Abstract
A gluing method for fiberboard based on laccase-activated tannin and wood fibers was investigated on a laboratory scale. Oxygen consumption measurements showed that hydrolyzable tannins (tannic acid and chestnut tannin) were more reactive toward laccase than condensed tannins from mimosa and quebracho. Wet-process hardboard prepared with laccase and the most reactive tannin, tannic acid, had superior mechanical strength compared to controls and boards made with laccase alone or laccase and other tannins. The other tannins did not improve mechanical properties more than laccase treatment alone. The addition of wax to the tannic acid-laccase formulation improved the dimensional stability of the boards enough for them to comply with industrial standards, although wax had a negative impact on the mechanical properties. The results cannot be directly applied to dry-process medium-density fiberboard (MDF) production; however, the positive effects of tannin and laccase on hardboard properties also warrant investigations on the green chemistry of MDF production.
©2009 by Walter de Gruyter Berlin New York
