Abstract
The mechanical properties of wood surface are of particular interest in applications where mainly the surface is exposed to use, such as flooring boards. Wood surface densification aims to improve these properties by compressing only the first few millimeters beneath the surface. Scots pine (Pinus sylvestris L.) sapwood was surface densified to three degrees of compression at 150 °C using a specially designed heated press. Half of the specimens were hydrothermally post-treated at 200 °C. To study the influence of the degree of compression and hydrothermal post-treatment on the set-recovery, specimens were subjected to water soaking-drying-cycles. The surface densification process resulted in a minor mass loss regardless of the degree of compression, whilst the hydrothermal post-treatment led to an average mass loss of 3.8 % in surface densified specimens and of 4.1 % in control un-densified specimens. Furthermore, considerable fixation of compressive deformation was obtained by hydrothermal post-treatment at 200 °C.
Zusammenfassung
Die mechanischen Eigenschaften von Holzoberflächen sind insbesondere bei solchen Anwendungen interessant, bei denen die Oberflächen stark beansprucht werden, wie zum Beispiel bei Fußböden. Oberflächenverdichtung bedeutet, dass oberflächennah die Eigenschaften von Holz im Bereich von wenigen Millimetern durch Druckbeanspruchung verbessert werden. Kiefernsplintholz (Pinus sylvestris L.) wurde mit Hilfe einer speziell konstruierten Heißpresse bei 150 °C in drei Verdichtungsgrade oberflächenverdichtet. Die Hälfte der Prüfkörper wurde bei 200 °C hydrothermisch nachbehandelt. Um den Einfluss des Verdichtungsgrades und der hydrothermischen Nachbehandlung auf die Rückverformung zu untersuchen, wurden die Prüfkörper abwechselnd in Wasser gelagert und getrocknet. Die Oberflächenverdichtung ergab einen geringen Masseverlust unabhängig vom Verdichtungsgrad, wohingegen die hydrothermische Nachbehandlung einen mittleren Masseverlust von 3,8 % bei oberflächenverdichteten Prüfkörpern und von 4,1 % bei unverdichteten Prüfkörpern zur Folge hatte. Des Weiteren wurde die Rückverformung durch die hydrothermische Nachbehandlung bei 200 °C deutlich reduziert.
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Acknowledgments
The authors would like to thank the COST Action FP0904 for financial support within the frame of Short Term Scientific Mission and Miss Cara Leitch for technical support.
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Laine, K., Rautkari, L., Hughes, M. et al. Reducing the set-recovery of surface densified solid Scots pine wood by hydrothermal post-treatment. Eur. J. Wood Prod. 71, 17–23 (2013). https://doi.org/10.1007/s00107-012-0647-2
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DOI: https://doi.org/10.1007/s00107-012-0647-2