返回Google圖書搜尋

Influence of selected environmental factors on moisture dynamics of wood

出版	M. Žlahtič Zupanc, 2017
URL	http://books.google.com.hk/books?id=4UicswEACAAJ&hl=&source=gbs_api

註釋The research work in the doctoral study was conducted on 17 different materials, based on spruce, pine, larch, beech, chestnut and oak wood. In order to improve the wood properties, thermal modification and impregnation with a copper-ethanolamine formulation, tung oil and a natural wax suspension were used. Specimens were exposed to various degradation-aging procedures: white and brown rot decay fungi, blue stain fungi, artificial accelerated weathering and natural weathering in the field test site. Our results indicated that the moisture dynamics of wood changes with ageing and it depends on the wood species and treatment applied. After exposure to various aging procedures, the ageing factors were characterized and the moisture dynamics of wood was evaluated. Mass loss, colour and chemical changes were determined. The moisture dynamics of wood were determined by capillary water uptake, by contact angle determination by the sessile drop method, long-term water uptake and a sorption test. Water exclusion efficacy and moisture performance in most of the materials investigated decreased after ageing. Materials treated with waxes were exceptions. The excellent hydrophobic properties even improved after some ageing procedures. Of all of the materials tested, thermally modified spruce and beech treated with an emulsion of natural waxes performed the best. Oil treated woods also retained good hydrophobicity. We found that it is with laboratory tests possible to determine moisture performance if specimens have been previously aged. Comprehensive moisture performance cannot be elucidated with a single laboratory test, but a variety of laboratory tests need to be applied. In the second part of the research, greater emphasis was placed on nuclear magnetic resonance. The magnetic resonance imaging method was applied to elucidate the moisture dynamics of wood, drying and uptake of preservation treatments in wood. The obtained signal and 3D model of water distribution give information that is much more comprehensive compared to the classic gravimetric method. Magnetic resonance is a suitable method for this research.