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Research article - Peer-reviewed, 2021

Preparation of Polyurethane Adhesives from Crude and Purified Liquefied Wood Sawdust

Jiang, Wen; Hosseinpourpia, Reza; Bizik, Vladimirs; Ahmed, Sheikh Ali; Militz, Holger; Adamopoulos, Stergios


Polyurethane (PU) adhesives were prepared with bio-polyols obtained via acid-catalyzed polyhydric alcohol liquefaction of wood sawdust and polymeric diphenylmethane diisocyanate (pMDI). Two polyols, i.e., crude and purified liquefied wood (CLW and PLW), were obtained from the liquefaction process with a high yield of 99.7%. PU adhesives, namely CLWPU and PLWPU, were then prepared by reaction of CLW or PLW with pMDI at various isocyanate to hydroxyl group (NCO:OH) molar ratios of 0.5:1, 1:1, 1.5:1, and 2:1. The chemical structure and thermal behavior of the bio-polyols and the cured PU adhesives were analyzed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Performance of the adhesives was evaluated by single-lap joint shear tests according to EN 302-1:2003, and by adhesive penetration. The highest shear strength was found at the NCO:OH molar ratio of 1.5:1 as 4.82 & PLUSMN; 1.01 N/mm(2) and 4.80 & PLUSMN; 0.49 N/mm(2) for CLWPU and PLWPU, respectively. The chemical structure and thermal properties of the cured CLWPU and PLWPU adhesives were considerably influenced by the NCO:OH molar ratio.


adhesive penetration; bio-polyol; bond strength; ethylene glycol; FTIR; liquefaction; pMDI; TGA

Published in

2021, volume: 13, number: 19, article number: 3267

Authors' information

Jiang, Wen
Linnaeus University
Hosseinpourpia, Reza
Linnaeus University
Bizik, Vladimirs
University of Göttingen
Ahmed, Sheikh Ali
Linnaeus University
Militz, Holger
University of Göttingen
Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology

Sustainable Development Goals

SDG12 Ensure sustainable consumption and production patterns

UKÄ Subject classification

Polymer Technologies
Wood Science

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