The Regulatory Mechanism Of Tungsten Trioxide Crystal On Surface Color And Properties Of Wood

In the wood modification research area,photosensitive material WO3 was used on micro/nano structures of wood surface modification,which could improve the hydrophobic properties,anti ultraviolet ageing performance,as well as photochromic and photocatalytic functions,so as to enhance the functional properties and practical value of wood.In this thesis,the perspective of wood surface modification was focused.Inorganic functional nano-WO3,WO3/TiO2,and WO3/SiO2 were prepared under the condition of low-energy state using hot solvent synthesis method.The properties of the modified layers were further analyzed through microstructure,phase structure,and chemical composition.Besides,thermal stability,characteristics of wood dyeing,photochromic characteristics were studied to systematically analyzing the modification effect and the modified mechanism of the single and compound nano-WO3,WO3/TiO2,and WO3/SiO2 layers.Based on the functional requirements of wood surface modification in practical production and life,the hydrophobic performance,anti-ultraviolet aging performance and photocatalytic removal of formaldehyde after wood surface modification were systematically detected and analyzed to verify the multi-effect target and value of wood surface modification.Specific research processes for the above problems are as follows:In terms of properties of wood surface nano-WO3 modification:WO3 modified wood was prepared by two-step heating using WCl6 ethanol solution as the precursor solution.Hexagonal phase WO3 crystal were grown on the wood surface.Various morphologies presented due to different addition surfactants.The size of bar-like particles is of 120 nm diameter and about 750 nm length.The size of flake-like particles is of 20 nm thick and 350 nm length.Squama like and irregular particles were also grown on wood.By adjusting the factors of preparation temperature and surfactant species,contrastive analyzing the modified wood color characteristics and photochromic properties,the optimal solvent thermal preparation process condition of 110℃ at low energy state by two-step heating method was obtained.In combination with the above analysis,the process can be adjusted to control the crystal growth characteristics,and then different micro/nano-structural characteristics can be formed to produce a regulatory mechanism for the modification function effect.By referring to the interface analysis principle of crystal growth theory and the experimental principle of wood surface WO3 modification,the hydrothermal crystallization mechanism of WO3 on wood was analyzed.Through the analysis of the causes of wood dyeing and the characteristics of injection and extraction of WO3 ions and electrons,photochromic principle of modified wood was studied.In order to meet the demand of functional composite modification,WO3-modified wood obtained a better super-hydrophobic effect at low surface energy state.The static contact Angle of the specimens synthesized at 110℃ is 153.7°,which reflects the function of super-hydrophobicity and self-cleaning properties.It also shows excellent performance in the experiment of accelerated aging and irradiation of formaldehyde in degradation gas by ultraviolet light.In terms of improving WO3 modification performance on wood surface by TiO2 doping:WO3/TiO2 solvent-heat composite modified wood was prepared by blending TBOT and WCl6 ethanol solutions as precursors,and adjusting solution ratio content,synthesis temperature and other conditions.Through the analysis of the color characteristics of the wood modification,combined with the determination and study of the photochromic property,photocatalytic property and anti-ultraviolet aging property,the optimized preparation process of WO3/Ti02 composite modified wood was clarified.By means of morphology analysis,phase structure analysis and chemical composition analysis,the growth characteristics of WO3 and TiO2 composite preparation on wood were analyzed.Combined with the specific solid phase growth environment of wood substrate in this experiment,the growth mechanism of WO3/TiO2 composite modified layer was obtained.Based on the analysis of the enhancement effect of TiO2 doping on the photosensitivity of WO3,the photocatalytic mechanism of the formaldehyde removal performance of WO3 in the ultraviolet irradiation of wood samples under TiO2 doping state was proposed.In functional promotion,the TiO2 doping does not play a role to improve the hydrophobicity.WO3/TiO2 composite modification significantly improved the efficiency of photochromic through the comparative analysis of wood color and photochromic properties.The photochromic color difference value △E*is 26.2.In terms of SiO2 doping on the influence of the color regulation and performance of wood WO3 modification:TEOS and WCl6 ethanol solutions were used as precursor solutions,and the preparation method of equal ratio blending was used to prepare WO3/SiO2 composite modified wood by adjusting the preparation temperature.Through SEM,EDS,XRD and FTIR analysis,the composition characteristics and chemical composition of WO3/SiO2 modified layer were analyzed,and the amorphous composite modified layer composition of WO3/SiO2 on wood surface was obtained.Through the testing and analysis of the color characteristics and photochromic performance of WO3/SiO2 modified samples,and the comparing of the color characteristics of WO3 modified wood,it was clear that the doping of SiO2 enriched the color and aesthetics of single WO3 modified wood.By testing and analyzing the hydrophobic properties,and comparing the hydrophobic properties among WO3 and WO3/TiO2 composite modified wood,and comprehensively analyzing the micro morphology of the samples,the hydrophobic mechanism of the modified wood at low surface energy state was obtained.Compared with the single modification effect of WO3,SiO2 doping in WO3 modified wood has little effect on the anti-ultraviolet aging performance,but reduces the photocatalytic formaldehyde removal performance.Through the above researches,WO3 nanoparticles modification method,function and principle on wood surface were systematically explored.On the basis of analyzing the optimized preparation conditions and the modification effect,using the concept of TiO2 and SiO2 doping modification,WO3/TiO2 and WO3/SiO2 modified wood properties and mechanism were explored,which deepen and expand the function of WO3 wood modification method and path,enrich the experimental effect,enhance the practical value.On the basis of summing up experience,analyzing principle,defining the mechanism,multiple effect modification target using single agent was achieved on wood surface modification field,The work provides references on improving wood function and use value by using photosensitive material.