Hierarchically ordered micro/meso/macroporous polymer-derived ceramic monoliths fabricated by freeze-casting. Issue 1 (January 2016)

• Record Type: Journal Article
• Authors: Zhang, Huixing; D'Angelo Nunes, Pedro; Wilhelm, Michaela; Rezwan, Kurosch
• Is Part Of: Journal of the European Ceramic Society. Volume 36:Issue 1(2016)
• Page Start: 51
• Page End: 58
• Publication Date: 2016-01
• Subjects: Hierarchical pore structure -- Polysiloxanes -- Freeze casting -- Ice template -- Silicon oxycarbide (SiOC); Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2015.09.018
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: A hierarchically-ordered macro/meso/microporous SiOC monolith was obtained via freeze-casting using commercial polysiloxane as a raw material and silica sol as a binder and template source. The pre-ceramic polymer polysiloxane was pyrolyzed at 600 °C to produce a hydrophilic surface; higher temperatures would fully decompose the organic groups. When silica sol and polysiloxane precursor were combined in freeze-casting method, after pyrolysis a polymer-derived SiOC ceramic monolith with a lamellar pore morphology and a hierarchically-ordered pore structure was obtained. Decomposition of the polysiloxane precursors results in the development of micropores, and particle packing is believed to be responsible for the mesopore formation. Macro/mesoporous hierarchically-ordered ceramics with a specific surface area of 74 m 2 /g are preserved at pyrolysis temperatures as high as 1000 °C. The influence of H44-derived filler amount (10 wt–40 wt%), freezing temperature (−20 °C, −80 °C, −150 °C), and pyrolysis temperature (600 °C, 700 °C, 1000 °C) on open porosity, pore size distribution, and surface characteristics were investigated.