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Gewählte Doctoral Thesis:

Marco Andreas Beaumont (2017): CHARAKTERISIERUNG UND MODIFIZIERUNG EINES CELLULOSE-II-GELS.
Doctoral Thesis - Abteilung für Chemie nachwachsender Rohstoffe, BOKU-Universität für Bodenkultur, pp 228. UB BOKU obvsg FullText

Abstract:

One of the most pressing issues of today is the global waste challenge. To overcome this challenge the amount of oil-derived and non-degradable plastics in everyday products has to be reduced and renewable and biodegradable polymers must be explored as alternative. Cellulose as the most abundant polymer source shows great promise in this respect. This thesis focuses on a novel nanomaterial from the cellulose II allomorph, namely TENCEL® gel (TENCEL® is a registered trademark of Lenzing AG), its first-time in-depth physicochemical characterization and novel ways for chemical modification. The material is composed of individual microparticles forming particle-like aggregates with a uniform nanostructure consisting of nanofibrils of 40-60 nm diameter. Highly porous aerogels with specific surface areas of up to 423 m2/g were produced from the gel showing high promise as insulating material. The introduction of negative charges onto the amorphous regions of the cellulose II gel via carboxymethylation caused a reorganization into spherical nanoparticles. Dependent on the amount of introduced charges, the particle size was tuned from a mean diameter of 73nm to 129 nm. A novel, straightforward and generally applicable functionalization strategy was established to introduce chemical anchor groups onto never-dried cellulosic surfaces. Based on an aqueous silanization protocol, never-dried nanocelluloses were decorated with azido groups and the resulting functional materials were successfully post-modified by a click chemistry approach. In summary, the economic and straightforward production of this gel, its high surface area and porosity, the possibility to influence its particle size and to derivatize it in non-dried form; make it a promising contribution to the family of nanocelluloses with lots of scientifically interesting and economically feasible future applications.

Betreuer: Rosenau Thomas

1. Berater: Gindl-Altmutter Wolfgang

2. Berater: Liebner Falk