Tailoring Kraft Lignin for Suitability in Material Synthesis

Purpose and goal

** Denna text är maskinöversatt ** Kraft Lignin has great potential for applications in material systems, however, it is very heterogeneous in terms of size, functionalities and structure. This limits possibilities for the synthesis of homogeneous materials directly from it. The aim of the project was to make the lignin more homogeneous and thus more attractive for applications in material systems. In this study, we have discovered hitherto unknown mechanistic sequences involved in the formation of the kraft lignin, which can lead to process modifications/ development

Expected results and effects

Complex mechanisms that lead to the heterogeneity of Kraft lignin have been identified. The new structures formed by these mechanisms contribute to homogeneity of functionalities which is desirable in material synthesis. Furthermore, they provide a certain degree of stiffness to the molecule which can also be used in materials where such effects are desired. In addition, knowing how the reactions that lead to these structures takes place gives us the opportunity to modify the production process. The work has resulted in two scientific publications in a well-credited journal.

Planned approach and implementation

The strategy was to first fractionate the parent Kraft lignin by use of green solvents, to facilitate the analysis of different structural populations. Then, advanced chemical analyses such as NMR spectroscopy, gas chromatography and size exclusion chromatography were performed. These analyses provide information on the structure, functionality and size of the molecules. Then they are used to decipher chemical reaction mechanisms. These are also supported by model compound studies.