Foaming of polysiloxane resins with ethanol: a new route to pyrolytic macrocellular SiOC foams

0447628 - ÚMCH 2016 RIV GB eng J - Článek v odborném periodiku
Strachota, Adam - Černý, Martin - Chlup, Zdeněk - Depa, Katarzyna - Šlouf, Miroslav - Sucharda, Zbyněk
Foaming of polysiloxane resins with ethanol: a new route to pyrolytic macrocellular SiOC foams.
Ceramics International. Roč. 41, č. 10 Part A (2015), s. 13561-13571. ISSN 0272-8842. E-ISSN 1873-3956
Grant CEP: GA ČR GAP107/12/2445
Institucionální podpora: RVO:61389013 ; RVO:67985891 ; RVO:68081723
Klíčová slova: silicon oxycarbide * siloxane * foams
Kód oboru RIV: JI - Kompozitní materiály; JH - Keramika, žáruvzdorné materiály a skla (USMH-B); JL - Únava materiálu a lomová mechanika (UFM-A)
Impakt faktor: 2.758, rok: 2015

Polysiloxane foams as precursors to silicon oxycarbide (SiOC) foams were prepared via simultaneous cure and foaming of liquid methylsiloxane resins, using the relatively environment-friendly ethanol as blowing additive of the boiling-solvent-type, and concentrated aqueous ammonia as catalyst. In order to achieve foam regularity, siloxane-based surfactants were added, and bubble nucleation by mechanical stirring was performed. The precursor foams were subsequently pyrolysed in nitrogen at 1000 °C, yielding SiOC foams as end products. The properties of the latter were fine-tuned during the foaming of the precursors, by the amount of added ethanol and by the time of mechanical stirring prior to foaming. The so-obtained SiOC foams displayed densities of 0.17–0.42 g/cm−3, corresponding to macro-porosities of 91–79%, compressive strength of 1–6 MPa, and elastic moduli of 0.2–1.6 GPa.
Trvalý link: http://hdl.handle.net/11104/0251668