Densified wood anatomical structure and the effect of heat treatment on the recovery of set

Darwis, Atmawi; Wahyudi, Imam; Dwianto, Wahyu; Cahyono, Tekat Dwi

doi:10.1007/s13196-017-0184-z

Cited by 27 publications

(30 citation statements)

References 17 publications

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“…An increase in time during the heating stage, as occurred in the present study, increases the compression of wood and reduces the level of stress stored in the wood during densification. In addition, an increase in heating time affects the chemical composition of the wood (Inoue et al 2008), because heating the wood to temperatures above 180 °C leads to degradation of components of hemicellulose and as a result, the stresses stored in the micro fibrils would be released (Norimoto et al 1993, Dwianto et al 1996 and the lignin will soften and flow to fill the space matrix that is in the wood fixing the wood dimensional stability (Darwis et al 2017). Inoue et al (2008) also point out the importance of the adequate use of time and temperature as a treatment to increase the stability of densified wood.…”

Section: Densification Processmentioning

confidence: 99%

“…Many studies have been conducted regarding stabilization of compressed wood, with techniques such as impregnation with resins and physical or chemical treatments (Inoue et al 1993, Kutnar and Kamke 2012, Pelit et al 2016. Among these techniques, physical treatments are preferred, such as steaming or heating, since they do not require any chemicals (Darwis et al 2017). Heating and/or steaming before compression have been found to reduce densified wood spring-back significantly (Inoue et al 2008, Darwis et al 2017.…”

Section: Introductionmentioning

confidence: 99%

“…Among these techniques, physical treatments are preferred, such as steaming or heating, since they do not require any chemicals (Darwis et al 2017). Heating and/or steaming before compression have been found to reduce densified wood spring-back significantly (Inoue et al 2008, Darwis et al 2017. However, heat treatments have the disadvantage of reducing the strength properties of the wood due to weight loss and chemical degradation of wood, when it exposed to high temperatures (Perçin et al 2015).…”

Section: Introductionmentioning

confidence: 99%

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Flooring characteristics of thermo-mechanical densified wood from three hardwood tropical species in Costa Rica

Moya

Navarro-Mora

2021

Maderas, Cienc. tecnol.

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Densification is one method used to modify low-density woods to make them achieve the hardness required for flooring application. The purpose of this study was to investigate the effect of thermo-mechanical densification with pre-heating in wood of Alnus acuminata, Vochysia ferruginea and Vochysia guatemalensis from, seeking to stabilize and reduce spring-back of the densified wood and evaluate its performance in flooring applications. The results showed that the wood of the three species turned dark. This is because brightness diminished and yellowness and redness increased. Weight loss due to pre-heating was statistically higher in V. ferruginea and V. guatemalensis. The final density and spring-back were statistically similar in the three species. The percentage of densification of A. acuminata and V. guatemalensis were statistically higher than for V. ferruginea and the degree of compression was statistically higher in V. guatemalensis. As for flooring evaluation, the percentage of densification, temperature and time of pre-heating affected the behavior of densified wood flooring. The low percentage of densification and high weight loss in the pre-heating stage caused greater values of wear, wear index, residual deformation, residual indentation for the falling ball indentation test, and more damages in the surface indentation test in wood of V. ferruginea.

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Section: Densification Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Flooring characteristics of thermo-mechanical densified wood from three hardwood tropical species in Costa Rica

Moya

Navarro-Mora

2021

Maderas, Cienc. tecnol.

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“…Therefore, studies on hardwood tropical species, whose anatomical structures affect to a further extent the result of the process, are scarce (Navi and Heger 2004). This is because the compression properties of the wood depend on the frequency, size, and distribution of its anatomical structures (Darwis et al 2017). For hardwoods, these structures are dominated by vessels, fibers, and radial parenchyma arranged in more complex matrixes (Gibson 2012) than the fiber tracheids of softwood species (Fratzl and Weinkamer 2007).…”

Section: Introductionmentioning

confidence: 99%

Effect of thermo-hydro-mechanical densification on the wood properties of three short-rotation forest species in Costa Rica

Moya

2020

BioRes

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Alnus acuminata, Vochysia ferruginea, and Vochysia guatemalensis are three low-density wood species used for reforestation in Costa Rica. The goal of this work was to study a thermo-hydro-mechanical densification process and test the characteristics of densified wood of these species. Twelve densifying treatments based on temperature, compression time, and use/no use of steam were tested. The variables of the densification process and the properties of the densified wood were determined. The results showed that the densification percentage was over 80% for wood of A. acuminata and over 70% for wood of V. ferruginea and V. guatemalensis. In the three species, the densification process was influenced by initial density. The influence of temperature during the densification process affected the heating rate and color change. An increase in the modulus of elasticity and modulus of rupture in static bending and in the hardness of the densified wood relative to the normal wood was observed, as well as a clear positive correlation of the properties with final density and maximum load, the latter being highly correlated with initial density. This showed that initial density was significant in the densification process and affects wood properties.

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“…Apart from the compression stability, the TM process may exacerbate the surface characteristics namely roughness and wettability, etc., which impacts bonding and coating performance [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Functionalized Surface Layer on Poplar Wood Fabricated by Fire Retardant and Thermal Densification. Part 2: Dynamic Wettability and Bonding Strength

Chu

Avramidis

et al. 2019

Forests

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In continuation of our former study on a novel combined treatment of nitrogen–phosphorus fire retardant and thermomechanical densification on wood, this study focuses on the dynamic wettability and the bonding strength. The contact angle was measured using the sessile drop method and the surface energy was calculated according to the van Oss method. Water surface penetrating and spreading is analyzed by both the Shi and Gardner model and the droplet volume changing model. The results reveal that the combined treatment increased the surface energy, especially the acid–base component. The contact angle declined and the water droplet spread more easily on the surface. Meanwhile, the rate of relative droplet volume decreased by 32.6% because the surface layer was densified and stabilized by the combined process. Additionally, the surface possesses the lowest roughness and highest abrasion resistance on the tangential section. Thus, the bonding strength of the combined treated poplar decreased by 29.7% compared to that of untreated poplar; however, it is still 53.3% higher than that of 220 °C heat-treated wood.

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Densified wood anatomical structure and the effect of heat treatment on the recovery of set

Cited by 27 publications

References 17 publications

Flooring characteristics of thermo-mechanical densified wood from three hardwood tropical species in Costa Rica

Flooring characteristics of thermo-mechanical densified wood from three hardwood tropical species in Costa Rica

Effect of thermo-hydro-mechanical densification on the wood properties of three short-rotation forest species in Costa Rica

Functionalized Surface Layer on Poplar Wood Fabricated by Fire Retardant and Thermal Densification. Part 2: Dynamic Wettability and Bonding Strength

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