【精选】研究生-专业英语.pptVIP

Improvement of Photoprotection of Wood Coatings By using Inorganic Nanoparticles as Absorbers Name : Zhao YUN Student No. : 200806110007 Contents Wood Degradation of wood The strategies to prevent degradation of wood The new absorbers (inorganic Nanoparticles) Materials and method Wood / coating systems analysis Conclusions Questions and Personal suggestions Wood Wood is the natural and reproducible resource. Cellulose, hemicellulose ,lignin and extractives are the main components of wood. Nice appearance ,low cost, low thermal conductivity and environmental protection. Degradation of wood Acid degradation. Alkaline degradation. Thermal degradation. Photodegradation. Mechanical degradation. Fungi degradation. Active enzyme degradation of wood and so on . The strategies to prevent degradation of wood Composite of wood and other material (metal plastic and so on ) . Impregnating with chemicals . The materials ,photodegradation resistance, used in the wood surface Surface coating . The new inorganic nanopaticles UV absorber As the nanometer scale ,matter has special properties A large specific surface . Improvement of Thermal conductively . Easily to aggregate . Strong chemical activity and so on. Materials and methods the inorganic absorbers are ZnO predispersed in water and powder and CuO only powder the organic absorbers are the Tinuvin292 and Tinuvin477DW . the costing is polyurethane-acrylate coating. wood species are tangential longitudinal sugar maple samples Wood\coating systems analysis The UV absorber : an analysis of UV absorbing properties of different UV absorbers was carried out by UV/Visible spectroscopy (lambda 40 UV/Visible spectrometer）. Gloss: the gloss of the different coatings before and after the aging test was measured with gloss -meter (BYK-Gardner Micro-TKI-Gloss) . Results and Discussion The absorbance spectra for organic absorbers are shown in the figure(1) . Figure (1) The absorb