At present, most carbon fibers are made from non-renewable polyacrylonitrile. Substantial efforts have been made to replace petroleum-based precursors for carbon fiber production. Interestingly, lignin is a carbon fiber precursor material that is cheap, highly available and sustainable. Submicron-scale lignin-based carbon nanofibers are used in numerous areas, such as electronic devices, batteries, supercapacitors and low-cost, high-performance structural composite materials. Trackspinning (TS) technology offers a way to scale up the versatile, but inefficient contact drawing technique to produce small-diameter lignin fibers from environmentally friendly aqueous solutions. In this study, the effects of TS based on probe drawing of low-concentration lignin nanofibers blended with poly(ethylene oxide) and glycerol in sodium hydroxide (NaOH) solution were investigated. The TS lignin fibers were well aligned and reached diameters as small as 500–1000 nm as the drawing length was increased. Lignin fiber macromolecular alignment was isotropic at low levels of draw, and the dichroic ratio increased from 1 to 2.25 with doubling of the drawing length. The most highly drawn trackspun lignin fibers had a mechanical strength of 3.92 MPa and a Young’s modulus of 2.15 GPa, which were similar to reported values for solvent-electrospun lignin nanofibers. These findings support the potential to utilize TS to produce small-diameter lignin fibers using a simple aqueous solvent approach.

中文翻译：

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作为绿色碳纳米纤维前体的对齐木质素纤维的自动履带纺丝

目前，大多数碳纤维是由不可再生的聚丙烯腈制成的。人们已经做出了大量努力来替代碳纤维生产中的石油基前体。有趣的是，木质素是一种廉价、高度可用且可持续的碳纤维前体材料。亚微米级木质素基碳纳米纤维广泛应用于电子设备、电池、超级电容器和低成本、高性能结构复合材料等领域。履带纺纱 (TS) 技术提供了一种扩大通用但效率低下的接触拉伸技术的方法，以利用环保的水溶液生产小直径木质素纤维。在本研究中，研究了基于探针拉伸的 TS 对与聚环氧乙烷和甘油在氢氧化钠 (NaOH) 溶液中混合的低浓度木质素纳米纤维的影响。随着拉丝长度的增加，TS 木质素纤维排列良好，直径可小至 500-1000 nm。木质素纤维大分子排列在低拉伸水平下是各向同性的，并且随着拉伸长度加倍，二色性比从1增加到2.25。最高度拉伸的径纺木质素纤维的机械强度为 3.92MPa，杨氏模量为 2.15GPa，与溶剂电纺木质素纳米纤维的报道值相似。这些发现支持利用 TS 通过简单的水溶剂方法生产小直径木质素纤维的潜力。