment has great potential to be applied in wood densification for commercial use.

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Section: Compression Ratio and Thickness Swellingsupporting

confidence: 91%

Section: Scanning Electron Microscopy Analysissupporting

confidence: 90%

Section: Effects Of Hp On Mechanical Propertiesmentioning

confidence: 97%

See 1 more Smart Citation

Effects of High-Pressure Treatment on Poplar Wood: Density Profile, Mechanical Properties, Strength Potential Index, and Microstructure

Yu¹,

Zhang²,

Zhu³

et al. 2017

BioResources

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“…In densification studies using different methods, collapses occurred most frequently in earlywood. In previous microscopic observations of compressed wood samples, the densification process especially deformed earlywood (Tabarsa and Chui 2001;Kutnar et al 2009;Doğu et al 2010;Kultikova 1999;Ahmed et al 2013;Standfest et al 2013). …”

Section: Fig 1 Comparison Of the Hardness Measurements In The Radiamentioning

confidence: 86%

“…In previous studies of solid wood and veneer densification, the compression ratio had an effect on the cell deformation, thus increasing the compression ratio resulted in collapses, breakage, and cracking in the cell wall (Tabarsa and Chui 1997;Kultikova 1999;Doğu et. al 2010;Ahmed et al 2013;Bekhta et al 2015). Furthermore, it was observed during the densification process that the internal stress increased significantly as a result of the elimination of the void spaces and the compression of the wood by the concentration of the collapsed cell walls.…”

Section: Fig 1 Comparison Of the Hardness Measurements In The Radiamentioning

confidence: 99%

The Effects of Densification and Heat Post-Treatment on Hardness and Morphological Properties of Wood Materials

Budakçı¹,

Pelit²,

Sönmez³

et al. 2016

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This study investigated the effects of densification and heat post-treatment on the Janka hardness and microscopic structure of relatively low-density Uludağ fir, linden, and black poplar woods. Wood samples were densified with compression ratios of 25% and 50% at 100 °C and 140 °C, respectively. Heat post-treatment was then applied to the samples at 185 °C and 212 °C for 2 h. The hardness in the radial and tangential directions was determined, and morphological changes in the cell structures were analyzed using scanning electron microscopy (SEM). The hardness values in the radial and tangential directions of the densified samples increased depending on the compression rate and treatment temperature. The hardness values in both directions were higher in the 50% compressed samples. For samples compressed at 140 °C, the hardness values were higher in the tangential direction, whereas the samples compressed at 100 °C were higher in the radial direction. After the heat post-treatment process, the hardness values of all samples decreased. As the treatment temperature increased, more adverse effects on the hardness was noted. According to the SEM analyses, the densification and heat post-treatment deteriorated the cell structure of the samples. The more cell deformation was observed in the samples densified at 100 °C with compression ratio 50% and high heat posttreatment temperature.

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Anatomical study of short-term thermo-mechanically densified alder wood veneer with low moisture content

et al. 2016

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Anatomical properties and process parameters affecting blister/blow formation in densified European aspen and downy birch sapwood boards by thermo-hygro-mechanical compression

Cited by 24 publications

References 17 publications

Effects of High-Pressure Treatment on Poplar Wood: Density Profile, Mechanical Properties, Strength Potential Index, and Microstructure

Effects of High-Pressure Treatment on Poplar Wood: Density Profile, Mechanical Properties, Strength Potential Index, and Microstructure

The Effects of Densification and Heat Post-Treatment on Hardness and Morphological Properties of Wood Materials

Anatomical study of short-term thermo-mechanically densified alder wood veneer with low moisture content

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