The effect of thermal treatment on physical and mechanical properties of Luehea divaricata hardwood

Schneid, Eduardo; Cademartori, Pedro Henrique González de; Gatto, Darci Alberto

doi:10.4067/s0718-221x2014005000033

Cited by 14 publications

(16 citation statements)

References 18 publications

(12 reference statements)

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“…In briefly, the findings of the present study revealed that heat treatment reduces considerably volumetric swelling and shrinkage. Similar findings were also reported by several previous researchers (Feist and Sell 1987, Esteves et al 2007, Schneid et al 2014, Bal 2015, Korkut and Aytin 2015. Stamm (1964) stated that this is mainly associated with the degradation of the hemicelluloses.…”

Section: Resultssupporting

confidence: 80%

Analysis of volumetric swelling and shrinkage of heat treated woods: Experimental and artificial neural network modeling approach

Tiryaki

Bardak

Aydın

et al. 2016

Maderas, Cienc. tecnol.

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Shrinkage and swelling characteristics of wood as a hygroscopic material affect negatively its effective utilization for a variety of applications. Heat treatment is widely used for minimizing the negative effects of volumetric swelling and shrinkage of wood. The present study aims to develop artificial neural network (ANN) models for predicting volumetric swelling and shrinkage of heat treated woods. For this purpose, wood samples were subjected to heat treatment at varying temperatures (130, 150, 170 and 190 ºC) for varying durations (2, 4, 6 and 8 h). Experimental results have showed that volumetric swelling and shrinkage of wood decreased by heat treatment. Then, neural networks models capable of predicting the swelling and shrinkage of the treated woods were developed based on the resulting data. It was seen that ANN models allowed volumetric swelling and shrinkage of such woods to predict successfully with a limited set of experimental data. This approach was able to predict volumetric swelling and shrinkage of wood with a mean absolute percentage error equal to 2,599% and 2,647% in test phase, respectively. The developed models might thus serve as a robust tool to predict volumetric swelling and shrinkage with less number of experiments.

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Section: Resultssupporting

confidence: 80%

Analysis of volumetric swelling and shrinkage of heat treated woods: Experimental and artificial neural network modeling approach

Tiryaki

Bardak

Aydın

et al. 2016

Maderas, Cienc. tecnol.

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“…Wood treated with this method achieves high structural and dimensional stability (Bekhta and Niemz 2003;ITA 2003;Calonego et al 2012;Kvietková et al 2015). On the other hand, the mechanical properties tested in these studies mostly reveal the negative impacts of increasing temperature during the heat treatment process (Borrega and Kärenlampi 2007;Shi et al 2007;Sonderegger et al 2007;Johansson 2008;Schneid et al 2014). The changing in mechanical properties of wood mainly depends on the species and treatment degree.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Stiffness and Strength Properties of Untreated and Heat-Treated Wood of Douglas Fir and Alder

Borůvka¹,

Zeidler²,

Holeček³

2015

BioResources

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This paper investigates the effect of heat treatment temperature on the stiffness and strength properties of Douglas fir (Pseudotsuga menziesii Franco) and common alder (Alnus glutinosa Gaertn.) woods. Two temperatures of heat treatment were used: 165 and 210 °C. The effects of dynamic elasticity modulus, static elasticity modulus, impact toughness, bending strength, and density were evaluated. It is already understood that the mechanical properties, primarily the bending strength, decreases with increasing temperature. In contrast to the favorable stability in shape and dimension that was achieved, the changes in the woods' properties with temperature were mostly negative. Higher heat treatment temperatures corresponded with lower stiffness and strength properties. For higher temperature treatments, above 200 °C, deterioration of the tested properties was noticable as a result of the significant changes in the wood chemical structure. Even the positive effect of the equilibrium moisture decrease was not able to counterbalance the unfavorable changes. Moreover, it was observed that as the hemicellulose content is higher in alder wood, density, static bending strength, and toughness all decreased steadily at high temperatures, compared to Douglas fir wood.

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“…Steam, nitrogen, and oil are used as the heat transfer media in these processes (Wang and Cooper 2005). Several factors have effects on the results of heat treatment, and these factors include temperature, duration, the heat transfer medium (Esteves and Pereira 2009, Baysal et al 2014, Schneid et al 2014, the species of wood (hardwood or softwood) (Ibach 2010), initial moisture content (Gaff and Gasparik 2013), the density of the wood (Bal 2013a), the maturity of the wood (Bal and Bektaş 2012, Bal and Bektaş 2013, and the extractive content of the wood (Kortelainen et al 2006, Bal 2013b, 2014. The OHT process is very different from the others because it is conducted in hot oil.…”

Section: Introductionmentioning

confidence: 99%

Physical properties of beech wood thermally modified in hot oil and in hot air at various temperatures

Bal

2015

Maderas, Cienc. tecnol.

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In this study, beech wood was treated in hot oil and in hot air to determine the differences in the effects of the two processes on the physical properties of the wood. Heat treatment was conducted at temperatures of 160, 190, and 220 °C for 2 h at atmospheric pressure. After the heat treatment, various properties of the wood, including mass increase in hot oil treatment (wt% gain), mass loss in hot air treatment (wt% loss), oven-dried density, swelling, equilibrium moisture content, fiber saturation point, and moisture content were determined. Regression analyses were conducted to assess the differences in mass change and volumetric swelling, and the findings were analyzed statistically. The results showed that heat treatment in hot oil influenced the physical properties of beech wood more than treatment in hot air. However, the extensive uptake of oil by the wood samples, resulting in mass increases, was a negative issue associated with the hot oil treatment.

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The effect of thermal treatment on physical and mechanical properties of Luehea divaricata hardwood

Cited by 14 publications

References 18 publications

Analysis of volumetric swelling and shrinkage of heat treated woods: Experimental and artificial neural network modeling approach

Analysis of volumetric swelling and shrinkage of heat treated woods: Experimental and artificial neural network modeling approach

Comparison of Stiffness and Strength Properties of Untreated and Heat-Treated Wood of Douglas Fir and Alder

Physical properties of beech wood thermally modified in hot oil and in hot air at various temperatures

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