Degradation of wood by UV light: a study by EGA-MS and Py-GC/MS with on line irradiation system

Publication date: Available online 22 February 2019Source: Journal of Analytical and Applied PyrolysisAuthor(s): Marco Mattonai, Atsushi Watanabe, Ai Shiono, Erika RibechiniAbstractUV degradation of wood is an important phenomenon that entails loss of aesthetic and mechanic properties. The changes are usually studied with artificial ageing followed by spectroscopy, and focus on colour changes. Analytical pyrolysis coupled with gas chromatography-mass spectrometry (Py-GC/MS) and evolved gas analysis-mass spectrometry (EGA-MS) are powerful tools for wood characterisation, but the change in pyrolytic behaviour of wood after UV irradiation is not well documented. In this work, a new instrumental setup was used to perform UV irradiation on line with EGA-MS and Py-GC/MS with in situ derivatisation of fir and chestnut wood. The effect of UV exposure was evaluated in terms of thermal stability and composition of the pyrolysate. The results showed that UV degradation of the samples was related to its lignin content. Fir wood, with higher lignin content, showed extensive degradation after 4 h of irradiation, while chestnut wood, with lower lignin content, showed very small changes. Qualitative comparison of the EGA-MS profiles and semi-quantitative analyses of the composition of the pyrolysates revealed that these techniques could be used as a fast monitoring tool to assess the UV degradation of wood.

Source: Journal of Analytical and Applied Pyrolysis - February 23, 2019 Category: Chemistry Source Type: research