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The mechanical properties of densified VTC wood relevant for structural composites

Mechanische Eigenschaften von verdichtetem VTC Holz als Ausgangsmaterial für Verbundwerkstoffe für tragende Zwecke

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Abstract

The mechanical properties of densified wood relevant for structural composites were studied. Low density hybrid poplar (Populus deltoides × Populus trichocarpa) was densified using the viscoelastic thermal compression (VTC) process to three different degrees of densification (63, 98, and 132%). The modulus of rupture (MOR) and the modulus of elasticity (MOE) of the control (undensified) wood and of the VTC wood were determined. The bonding performance of the control and VTC wood, using two phenol-formaldehyde (PF) adhesives, was studied. Four different 3-layer composites were also prepared from undensified and VTC wood, and tested in four-point bending. The results showed that the bending properties of the VTC wood (MOR and MOE) were significantly improved due to the increased density. The bonding performance of VTC wood with PF adhesives was comparable with or better than in the case of the control wood. Increased density of the face layers in the 3-layer VTC composites was advantageous for their mechanical performance.

Zusammenfassung

Die für tragende Verbundwerkstoffe relevanten mechanischen Eigenschaften von verdichtetem Holz wurden untersucht. Das Holz der Hybridpappel (Populus deltoides × Populus trichocarpa), einer Holzart mit geringer Dichte, wurde mit viskoelastischer thermischer Verdichtung (VTC) in drei verschiedenen Graden (63, 98, und 132%) verdichtet. Die Biegefestigkeit und der Elastizitätsmodul einer Referenzprobe und des VTC Holzes wurden bestimmt. Das Verklebungsverhalten mit Phenolformaldehyd (PF)-Harz einer Referenzprobe und des VTC Holzes wurden untersucht. Vier verschiedene dreilagige Schichthölzer wurden aus unverdichtetem und aus VTC Holz hergestellt und anschließend im 4-Punkt-Biegeversuch geprüft. Die Biegefestigkeit und der Elastizitätsmodul des verdichteten Holzes wurden durch die Verdichtung signifikant verbessert. Das Verklebungsverhalten des VTC Holzes mit PF-Harz war vergleichbar oder besser als das der Referenzprobe. Die erhöhte Verdichtung der Deckschicht des dreilagigen VTC Schichtholzes wirkte sich vorteilhaft auf die mechanischen Eigenschaften aus.

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Authors and Affiliations

  1. Biotechnical Faculty, Department of Wood Science and Technology, University of Ljubljana, Rozna dolina c. VIII/34, 1001, Ljubljana, Slovenia

    Andreja Kutnar & Milan Sernek

  2. Department of Wood Science and Engineering, Oregon State University, 119 Richardson Hall, 97331-5751, Corvallis, Oregon, USA

    Frederick A. Kamke

Authors
  1. Andreja Kutnar
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  2. Frederick A. Kamke
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  3. Milan Sernek
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Correspondence to Andreja Kutnar.

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Kutnar, A., Kamke, F.A. & Sernek, M. The mechanical properties of densified VTC wood relevant for structural composites . Holz Roh Werkst 66, 439–446 (2008). https://doi.org/10.1007/s00107-008-0259-z

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