Effect of steaming and furfuryl alcohol impregnation pre-treatments on the spring back, set recovery and thermal degradation of densified wood of three tropical hardwood species

Moya, Róger; Moya, Róger; Starbird, Ricardo

doi:10.1007/s00107-022-01890-8

Cited by 5 publications

(2 citation statements)

References 42 publications

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“…The compression ratio at a similar level for aspen, spruce, and beech wood was obtained by Schwarzkopf (2021) [16]. Tenorio et al (2022) [46], by densifying several species of tropical wood, obtained a much lower density in the range of 600-1100 kg•m −3 .…”

Section: Densificationsupporting

confidence: 65%

Densification of Delignified Wood: Influence of Chemical Composition on Wood Density, Compressive Strength, and Hardness of Eurasian Aspen and Scots Pine

Mania,

Kupfernagel,

Curling

2024

Forests

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The densification of solid wood is a well-studied technique that aims to increase the strength and hardness of the material by permanently compressing the wood tissue. To optimise the densification process in this study, a pre-treatment with sodium sulphite was used (delignification). With delignification prior to densification, one achieves higher compression ratios and better mechanical properties compared to densification without pre-treatment. The reactivity of syringyl (dominant in hardwoods) and guaiacyl (dominant in softwoods) lignin towards delignification is different. The influences of this difference on the delignification and densification of softwoods and hardwoods need to be investigated. This study aimed to densify wood after delignification and investigate how variations in chemical composition between coniferous and deciduous species affect the densification process. Scots pine and Eurasian aspen specimens with a similar initial density were investigated to study the influence of the different lignin chemistry in softwoods and hardwoods on the densification process. Both timbers were delignified with sodium sulphite and sodium hydroxide and subsequently densified. While the delignification was twice as efficient in aspen than in pine, the compression ratios were almost identical in both species. The Brinell hardness and compressive strength showed a more significant increase in aspen than in Scots pine; however, one exception was the compressive strength in a radial direction, which increased more effectively in Scots pine. Scanning electron microscopy (SEM) revealed the microstructure of densified aspen and Scots pine, showing the crushing and collapse of the cells.

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Section: Densificationsupporting

confidence: 65%

Densification of Delignified Wood: Influence of Chemical Composition on Wood Density, Compressive Strength, and Hardness of Eurasian Aspen and Scots Pine

Mania,

Kupfernagel,

Curling

2024

Forests

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“…The method consists of compacting the wood through pressing under heat, condensing the porous cells of the wood. This intensifies the internal friction between them, obtaining a denser cellular structure, which improves the characteristics of the wood (He et al 2020, Carvalho et al 2021, Tenorio et al 2023.…”

Section: Introductionmentioning

confidence: 99%

Surface changes in wood submitted to thermomechanical densification

Carvalho,

Pereira da Rocha,

Klitzke

et al. 2024

Maderas-Cienc Tecnol

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Ideal thermomechanical treatment conditions that reduce roughness and increase hydrophobicity of the wood surface require further investigation. In this study, a thermo-mechanical densification process was applied to Gmelina arborea (gamhar) wood. Three temperatures were used (140 °C, 160 °C and 180 °C) and two compaction rates (20 % and 40 %), applied for 30 minutes in a hot hydraulic press with final pressure of 2,5 MPa. Chemical changes, wettability and surface roughness of control and densified samples were investigated, as well as morphological changes. Densification partially degraded the hemicelluloses. Consequently, the wettability of the tangential surface of the densified wood decreased, with a more hydrophobic surface. Similarly, densification reduced surface roughness, especially when filtering was used for natural wood structures, with morphological changes on the surface of the densified samples. Densification with the highest temperature (180 °C) and 20 % compaction created the most hydrophobic surface (>90 °). In contrast, densification with the lowest temperature (140 °C) and compaction of 40 % provided the best results of the roughness parameters, with significant reductions, making it an applicable technique to minimize the roughness of wood in general and improve surface quality.

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Effective strategy for fabricating surface impregnated and unilaterally densified wood with furfuryl alcohol/flame retardants for enhanced mechanical performance and flame retardancy

Huang,

Zheng,

Chen

et al. 2024

Eur. J. Wood Prod.

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Effect of steaming and furfuryl alcohol impregnation pre-treatments on the spring back, set recovery and thermal degradation of densified wood of three tropical hardwood species

Cited by 5 publications

References 42 publications

Densification of Delignified Wood: Influence of Chemical Composition on Wood Density, Compressive Strength, and Hardness of Eurasian Aspen and Scots Pine

Densification of Delignified Wood: Influence of Chemical Composition on Wood Density, Compressive Strength, and Hardness of Eurasian Aspen and Scots Pine

Surface changes in wood submitted to thermomechanical densification

Effective strategy for fabricating surface impregnated and unilaterally densified wood with furfuryl alcohol/flame retardants for enhanced mechanical performance and flame retardancy

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