The Dissolution And Regeneration Fibers Of Biomass Polymer In Ionic Liquids

In recent years, ionic liquids are extensively studied and it is utilized in the field of spinning technology such as cellulose spinning, natural protein fiber spinning and lignin fiber spinning.Based on the application of ionic liquid in spinning, natural biopolymer corn straw is selected as raw material in this study. An ionic liquid and DMSO are chosen as the solvent, which demonstrates broad utility in biomass conversion by comprehensively ustilizing all biomass ingredients. A new method for synthesis of lignin fiber has been developed by pretreating biomass with the organic electrolyte system preparing lignin-based polymers with in-situ extracted lignin by electrostatic spinning. The preparation and characterization of lignin-based nanofiber by spinning technology have been studied in detail.This study is focused on using a new mixed solution of the ionic liquid/DMSO to dissolve and pretreat the biomass polymers and separate lignin from the corn straw. Then the lignin is in situ mixed with synthetic polymers to produce new composite material of lignin-based nano/micro fiber through electrostatic spinning. The main process is described as follows:1. Mixed solution consists of the 1-ethyl-3-methyl imidazole acetate ([Emim][Ac],20 mol%) ionic liquid and dimethyl sulfoxide (DMSO,80 mol%) was prepared before use. The pretreatment of corn straw in the mixed solution was performed for 2 h at 140℃. After full dissolution, the regenerated corn straw was obtained by adding anhydrous methanol as antisolvent at 50℃. After that, the corn straw residue was filtrated, while the methanol in the filtrate was removed by rotary evaporation to obtain the extracted lignin in [Emim][Ac]/ DMSO solution(XILs=20%).2. The residue (regenerated corn straw) was treated with enzymatic hydrolysis methodology to obtain Enzymatic hydrolysis lignin, then the Enzymatic hydrolysis lignin dissolved in [Emim][Ac]/DMSO (XIls=20%) of organic electrolyte system to prepare Enzymatic hydrolysis lignin solution. The Enzymatic hydrolysis lignin solution was mixed with polyacrylonitrile (PAN)/[Emim][Ac]/DMSO solution at different mass ratios of 2:8,4:6, 6:4,8:2 to form spinning solution, and then the spinning solution was treated by electrospining to get Enzymatic hydrolysis lignin/PAN composite electrospun nanofibers.3. The [Emim][Ac]/DMSO(XILs=20%) filtrate solution which containing extracted lignin solvent, dissolved Enzymatic hydrolysis lignin to prepare corn straw lignin solution in situ,The corn straw lignin solution was mixed with polyacrylonitrile (PAN)/[Emim][Ac]/ DMSO solution at different mass ratios of 2:8,4:6,6:4,8:2 to form spinning solution, and then the spinning solution was treated by electrostatic spinning to get lignin/PAN composite electrospun nanofibers.Lignin/PAN composite electrospun nanofibers were characterizedby Scanning Electron Microscopy (SEM),Fourier Transform Infrared(FT-IR),Thermogravimetric Analysis (TGA)and Differential Scanning Calorimetry (DSC). These characterization techniqueswere used to characterize thestructure and properties of samples.