Wood modification with N-methylol and N-methyl compounds: a case study on how non-fixated chemicals in modified wood may affect the classification of their durability
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Lukas Emmerich
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Christian Brischke
Abstract
Chemical modification is increasing the durability of wood against biological deterioration. Usually, the effect of a new treatment on the durability of wood is screened in laboratory decay tests, where durability classes are assigned on the basis of the mass loss (ML) caused by degrading fungi. The aim of this study was to demonstrate how non-fixated chemicals in modified wood may affect fungal ML measurements and corresponding durability classification when wood samples are incubated under humid conditions for long periods. Wood blocks were treated with solutions of 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU), methylated DMDHEU (mDMDHEU) and 1,3-dimethyl-4,5-dihydroxyethyleneurea (DMeDHEU) and subjected to consecutive cold-water leaching cycles. Significant amounts of non-fixated chemicals were removed from the wood by three leaching cycles and might lead to ML mistaken as response of fungal decay. Consequently, the treated material was assigned erroneously by up to four durability classes (DC) worse than material which did not include leachable, non-fixated chemicals. Thus, for a reliable durability classification of chemically modified wood, prolonged leaching procedures are recommended to assure that the measured ML is entirely attributed to fungal decay.
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Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
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Research funding: None declared.
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Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
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- Short Note
- Wood modification with N-methylol and N-methyl compounds: a case study on how non-fixated chemicals in modified wood may affect the classification of their durability
Articles in the same Issue
- Frontmatter
- Original Articles
- Variations in heartwood formation and wood density as a function of age and plant spacing in a fast-growing eucalyptus plantation
- On-line characterization of wood chip brightness and chemical composition by means of visible and near-infrared spectroscopy
- Extractives in Betula celtiberica stemwood and isolation and identification of diarylheptanoids in the hydrophilic extract
- High recovery of stilbene glucosides by acetone extraction of fresh inner bark of Norway spruce
- Natural cork and its agglomerates as substitutes for high-density expanded polystyrene foams in sandwich cores
- Understanding the thermal durability of wood-based composites (WBCs) using crack propagation fracture toughness
- Evaluation of changes in cellulose micro/nanofibrils structure under chemical and enzymatic pre-treatments
- Multi-scale evaluation of the effect of saturated steam on the micromechanical properties of Moso bamboo
- Short Note
- Wood modification with N-methylol and N-methyl compounds: a case study on how non-fixated chemicals in modified wood may affect the classification of their durability
