Abstract
Physical, mechanical, and fire properties of the flat-pressed wood plastic composites (WPCs) incorporated with various fire retardants (10% by weight) at different levels of wood flour (WF) content, 40, 50, or 60 wt%, were investigated. The WPC panels were made from dry-blended WF, polypropylene (PP), and fire retardant (FR) powders with maleic anhydride-grafted PP (2 wt%) formulations using a conventional flat-pressing process under laboratory conditions. Incorporation of the fire retardants into the WPC panels significantly decreased the internal bond strength compared to the WPC panels without FR at all levels of the WF content. The modulus of rupture of the WPC panels containing FRs decreased with the increase in the WF content from 40 to 60 wt%. The modulus of elasticity increased with the increase in the WF content from 40 to 50 wt% and then decreased as the WF content reached 60 wt%. The WPC panels incorporated with zinc borate gave an overall best performance in both physical and mechanical properties followed by the panels treated with decabromodiphenyl oxide, magnesium hydroxide, and ammonium polyphosphate. Higher levels of the WF content resulted in significantly improved fire resistance of the WPC panels with and without FR as measured in the cone calorimeter. Of the four fire retardants tested, ammonium polyphosphate showed the most improvement over untreated ones.
Zusammenfassung
Die physikalischen, mechanischen und Brandeigenschaften flachgepresster Holz-Kunststoff-Verbundplatten (WPC) wurden mit verschiedenen Brandschutzmitteln (10% Masseanteil) mit unterschiedlichen Holzmehlanteilen (WF: 40, 50 und 60% Masseanteil) untersucht. Die WPC-Platten wurden trocken gemischt aus Holzmehl, Polypropylen (PP) und Brandschutzmitteln (FR) mit Maleinsäureanhydrid gepfropftem PP (2% Masseanteil) mit einer herkömmlichen Formulierung im Flachpressverfahren unter Laborbedingungen hergestellt. Die Zugabe von Brandschutzmittel in die WPC-Platten verringerte deren Querzugfestigkeit unabhängig vom Holzmehlanteil deutlich.
Die Biegefestigkeit der WPC-Platten mit FR nahm mit zunehmendem Holzmehlanteil von 40 bis 60% Masseanteil ab. Der Elastizitätsmodul nahm mit der Erhöhung des Holzmehlanteils von 40 bis 50% Masseanteil zu und nahm bei einem Holzmehlanteil von 60% wieder ab. Die mit Zinkborat hergestellten WPC-Platten wiesen im Allgemeinen die besten physikalischen und mechanischen Eigenschaften auf, gefolgt von den Platten, in die Decabromdiphenyloxid, Magnesiumhydroxid und Ammoniumpolyphosphat eingebracht wurde.
Gemessen im Kegelkalorimeter führten höhere Holzmehlanteile zu einem deutlich verbesserten Verhalten im Brandfall gegenüber den WPC-Platten mit oder ohne FR. Von den vier geprüften Brandschutzmitteln ergab Ammoniumpolyphosphat die beste Verbesserung gegenüber den unbehandelten Proben.
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Acknowledgements
This work was carried out while N. Ayrilmis was visiting Professor at the Department of Wood Science, Hamburg University. It was supported by the Scientific and Technological Research Council of Turkey (Tubitak), The Federal Ministry of Food, Agriculture and Consumer Protection (Germany) through the Agency for Renewable Resources (FNR), and United States Department of Agriculture, Forest Service, Forest Products Laboratory, Madison WI. Their support is gratefully acknowledged.
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Ayrilmis, N., Benthien, J.T., Thoemen, H. et al. Effects of fire retardants on physical, mechanical, and fire properties of flat-pressed WPCs. Eur. J. Wood Prod. 70, 215–224 (2012). https://doi.org/10.1007/s00107-011-0541-3
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DOI: https://doi.org/10.1007/s00107-011-0541-3