Effects of furfurylation on white pocket rot in Japanese larch heartwood caused by Porodaedalea chrysoloma

Abstract

Porodaedalea chrysoloma (Fr.) Fiasson et Niemelä is a basidiomycete that causes pitting white rot in conifer trees such as Japanese larch, leading to significant losses in wood density and mechanical strength. Consequently, the utilization of decayed wood is severely limited in the wood industry. Herein, furfurylation was applied to improve the properties of white pocket-rot wood, particularly its density and dimensional stability. The furfurylation process involved the maleic anhydride followed by the polymerization of furfuryl alcohol (FA) under vacuum impregnation. Fourier transform infrared spectroscopy confirmed that FA was impregnated into the white pocket-rot samples and polymerized in situ within the cell walls. In the early stages of decay, furfurylation resulted in a higher mass percent gain (86.2 %–181.3 %) than in sound wood. As the decay-area ratio increased, the mass change of the furfurylated wood also increased. Additionally, furfurylation enhanced anti-swelling efficiency, and reduced water absorption, even after extraction of untreated FA. These results suggest that the pore structure formed facilitates the penetration of both the acid catalyst and FA, thereby improving furfurylation efficiency in decayed wood. This study provides new insights into the potential for upgrading decayed wood by combining the decay characteristics of white pocket rot with furfurylation.