Novel wood adhesive based on tannin and polyethyleneimine

CELL 121

Kaichang Li1, John Simonsen1, Nicholas Masson2, and Joe Karchesy1. (1) Department of Wood Science and Engineering, Oregon State University, 102 Richardson Hall, Corvallis, OR 97331, (2) Ecole Nationale Superieure des technologies et industries du bois, universite Henri Poincare, 21, rue du Merie Blanc, Epinal Cedex 9, F-88051, France
Condensed tannins are natural polyphenolic substances in the wood and bark of certain species. They react with appropriate cross-linking agents to form high-molecular weight condensation products. In the past, tannin-based adhesives have been heavily fortified with urea, urea-formaldehyde (UF), phenol formaldehyde (PF), and resorcinol formaldehyde (RF) with encouraging results. However, no work has been done on the reaction between polyethyleneimine (PEI) and tannin. We report here on the development of a PEI/tannin blend adhesive with good adhesive properties. Various combinations were tested, with ultimate shear stress results exceedig 3.5 MPa, which is in the range of commercial resin systems.