Effect of heat treatment on the mechanical properties of North American jack pine: thermogravimetric study

Kocaefe, Duygu; Poncsák, Sándor; Tang, Junjun; Bouazara, Mohamed

doi:10.1007/s10853-009-3985-7

Cited by 67 publications

(65 citation statements)

References 19 publications

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“…Heat treatment at temperatures higher than 160 °C, and especially above 210 °C, causes thermal degradation of wood, which reduces resistance to screw withdrawal (Poncsak et al 2006;Kocaefe et al 2010). On the other side, treatment time does not appear to have a significant effect on screw withdrawal strength (Kocaefe et al 2010).…”

Section: Introductionmentioning

confidence: 99%

The Effect of Heat Treatment on the Withdrawal Capacity of Screws in Spruce Wood

Kariž¹,

Kuzman²,

Šernek³

2013

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The withdrawal capacity of screws in heat-treated spruce wood (Picea abies Karst.) was measured in the radial and tangential directions. Wood was heat-treated at temperatures of 150, 170, 190, 210, and 230 °C. Screw withdrawal capacity decreased as the degree of thermal modification was increased. Also, image analysis was used to measure the size of the deformed wood area around the screw, which increased with higher thermal modification temperatures. This leads to the practical recommendation that connections in heat-treated wood should be constructed with screws with larger diameters and deeper penetration. Moreover, larger spacing between screws is needed to ensure sufficient withdrawal capacity compared to non-treated wood.

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Section: Introductionmentioning

confidence: 99%

The Effect of Heat Treatment on the Withdrawal Capacity of Screws in Spruce Wood

Kariž¹,

Kuzman²,

Šernek³

2013

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“…Un tratamiento térmico en la madera, mejora su estabilidad dimensional y su resistencia contra la biodegradación por hongos de la pudrición, y reduce algunas de sus propiedades mecánicas (Kocaefe et al 2010). Un tratamiento térmico a altas temperaturas (mayores a 170 ºC) produce cambios químicos de los constituyentes de la pared celular (hemicelulosa, celulosa y lignina) (Niemz et al 2004, Metsä-Kortelainen y Viitanen 2012), y puede mejorar la estabilidad dimensional de la matriz celular y con ello, la de las partículas y fibras de madera que conforman un tablero (Boonstra et al 2006a).…”

Section: Introductionunclassified

Propiedades químicas, color y humectabilidad de partículas de Laureliopsis philippiana (tepa) con y sin tratamiento térmico

H³

et al. 2013

Maderas, Cienc. tecnol.

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El propósito de este trabajo fue determinar el efecto de un tratamiento térmico, en una atmósfera saturada de vapor de agua, en partículas de madera de la especie Laureliopsis philippiana. Las partículas fueron tratadas en autoclave a 150 ºC por 90 minutos y a una presión de 430 kPa, la cual se generó durante el proceso por la evaporación del agua en el autoclave herméticamente cerrado. Se determinaron la cantidad de extraíbles en soda, etanol tolueno, agua caliente y fría, así también, los porcentaje de celulosa, holocelulosa y lignina, el valor pH, los porcentajes de ácidos volátiles y solubles en agua, y la capacidad tampón, tanto para partículas sin tratamiento como con tratamiento. Para las partículas con tratamiento térmico, se encontró un aumento en el porcentaje de extraíbles, de celulosa, y de ácidos volátiles y lavables, así como también, un aumento de la acidez y de una mayor capacidad tampón, en comparación con las partículas sin tratamiento. El tratamiento térmico produjo un cambio de color en las partículas y una reducción de la humectabilidad. Debido a los cambios químicos encontrados en las partículas tratadas, estas presentarían ventajas en la fabricación de tableros de partículas, favoreciendo el fraguado de la ureaformaldehído. Palabras claves:Composición química, acidez, Laureliopsis philippiana, tratamiento térmico, tableros de partículas. ABSTRACTThe purpose of this work was to determine the effect of a thermal treatment in a vapor water saturated atmosphere, on wood particles of Laureliopsis philippiana. The particles in autoclave at 150 ºC for 90 minutes and with a pressure of 430 kPa were thermally treated, the pressure generated by the evaporation of water in the sealed autoclave. The amount of extractives in soda, ethanol-toluene, cold and hot water, as well as, the percentages of cellulose, holocellulose and lignin, the pH value, the percentages of volatiles and washables acids, and buffer capacity, for both particles without and with treatment, were determined. In thermally treated particles an increase in the percentage of extractives, cellulose and volatiles and water soluble acids was found, as well as, in thermally treated particles an increment of acidity and a higher buffer capacity was found, in comparison with the particles without treatment. The thermal treatment produced a color change in the particles and a reduction in their wettability. Due to the chemical changes found in the treated particles they could present advantages in the particleboard production, allowing a better ureaformaldehyde polymerization.

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“…The improvement in the dimensional stability of wood obtained by several authors (Kocaefe et al , 2010Welbzbacher et al 2005;Tjeerdsma et al 1998) is one of the main objectives of thermal treatments and was not achieved in the thermomechanical treatments proposed in this study. For the cleavage of cellulose and hemicelluloses molecules, thus reducing the wood hygroscopicity, a longer treatment time at higher temperature would be required.…”

Section: Physical Mechanical and Wettabillity Propertiesmentioning

confidence: 60%

Properties of Thermo-Mechanically Treated Wood From Pinus Caribaea Var. Hondurensis

Santos¹,

Menezzi²,

Souza³

2012

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This study aimed at evaluating the effect of thermo-mechanical treatment on properties of Pinus caribaea var. hondurensis wood. Two pressure levels (25% and 50% of the compression strength perpendicular to grain) were evaluated. The treatment was applied in a laboratory hot press in one-step or two-step modes for 50 minutes. In the one-step treatment, the total pressure was applied after the temperature of the center of the wood reached 170°C. In the two-steps treatment, half of the pressure was applied after the center of the wood reached 100°C, and the final pressure was applied when it reached 170°C. The weight loss immediately after treatment was equivalent to the wood moisture content, indicating that degradation of wood polymers did not occur. However, the treatments showed decreasing values of the moisture content, which were reduced from 12.3% to 9.8%. A moderate improvement on surface roughness was achieved, while wood wettability was highly reduced in all treatments, as determined by contact angle measurement. On the other hand, the treatment applied did not improve the wood dimensional stability, but all mechanical properties presented a trend of improvement.

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Effect of heat treatment on the mechanical properties of North American jack pine: thermogravimetric study

Cited by 67 publications

References 19 publications

The Effect of Heat Treatment on the Withdrawal Capacity of Screws in Spruce Wood

The Effect of Heat Treatment on the Withdrawal Capacity of Screws in Spruce Wood

Propiedades químicas, color y humectabilidad de partículas de Laureliopsis philippiana (tepa) con y sin tratamiento térmico

Properties of Thermo-Mechanically Treated Wood From Pinus Caribaea Var. Hondurensis

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