Search

Abstract: This study shows the photo-stabilizing effect of extractives on wood. XPS and FTIR techniques were used to analyze the variations in chemical characteristics on the surfaces of non-extracted and extracted Acacia confusa heartwood after lightfastness test. XPS survey analyses reveal that non-extracted heartwood exhibits a higher O/C ratio than the extracted wood. Furthermore, results from the detailed analysis of C1s indicated that the photo-oxidative derivatives increased in both extracted and non-extracted specimens after lightfastness test. On extracted wood, the derivatives are mainly derived from lignin, whereas extractives are the major component responsible for the generation of derivatives on non-extracted wood surface. After leaching test of UV-irradiated specimens, it was noted that the degradation products were readily removed by water. More water-soluble derivatives were leached out from the extracted wood, although higher lignin content was observed on the non-extracted wood surface. In conclusion, it is shown that photodegradation of A. confusa wood can be retarded by extractives oxidation. [ABSTRACT FROM AUTHOR]

Abstract: Wood is susceptible to photodegradation when exposed to light. In addition to three main components of wood, the influence of extractives on photodegradation is not fully understood. This study examines the role of wood extractives in photodegradation process, and so the variations in the surface properties of non-extracted and extracted Cryptomeria japonica and Acacia confusa heartwood were examined after exposure to ultraviolet light. FTIR and UV–visible techniques were used to analyze the variations in chemical characteristics on the wood surfaces after irradiation. Following the lightfastness test, the contents of quinonoids and carbonyl groups derived from the lignin increased. However, the wood surface deteriorated less when the extractives existed. In conclusion, extractives play an essential role in the photodegradation of wood, and the rate of wood degradation was lessened by the presence of extractives. [Copyright &y& Elsevier]