Long-term performance of DMDHEU-treated wood installed in different test set-ups in ground, above ground and in the marine environment

Emmerich, Lukas; Militz, Holger; Brischke, Christian

doi:10.1080/20426445.2020.1715553

Cited by 18 publications

(15 citation statements)

References 26 publications

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“…Preventive treatment of wood against termite attack is dominated by the use of biocides, either pressure-treated with copper-based products for higher risk applications (e.g., Use Class 4, [3]) or insecticides like permethrin and borates. Several techniques of wood modification have also been shown to provide improved resistance to subterranean termite attack [4].…”

Section: Introductionmentioning

confidence: 99%

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Macrobiological Degradation of Esterified Wood with Sorbitol and Citric Acid

Treu

Nunes

Larnøy

2020

Forests

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There is a need for new solutions in wood protection against marine wood borers and termites in Europe. A new solution could be the esterification of wood with sorbitol and citric acid (SCA) since these are inexpensive and readily available feedstock chemicals and have shown protective properties against fungal wood degradation in earlier studies and prevented macrobiological degradation, as shown in this study. Protection of wood products in the marine environment lacks available wood preservatives that are approved for marine applications. Termite infestation is opposed mainly by biocide treatments of wood. Several wood modification systems show high resistance against both marine borers and subterranean termites. However, the existing commercialized wood modification products are costly. Both macrobiological forms of degradation represent a great threat for most European wood species, which are rapidly and severely degraded if not properly treated. This study investigated esterified wood in standard field trials against marine wood borers, and against subterranean termites in laboratory trials in a no-choice and choice test. The treatment showed good resistance against wood borers in the marine environment after one season and against subterranean termites in the laboratory after eight weeks. The low termite survival rate (SR) in the no-choice test during the first week of testing indicates a mode of action that is incomparable to other wood modification treatments.

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Section: Introductionmentioning

confidence: 99%

“…Wood modification methods proven to perform well in the marine environment for many years are acetylation and furfurylation [13]. In addition, 1.3-dimethylol-4.5-dihydroxyethyleneurea (DMDHEU)-treated wood has shown promising results after almost 10 years of exposure [4,14].…”

Section: Introductionmentioning

confidence: 99%

Macrobiological Degradation of Esterified Wood with Sorbitol and Citric Acid

Treu

Nunes

Larnøy

2020

Forests

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“…1) were also used to modify wood and improve its dimensional stability and decay resistance (Militz 1993;Krause 2006;Bollmus 2011). The latter has been demonstrated during laboratory (Ritschkoff et al 1999;Krause 2006;Schaffert 2006;Verma et al 2009; Bollmus 2011) and field decay tests (Emmerich et al 2020a). The modes of protective action of DMDHEU treatments, which render an improved decay resistance, are not fully understood, yet.…”

Section: Introductionmentioning

confidence: 88%

“…Non-biocidal, reactive chemicals have been used to modify wooden cell walls (Hill 2011;Gérardin 2016;Sandberg et al 2017;Jones and Sandberg 2020) and improve its resistance against wood-destroying organisms (Brelid and Westin 2007;Rowell 2012Rowell , 2014Meyer et al 2012;Alfredsen et al 2013;Emmerich et al 2020a). In this field of 'chemical wood modification', glyoxal-based condensation resins such as 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU, Fig.…”

Section: Introductionmentioning

confidence: 99%

Comparative studies on the durability and moisture performance of wood modified with cyclic N-methylol and N-methyl compounds

et al. 2021

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Glyoxal-based condensation resins like 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) have been used to modify wood and improve its resistance against decaying fungi. High biological durability of DMDHEU-treated wood has already been confirmed in laboratory and field tests in the past. However, the modes of protective action behind an improved decay resistance are not fully understood yet. Furthermore, it is questionable how the use of formaldehyde-poor N-methylol and formaldehyde-free N-methyl compounds instead of DMDHEU affects the moisture behavior and durability, respectively. In this study, wood blocks were treated with N-methylol (DMDHEU, methylated DMDHEU) and N-methyl compounds (1,3-dimethyl-4,5-dihydroxyethyleneurea; DMeDHEU). Untreated and modified specimens were exposed to different moisture regimes and wood-destroying fungi in order to study the indicators that control changes in the wetting ability and decay resistance. Both N-methylol and N-methyl compounds decreased the water uptake and release and increased the durability of Scots pine sapwood from ‘not durable’ (DC 5) to ‘very durable to durable’ (DC 1–2). However, high fluctuations were observed in water uptake and release as well as mass loss (ML) caused by fungal decay, when modified specimens were tested without passing through a cold-water leaching. Consequently, a significant effect of the leaching procedure according to EN 84 on the durability classification could be established. The latter appeared more pronounced for treatments with N-methyl compounds compared to N-methylol compounds. Finally, wetting ability (kwa) and resistance indicating factors (kinh) enabled a forecast of high biological durability for both treatments with N-methylol and N-methyl compounds under real service life conditions.

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“…The model was next validated using data from laboratory and field tests by different authors [18][19][20]. Material resistance data were determined for additional wood species [21][22][23] and wood treatments [19,24].…”

Section: Introductionmentioning

confidence: 99%

Modelling the Material Resistance of Wood—Part 2: Validation and Optimization of the Meyer-Veltrup Model

Brischke

Alfredsen

Humar

et al. 2021

Forests

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Service life planning with timber requires reliable models for quantifying the effects of exposure-related parameters and the material-inherent resistance of wood against biotic agents. The Meyer-Veltrup model was the first attempt to account for inherent protective properties and the wetting ability of wood to quantify resistance of wood in a quantitative manner. Based on test data on brown, white, and soft rot as well as moisture dynamics, the decay rates of different untreated wood species were predicted relative to the reference species of Norway spruce (Picea abies). The present study aimed to validate and optimize the resistance model for a wider range of wood species including very durable species, thermally and chemically modified wood, and preservative treated wood. The general model structure was shown to also be suitable for highly durable materials, but previously defined maximum thresholds had to be adjusted (i.e., maximum values of factors accounting for wetting ability and inherent protective properties) to 18 instead of 5 compared to Norway spruce. As expected, both the enlarged span in durability and the use of numerous and partly very divergent data sources (i.e., test methods, test locations, and types of data presentation) led to a decrease in the predictive power of the model compared to the original. In addition to the need to enlarge the database quantity and improve its quality, in particular for treated wood, it might be advantageous to use separate models for untreated and treated wood as long as the effect of additional impact variables (e.g., treatment quality) can be accounted for. Nevertheless, the adapted Meyer-Veltrup model will serve as an instrument to quantify material resistance for a wide range of wood-based materials as an input for comprehensive service life prediction software.

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Long-term performance of DMDHEU-treated wood installed in different test set-ups in ground, above ground and in the marine environment

Cited by 18 publications

References 26 publications

Macrobiological Degradation of Esterified Wood with Sorbitol and Citric Acid

Macrobiological Degradation of Esterified Wood with Sorbitol and Citric Acid

Comparative studies on the durability and moisture performance of wood modified with cyclic N-methylol and N-methyl compounds

Modelling the Material Resistance of Wood—Part 2: Validation and Optimization of the Meyer-Veltrup Model

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