Upscaling of lignin precursor melt spinning by bicomponent spinning and its use for carbon fibre production

Abstract

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)’.

Kraft Lignin: A Valuable, Sustainable Resource, Opportunities and Challenges

“…[232] In general, melt-spun, single component, lignin fibers have not yet reached mechanical properties and processing times that can compete with commercial CFs. [233] There have been, however, numerous accounts aimed at improving the processing of lignin for CF production including various pretreatments and purification, [234] chemical modification (e. g., phenolysis, hydrogenolysis and acetylation), [235] chain extension, [236,237] addition of plasticizers, [238] blending with other polymers, such as polypropylene (PP), [239] polyethylene oxide (PEO) polyethylene terephthalate (PET), [240] polyvinyl alcohol (PVA), [241] as well as reinforcing the fibers with clay or carbon nanotubes. [242][243][244][245] Combining lignin with PAN or other polymers is a more recent research direction aimed at capitalizing on its facile spinning, stabilization and regular graphitization and effectively using lignin as the second component.…”

Lignin Modification for Enhanced Performance of Polymer Composites

“…However, under extreme acid treatment conditions, inhibitory compounds such as furfural and hydroxymethylfurfural are produced. 183 Bostan et al 184 the extraction of lignin with methanol yielded a 38.5 wt % fraction with melt-spinningsuitable properties. To facilitate continuous fiber spinning, bicomponent spinning was used.…”

Mechanically recyclable melt-spun fibers from lignin esters and iron oxide nanoparticles: towards circular lignin materials

“…20 Similarly, lignin esters were found to be usable as lubricants and plasticizers, 21 as well as in colored polyesters for containers exhibiting lower UV light transmittance, 22 packaging 18 and components of polystyrene blends. 23 Formulation with lignin-based plasticizers 24 and using solvent-fractionated lignin 25 have been used to achieve spinnability of lignin, but the literature is lacking examples on fiber production using lignin esters. In view of large-scale production, triglyceride oils are among the most plausible sources of C 12 -C 20 fatty acids.…”