Carbon Materials from Lignin and Sodium Lignosulfonate via Diisocyanate Cross-Linking and Subsequent Carbonization
Sprache des Titels:
Englisch
Original Kurzfassung:
Applications for lignin and lignosulfonates are limited today due to the undefined
structure and varying properties of the substance. However, lignin, as the second most
abundant bio-resource besides cellulose and the bio-resource with one of the highest natural
carbon contents, has the potential to act as a precursor for carbon materials. In this study we
have applied a Kraft lignin and a sodium lignosulfonate with the cross-linker
toluene-2,4-diisocyanate. The reaction mixture was molded to form small cylindrical shaped
paddings. Cross-linked lignin-polyurethane and lignosulfonate-polyurethane networks were
analyzed via elemental analysis and thermogravimetric analysis and finally carbonized. The
carbon material was analyzed for its BET surface area and its surface structure via scanning
electron microscopy. Surface areas between 70 and 80 m²·g?1 could be reached. Moreover,
the material was tested for its adsorption potential of crude oil from water and could take up
to twice its own weight. For better understanding of the core chemistry of the cross-linking
reaction, we have studied the reaction with model substances to define the reactive groups and
the influence of sulfonate groups in the cross-linking reaction of lignin and lignosulfonates
with toluene-2,4-diisocyanate.