Study On The Influence And Mechanism Of Wood Veneer Pretreatment On Dyeing Effect

Wood permeability is an important factor that affects the dyeing of wood,and it is usually to improve the permeability of wood to improve the dyeing properties of wood.In order to enrich the visual characteristics of maple(Acer Saccharum Marsh),improve its additional value and expand its use scope,the paper explored the effects of the water cycle oscillation dyeing(WCO),supercritical fluid(SCF)and air compressed micro explosion(AE)pretreatments on the dyeing properties of maple.The dye-uptake and K/S were evaluated by fuzzy mathematics comprehensive and the optimal process parameters was concluded then.The scanning electron microscopy(SEM),X-ray energy spectrum analysis(EDS),fourier transform infrared spectrometry(FTIR),thermogravimetric analysis(TG),X-ray photoelectron spectroscopy(XPS),nitrogen adsorption and mercury injection apparatus(MIP)were used to analyze the pore structure,the change ofchemical functional group and the combination of reactive dyes with wood of maple after dyed and treated by SCF and AE.The results show that:1.In the optimal process condition,the dye-uptake was 7.1 8%,the K/S was 4.13.The SEM and EDS results show that the dye disperse(in the vessel)and agglomerate(around the wood ray)in the wood.The FTIR and TG results show that the-C=N of reactive brilliant blue X-BR dye combined with the-OH of cellulose in a way of nucleophilic reaction and generated ester bond Cell-O-C=N,realizing the chemical combination of dye molecules and wood.2.Water cycle oscillation dyeing process,supercritical fluid treatment,micro blasting treatment,as well as supercritical fluid and micro blasting synergistic treatment have different levels of contribution to wood dyeing performance.In compare to traditional dyeing process,wood dyeing performance advanced.The dye-uptake and K/Swere obtained by the WCO dyeing process,increased by 31.75%and 17.19%respectively.The dye-uptake and K/Swere obtained by SCF-CO2 treatmentdyeing process,increased by 80.50%and 24.21%respectively.The dye-uptake and K/S were obtained bysupercritical entrainer treatment dyeing process,increased by 120.47%and 30.51%respectively.The dye-uptake and K/Swere obtained by AE treatment dyeing process,increased by 40.53%and 19.61%respectively.The AE-SB was the best process in cooperative processing of SCF and AE.In this process condition,the dye-uptake was19.89%and the K/S was 5.65,177.02%and 36.80%higher than that of untreated veneer respectively.3.Wood lignin and extractivescan be dissolved by supercritical fluid treatment,on the other hand,supercritical cosolvent treatment made-OH content of the wood surface increased.The air compressed explosion treatment makes the impact of cell wall and pitmembrane cracked,which was conducive to the circulation and the penetration of dye into the veneer.The cracks produced by micro blasting treatment are more favorable for supercritical fluid infiltration into wood to improve the permeability,surface wettability and hydroxyl content of wood.The best dyeing results was treated by supercritical fluid treatment and air compressed explosion treatment.