Fabrication of polymer-derived ceramics with hierarchical porosities by freeze casting assisted by thiol-ene click chemistry and HF etching
- The freeze casting technique assisted with cryo thiol-ene photopolymerization is successfully employed for the fabrication of macroporous polymer-derived silicon oxycarbide with highly aligned porosity. It is demonstrated that the free radical initiated thiol-ene click reaction effectively cross-linked the vinyl-containing liquid polysiloxanes into infusible thermosets even at low temperatures. Furthermore, mixed solution- and suspension-based freeze casting is employed by adding silica nanopowders. SiOC/SiO2 foams with almost perfect cylindrical shapes are obtained, demonstrating that the presence of nano-SiO2 does not restrict the complete photoinduced cross-linking. The post-pyrolysis HF acid treatments of produced SiOC monoliths yields hierarchical porosities, with SiOC/SiO2 nanocomposites after etching demonstrating the highest specific surface area of 494 m2/g and pore sizes across the macro-, meso- and micropores ranges. The newly developed approach gives a versatile solutionThe freeze casting technique assisted with cryo thiol-ene photopolymerization is successfully employed for the fabrication of macroporous polymer-derived silicon oxycarbide with highly aligned porosity. It is demonstrated that the free radical initiated thiol-ene click reaction effectively cross-linked the vinyl-containing liquid polysiloxanes into infusible thermosets even at low temperatures. Furthermore, mixed solution- and suspension-based freeze casting is employed by adding silica nanopowders. SiOC/SiO2 foams with almost perfect cylindrical shapes are obtained, demonstrating that the presence of nano-SiO2 does not restrict the complete photoinduced cross-linking. The post-pyrolysis HF acid treatments of produced SiOC monoliths yields hierarchical porosities, with SiOC/SiO2 nanocomposites after etching demonstrating the highest specific surface area of 494 m2/g and pore sizes across the macro-, meso- and micropores ranges. The newly developed approach gives a versatile solution for the fabrication of bulk polymer-derived ceramics with controlled porosity.…
Autor*innen: | X. Wang, Franziska Schmidt, A. Gurlo |
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Dokumenttyp: | Zeitschriftenartikel |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | Journal of the European Ceramic Society |
Jahr der Erstveröffentlichung: | 2019 |
Organisationseinheit der BAM: | 5 Werkstofftechnik |
5 Werkstofftechnik / 5.4 Multimateriale Fertigungsprozesse | |
Verlag: | Elsevier |
Jahrgang/Band: | 40 |
Ausgabe/Heft: | 2 |
Erste Seite: | 315 |
Letzte Seite: | 323 |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten |
Freie Schlagwörter: | Freeze casting; Frozen state photopolymerization; Hierarchical porosities; Preceramic polymer; Thiol-ene click chemistry |
Themenfelder/Aktivitätsfelder der BAM: | Material |
Material / Nano | |
DOI: | 10.1016/j.jeurceramsoc.2019.09.038 |
ISSN: | 0955-2219 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 01.10.2019 |
Referierte Publikation: | Ja |
Datum der Eintragung als referierte Publikation: | 09.12.2019 |