Study On Coloration Technology And Mechanism Of Oak Based On Ferrous Chloride

The color of wood can be changed by the reaction of chemical reagent with lignin,extract and other components,which achieves the purpose of wood surface modification.In this study,oak(Quercus acutissima.)veneer was used as the experimental material,ferrous chloride(FeCl2)as the coloration reagent,and the coloration veneer was obtained by impregnation.The orthogonal experiment was used to study the effect of various process parameters on the coloration of oak,and the best process was obtained.The surface chromaticity coefficient of oak before and after coloration was tested by colorimeter;the color stability of oak veneer was tested by water resistance and UV resistance experiments;the influence of different solvents on the coloration of oak was explored by extraction treatment;the coloration reaction of the extract was tested by analyzing the extract and the standard solution of the extract.The mechanism of chemical coloration of oak treated with ferrous chloride was studied by FTIR,UV,XRD and XPS.The main conclusions are as follows:(1)Using ferrous chloride to react with oak to prepare discolored wood,the technology is simple and the reaction time is short.After treatment,oak veneer is blue black with natural color and clear texture.The best process parameters of the chemical coloration treatment of oak with ferrous chloride are:the mass concentration of ferrous chloride is 1.0%,the treatment time is 10 minutes,the treatment temperature is 80℃,and the drying temperature is 40℃;the primary and secondary order of the factors affecting the coloration of oak veneer is:the concentration of ferrous chloride>the drying temperature>the treatment temperature>the treatment time.(2)After cold and hot water treatment,the color of oak veneer changed little,and the value of ΔE*was below 2.After 720 hours of irradiation,the color coefficient of the surface of the colored oak veneer changed greatly,and the value of ΔE*was 4.40;the color stability of the colored oak veneer under UV irradiation could be significantly improved by applying UV-1130,and the value of ΔE*could be reduced to 2.06 by applying 2%of the color fixing agent.(3)the coloration of oak mainly occurs on the hydroxyl,phenolic hydroxyl and aromatic ring substituents in wood,and the complexation of phenolic substances and iron ions in oak is the main reason for the coloration of oak.In the process of coloration,iron ions are attached to the surface of oak by complexation reaction,and most of the divalent iron ions are changed into trivalent iron ions.(4)the coloration of wood was weakened after extraction,which indicated that the extract was the important reason of oak coloration.Different solvents have different extraction effects on oak samples,among which alkali extraction has better effect than other solvents,which is mainly due to the removal of some extracts,such as tannins,flavonoids and other phenolic substances,as well as the removal of some lignin in the wood,further weakening the coloration reaction.The color change of oak wood is caused by the formation of new coordination body in complexation reaction.