Study On The Mechanism For Veneer Of Poplar Ⅰ-214 Dyeing And Color Changing

Study on　the Mechanism for Veneer of Poplar I-214 Dyeing and Color Changing Zhou Yu (Wood Science and Technology)Directed by Wang JinlinAs one of the most important plantation wood species in China, Poplar has been widely used in wood veneer industry. Many problems occur during processing and utilizing due to poplar's characteristic properties and defects, which affect its value in use. Since poplar has unclear grain, monotonous color and large parts of 'wet heartwood', it's an important way to improve the dollar value of poplar wood resources by applying imitation technology to produce decorative veneers similar to natural rare wood species. This paper focuses on the absorption of veneer to dyestuff, color changes on the veneer surface and dyeing degree, dyeing ability of the dipped veneer, the mechanism of wood dyeing and color change of the dyed veneer by Xenon radiation. The regularities of wood dyeing and light change of the colored veneer are studied and to provide theories base for Poplar veneer dyeing technology. In the paper Poplar I-214 (Populus×euramericana(Dode)Guineir cv.'I-214')was chose to make cellulose and veneer samples, and acid dyestuff and active dyestuff and other correlative chemistry reagent were selected, the researches are based on the following methods: 1,dyeing amount on veneers and adsorption isotherm. 4 kinds of dyestuff are used to confect 5 kinds of dyeing liquid with different concentration. The veneers are dipped under the condition of five kinds of temperature and five kinds of time. The difference of consistence of dye liquid is used to calculate dyeing amount on veneers, and the connection between dyeing amount and consistence of dyeing liquid,dyeing temperature,dying time and adsorb isotherm types were analyzed.2,color change and pigmentation degree of dyed veneers. The color of dyed veneers in above methods was measured by the instrument after drying, and then pigmentation degree (△E*ab) was calculated, change of color and the relations between △E*ab and concentration of dyeing liquid,dyeing temperature,dyeing time were analyzed.3,4 kinds of dyestuff are used to confect 1% dyeing liquid respectively. Under temperature 90℃ and time 45min, the veneers are dyed and dried . The color is measured and the difference color (△E*ab) is calculated. The dyeingdeepness in cut break surface and even chromophile are observed by using microscope to analysis the influence of dying treatment on the dyeing quality of veneer surface and wood structure. 4,The color change of untreated veneer, bleached and dyed veneers. The colors of those veneers are measured and correspondingly the color difference of each veneer is obtained after they are irradiated by Xenon in X25F Xenon Fade Meter. Finally the color change mechanism and its influence on the color change are analyzed. 5,Energy chart analysis of Xenon attenuation of untreated and dyed veneers. Untreated and treated α cellulose and veneer are measured using XSAM800 instrument(multifunctional surface analysis). By using the analysis method of XPS, and from the whole chart,Cｌsand O1s and the change of chart apex, wood dyeing and the mechanism of light attenuation are discussed. The results are as follows:1,Using dyestuffs such as Acid Red GR and Active Blue KN－R,the dyeing amount in veneer is linear with the concentration of dyeing liquid. The dyeing amount of Active Blue KN－R are higher than Acid Red GR. All adsorption curves are "C" isotherm. Under dyeing temperature 100 or 90℃,dyeing time between 1 to 8h has no influence on dyeing amount. While the dyeing time is 5h,dyeing temperature have no remarkable affection on the dyeing amount of Active Blue KN-R. Below 60℃, the dyeing amount increase remarkably as temperature increase. 2,While the temperature is 90℃, the L* value of veneer surface of dyed veneer with acidity red GR and active blue KN－R all decrease markedly with the increase of dyeing concentration from 0.005% to 0.1%,and when the concentration v...