Chemical analysis of heat treated softwoods

Boonstra, Michiel J.; Tjeerdsma, Bôke F.

doi:10.1007/s00107-005-0078-4

Cited by 363 publications

(293 citation statements)

References 20 publications

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“…This evolution of O/C ratio can be attributed to polysaccharide thermal degradation. Hemicelluloses are easily de-acetylated to form acetic acid that catalyzes dehydration and depolymerisation reactions leading to the production of anhydromonosaccharides like furfural (Boonstra et al 2006, Nguila et al 2007and Nguila et al 2006. O/C ratio decreased when as mass loss due to thermal degradation reactions increased for all wood species.…”

Section: Correlation Between O/c Ratio and Intensity Level Of Treatmementioning

confidence: 99%

Heat treatment of Tunisian soft wood species: Effect on the durability, chemical modifications and mechanical properties

Elaieb

Candelier

Pétrissans³

et al. 2015

Maderas, Cienc. tecnol.

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Last decades, wood was promoted as building material. Wood heat treatment by mild pyrolysis has been reported to improve biological durability and dimensional stability of the material and constitutes an attractive « non biocidal » alternative to classical preservation treatments. Previous studies have shown that conferred properties strongly depend on the heat treatment intensity. A quality control marker based on mass loss has been developed. For several years, the increased development of Tunisian wood industry provides a significant capacity of wood production and transformation. Forests in Tunisia consist essentially of coniferous species [Aleppo pine (Pinus halepensis), Radiata pine (Pinus radiata), Maritime pine (Pinus pinaster), Stone pine (Pinus pinea)], characterised by a weak natural durability. Improved durability and fungal resistance should allow the use of Tunisian species in the wood industry. Import limitation of European species and the use of local species allow the conservation of economic value added in the country and improve the economic balance. For this reason, several Tunisian softwood species (Aleppo pine, Radiata pine and Maritime pine) have been heat-treated under vacuum atmosphere at 230°C to obtain a thermal degradation with mass losses of approximately 8, 10 and 12%. The oven device allows recording the dynamic Mass Loss (ML) during the treatment and following the thermodegradation kinetic. The chemical composition of the studied wood samples was determined before and after heat treatment. For each wood species and treatment intensity, wood chemical and mechanical analyses were performed by measuring O/C ratio, bending and hardness tests. Afterward, tests of decay resistance were performed according to the EN 113 Standard, with different fungal attacks (Poria Placenta, Coriolus Versicolor) at 22°C and 70% of humidity for 16 weeks. Results were related to the mass loss. Furthermore, intensity of thermal degradation was evaluated by TD-GC-MS. Treated and untreated wood samples were maintained during 15 minutes at 230 °C under nitrogen in the thermodesorption tube in order to analyse and compare resulting from the wood thermodegradation volatile compounds.

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Section: Correlation Between O/c Ratio and Intensity Level Of Treatmementioning

confidence: 99%

Heat treatment of Tunisian soft wood species: Effect on the durability, chemical modifications and mechanical properties

Elaieb

Candelier

Pétrissans³

et al. 2015

Maderas, Cienc. tecnol.

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“…Of the main components of wood, lignin is the most resistant to thermal degradation (Fengel and Wegener 1989). The relative increase in lignin content with heat treatment is associated with structural changes (cross-linking) in lignin composition (Esteves et al 2008, Boonstra andTjeerdsma 2006). Lignin also undergoes polycondensation reactions with other cell wall components (Esteves et al 2008).…”

Section: Chemical Contentmentioning

confidence: 99%

Changes in the chemical structure and decay resistance of heat-treated narrow-leaved ash wood

Yalçın

Şahin

2015

Maderas, Cienc. tecnol.

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We analyzed the effects of heat treatment on the chemical structure of wood from narrow-leafed Ash (Fraxinus angustifolia), a fast-growing and economically valuable species. We also analyzed the effects of heat treatment on the wood's resistance to four decay fungi. Narrow-leafed Ash wood samples were heated with saturated steam to 140, 180, 200, and 220°C for 2, 4, and 6 h. The relative contents of extractable components were analyzed, as well as the levels of holocellulose, cellulose, and lignin. In addition, the density, equilibrium moisture content, and pH of the samples were measured. To determine the effects of heat treatment on resistance to decay fungi, the samples were exposed to the white rot fungus Trametes versicolor, dry rot fungus Serpula lacrymans, and the brown rot fungi Coniophora puteana and Gloeophyllum trabeum. Changes in the chemical composition of the wood due to heat treatment were correlated with increased resistance to fungal decay. While the hemicellulose content was dramatically reduced with increasing temperature and treatment duration, the lignin content increased proportionately. Thus, heat treatment is an environmentally friendly method of preserving narrow-leafed Ash wood against various decay fungi.

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“…Em geral, as amostras de madeiras deterioradas apresentaram redução dos percentuais de contração em relação ao grupo controle (exceção para E. dunnii, no plano radial). A celulose e as hemiceluloses são compostos hidrófilos, ou seja, possuem como característica a fácil adsorção de água (Borges & Quirino, 2004;Boonstra & Tjeerdsma, 2006). Possivelmente, essa redução da contração ocorreu devido à decomposição dos sítios (presentes na celulose e hemiceluloses amorfas) que possuem afinidade com a água no interior da madeira, dificultando a absorção de umidade por parte desse material (Hill, 2006).…”

Section: 61unclassified

Higroscopicidade da madeira de três espécies florestais deterioradas por térmitas Nasutitermes

et al. 2018

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Resumo -Este trabalho objetivou avaliar as modificações resultantes do ataque de cupins quanto à higroscopicidade da madeira de Eucalyptus dunnii, E. saligna e Corymbia maculata. Foram utilizados corpos de prova com dimensões de 20 x 20 x 150 mm³ (tangencial x radial x longitudinal), sendo avaliado o teor de umidade de equilíbrio (TU E ), as contrações lineares dos planos tangencial e radial (β T e β R ), a anisotropia da contração (CA β ), a absorção de água (AA) e a taxa de absorção de água (TAA) de amostras de madeira sadias e deterioradas por térmitas Nasutitermes sp. Verificou-se que o ataque dos térmitas causou aumento no TU E e redução no β T , entretanto, β R e CA β apresentaram variação entre as diferentes espécies. AA e TAA apresentaram alta intensidade de absorção de água nas primeiras horas de imersão, sendo maiores nas amostras do grupo controle em relação às deterioradas. Possivelmente, as variações nos parâmetros relativos à higroscopicidade da madeira das espécies estudadas estão relacionadas ao aumento da porosidade e deterioração, principalmente da celulose e hemiceluloses, afetando diretamente a capacidade da madeira em absorver e perder umidade, comprometendo a sua qualidade. Wood hygroscopicity of three forestry species deteriorated byNasutitermes termites Abstract -The objective of this work was to evaluate hygroscopicity modification of Eucalyptus dunnii, E. saligna and Corymbia maculata wood due to termites attack. Using samples measuring 20 x 20 x 150 mm³ (tangential x radial x longitudinal) the equilibrium moisture content (MC E ), linear contractions of the tangential and radial planes (β T e β R ), contraction anisotropy (CA β ), water absorption (AA) and water absorption rate (TAA) of healthy and deteriorated wood by Nasutitermes termites were evaluated. It was verified that the termite attack caused increase in TU E and reduction in β T . However, β R and CA β presented different behaviors, varying among the different species. AA and TAA presented higher water absorption intensity in the first hours of immersion, being higher in the control group in comparison with the deteriorated samples. Possibly the variations in the parameters related to the wood hygroscopicity of the studied species are correlated to the increase of porosity and deterioration mainly of cellulose and hemicelluloses, directly affecting the wood's ability to absorb and lose moisture, compromising the material quality.

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Chemical analysis of heat treated softwoods

Cited by 363 publications

References 20 publications

Heat treatment of Tunisian soft wood species: Effect on the durability, chemical modifications and mechanical properties

Heat treatment of Tunisian soft wood species: Effect on the durability, chemical modifications and mechanical properties

Changes in the chemical structure and decay resistance of heat-treated narrow-leaved ash wood

Higroscopicidade da madeira de três espécies florestais deterioradas por térmitas Nasutitermes

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