Stefan Veigel
University of Natural Resources and Life Sciences, Austria
Title: Nanocellulose-modified Oil-based Wood Coatings
Biography
Biography: Stefan Veigel
Abstract
Due to their bio-based character, oil-based coatings are prevailing more and more in wood surface finishing. These coatings impart appealing optical and haptical properties to the wood surface but lack sufficient protection against water and mechanical influences. The aim of the present study is therefore to modify oil-based coating formulations by the addition of hydrophobised cellulose nanofibrils (CNF) which are thought to form an ultra-thin protective layer on the wood surface without affecting its pleasant optics and haptics. Hydrophobisation of CNF was performed by an esterification with different carboxylic acids as well as by a modification using the paper sizing agent alkyl ketene dimer. Modified nanofibrils were added to an oil-based coating material either by a solvent exchange approach or spray drying and subsequent addition of the dry cellulose powder. Oil formulations containing 1 wt% CNF modified with (2-Dodecen-1-yl) succinic anhydride showed almost no sedimentation after 48h. An enhanced abrasion resistance along with a slightly higher resistance to chemicals was found for oak wood surfaces coated with cellulose-modified oil formulations. The increased surface resistance might be attributed to the loose network structure of CNF which effectively prevents the oil from penetration into the wood surface, thus forming a protective CNF/oil composite layer on the wood surface.