Microwave-Assisted Fractionation and Functionalization of Technical Lignin Towards Thermoset Resins

KTH, Ytbehandlingsteknik KTH, Wallenberg Wood Science Center KTH, Polymerteknologi

Lignin is the main source of aromatic natural polymers, with a potential to serve as a building block of rigid and thermally stable bio-based materials. However, because of its heterogeneity differences and not fully understood chemical structure it is still underutilized. Therefore, in this paper, technical softwood Kraft lignin is refined in to narrow-dispersity and relatively low molecular weight fractions by microwave-assisted processing. This process was carried out under non-catalytic conditions using a low boiling point solvent and higher pressure. The chemical properties of the retrieved fractions were investigated by 31P NMR, HSQC NMR, SEC, DSC, and TGA. One of the retrieved soluble lignin fractions was successfully chemically modified by microwave processing. The chemically modified lignin was characterized by 31P NMR and FTIR, which provided evidence of the introduction of the allyl moieties. Subsequently, the allylated lignin was cross-linked through thermally induced thiol-ene chemistry to produce lignin-based thermosets.
QC 20230524

Softwood lignin; microwave-assisted fractionation; microwave-assisted functionalization; allylation; thiol-ene thermosets.; Polymer Chemistry; Polymerkemi; Polymer Technologies; Polymerteknologi; Paper, Pulp and Fiber Technology; Pappers-, massa- och fiberteknik; Manuscript (preprint); info:eu-repo/semantics/preprint; text

Open access content. Open access content

English

UPE oai:DiVA.org:kth-327223
0000-0002-1184-1310
0000-0002-8127-9183
0000-0002-6313-8539
0000-0002-7790-8987
0000-0003-3201-5138
1400069685

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