Lignin cuts PAN content in carbon fibre

Researchers at Washington University in St. Louis have developed a route in which lignin replaces a substantial share of the polyacrylonitrile (PAN) normally used in carbon fibre. Lignin is generated in large volumes as a by-product of pulp and biorefinery operations. The university reports that PAN use can be cut by half, with corresponding potential reductions in production cost and emissions.

The central technical challenge is mechanical performance. The team functionalises single-walled carbon nanotubes and incorporates them into the lignin-PAN matrix. The nanotubes act as nanoscale reinforcement and promote stronger crystalline alignment during spinning and thermal treatment.

The precursor solution is wet-spun, tension-assisted heat-treated and carbonised. The researchers report that the resulting renewable carbon fibre can reach quality requirements relevant to automotive manufacturing. Aerospace, energy infrastructure, sporting goods and wind energy are cited as additional markets.