Synthese und Charakterisierung von superabsorbierenden Polymeren mit Kern/Schale-Struktur
In the course of this thesis different methods to generate superabsorbents with core/shell structure were employed. These systems were expected to exhibit improved absorbent capabilities in water and in an aqueous saline solution (compared to conventional superabsorbents). By encapsulating uncrosslinked hydrophilic polymers (guar, sodium polyacrylate) with different shell materials (polycyanoacrylate, polyvinylbutyral, crosslinked polyacrylate) it was impossible to generate stable swellable core/shell systems. By embedding sodium chloride into crosslinked sodium polyacrylate so-called osmotic superabsorbents were synthesized. These systems were capable of taking up water not only in form of a swollen polyacrylate gel, but (as a consequence of the osmotic effect of the embedded salt) also in form of an aqueous saline solution in the interior of the particles. Furthermore, by embedding hollow glass spheres into crosslinked sodium polyacrylate superabsorbents were obtained which could take up additional free water between the glass spheres and the polyacrylate matrix. For characterization of the synthesized superabsorbents swelling measurements and NMR spectroscopic investigations were performed.
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