Carbon fibers derived from liquefied and fractionated poplar lignins: The effect of molecular weight

Sagar V Kanhere; Graham W Tindall; Amod A Ogale; Mark C Thies

doi:10.1016/j.isci.2022.105449

Carbon fibers derived from liquefied and fractionated poplar lignins: The effect of molecular weight

iScience. 2022 Oct 29;25(12):105449. doi: 10.1016/j.isci.2022.105449. eCollection 2022 Dec 22.

Authors

Sagar V Kanhere¹, Graham W Tindall¹, Amod A Ogale¹, Mark C Thies¹

Affiliation

¹ Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, SC 29634-0909, USA.

Abstract

Lignin recovered from poplar, a key woody biomass resource proposed for lignocellulosic refineries, was investigated for conversion into carbon fibers. Aqueous solutions of ethanol at selected temperatures and compositions, where the requisite solvent and liquefied-lignin phases form, were used to purify and fractionate hybrid poplar (HP) lignin using the Aqueous Lignin Purification with Hot Agents (ALPHA) process. Sugars (<0.1%) and ash (0.01 ± 0.01%) content of the highest molecular weight fraction (Mw = 52 kDa) approached the limits of detection. This 52 kDa fraction could be dry spun with excellent stability and was subsequently converted into carbon fibers having strength (1.1 ± 0.2 GPa) and modulus (78 ± 8 GPa) essentially double those previously achieved with neat poplar and other hardwood lignins. Of equal importance, stabilization times were decreased by a factor of five. Such stabilization and strength/modulus improvements are essential for reducing the overall manufacturing cost of carbon fibers being proposed for cost-sensitive applications.

Keywords: Chemical engineering; biomass; biotechnology; chemistry.