The Induced Discoloration Of Robinia Pseudoacacia Treated By Saturated Vapor And Characters Of The Extractive

In this paper,Robinia pseudoacacia are the research object.This test used different conditions saturated vapor to lead the wood to discolor,and summed up the trend of induced discoloration of Robinia pseudoacacia and conditions.The study tried to research the change internal groups of Robinia pseudoacacia and the role in the discoloration trough analyzing infrared spectrum,UV-visible spectra and GC-MS extractive before and after treatment,combined infrared spectroscopy of powder before and after discoloration,and made conjecture upon part of the mechanism of discoloration.The results show that:(1) Saturated water vapor treatment is the better method for Robinia pseudoacacia induced discoloration than conventional wood drying methods.The color of Robinia pseudoacacia tends to be dark and more uniform.And the relationship between the temperature,time and moisture content should be considered before deciding the pretreatment conditions.(2) Low molecular weight substances in the extractive were produced in the process of the wood induced discoloration,which increased the content of the extractive.And the content gradually increased with the extension of holding time.(3) These were found in by the study on the characers of the extractive in the processing of the induced discoloration,â‘ By comparing infrared spectrum of extractive and power of the wood before and after induced discoloration,we can find that the concentration of hydroxyl was reduced and ester was changed with holding time and accompanied by esterification and deacetylation.Oxidation and dehydration occurred in the timber interior and the conjugate of the system was complicated,which enabled the color to be deeper.â‘¡There are some flavanols in the extractives through UV spectral and GC-MS analysis such as quinines,quercetin,coumarin and so on.Aromatic groups linked with substituting groups in the discoloration.So the wood color became darker.â‘¢The extractive of the wood contained 3-hydroxyl-flavanol,cyanidin,quercetin and other substances which increased in the induced discoloration.This was one of the reasons of the color deepen of Robinia pseudoacacia after treatment.