Lignin Structure and Aggregation Behavior in a Two-Component Ionic Liquid Solvent System
2014 (English)In: BioResources, ISSN 1930-2126, Vol. 9, no 4, 6002-6018 p.Article in journal (Refereed) Published
Ionic liquids are of potential interest in the processing of lignocellulosic biomass. In this study, the ionic liquid co-solvent system of 1-methylimidazole (MIM) and 1-ethyl-3-methyl-imidazolium acetate (EMIMAc) was used to solvate LignoBoost lignin fractionated from black liquor obtained from a kraft paper mill. Lignin ethanol-precipitated (LEP) and ethanol-soluble (LES) fractions were characterized via gel permeation chromatography (GPC) and C-13- and P-31-nuclear magnetic resonance spectroscopy (NMR) to determine structural characteristics and their relationship to polymer solubility in the system. Polymer integrity and solubility were optimal at -20% lignin loading (w/w). Results showed that LEPs were generally of higher apparent molecular weight (Mw) and enriched with condensed/aliphatic ether linkages and aliphatic hydroxyls. The LESs had a lower apparent Mw and were enriched with carboxylic and phenolic groups. This newly gained knowledge on lignin fractionation and aggregation in the present solvent system provides future opportunities for tuning fractionation/extraction to suit a specific biomass-derived product, e.g., carbon fibers.
Place, publisher, year, edition, pages
2014. Vol. 9, no 4, 6002-6018 p.
Lignin, Ionic liquids, Biomass, GPC, NMR
Paper, Pulp and Fiber Technology
IdentifiersURN: urn:nbn:se:kth:diva-158448ISI: 000345396900022ScopusID: 2-s2.0-84911396979OAI: oai:DiVA.org:kth-158448DiVA: diva2:777155
QC 201501082015-01-082015-01-082015-01-08Bibliographically approved