Heat-treated softwood exposed to weathering

Mari Nuopponen (Corresponding Author), H. Wikberg, Tapani Vuorinen, S. Maunu, Saila Jämsä, Pertti Viitaniemi

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Scots pine samples, heat‐treated (225°C under steam) and reference (kiln‐dried), were exposed to natural weathering for 7 years in Espoo, Finland. The weathered and unweathered samples were examined with FTIR, UV resonance Raman, and 13C CPMAS NMR spectroscopies. The spectroscopic results revealed that the lignin contents of the weathered heat‐treated and especially of the weathered reference softwood samples diminished significantly. The surface of the weathered heat‐treated sample was still rich in aromatic and conjugated carbonyl structures, whereas the surface of the reference sample was enriched with cellulose. These results indicated that weathering products of lignin were leached out with water from the reference sample, whereas in the heat‐treated wood they were largely unleachable. The structure of the heat‐treated wood was modified and degradation products did not leach out as easily as in the case of the reference sample. The weathering also resulted in a decreased content of amorphous polysaccharides of the reference sample, whereas the changes in the polysaccharide contents between weathered and unweathered heat‐treated samples were not as dramatic because the amorphous carbohydrates were already degraded in the heat treatment. The results indicated that heat‐treated wood is more resistant to natural weathering than untreated wood.
Original languageEnglish
Pages (from-to)2128 - 2134
Number of pages7
JournalJournal of Applied Polymer Science
Volume91
Issue number4
DOIs
Publication statusPublished - 2004
MoE publication typeA1 Journal article-refereed

Fingerprint

Softwoods
Weathering
Wood
Lignin
Polysaccharides
Steam
Carbohydrates
Cellulose
Nuclear magnetic resonance spectroscopy
Heat treatment
Degradation
Hot Temperature
Water

Keywords

  • FTIR
  • NMR
  • Raman spectroscopy
  • heat-treated wood
  • weathering

Cite this

Nuopponen, M., Wikberg, H., Vuorinen, T., Maunu, S., Jämsä, S., & Viitaniemi, P. (2004). Heat-treated softwood exposed to weathering. Journal of Applied Polymer Science, 91(4), 2128 - 2134. https://doi.org/10.1002/app.13351
Nuopponen, Mari ; Wikberg, H. ; Vuorinen, Tapani ; Maunu, S. ; Jämsä, Saila ; Viitaniemi, Pertti. / Heat-treated softwood exposed to weathering. In: Journal of Applied Polymer Science. 2004 ; Vol. 91, No. 4. pp. 2128 - 2134.
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Nuopponen, M, Wikberg, H, Vuorinen, T, Maunu, S, Jämsä, S & Viitaniemi, P 2004, 'Heat-treated softwood exposed to weathering', Journal of Applied Polymer Science, vol. 91, no. 4, pp. 2128 - 2134. https://doi.org/10.1002/app.13351

Heat-treated softwood exposed to weathering. / Nuopponen, Mari (Corresponding Author); Wikberg, H.; Vuorinen, Tapani; Maunu, S.; Jämsä, Saila; Viitaniemi, Pertti.

In: Journal of Applied Polymer Science, Vol. 91, No. 4, 2004, p. 2128 - 2134.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Heat-treated softwood exposed to weathering

AU - Nuopponen, Mari

AU - Wikberg, H.

AU - Vuorinen, Tapani

AU - Maunu, S.

AU - Jämsä, Saila

AU - Viitaniemi, Pertti

PY - 2004

Y1 - 2004

N2 - Scots pine samples, heat‐treated (225°C under steam) and reference (kiln‐dried), were exposed to natural weathering for 7 years in Espoo, Finland. The weathered and unweathered samples were examined with FTIR, UV resonance Raman, and 13C CPMAS NMR spectroscopies. The spectroscopic results revealed that the lignin contents of the weathered heat‐treated and especially of the weathered reference softwood samples diminished significantly. The surface of the weathered heat‐treated sample was still rich in aromatic and conjugated carbonyl structures, whereas the surface of the reference sample was enriched with cellulose. These results indicated that weathering products of lignin were leached out with water from the reference sample, whereas in the heat‐treated wood they were largely unleachable. The structure of the heat‐treated wood was modified and degradation products did not leach out as easily as in the case of the reference sample. The weathering also resulted in a decreased content of amorphous polysaccharides of the reference sample, whereas the changes in the polysaccharide contents between weathered and unweathered heat‐treated samples were not as dramatic because the amorphous carbohydrates were already degraded in the heat treatment. The results indicated that heat‐treated wood is more resistant to natural weathering than untreated wood.

AB - Scots pine samples, heat‐treated (225°C under steam) and reference (kiln‐dried), were exposed to natural weathering for 7 years in Espoo, Finland. The weathered and unweathered samples were examined with FTIR, UV resonance Raman, and 13C CPMAS NMR spectroscopies. The spectroscopic results revealed that the lignin contents of the weathered heat‐treated and especially of the weathered reference softwood samples diminished significantly. The surface of the weathered heat‐treated sample was still rich in aromatic and conjugated carbonyl structures, whereas the surface of the reference sample was enriched with cellulose. These results indicated that weathering products of lignin were leached out with water from the reference sample, whereas in the heat‐treated wood they were largely unleachable. The structure of the heat‐treated wood was modified and degradation products did not leach out as easily as in the case of the reference sample. The weathering also resulted in a decreased content of amorphous polysaccharides of the reference sample, whereas the changes in the polysaccharide contents between weathered and unweathered heat‐treated samples were not as dramatic because the amorphous carbohydrates were already degraded in the heat treatment. The results indicated that heat‐treated wood is more resistant to natural weathering than untreated wood.

KW - FTIR

KW - NMR

KW - Raman spectroscopy

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Nuopponen M, Wikberg H, Vuorinen T, Maunu S, Jämsä S, Viitaniemi P. Heat-treated softwood exposed to weathering. Journal of Applied Polymer Science. 2004;91(4):2128 - 2134. https://doi.org/10.1002/app.13351