Chitosan itaconate based water- and stain-repellent coatings for wood

Progress in Organic Coatings, vol. 194, pp. 108630

Abstract

Wood is experiencing a resurgence in popularity, driven by an increasing awareness of environmental issues. Because wood readily absorbs humidity and can even soak up substantial quantities of water, particularly via the end grain, it usually requires protective treatment. For this, we developed a sustainable hydrophobic coating based on chitosan from food-industry waste. Aqueous solutions of chitosan itaconate are thixotropic, due to the entanglement of the helical chains. After application to the surface of beech and spruce wood, polymerisation of the itaconate is essential to effect the transformation from water soluble salt to water insoluble film by crosslinking the chitosan chains. The films are transparent, approx. 0.5 mm thick, accentuate the wood grain, strongly adhere to the wood surface, and completely seal the end grain with contact angles of approx. 93°. Mayonnaise and coffee can be removed completely from the coated surfaces, only red wine leaves a stain, but much less pronounced than on untreated wood. The coating also offers protection against UV-induced degradation, as no yellowing is observed under irradiation for four weeks.

Authors 2

1. Nils Münstermann Aachen Institute of Building Materials Research

   RWTH Aachen University

   Affiliation as printed

   Institute of Building Materials Research, Schinkelstraße 3, 52062 Aachen, Germany

2. Oliver Weichold corresponding Aachen Institute of Building Materials Research

   RWTH Aachen University

   Affiliation as printed

   Institute of Building Materials Research, Schinkelstraße 3, 52062 Aachen, Germany