title: Polymer-Schichtsilikat-Nanokomposite : die Allrounder ; Vom Lebensmittelregal bis in den Weltraum?
Creators: name: Habel, Christoph
Publisher: name: University of Bayreuth
Year: 2021
Subjects: subject: Schichtsilikat
subject: Hectorit
subject: Nanokomposite
subject: Gasbarriere
subject: Beschichtung
subject: 540

description: Within the scope of this work, it was accomplished to produce (bio-) nanocomposites/hybrids based on synthetic layered silicates. These can be used in various low- and high-tech applications due to their versatile characteristics. The main focus was on the barrier properties of these polymeric layered silicate nanocomposites/hybrids. In addition to the determination of suitable manufacturing processes and the research of multi-functional properties, which are of interest for a wide range of applications, a deeper understanding of the influence of layered silicates as fillers on various resulting (composite/polymer) properties was gained. The solvent route used in this work initially made it possible to produce delaminated layered silicate lamellae, polymeric dispersions. These dispersions can then be further processed by doctor blading or spray coating. In the course of this work, a combined production process of electrospinning and filtration was developed to reduce the production time and increase the drying efficiency. By creating a sandwich structure and subsequent hot pressing, it was possible to produce transparent nanocomposite membranes with improved mechanical and barrier properties. As already mentioned, spray coating represents a further processing option. This was used in another project to produce a biopolymer layered silicate nanocomposite barrier coating. Especially in the field of food packaging, barrier properties play an important role in terms of food shelf life. Biopolymers, which are considered environmentally friendly alternatives for current petro-based commercial packaging materials, often do not show the desired properties. In this thesis, a water-based thin biopolymer nanocomposite coating was successfully produced, which makes the biopolymer-substrate a competitive sustainable alternative due to the resulting competitive barrier and optical properties, the predominant flexibility and the anti-colonization potential. However, barrier properties do not only play a major role in the field of food packaging. Highly diffusive gases such as hydrogen, or even helium, are particularly important in the aerospace industry. A water-based high-barrier nanocomposite liner against helium and hydrogen has been developed, which can be used as a barrier coating in lighter-than-air vehicles or space technology. Additionally, the flexibility and competitive barrier properties even outperform high barrier polymers. The developed system is particularly convincing due to its low application weight, which is of enormous relevance especially in lightweight construction applications. In many fields of application, it is necessary that the above-mentioned barrier properties are maintained even at high humidity levels. For this purpose, copolymers with varying hydrophobic components are often used to control the swelling behavior and thus the barrier properties. Fillers can also change this swelling behavior. Within the scope of this work, a perfectly structured polymer hybrid was produced, which served as a model system to work out a detailed relationship between the filler content, the dependence of the barrier properties on the humidity and the impact of the confinement effect due to high filler contents. But not only the impermeability of the layered silicates has a positive influence on the barrier properties. Crystalline areas in polymers are also considered impermeable to gases and water vapor. Using a water-based polymer, the interplay of the nucleation and confinement effect based on the filler content of the layered silicates could be worked out. By varying the filler content, it was thus possible to produce nanocomposites with tailor-made crystallinity. The present work is a cumulative thesis. Therefore, all results are presented in the attached publications.