Decay Resistance of Nano-Zinc Oxide, and PEG 6000, and Thermally Modified Wood

Abstract

In Central Europe, European beech (Fagus sylvatica L.) wood has a high potential for the production of construction and decorative materials, with the aim of replacing Norway spruce, oaks, and other traditionally used tree species. However, the biological resistance of beech wood—to decaying fungi, molds, and insects—is low, and in damp conditions its resistance must be increased with suitable preservatives or modification methods. In the present experiment, beech wood was first treated with water systems of nano-zinc oxide (0.1 to 3.3 wt.% of nano-ZnO) and/or polyethylene glycol 6000 (20 wt.% of PEG 6000), without/with additional thermal modification at 190 °C/2 h. In the presence of nano-ZnO, the decay resistance of beech wood to the brown-rot fungus Rhodonia placenta and the white-rot fungus Trametes versicolor significantly increased, mainly after its additional thermal modification. The presence of nano-ZnO in beech wood—(a) alone, (b) with a subsequent application of PEG 6000, (c) with additional thermal modification—had a more apparent inhibition effect on T. versicolor than on R. placenta. PEG 6000 alone did not improve the resistance of beech wood to rot.