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This dissertation focuses on the field of “bio-materials” based on the renewable resource lignin, attempting to add a higher value to this side product of the paper making process and to find suitable utilizations towards novel applications. At the department of chemistry at TU Darmstadt, lignins from different source and of different quality were characterized and utilized in different applications, such as novel functional lignins or towards the design of lignin‑based polyurethane materials. Detailed characterization techniques were developed for different kinds of lignins with respect to chemical identity, thermal stability or amounts of functional groups accessible for several functionalization reactions. These methods constitute a strategy/toolbox, which enables comparing properties between the raw materials and novel functional lignins. Furthermore, isocyanate functionalizations of various types of lignin were subject of modification experiments. Lignins were “activated” resulting in reactive isocyanate groups, covalently attached to lignins, which are then accessible for further reactions. A new two-step modification strategy towards an aminated lignin, different from the well-known Mannich reaction, was developed. All novel functionalized lignins were characterized in detail, especially regarding the amount of functional groups. First studies aiming for the incorporation of lignins into polyurethanes, towards novel bio‑based materials were also performed. In first attempts lignin as bio‑polyol was inserted into the polyol component of polyurethanes to replace parts of the synthetic polyol matrix. In contrast to this, a new strategy focused on the creation of a prepolymer by forming urethane linkages between the hydroxyl groups of lignin and the isocyanate groups of an excess polyisocyanate. Prepared polyurethanes containing different amounts of lignin as building block were characterized with respect to their future application.

This thesis presents novel pathways for one‑step or two‑step modifications of different types of lignin without the need of any catalyst. Such novel functional lignins were characterized in detail and are now ready for their utilization in novel polymeric materials and thus for new applications. Hereby the value of lignin can be increased by offering novel strategies of incorporating lignins as building block into polyurethanes, but also various other polymer matrices are thinkable for future studies.

Details
Autor Dietz, Jennifer
Lieferzeit 3-4 Tage
Erscheinungsdatum 02.12.2015
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Dietz, Jennifer

Synthesis and Characterization of Novel Functional Lignins – towards Bio-based Polyurethane Materials (E-Book)

ISBN: 978-3-86359-388-9
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Dieses E-Book können Sie hier herunterladen.

This thesis presents novel pathways for one‑step or two‑step modifications of different types of lignin without the need of any catalyst. Such novel functional lignins were characterized in detail and are now ready for their utilization in novel polymeric materials and thus for new applications. Hereby the value of lignin can be increased by offering novel strategies of incorporating lignins as building block into polyurethanes, but also various other polymer matrices are thinkable for future studies.

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