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Holz als Roh- und Werkstoff

, Volume 64, Issue 1, pp 21–23 | Cite as

Bonding behaviour of chemically modified wood particles for board production

  • Antonios N. PapadopoulosEmail author
  • George A. Ntalos
  • Kostas Soutsas
  • Vyron Tantos
ORIGINALARBEITEN ORIGINALS

Abstract

The objective of this paper was to evaluate the bonding behaviour of chemically modified wood particles towards an isocyanate resin system, as determined from internal bond strength of the board, and to determine which resin system, isocyanate or formaldehyde is suitable for use in boards made from modified raw material. It was found that chemical modification of wood chips and strands did not significantly affect the bonding efficiency of isocyanate resin, but the bonding efficiency of formaldehyde resins was strongly influenced. This behaviour can be a consequence of the usage of a less pH dependent resin that is fully cured during hot pressing in combination with the high mobility of the resin which causes penetration to considerable depth into compressed particles repairing weak zones, which are created during the modification process as chips are exposed to elevated temperatures, by sticking them together. It is suggested therefore, that the isocyanate resin system is more suitable for use in boards made from modified raw material than the formaldehyde resin system.

Keywords

Isocyanate Wood Chip Internal Bond Urea Formaldehyde Resin System 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Klebeverhalten chemisch modifizierter Holzspäne für die Herstellung plattenförmiger Holzwerkstoffe

Zusammenfassung

Das Klebeverhalten chemisch modifizierter Späne wurde durch Prüfung der Querzugfestigkeit daraus hergestellter Platten untersucht, um zu bestimmen, welches Klebstoffsystem, Isocyanat- oder Formaldehyd-Harz, sich für die Plattenherstellung aus modifiziertem Rohmaterial eignet. Es zeigte sich, dass die chemische Modifizierung von Holzspänen die Klebewirkung von Isocyanat-Harz nicht signifikant beeinflusst, wogegen die Klebewirkung von Formaldehyd-Harzen stark beeinträchtigt wird. Dieses Verhalten kann zurückzuführen sein auf die Verwendung eines weniger pH-abhängigen Harzes, welches bei der Heisspressung voll aushärtet, in Verbindung mit der hohen Mobilität des Harzes, durch die es in beträchtliche Tiefe in gepresste Späne eindringt. Dadurch werden Schwachstellen, die während des Modifizierungsvorganges entstehen, bei dem Späne erhöhten Temperaturen ausgesetzt sind, repariert, indem sie die Teile miteinander verbinden. Dies deutet darauf hin, dass Isocyanat-Harz zur Herstellung von Platten aus modifiziertem Rohmaterial besser geeignet ist als Formaldehyd-Harz.

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References

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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Antonios N. Papadopoulos
    • 1
    Email author
  • George A. Ntalos
    • 2
  • Kostas Soutsas
    • 3
  • Vyron Tantos
    • 3
  1. 1.Department of Forestry and Management of Natural EnvironmentTechnological Educational Institute of DramaDramaGreece
  2. 2.Department of Wood and Furniture, Technology-DesignTechnological Educational Institute of KarditsaKarditsaGreece
  3. 3.Department of Forestry and Management of Natural EnvironmentTechnological Educational Institute of KarditsaKarditsaGreece

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