Effect of thermal modification temperature on the mechanical properties, dimensional stability, and biological durability of black spruce (<i>Picea mariana</i>)

Lekounougou, S.; Kocaefe, Duygu

doi:10.1080/17480272.2013.869256

Cited by 19 publications

(10 citation statements)

References 33 publications

(36 reference statements)

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“…MORs tended to decline with increasing treatment time and temperature in a pattern that was consistent with previous studies (Boonstra et al 2007;Ding et al 2011;Lekounougou and Kocaefe 2014); however, the effects were only significant with borontreated samples heated at 200 o C for 4 or 6 h. Interestingly, MOR increased slightly in boron-treated and non-pretreated samples heated for 2 h at 160 o C, but then declined. Similar results were obtained by Kubojima et al (2000), who found that the bending strength increased at the initial stage of the heat treatment and then later decreased.…”

Section: Effects Of Thermal Modification On Morsupporting

confidence: 80%

“…A number of approaches have emerged for this purpose under the broader title of wood modification including furfurylation (Esteves et al 2011), acetylation (Popescu et al 2014), and thermal treatment (Poncsάk et al 2006;Lekounougou and Kocaefe 2014). Each has merits under certain applications and there is evidence of increasing use of these technologies for wood protection in Europe.…”

Section: Introductionmentioning

confidence: 99%

“…Thermal treatment has drawn substantial commercial interest in Europe because it is relatively simple to apply and has the potential to enhance some wood properties, including dimensional stability and durability without the addition of chemicals (Poncsάk et al 2006;Esteves et al 2008;Calonego et al 2010;Lekounougou and Kocaefe 2014). Most thermal modification processes employ temperatures between 160 and 250 o C, usually above 200 o C depending on the wood species and the desired material properties.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Thermal Modification on Physical and Mechanical Properties of Douglas-Fir Heartwood

Morrell

2014

BioResources

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The flexural properties, mass losses, and moisture behavior of thermally modified Douglas-fir pretreated with boron or glycerol were examined. Pretreatments were associated with slight, but not significant, reductions in modulus of rupture (MOR) and modulus of elasticity (MOE) of Douglasfir at different thermal treatment levels. Boron pretreatment had the greatest effect on MOR. MOR of non-pretreated and boron-treated samples increased slightly at the initial stage of thermal treatment and then decreased with rising temperature and time. The MOR of glycerol-treated samples decreased with increasing temperature and time. The thermal treatments employed had no significant effect on MOE. Both temperature and pretreatments improved anti-swell efficiency. Further studies are underway to characterize the nature of the chemical changes associated with the thermal modification process.

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Section: Effects Of Thermal Modification On Morsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of Thermal Modification on Physical and Mechanical Properties of Douglas-Fir Heartwood

Morrell

2014

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“…(140°C for 90 minutes) to 33.53 N/mm 2 (160°C for 90 minutes). MOR of the samples therefore declined with increasing temperature and time in a pattern that was consistent with the previous studies [17,18,19].…”

Section: Mass Losssupporting

confidence: 90%

Impact of Thermal Treatment on Anatomical and Mechanical Properties of Ricinodendron heudelotii Wood

Iyiola

Ayanleye

Catherine

et al. 2019

JSRR

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The study examined the impact of thermal treatment on anatomical and mechanical properties Ricinodendron heudelotii wood. Wood samples were oven dried at 105°C and cooled in a desiccator to a constant weight before the thermal treatment. Heat treatment of wood was carried out in a Furnace at 120°C, 140°C and 160°C for 45 minutes and 90 minutes. The Density, Modulus of Elasticity (MOE), Modulus of Rupture (MOR), and the anatomical properties were assessed. The results for Density of Ricinodendron heudelotii wood showed decrease from 279 kg/m3 (120°C at 45 minutes) to 256 kg/m3 (160°C at 90 minutes) while that of control was 281 kg/m3 which was lower than the treated samples. The increase in temperature with time had effect of the color of wood as it changed from creamy white to dark brown. The image of untreated and treated samples showed no significant changes within and among treatment groups as there was no effect of treatment time and exposure on the samples. The MOE of heat treated Ricinodendron heudelotii increased from 2064.84 N/mm2 (140°C for 45 minutes) to 2271.93 N/mm2 (160°C for 90 minutes) while MOR decreased from 40.56 N/mm2 (140°C for 90 minutes) to 33.53 N/mm2 (160°C for 90 minutes). The study revealed that the wood could be used in a light furniture as unnecessarily heavy wood is not important. Also, the study proved effective in improving the modulus of elasticity of the wood.

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“…However, the surface hardness of the heat treated wood can be improved for several wood species thermally modified at treatment temperature lower than 210°C (Sivrikaya et al 2015a). Low temperature and time cause the increase in the hardness value while high temperature and time decrease the hardness value of heattreated wood (Lekounougou and Kocaefe 2014), due to higher degradation of hemicellulose and cellulose and evaporation of extractive compounds (Karamanoglu and Akyıldız 2013;Esteves and Pereira 2009). These last improvements have an adverse effect on wood mechanical properties such as bending and compression strength, stiffness and shear strength (Dilik and Hiziroglu 2012;Candelier et al 2013;Hannouz et al 2015, Hermoso et al 2015.…”

Section: Introductionmentioning

confidence: 99%

Resistance of thermally modified ash (Fraxinus excelsior L.) wood under steam pressure against rot fungi, soil-inhabiting micro-organisms and termites

et al. 2016

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Thermal modification processes have been developed to increase the biological durability and dimensional stability of wood. The aim of this paper was to study the influence of ThermoWood Ò treatment intensity on improvement of wood decay resistance against soil-inhabiting microorganisms , brown/white rots and termite exposures. All of the tests were carried out in the laboratory with two different complementary research materials. The main research material consisted of ash (Fraxinus excelsior L.) wood thermally modified at temperatures of 170, 200, 215 and 228°C. The reference materials were untreated ash and beech wood for decay resistance tests, untreated ash wood for soil bed tests and untreated ash, beech and pine wood for termite resistance tests. An agar block test was used to determine the resistance to two brown-rot and two white-rot fungi according to CEN/TS 15083-1 directives. Durability against soil-inhabiting microorganisms was determined following the CEN/TS 15083-2 directives, by measuring the weight loss, modulus of elasticity (MOE) and modulus of rupture (MOR) after incubation periods of 24, 32 and 90 weeks. Finally, Reticulitermes santonensis species was used for determining the termite attack resistance by non-choice screening tests, with a size sample adjustment according to EN 117 standard directives on control samples and on samples which have previously been exposed to soil bed test. Thermal modification increased the biological durability of all samples. However, high thermal modification temperature above 215°C, represented by a wood mass loss (ML%) due to thermal degradation of 20%, was needed to reach resistance against decay comparable with the durability classes of ''durable'' or ''very durable'' in the soil bed test. The brown-rot and white-rot tests gave slightly better durability classes than the soil bed test. Whatever the heat treatment conditions are, thermally modified ash wood was not efficient against termite attack neither before nor after soft rot degradation.

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Effect of thermal modification temperature on the mechanical properties, dimensional stability, and biological durability of black spruce (Picea mariana)

Cited by 19 publications

References 33 publications

Effects of Thermal Modification on Physical and Mechanical Properties of Douglas-Fir Heartwood

Effects of Thermal Modification on Physical and Mechanical Properties of Douglas-Fir Heartwood

Impact of Thermal Treatment on Anatomical and Mechanical Properties of Ricinodendron heudelotii Wood

Resistance of thermally modified ash (Fraxinus excelsior L.) wood under steam pressure against rot fungi, soil-inhabiting micro-organisms and termites

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