Abstract
Bonding of untreated, intermediate (hydro-thermolysed) and heat treated wood with melamine-urea-formaldehyde (MUF), phenol-resorcinol-formaldehyde (PRF) and polyurethane (PUR) adhesives was studied. An industrial heat treatment process (Plato
®) was used, which included two separate heat treatment stages and a drying stage in-between. Laminated beams having four lamellas were prepared from untreated and treated timber for mechanical testing of the bond lines. The results of the tests showed that heat treatment affected the shear strength and the delamination of the laminated wood depending on the adhesive system used for bonding. The PUR and MUF adhesives performed in a rather similar way, and better than the PRF adhesive. The shear strength of laminated wood bonded with the waterborne MUF and PRF adhesives decreased for the specimens made of hydro-thermolysed timber and decreased further for the specimens made of fully heat treated timber. The difference in adhesive bond shear strength between untreated, intermediate and fully treated wood was less obvious in the case of the PUR adhesive. Delamination of the PRF bond line decreased drastically for all the specimens made of heat treated timber.
Zusammenfassung
Die Verklebung von unbehandeltem, hydrothermisch behandeltem und wärmebehandeltem Holz mit Melamin-Harnstoff-Formaldehyd-Klebstoff (MUF), Phenol-Resorcin-Formaldehyd-Klebstoff (PRF) und Polyurethan-Klebstoff (PUR) wurde untersucht. Die Wärmebehandlung erfolgte nach dem Plato
®-Verfahren, das aus zwei durch eine Trocknungsphase getrennte Wärmebehandlungszyklen besteht. Zur mechanischen Prüfung der Klebstofffugen wurde aus behandeltem und unbehandeltem Material Brettschichtholz mit vier Lamellen hergestellt. Die Ergebnisse zeigten, dass der Einfluss der Wärmebehandlung auf die Scherfestigkeit und die Delaminierung des Brettschichtholzes vom verwendeten Klebstoff abhängt. PUR und MUF ergaben ähnliche Werte, die besser waren als diejenigen von PRF. Die Scherfestigkeit von Brettschichtholz, das mit den Wasser basierten MUF- bzw. PRF-Klebstoffen verklebt worden war, nahm bei den hydrothermisch behandelten Proben und noch stärker bei den voll wärmebehandelten Proben ab. Bei PUR-Klebstoff war der Unterschied in der Scherfestigkeit zwischen unbehandelten, hydrothermisch behandelten und voll wärmebehandelten Proben weniger deutlich. Die Delaminierung der PRF-Klebstofffugen nahm bei allen wärmebehandelten Holzproben sehr stark zu.
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References
Boonstra MJ, Tjeerdsma BF, Groeneveld HAC (1998) Thermal modification of non-durable wood species. Part 1, The Plato technology: thermal modification of wood. International Research Group on Wood Preservation, Document no. IRG/WP 98-40123
Boonstra MJ, Tjeerdsma BF (2006) Chemical analysis of heat treated softwoods. Holz Roh- Werkst 64:204–211
Boonstra MJ, Van Acker J, Kegel E (2007a) Strength properties of thermally modified softwoods and its relation to polymeric structural wood constituents. Ann For Sci 64:679–690
Boonstra MJ, Van Acker J, Kegel E, Stevens M (2007b) Optimisation of the two-stage heat treatment process: durability aspects. Wood Sci Technol 41:31–57
EN 386 (2001) Glued laminated timber – Performance requirements and minimum production requirements
EN 391 (2001) Glued laminated timber – Delamination test of glue lines
EN 392 (1995) Glued laminated timber – Shear test of glue lines
Follrich J, Müller U, Gindl W (2006) Effects of thermal modification on the adhesion between spruce wood (Picea abies Karst.) and a thermoplastic polymer. Holz Roh- Werkst 64:373–376
Gérardin P, Petrič M, Pétrissans M, Lambert J, Ehrhrardt JJ (2007) Evolution of wood surface free energy after heat treatment. Polym Degrad Stabil 92:653–657
Kamdem DP, Pizzi A, Jermannaud A (2002) Durability of heat treated wood. Holz Roh- Werkst 60:1–6
Militz H (2002) Thermal treatment of wood: European Processes and their background. International Research Group on Wood Preservation, Document no. IRG/WP 02-40241
Nguila Inari G, Pétrissans M, Lambert J, Ehrhardt JJ, Gérardin P (2006) XPS characterization of wood chemical composition after heat-treatment. Surf Interf Anal 38:1336–1342
Nguila Inari G, Pétrissans M, Gérardin P (2007) Chemical reactivity of heat-treated wood. Wood Sci Technol 41:157–168
Nuopponen M (2005) FT-IR and UV Raman spectroscopic studies on thermal modification of Scots pine wood and its extractable compounds. Helsinki University of Technology, Espoo, Finland
Paul W, Ohlmeyer M, Leithoff H (2007) Thermal modification of OSB-strands by a one-step heat pre-treatment – Influence of temperature on weight loss, hygroscopicity and improved fungal resistance. Holz Roh- Werkst 65:57–63
Pétrissans M, Gérardin P, El Bakali I, Serraj M (2003) Wettability of Heat-Treated Wood. Holzforschung 57:301–307
Pizzi A (1983) Wood adhesives: chemistry and technology. M. Dekker, New York
Properzi M, Pizzi A, Uzielli L (2001) Honeymoon MUF adhesives for exterior grade glulam. Holz Roh- Werkst 59:413–421
Sernek M, Kamke FA, Glasser WG (2004) Comparative analysis of inactivated wood surface. Holzforschung 58:22–31
Tjeerdsma BF, Boonstra M, Militz H (1998a) Thermal modification of nondurable wood species. Part 2, Improved wood properties of thermally treated wood. International Research Group on Wood Preservation, Document No IRG/WP 98-40124
Tjeerdsma BF, Boonstra M, Pizzi A, Tekely P, Militz H (1998b) Characterisation of thermally modified wood: molecular reasons for wood performance improvement. Holz Roh- Werkst 56:149–153
Tjeerdsma BF, Militz H (2005) Chemical changes in hydrothermal treated wood: FTIR analysis of combined hydrothermal and dry heat-treated wood. Holz Roh- Werkst 63:102–111
Weiland JJ, Guyonnet R (2003) Study of chemical modifications and fungi degradation of thermally modified wood using DRIFT spectroscopy. Holz Roh- Werkst 61:216–220
Yildiz S, Gezer ED, Yildiz UC (2006) Mechanical and chemical behavior of spruce wood modified by heat. Build Environ 41:1762–1766
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Sernek, M., Boonstra, M., Pizzi, A. et al. Bonding performance of heat treated wood with structural adhesives . Holz Roh Werkst 66, 173–180 (2008). https://doi.org/10.1007/s00107-007-0218-0
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DOI: https://doi.org/10.1007/s00107-007-0218-0