Upscaling lignin-based precursor fibre production is an essential step in developing bio-based carbon fibre from renewable feedstock. The main challenge in upscaling of lignin fibre production by melt spinning is its melt behaviour and rheological properties, which differ from common synthetic polymers used in melt spinning. Here, a new approach in melt spinning of lignin, using a spin carrier system for producing bicomponent fibres, has been introduced. An ethanol extracted lignin fraction from LignoBoost process of commercial softwood kraft black liquor was used as feedstock. After additional heat treatment, melt spinning was performed in a pilot-scale spinning unit. For the first time, biodegradable polyvinyl alcohol (PVA) was used as a spin carrier to enable the spinning of lignin by improving the required melt strength. PVA-sheath/lignin-core bicomponent fibres were manufactured. Afterwards, PVA was dissolved by washing with water. Pure lignin fibres were stabilized and carbonized, and tensile properties were measured. The measured properties, tensile modulus of 81.1 ± 3.1 GPa and tensile strength of 1039 ± 197 MPa, are higher than the majority of lignin-based carbon fibres reported in the literature. This new approach can significantly improve the melt spinning of lignin and solve problems related to poor spinnability of lignin and results in the production of high-quality lignin-based carbon fibres.

This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)’.

升级木质素基前体纤维的生产是从可再生原料开发生物基碳纤维的重要一步。通过熔体纺丝生产木质素纤维的主要挑战是其熔体行为和流变特性，这与熔体纺丝中使用的普通合成聚合物不同。在这里，介绍了一种使用纺丝载体系统生产双组分纤维的木质素熔融纺丝的新方法。来自商业软木硫酸盐黑液的 LignoBoost 工艺的乙醇提取木质素部分用作原料。在额外的热处理之后，在中试规模的纺丝装置中进行熔体纺丝。首次使用可生物降解的聚乙烯醇 (PVA) 作为纺丝载体，通过提高所需的熔体强度来实现木质素的纺丝。制造了 PVA-鞘/木质素-芯双组分纤维。然后，通过用水洗涤溶解PVA。纯木质素纤维被稳定和碳化，并测量拉伸性能。测得的性能、81.1 ± 3.1 GPa 的拉伸模量和 1039 ± 197 MPa 的拉伸强度高于文献中报道的大多数木质素基碳纤维。这种新方法可以显着改善木质素的熔融纺丝，解决与木质素可纺性差相关的问题，从而生产出高质量的木质素基碳纤维。1 GPa 和 1039 ± 197 MPa 的拉伸强度高于文献中报道的大多数木质素基碳纤维。这种新方法可以显着改善木质素的熔融纺丝，解决与木质素可纺性差相关的问题，从而生产出高质量的木质素基碳纤维。1 GPa 和 1039 ± 197 MPa 的拉伸强度高于文献中报道的大多数木质素基碳纤维。这种新方法可以显着改善木质素的熔融纺丝，解决与木质素可纺性差相关的问题，从而生产出高质量的木质素基碳纤维。

本文是主题问题“用于新兴技术的生物衍生和仿生可持续先进材料（第 2 部分）”的一部分。