Improvement of the durability of heat-treated wood against termites

Salman, Solafa; Thevenon, Marie France; Pétrissans, Anelie; Dumarçay, Stéphane; Candelier, Kévin; Gérardin, Philippe

doi:10.4067/s0718-221x2017005000027

Cited by 29 publications

(26 citation statements)

References 13 publications

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“…When the temperature is above 150 °C, the heat treatment will reduce the hygroscopic property of the wood, consequently reduce its shrinkage and swelling properties, and thus improve the dimensional stability [16]. At 180 °C or higher temperature, heat treatment can significantly improve the anti-fungi performance of wood [17]. However, high-temperature heat treatment also leads to a decrease in its mechanical properties, which in turn limits its application.…”

Section: Introductionmentioning

confidence: 99%

Effect of high-temperature saturated steam treatment on the physical, chemical, and mechanical properties of moso bamboo

et al. 2020

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Moso bamboo (Phyllostachys heterocycla (Carr.) Mitford cv. Pubescens) was subjected to heat treatment with saturated steam at 140, 160, and 180 °C for 10-30 min to evaluate the effects of the treatment on the properties of bamboo. The changes in the physical, mechanical, and chemical properties as well as microscopic structures of moso bamboo were analyzed in this study. Results indicated that its equilibrium moisture content (EMC) decreased gradually after being treated by high-temperature saturated steam mostly due to the hemicelluloses' degradation. Both the temperature and duration of treatment affect the mechanical properties of bamboo. The modulus of elasticity (MOE) of bamboo was prone to be affected by heat treatment with saturated steam as compared to the modulus of rupture (MOR). The MOR and MOE increased as compared to the control when the sample was treated at 140 °C. However, a severe treatment negatively affects the mechanical properties of bamboo. The MOR and MOE decreased by 47% and 20% as compared to the control when the sample was heated at 180 °C for 30 min.

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Section: Introductionmentioning

confidence: 99%

Effect of high-temperature saturated steam treatment on the physical, chemical, and mechanical properties of moso bamboo

et al. 2020

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“…Several methods have been proposed so far for improving the natural durability of wood [1]. Apart from chemical protection measures, one of the most effective ways to prevent or limit the action of microorganisms in wood is to keep the moisture content low enough or to prevent at least one of the necessary growth requirements of the microorganisms to be fulfilled, such as the presence of oxygen in wood, proper pH (3)(4)(5)(6)(7)(8), appropriate temperature (15 • C-40 • C), absence of toxic extracts, presence of other growth factors such as vitamins, nitrogen etc. [2].…”

Section: Introductionmentioning

confidence: 99%

“…Heat induces changes to the chemical constituents of wood, and therefore, to the chemical, physical and mechanical properties of wood, as well. Despite the fact that thermal treatment decreases the density and most of the times the mechanical strength of wood, since it increases its brittleness, it seems to limit the hygroscopic nature and enhance the natural durability of wood, providing the chance, (especially to species characterized by low water resistance, dimensional stability and susceptibility to bio-degradation factors), to be adequately utilized, participating in a much wider range of applications [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

The Biological Durability of Thermally- and Chemically-Modified Black Pine and Poplar Wood Against Basidiomycetes and Mold Action

Kamperidou

2019

Forests

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Wood of black pine and poplar species were subjected to thermal modification under variant conditions, while subsequently, a number of the thermally-modified black pine specimens were subjected to surface modification with organosilane solutions, and the biological resistances of the different materials were examined using laboratory agar block tests against the action of basidiomycetes and microfungi. Thermally-modified pine specimens were exposed to the brown rot fungi Coniophora puteana and Oligoporus placenta, whereas poplar wood was exposed to the white rot fungus Trametes versicolor and O. placenta. Regarding the biological durability of thermally-chemically-treated pine wood with organosilanes, it was tested against the action of C. puteana. Additionally, both of the thermally-treated wood species, as well as thermally-chemically-treated pine wood were exposed to a microfungi mixture, so that the wood treatments efficacy would be evaluated through a visual assessment of fungal growth on the specimen’s surface The thermal treatments seem to increase the biological resistance of black pine against C. puteana by 9.65–36.73% compared to unmodified wood. The most significant increase in biological durability among all the thermally-treated wood categories was recorded by O. placenta, with 28.75–68.46% lower mass losses in treated pine specimens and 31.98–64.72% in thermally-treated poplar, respectively, compared to unmodified wood. The resistance of treated poplar against T. versicolor was also found increased (13.25–46.08%), compared to control. Thermal modification affected positively the biological resistance of both species, though it did not manage to protect effectively pine and poplar wood from the microfungi action. The combination of thermal and organosilanes treatment revealed a significant improvement of the durability of pine wood compared to? control (45.68–87.83% lower mass losses against C. puteana), as well as against the microfungi action, with the presence of benzin to have a positive effect on the silanes solutions performance and protective action.

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“…The intense white-rot fungal degradation on YP may be due to the increase of laccase activity, which is a phenoloxidase enzyme produced by white-rot fungi [44][45][46]. In fact, phenol rings are present in the chemical composition of tannin molecules [47]. Furthermore, such composition favored the development of the fungi by catalyzing the oxidation of phenol rings and thereby increasing weight loss 3.5 times.…”

Section: Fungi Resistancementioning

confidence: 99%

Influence of Heat Treatment and Tannin Impregnation on Boron Depletion and Wood Durability

Lopes

Barnes

Bobadilha

2020

Forests

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Heat treatment (HT) of a mixture of tannins and inorganic boron compounds showed effective results against wood decay organisms. Boron compounds play a critical role in the preservation of wood against wood decay organisms. The use of tannins and HT represents a relatively new environmentally friendly approach to the wood preservation industry. The aim of this study was to investigate the effect of tannin impregnation and HT on boron depletion, and termite and fungi resistance. Southern yellow pine (SYP) and yellow-poplar (YP) cube samples were used for this study. A mixture of condensed tannins from the Quebracho tree and disodium octaborate tetrahydrate (DOT) was injected into the specimens using a vacuum/pressure cycle, and the specimens were then heat-treated under N 2 atmosphere for four hours at 190 • C to investigate both the tannin's fixative ability to reduce boron leaching and the performance of the mixture against brown and white-rot fungi and termites. Tannins restricted boron leaching in 46% and 34% for SYP and YP, respectively, and also significantly increased the resistance against white-rot fungi for YP. Tannins and HT showed unpredictably good performance against termites. Tannins may be acting to denature proteins; in that case, fungal enzymes would be inhibited. This study revealed the importance of HT on a mixture of boron and tannins to decrease boron leaching and increase the durability of preservative systems.products is limited because of boron's natural solubility in water, which leads to a rapid depletion of treated wood in outdoor exposed conditions [7][8][9][10][11][12].Research has been conducted to address boron depletion. The most common strategies for reducing boron leaching are surface and envelope treatments, wood bulking, the use of water repellant, organo-boron compounds, a combination of biocides and non-biocidal agents, metallo-borates, stabilized boro-esters, protein borates, in situ polymerization and boron silicates [13][14][15][16][17][18][19].Previous research has shown the potential of boron fixation by tannin auto condensation. The authors in [20] described a mechanism in which boric acid was partly fixed to a condensed tannin network with boron mobility being maintained. The authors in [21] leached a mixture of tannins and boron for 80 h. After the leaching period, a 30% loss of boron occurred. The trend of increased leaching continued as the experiment progressed.The effectiveness of tannins toward fixing boron under high temperatures and for longer leaching periods has not yet been investigated. In addition, little research has been done regarding boron's efficacy on multiple wood species. Broadening this spectrum is relevant in order to improve durability across the widely varying range of species and characteristics of wood [22][23][24].In this study, a solution of disodium octaborate tetrahydrate (DOT) and condensed tannins were pressure and heat-treated into southern yellow pine and yellow-poplar with the aim of reducing boron leaching. In addition, performance ...

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Improvement of the durability of heat-treated wood against termites

Cited by 29 publications

References 13 publications

Effect of high-temperature saturated steam treatment on the physical, chemical, and mechanical properties of moso bamboo

Effect of high-temperature saturated steam treatment on the physical, chemical, and mechanical properties of moso bamboo

The Biological Durability of Thermally- and Chemically-Modified Black Pine and Poplar Wood Against Basidiomycetes and Mold Action

Influence of Heat Treatment and Tannin Impregnation on Boron Depletion and Wood Durability

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