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

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