Effect of partial delignification and densification on chemical, morphological, and mechanical properties‏ of wood: Structural property evolution

Alqrinawi, Hussein; Ahmed, Bulbul; Wu, Qinglin; Lin, Hai; Kameshwar, Sabarethinam; Shayan, Mohammad

doi:10.1016/j.indcrop.2024.118430

Cited by 8 publications

(2 citation statements)

References 43 publications

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“…In the region of 1733 cm -1 it is possible to notice the lower intensity of peaks as a function of the increase in densification temperature. This change is attributed to the elongation of carbonyl groups (C=O) in hemicelluloses, lignin and extractives (Fu et al 2019, Alqrinawi et al 2024. Decreasing intensity peaks suggest the cleavage of ester groups associated with the decomposition of hemicellulose polysaccharides (Inari et al 2006),…”

Section: Changes In Chemical Constituentsmentioning

confidence: 99%

“…Chemical and physical changes in the main constituents of wood surfaces reveal differences in its chemical structure, in particular changes in the OH groups of densified wood (Gonultas and Candan 2018, Li et al 2022, Alqrinawi et al 2024. The behavior of water on the wood surface is affected by chemical factors and surface irregularities, generating different shapes of water droplets, depending on the time of contact with the wood.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Changes In Chemical Constituentsmentioning

confidence: 99%

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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Effect of delignification on shrinking and swelling of poplar wood assessed using digital image correlation technique

Li,

Sun,

Wang

et al. 2025

International Journal of Biological Macromolecules

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Mechanical Performance Related to Chemical Variability in Differently Pretreated and Densified Birch Wood

Jakob,

Janesch,

Müller

et al. 2024

ACS Sustainable Chem. Eng.

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Birch wood veneer specimens were subjected to alkaline delignification with varying degrees of severity, in terms of concentration, temperature, and duration, resulting in up to 50% mass loss. Upon densification, substantial improvements in wood mechanical performance beyond the expected scaling with an increased density were obtained. With values of 50 GPa (elastic modulus) and 450 MPa (tensile strength), the elastic modulus increased by more than a factor of 2, and the strength roughly tripled. The mechanical performance first increased with increasing mass loss, peaked at intermediate levels, and then decreased again. Fourier-transform infrared (FT-IR) spectroscopy revealed that the initial mass loss was primarily related to the removal of hemicellulose, while with increasing mass loss, bands assigned to lignin were also affected. A correlation analysis between IR bands showing changes due to pretreatment and the mechanical performance of the respective wood specimens showed positive correlations for bands associated with cellulose and lignin, whereas bands assigned to hemicellulose showed a negative correlation with mechanics. In total, 71% of the variability of the mechanical performance was explained by IR spectra. Within the setting of the present study dealing with alkaline treatment of birch wood, it is concluded that the initial removal of hemicellulose under very mild alkaline extraction conditions had a positive effect on the mechanical performance of specimens. The progressive removal of lignin components with more severe treatment did not lead to further improvements but ultimately led to reduced improvements compared to the untreated reference.

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Effect of partial delignification and densification on chemical, morphological, and mechanical properties‏ of wood: Structural property evolution

Cited by 8 publications

References 43 publications

Surface changes in wood submitted to thermomechanical densification

Surface changes in wood submitted to thermomechanical densification

Effect of delignification on shrinking and swelling of poplar wood assessed using digital image correlation technique

Mechanical Performance Related to Chemical Variability in Differently Pretreated and Densified Birch Wood

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