Particleboards Bonded by an Imidazole-Based Adhesive System

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  • Alexander Scharf
    Lulea University of Technology
  • Carmen-Mihaela Popescu
    Petru Poni Institute of Macromolecular Chemistry
  • Henric Dernegard
    Holmen AB, Sweden
  • Johan Oja
    Norra Timber, Sweden
  • Graham Ormondroyd
  • Sergej Medved
    University of Ljubljana, Slovenia
  • Dick Sandberg
    Lulea University of Technology
  • Dennis Jones
    Lulea University of Technology
Particleboards with different combinations of the adhesive material imidazole, citric acid, and sorbitol were produced. Softwood sawdust from a Swedish sawmill was mixed with an aqueous solution of the chemicals and then dried to 0% moisture content prior to pressing. The boards were pressed to a target density of 700 kg m􀀀3 at either 200  C or 220  C for 10 min. The hygroscopic and mechanical properties of the boards were clearly better at 220  C than 200  C for all used chemical combinations. A combination of imidazole (14.4 wt%) and citric acid (11.3 wt%) led to the best results, where the thickness swelling after 24 h of water immersion was 6.3% and the internal bonding strength was 0.57 MPa. The modulus of rupture and modulus of elasticity were 3.3 MPa and 1.1 GPa, respectively. Cyclic accelerated weathering showed exceptional stability with a thickness change after boiling and drying of only 2.1% compared to the initial dry thickness. This study indicates that the presence of imidazole leads to greatly improved hygroscopic properties and good internal bonding strength when used in particleboards.
Original languageEnglish
Article number7201
Number of pages19
Issue number22
Publication statusPublished - 17 Nov 2023
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