Protein Adhesives: Investigation of Factors Affecting Wet Strength of Alkaline Treated Proteins Crosslinked with Glyoxal

Elena Averina; Johannes Konnerth; Hendrikus W G van Herwijnen

doi:10.3390/polym14204351

Protein Adhesives: Investigation of Factors Affecting Wet Strength of Alkaline Treated Proteins Crosslinked with Glyoxal

Polymers (Basel). 2022 Oct 15;14(20):4351. doi: 10.3390/polym14204351.

Authors

Elena Averina^{1

2}, Johannes Konnerth¹, Hendrikus W G van Herwijnen²

Affiliations

¹ Institute of Wood Technology and Renewable Materials, Department of Material Sciences and Process Engineering, University of Natural Resources and Life Science, Konrad-Lorenz-Strasse 24, 3430 Tulln an der Donau, Austria.
² Wood K Plus-Kompetenzzentrum Holz GmbH, Altenberger Straße 69, 4040 Linz, Austria.

Abstract

Proteins obtained as side-products from starch production (potato and corn proteins) were investigated for wood adhesives application. To improve the wet strength of protein-based adhesives, glyoxal was added as a crosslinking agent. The effect of glyoxal on the wet strength of protein-based adhesives was investigated at different pH, protein: glyoxal ratios and solid content. The alkaline pretreatment of proteins was carried out by two different methods which reduced the molecular weight of proteins to different extents. The effect of molecular weight reduction on the wet strength of protein-glyoxal adhesives was also observed. It was found that pH level affects wet strength more significantly compared to solid content and protein-to-crosslinker ratio. Potato and corn proteins crosslinked with glyoxal showed maximal wet strength results in an acidic pH range.

Keywords: cross-linking agent; glyoxal; protein adhesives; wet strength; wood adhesives.

Grants and funding

The authors greatly appreciate the financial support for this work as a part of the project “High-performance Materials” (grant K3-F-670/003-2017) from the state of Lower Austria.