Solubility of kraft lignin-g-polyacrylonitrile copolymer in various ionic liquids and characterization of its solution

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• 作者：Chan-Woo Park ; Won-Jae Youe ; Song-Yi Han ; Yong Sik Kim…
• 刊名：Wood Science and Technology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：51
• 期：1
• 页码：151-163
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Wood Science & Technology; Ceramics, Glass, Composites, Natural Materials; Operating Procedures, Materials Treatment;
• 出版者：Springer Berlin Heidelberg
• ISSN：1432-5225
• 卷排序：51

文摘

Lignin is a potential precursor for low-cost carbon fiber production, but it is difficult to spin and spool lignin because of its complex and interconnected molecular structure. This disadvantage can be overcome by introducing g-polyacrylonitrile (PAN) to lignin. However, the resulting copolymer is insoluble in common organic solvents. In this study, kraft lignin (KL)-g-polyacrylonitrile copolymers with different KL/PAN proportions were prepared via atom transfer radical polymerization (ATRP) method and their solubility in ionic liquids (ILs) was investigated at different temperatures. 1-Ethyl-3-methylimidazolium acetate ([EMIM]Ac), 1,3-dimethylimidazolium methyl sulfate ([MMIM]MeSO4), 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), and 1-butyl-3-methylimidazolium bromide ([BMIM]Br) were used as the ILs. At all investigated temperatures, the highest solubility of KL-g-PAN was observed in [EMIM]Ac, with the order of [MMIM]MeSO4 > BMIM]Br > [BMIM]Cl. The solubility in BMIM]Br and [BMIM]Cl was remarkably low, reaching values of less than 4 g/Kg. The viscosity and surface tension of the KL-g-PAN/[EMIM]Ac solution increased and decreased, respectively, with increasing amounts of PAN and further by the addition of dimethylformamide (DMF) to the solution. FTIR spectra of KL-g-PAN copolymers before and after dissolution suggested that PAN was partially depolymerized from the copolymer during the dissolution process.