Abstract
Outdoor applications of composites have raised questions about their durability. In this study, the effects of outdoor weathering on the properties of wood-polypropylene composites with and without pigments were examined. The composites were placed outdoors for one year, and their colour changes were evaluated after 1, 3, 6, 9 and 12 months of weathering. The durability of the composites was assessed by testing flexural strength and density. Scanning electron microscopy was applied to evaluate the surface degradation of the composites. The weathering resulted in considerable colour fading of the composites. The composites containing darker colour pigments had better colour stability. After weathering, the general trend was a decrease of the flexural strength and density of the composites. The decrease in flexural strength was found to be lower for the composites having higher density.
Zusammenfassung
Der Einsatz von Verbundwerkstoffen im Außenbereich hat Fragen bezüglich ihrer Dauerhaftigkeit aufgeworfen. In dieser Studie wurde der Einfluss einer Freibewitterung auf die Eigenschaften von Holz-Polypropylen-Verbundwerkstoffen mit und ohne Pigmente untersucht. Die Verbundwerkstoffe wurden über einen Zeitraum von einem Jahr im Freien gelagert und die Farbänderungen wurden nach 1-, 3-, 6-, 9- und 12-monatiger Bewitterung gemessen. Anhand von Biegefestigkeits- und Dichteprüfungen wurde die Dauerhaftigkeit der Verbundwerkstoffe bestimmt. Die Veränderung der Oberflächen wurde mittels Raster-Elektronenmikroskopie beurteilt. Die Bewitterung führte zu starkem Ausbleichen der Farbe. Verbundwerkstoffe mit dunkleren Farbpigmenten zeigten eine bessere Farbbeständigkeit. Nach der Bewitterung wurde generell eine Abnahme der Biegefestigkeit und der Dichte der Verbundwerkstoffe festgestellt. Bei Verbundwerkstoffen mit höherer Dichte nahm die Biegefestigkeit weniger stark ab.
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Butylina, S., Hyvärinen, M. & Kärki, T. Weathering of wood-polypropylene composites containing pigments. Eur. J. Wood Prod. 70, 719–726 (2012). https://doi.org/10.1007/s00107-012-0606-y
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DOI: https://doi.org/10.1007/s00107-012-0606-y