木素分子结构对木素基碳纤维前驱体可纺性的研究

Effect of lignin structure from different raw materials on spinnability of lignin-based carbon fiber precursor

采用芦苇、玉米秸秆酶解残渣和杨木作为原料,经乙醇制浆提取木素,经过乙酸乙酯/乙醚梯度洗涤的方法提纯后,和PEO共混,以DMF为溶剂制备纺丝液,用静电纺丝的方法制备木质素基碳纤维前驱体。研究了来自不同原料的木素的结构特性以及助纺剂PEO的用量对碳纤维前驱体可纺性的影响,结果显示:木素分子量的大小及分散系数,木素结构中愈创木基、侧链基团及乙酰基的含量均对纺丝液可纺性能和碳纤维前驱体的形态产生影响;PL(杨木木素)制备的碳纤维前驱体在木素与PEO比例98∶2时就能形成连续均匀的纤维,而RL(芦苇木素)和C L(玉米秸秆酶解残渣木素)则为96∶4,木材原料木素的可纺性能要优于草类原料。且随PEO用量的加大,碳纤维前驱体的形态特征变好,直径加大,当PEO含量到达4%之后便不再对碳纤维前驱体形态产生影响。

In this study, ethanol-organosolv lignin from reed （RL）, corn stalk （CL） and poplar （PL）, through purified by the methods of ethyl acetate/methyl tert-butyl ether gradient washing, were used to produce carbon fiber precursor by electrospinning of the solution of lignin and high molecular weight poly（ethylene oxide） （PEO） in N,N-dimethylformamide （DMF） solution. The obtained nanofibers were characterized by the technique of SEM. The results of SEM showed that the morphology of carbon fiber precursor was influenced by the molecular weight of lignin and their function group contents. It was found that the RL （reed lignin） or CL （corn stalk enzymolysis residue lignin） samples and PEO with a weight ratio of 96/4 （wt） in DMF solution were successfully spun into fibers. However, for the PL （popular lignin） sample, the weight ratio of lignin to PEO was decreased to 98/2 （wt）. The properties of carbon fiber precursor from hardwood lignin were more excellent than that from grass lignin. With increasing the weight ratio of PEO to lignin, the diameter of prepared fibers was enhanced. Further increasing the weight ratio of PEO to lignin to 4% （wt）, the morphology of carbon fiber precursor was scarcely changed.