The effects of impregnation with secondary metabolite extracted from Ipe on durability of Japanese cedar and beech wood
T Iida, R Konuma, K Kawarada
Ipe wood is known for its high durability; it has been widely used in exterior structures that are exposed to the weather. In this paper, to increase the durability of less durable wood, Japanese cedar and beech specimens were impregnated with a secondary metabolite from Ipe. In a previous study, secondary metabolites extracted by a Soxhlet extraction method showed antifungal properties. Therefore, to establish a simpler and more economical extraction method, we investigated extraction by soaking with a solvent. Then, non-durable wood specimens were impregnated with extractives and examined by accelerated fungal tests. After exposure to fungal attack with wood-decaying fungi such as Fomitopsis palustris, Japanese cedar specimens exhibited less than 3% mass losses. Extractives retention after weathering treatment of Japanese cedar and beech specimens were 86.1% and 59.1%, respectively. Moreover, both specimens demonstrated bulk coefficients that suggested the permeation of extractives into cell walls. These results indicated that the extractives of Ipe have high compatibility with cell walls of other types of wood, and can transfer durability against wood-decaying fungi.