Adamopoulos, Stergios
- Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences
Abstract
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.
Keywords
adhesive penetration; bio-polyol; bond strength; ethylene glycol; FTIR; liquefaction; pMDI; TGA
Published in
Polymers
2021, volume: 13, number: 19, article number: 3267
SLU Authors
Global goals (SDG)
SDG12 Responsible consumption and production
UKÄ Subject classification
Polymer Technologies
Wood Science
Publication identifier
- DOI: https://doi.org/10.3390/polym13193267
Permanent link to this page (URI)
https://res.slu.se/id/publ/113749