scholarly journals Changes in microstructure and stiffness of Scots pine (Pinus sylvestris L) sapwood degraded by Gloeophyllum trabeum and Trametes versicolor – Part II: Anisotropic stiffness properties

Holzforschung ◽  
2012 ◽  
Vol 66 (2) ◽  
Author(s):  
Thomas K. Bader ◽  
Karin Hofstetter ◽  
Gry Alfredsen ◽  
Susanne Bollmus
Keyword(s):  
Mechanical Properties ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Trametes Versicolor ◽  
Brown Rot ◽  
White Rot ◽  
Cellulose Microfibrils ◽  
Gloeophyllum Trabeum ◽  
Fungal Decay ◽  
Tangential Stiffness

Abstract Fungal decay considerably affects the macroscopic mechanical properties of wood as a result of modifications and degradations in its microscopic structure. While effects on mechanical properties related to the stem direction are fairly well understood, effects on radial and tangential directions (transverse properties) are less well investigated. In the present study, changes of longitudinal elastic moduli and stiffness data in all anatomical directions of Scots pine (Pinus sylvestris) sapwood which was degraded by Gloeophyllum trabeum (brown rot) and Trametes versicolor (white rot) for up to 28 weeks have been investigated. Transverse properties were found to be much more deteriorated than the longitudinal ones. This is because of the degradation of the polymer matrix between the cellulose microfibrils, which has a strong effect on transverse stiffness. Longitudinal stiffness, on the other hand, is mainly governed by cellulose microfibrils, which are more stable agains fungal decay. G. trabeum (more active in earlywood) strongly weakens radial stiffness, whereas T. versicolor (more active in latewood) strongly reduces tangential stiffness. The data in terms of radial and tangential stiffnesses, as well as the corresponding anisotropy ratios, seem to be suitable as durability indicators of wood and even allow conclusions to be made on the degradation mechanisms of fungi.

scholarly journals PROPRIEDADES BIOLÓGICAS DE PAINÉIS DE CASCA DE ARROZ E ADESIVO TANINO-FORMALDEÍDO

Nativa ◽  
2018 ◽  
Vol 6 (5) ◽  
pp. 532 ◽  
Author(s):  
Joel Telles de Souza ◽  
Clóvis Roberto Haselein ◽  
Walmir Marques de Menezes ◽  
Alencar Garlet ◽  
Maiara Talgatti
Keyword(s):  
Rice Husk ◽  
Trametes Versicolor ◽  
Oryza Sativa L ◽  
Pearson Correlation ◽  
Brown Rot ◽  
Biological Properties ◽  
White Rot ◽  
Gloeophyllum Trabeum ◽  
Natural Form ◽  
Decay Fungi

O presente estudo tem como objetivo avaliar as propriedades biológicas, por meio de ensaio de apodrecimento acelerado com fungos xilófagos, em chapas aglomeradas de casca de arroz (Oryza sativa L) coladas com adesivo à base de tanino-formaldeído. Para tanto, foram utilizadas casca de arroz na forma natural e processada em moinho de martelo, compactadas a diferentes massas específicas (0,65; 0,95 e 1,15 g.cm-³) e aplicando-se teores de adesivos de 7, 10 e 13%, totalizando 54 chapas. Os resultados de perda de massa foram submetidos ao teste de correlação simples de Pearson e analisados por regressão. De acordo com os requisitos da norma ASTM D-2017 (2005), os testes biológicos, para todos os tratamentos, foram classificados como resistentes ao fungo Trametes versicolor, podridão branca. Já para o fungo Gloeophyllum trabeum a maioria dos tratamentos foram classificados como moderadamente resistente. Portanto, a casca de arroz mostra-se como uma alternativa de elevado potencial para a manufatura de chapas de maior resistência aos fungos apodrecedores de madeiras.Palavras-chave: massa específica, correlação simples de Pearson, fungos apodrecedores. BIOLOGICAL PROPERTIES OF RICE HUSK PARTICLEBOARD MANUFACTURED WITH TANNIN-FORMALDEHYDE  ABSTRACT:Resistance to decay fungi Trametes versicolor and Gloephyllum trabeum of panels produced with rice husk and tannin - formaldehyde adhesive was evaluated. In the production of the panels, rice hulls were used in its natural form or hammer milled, compacted at different densities (0.65, 0.95 and 1.15 g/cm³) and with adhesives levels of 7, 10 and 13 % (based on the ovendry weight of the particles. The results were submitted to the Pearson correlation test and analyzed by regression. According to the requirements of ASTM D- 2017 (2005), the biological tests for all treatments were classified as resistant to white rot ungus Trametes versicolor. For the brown rot fungus Gloeophyllum trabeum, most treatments were classified as moderately resistant. Therefore, rice husk can be a high potential alternative to for the manufacture of particleboards for greater resistance to decay wood fungi.Keywords: specific gravity, simple Pearson correlation, decay fungi.

Microstructure and stiffness of Scots pine (Pinus sylvestris L) sapwood degraded by Gloeophyllum trabeum and Trametes versicolor – Part I: Changes in chemical composition, density and equilibrium moisture content

Holzforschung ◽  
2012 ◽  
Vol 66 (2) ◽  
Author(s):  
Thomas K. Bader ◽  
Karin Hofstetter ◽  
Gry Alfredsen ◽  
Susanne Bollmus
Keyword(s):  
Moisture Content ◽  
Pinus Sylvestris ◽  
Mass Loss ◽  
Sample Size ◽  
Equilibrium Moisture Content ◽  
Scots Pine ◽  
Trametes Versicolor ◽  
Mass Density ◽  
Gloeophyllum Trabeum ◽  
Physical And Chemical

Abstract Fungal degradation alters the microstructure of wood and its physical and chemical properties are also changed. While these changes are well investigated as a function of mass loss, mass density loss and changes in equilibrium moisture content are not well elucidated. The physical and chemical alterations are crucial when linking microstructural characteristics with macroscopic mechanical properties. In the present article, a consistent set of physical, chemical and mechanical characteristics is presented, which were measured on the same sample before and after fungal degradation. In the first part of this two-part contribution, elucidating microstructure/stiffness-relationships of degraded wood, changes in physical and chemical data are presented, which were collected from specimens of Scots pine (Pinus sylvestris) sapwood degraded by Gloeophyllum trabeum (brown rot) and Trametes versicolor (white rot) for up to 28 weeks degradation time. A comparison of mass loss with corresponding mass density loss demonstrated that mass loss entails two effects: firstly, a decrease in sample size (more pronounced for G. trabeum), and secondly, a decrease of mass density within the sample (more pronounced for T. versicolor). These two concurrent effects are interrelated with sample size and shape. Hemicelluloses and cellulose are degraded by G. trabeum, while T. versicolor was additionally able to degrade lignin. In particular because of the breakdown of hemicelluloses and paracrystalline parts of cellulose, the equilibrium moisture content of degraded samples is lower than that in the initial state.

scholarly journals Design and synthesis of new benzofuran-1,2,3-triazole hybrid preservatives and the evaluation of their antifungal potential against white and brown-rot fungi

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 7828-7843
Author(s):  
Fahimeh Abedinifar ◽  
S. Morteza F. Farnia ◽  
Seyyed Khalil Hosseinihashemi ◽  
Abbas Jalaligoldeh ◽  
Shahrbanoo Arabahmadi ◽  
...  
Keyword(s):  
Trametes Versicolor ◽  
Brown Rot ◽  
White Rot ◽  
Gloeophyllum Trabeum ◽  
Coniophora Puteana ◽  
Brown Rot Fungi ◽  
Design And Synthesis ◽  
Poria Placenta ◽  
Antifungal Potential ◽  
Antifungal Effects

A series of novel benzofuran-1,2,3-triazole hybrids were synthesized and investigated as fungicidal preservatives. The compounds were evaluated for their antifungal potential against white-rot (Trametes versicolor), dry brown-rot (Poria placenta), and wet brown-rot (Coniophora puteana and Gloeophyllum trabeum) fungi, at different concentrations (500 ppm and 1000 ppm). The tests of the final products (8a, 8b, 8c, 8d, 8e, 8f, and 8g) demonstrated that compound N-((1-(4-fluorobenzyl)-1H-1,2,3-triazol-4-yl)methyl)benzofuran-2-carboxamide (8f) at a concentration of 500 ppm was the most active against wet brown-rot C. puteana (23.86% inhibition) and G. trabeum (47.16% inhibition) fungi. However, testing demonstrated that compounds 8a, 8b, 8c, 8d, and 8g at a concentration of 500 ppm did not exhibit acceptable antifungal effects against white-rot T. versicolor and dry brown-rot P. placenta fungi.

Investigation of fungal decay of poplar wood treated with pistachio resin

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 779-788
Author(s):  
Maede Ahadnezhad ◽  
Soheila Izadyar ◽  
Davood Efhamisisi
Keyword(s):  
Mass Loss ◽  
Trametes Versicolor ◽  
Populus Deltoides ◽  
Treated Wood ◽  
Brown Rot ◽  
White Rot ◽  
White Rot Fungus ◽  
Poplar Wood ◽  
Fungal Decay ◽  
Brown Rot Fungus

The density, swelling, and fungal decay of poplar (Populus deltoides) wood treated with pistachio resin (PR) obtained from Pistacia atlantica were investigated. The white-rot fungus Trametes versicolor and the brown-rot fungus Coniophora puteana were used. Methanolic solutions of PR with different concentrations of 1%, 6%, 12%, and 15% were used as the preservative solution. Wood samples were saturated by two different vacuum/pressure (V/P) and dipping methods. The density, volumetric swelling of treated wood, and their mass loss (ML) caused by fungal decay were determined. The density of treated species increased to 15.4% and 5.8% for V/P and dipping methods, respectively, at 15% PR concentration. The volumetric swelling of the treated samples was reduced to 24.5% and 16.8% for V/P and dipping procedure, respectively, at 15% PR concentration. The mass loss of treated samples after exposure to T. versicolor was less than the untreated one (17.4% for V/P and 22.6% for dipping methods at 15% PR concentration). The results showed the better performance of V/P treatment in promotion of wood durability against fungal decay than the dipping method.

Effects of extractives on mechanical properties and durability of rubberwood-HDPE composites

Holzforschung ◽  
2020 ◽  
Vol 74 (11) ◽  
pp. 1061-1070
Author(s):  
Zilun Wang ◽  
Chuanshuang Hu ◽  
Jin Gu ◽  
Banyat Cherdchim ◽  
Dengyun Tu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Brown Rot ◽  
Decay Resistance ◽  
Deionized Water ◽  
White Rot ◽  
Fungal Decay ◽  
Plastic Composites ◽  
Surface Topographies ◽  
Positive Effect ◽  
Scanning Electron

AbstractIn this study, the effects of rubberwood extractives on the mechanical properties and fungal decay resistance of rubberwood-based wood plastic composites (WPCs) were explored. Three different solvents, benzene-ethanol, methanol, and deionized water, were used to remove the extractives of the rubberwood flour (RWF). The surface topographies of the prepared rubberwood-based WPC and the rubberwood itself were characterized using digital instruments and scanning electron microscopy (SEM). The results indicate that the mechanical properties of the WPC prepared using extracted RWF were higher than those of the WPC prepared with unextracted RWF. The sequences of resistance to the growth of mold on the surface of the WPC were ranked as follows: deionized-water-extracted WPC > methanol-extracted WPC > benzene-ethanol-extracted WPC > unextracted WPC. The WPC made with extracted RWF had better brown-rot resistance and worse white-rot resistance than the unextracted WPC. These results demonstrate that the removal of rubberwood extractives has a positive effect on the mechanical properties and mold and fungal decay resistance of rubberwood-based WPCs.

Detection of fungal decay by high-energy multiple impact (HEMI) testing

Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Christian Brischke ◽  
Christian Robert Welzbacher ◽  
Andreas Otto Rapp
Keyword(s):  
Structural Changes ◽  
Brown Rot ◽  
High Energy ◽  
White Rot ◽  
Fungal Decay ◽  
Highly Correlated ◽  
Thermally Modified Wood ◽  
Impact Milling ◽  
Multiple Impact ◽  
Steel Balls

Abstract The suitability of a previously described high-energy multiple impact (HEMI) test for the detection of early fungal decay was examined. The HEMI test characterises the treatment severity of thermally modified wood by stressing the treated material by thousands of impacts of pounding steel balls. This method differentiates between heat treatment intensities, which are manifest as structural changes in the wood. Similar changes in wood structure are known for wood decayed by fungi. Pine (Pinus sylvestris L.) decayed by brown rot and beech (Fagus sylvatica L.) decayed by white rot were tested. Mass loss caused by fungal decay and resistance to impact milling (RIM) determined in HEMI tests were found to be highly correlated. Testing of non-degraded pine, beech, and ash (Fraxinus exelsior L.) showed only marginal effects of wood density on RIM. Furthermore, annual ring angles and RIM of spruce (Picea abies Karst.) were not correlated. Accordingly, the detection of RIM reduction in decayed wood is not masked by variations in density and orientation of the annual rings. Previous results showed no adverse effects of weathering on RIM. Thus, the detection of fungal decay with HEMI tests is feasible not only for laboratory purposes, but also for wood in outdoor applications that has already undergone weathering.

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