| 1. |
- Adamopoulos, Stergios, et al.
(författare)
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Resistance of Pinus leucodermis heartwood and sapwood against the brown-rot fungus Coniophora puteana
- 2012
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Ingår i: Wood Material Science & Engineering. - 1748-0272 .- 1748-0280. ; 7:4, s. 242-244
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Tidskriftsartikel (refereegranskat)abstract
- This study assessed the decay resistance of Pinus leucodermis wood to the brown-rot fungus Coniophora puteana. Based upon the median weight losses of 30.65% for heartwood and of 34.68% for sapwood obtained in the biological tests, both the heartwood and sapwood material examined was classified as not durable (durability class 5) according to the CEN/TS 15083-1 classification. Total extractives were low, 3.93% in heartwood and 1.00% in sapwood, while lignin content was 22.60% and 25.41% in heartwoodand sapwood, respectively. It is highly recommended to use protective treatments before using P.leucodermis wood in outdoor conditions.
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| 2. |
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| 3. |
- Gascón-Garrido, P, et al.
(författare)
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Resistance of wood modified with different technologies against Mediterranean termites (Reticulitermes spp.)
- 2013
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Ingår i: International Biodeterioration & Biodegradation. - : Elsevier BV. - 0964-8305 .- 1879-0208. ; 82, s. 13-16
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Tidskriftsartikel (refereegranskat)abstract
- A laboratory no-choice test following the standard EN-117 was conducted to evaluate the efficacy of wood modified with different technologies against subterranean termites of the genus Reticulitermes spp. European beech modified with DMDHEU, acetylated radiata pine, and furfurylated Southern yellow pine were used for termite testing. Before the bioassay, half the number of the specimens (including controls) was subjected to an accelerated aging test according to EN-84. The specimens were exposed for 8 wk to the termites. Additionally, mass losses were measured. The results indicated that the feeding pressure was sufficient according to EN-117 for a valid test. Acetylated wood and DMDHEU-modified wood were classified as durable, showing excellent termite resistance. Furfurylated wood was resistant in the case of non-leached specimens; however, the leaching process led to a classification of non-durable. Thus, the new modification technologies open a real possibility of their use in the Mediterranean region as alternative preventive treatments against subterranean termites.
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| 4. |
- Kielmann, B, et al.
(författare)
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Decay resistance of ash, beech and maple wood modified with N-methylol melamine and a metal complex dye
- 2014
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Ingår i: International Biodeterioration & Biodegradation. - : Elsevier BV. - 0964-8305 .- 1879-0208. ; 89, s. 110-114
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the decay resistance of ash (Fraxinus excelsior L.), beech (Fagus sylvatica L.), and maple (Acer platanoides L.) wood impregnated by a full cell process with N-methylol melamine (NMM) and combined NMM-metal complex dye (NMM-BS) in aqueous solutions. Basidiomycete decay testing involved incubation with Coniophora puteana (brown rot) and Trametes versicolor (white rot) according to a modified EN 113 (1996) standard, while for the soft rot fungal resistance was evaluated following the standard ENv 807 (2001). NMM and NMM-BS modifications at a WPG range of 7–11% provided decay protection against brown rot resulting in a mass loss less than the required limit (3%). The NMM and NMM-BS modified wood showed increased resistance to white rot decay; however, a higher WPG is needed to prohibit attack from this hardwood specific fungus. The metal-complex dye alone revealed biocidal effects against basidiomycetes. An increased WPG in NMM or NMM-BS had a positive impact against soft rot decay and the lowest mass losses after 32 weeks of exposure were obtained with NMM modification at about 18–21% WPG. NMM modification at this WPG range, however, was not sufficient to protect the wood from soft rot decay. The wood of beech and maple showed slightly higher resistance to all decay types than ash, probably due to the poorer degree of modification of the latter.
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| 5. |
- Kielmann, B, et al.
(författare)
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Modification of three hardwoods with an N-methylol melamine compound and a metal-complex dye
- 2014
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Ingår i: Wood Science and Technology. - : Springer Science and Business Media LLC. - 0043-7719 .- 1432-5225. ; 48:1, s. 123-136
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the combined modification and staining of ash, beech and maple wood with a low molecular weight N-methylol melamine compound (NMM) and a metal-complex dye. Wood samples were treated with aqueous solutions of 10, 20 and 30 wt% NMM and 5 wt% of the dye. The treatment caused the fixation of the water-soluble dye by the NMM resin. Vacuum pressure impregnation of unsealed wood blocks did not result in different solution uptake and weight percent gain after curing among the three species, but sealing of the surfaces of the wood blocks to allow penetration only into one direction revealed easiest penetrability of beech followed by maple and ash. UV micro-spectrophotometry and light microscopy indicated that NMM was partly deposited in the cell wall and partly in the lumens. Penetration of the metal-complex dye was shown by means of X-ray micro-analysis (SEM–EDX). The study shows that a combined resin modification and staining of the three wood species tested is possible and that NMM causes fixation of the water-soluble dye.
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| 6. |
- Kielmann, B, et al.
(författare)
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Strength changes in ash, beech and maple wood modified with a N-methylol melamine compound and a metal-complex dye
- 2013
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Ingår i: Wood research. - 1336-4561. ; 58:3, s. 343-350
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Tidskriftsartikel (refereegranskat)abstract
- Ash, beech and maple wood was modified with aqueous solutions of methylated N-methylol melamine (NMM) and a metal-complex dye (BS) consisting of 10, 20, and 30 % NMM and 5 % BS. Static bending strength and stiffness, impact bending strength and hardness were examined to evaluate the suitability of modified wood for structural uses. The combined NMMBS modification resulted in significant higher dynamic (MOEdyn) and static (MOE) moduli of elasticity for all species. Beech and maple exhibited enhanced static bending strength (MOR), while that of ash was unchanged. The higher stiffness and strength of NMM-BS modified wood is attributed to its higher wood density and lower EMC and to the stiff character of NMM resin incorporated in the wood matrix. Impact bending strength decreased substantially after modification as a result of reduced pliability of treated wood. Brinell hardness significantly increased with the weight percent gain (WPG) due to modification, and, unlike the other properties, it was positively correlated with the WPG.
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| 7. |
- Mahnert, K-C, et al.
(författare)
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Topochemistry of heat-treated and N-methylol melamine modified wood of Koto (Pterygota macrocarpa K. Schum.) and Limba (Terminalia superba Engl. et Diels)
- 2013
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Ingår i: Holzforschung. - : Walter de Gruyter GmbH. - 0018-3830 .- 1437-434X. ; 67:2, s. 137-146
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Tidskriftsartikel (refereegranskat)abstract
- To broaden the knowledge about the chemical changes at the cell wall level of differently modified tropical hardwoods, heat-treated and N-methylol melamine (NMM)-treated samples of koto (Pterygota macrocarpa) and limba (Terminalia superba) were prepared. UV microspectrophotometry (UMSP) was applied at 278 and 240 nm as specific wavelengths to analyze chemical alterations of the samples caused by heat and NMM treatment, respectively. The absorbance of koto exceeded that of limba before and after treatment, potentially due to the higher extractive content of the former. Regardless of the wood species, the absorbance of the samples increased with increasing intensity of the NMM treatment. Additionally, the absorbance of lignin within the spectrum of 230–350 nm was altered due to the NMM treatment. The functionality of applying specific wavelengths for the analysis of different modification methods of wood was proven. However, the comparison with literature did not show differences in the absorbance, which could be assigned to the characteristics of tropical hardwoods.
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| 8. |
- Sint, KM, et al.
(författare)
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Impregnation of Bombax ceiba and Bombax insigne wood with a N-methylol melamine compound
- 2013
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Ingår i: Wood Science and Technology. - : Springer Science and Business Media LLC. - 0043-7719 .- 1432-5225. ; 47:1, s. 43-58
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Tidskriftsartikel (refereegranskat)abstract
- Methylated N-methylol melamine (NMM) is known for its ability to enhance physico-mechanical properties, anti-fungal ability, and hydrophobicity and was therefore used to impregnate two less used and non-durable wood species from Myanmar, Bombax ceiba and Bombax insigne. Solution uptake, weight percent gain and nitrogen content were increased by increasing melamine concentrations with B. ceiba always achieving higher values compared with B. insigne. According to the leaching results, a higher degree of condensation after curing as well as a better crosslinking of NMM could be obtained at higher temperatures. However, both curing temperatures used (90 and 120 °C) resulted in almost the same amount of nitrogen fixed in the cell wall. UV microspectrophotometry confirmed the penetration of the NMM into different morphological regions of wood tissues, which was again supported by the analysis of point measurement spectra of treated and untreated specimens.
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| 9. |
- Sint, KM, et al.
(författare)
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Treatability and penetration indices of four lesser-used Myanmar hardwoods
- 2011
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Ingår i: Wood research. - 1336-4561. ; 56:1, s. 13-22
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Tidskriftsartikel (refereegranskat)abstract
- Depletion of Myanmar's top commercial timbers has grown the attention towards lesser-used timbers, which present: low durability and require protection against biodegradation. This research tested the treatability of four nondurable Myanmar hardwoods: Bombax ceiba, Bombax insigne, Spondias pinnata and Tetrameks nudiflora. Conditioned heartwood samples were pressure-treated according to standard schedules using a staining solution. Solution uptake,penetration depths, and percent of each cell type penetrated were determined and discussed according to wood anatomical characteristics. B. ceiba, B. insigne and S. pinnata had high uptakes and good penetration making them promising for protective treatment. T nudiflora was also classified as easy to treat based on its penetration index but as generally difficult to treat according to retention and depth of penetration. This different behavior was attributed to the tyloses occluding its vessels. The results are useful for the development of specific treatment schedules to achieve the retentions and penetration required for the effective protection of these lesser-used hardwoods.
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| 10. |
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