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Novel SiC/C Aerogels Through Pyrolysis of Polycarbosilane Precursors
Author(s) -
Zera Emanuele,
Campostrini Renzo,
Aravind Parakkulam Ramaswamy,
Blum Yigal,
Sorarù Gian Domenico
Publication year - 2014
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201400134
Subject(s) - materials science , hydrosilylation , aerogel , pyrolysis , supercritical fluid , chemical engineering , solvent , porosity , supercritical drying , cyclohexane , carbon fibers , pyrolytic carbon , ceramic , composite material , catalysis , organic chemistry , composite number , chemistry , engineering
A new approach for forming aerogels with various silicon‐based compositions and hybrids between ceramics and carbon has been developed by combining efficient hydrosilylation as the hybridization‐crosslinking approach associated with gelation in the presence of solvent and followed by supercritical drying techniques. Highly porous carbon‐enriched SiC/C aerogels with adequate mechanical durability have been synthesized, pyrolyzed, and characterized. The “wet” gels were obtained by crosslinking a commercial polycarbosilane with divinylbenzene via Pt‐catalyzed hydrosilylation reaction in highly diluted condition (90 vol% of solvent). A supercritical drying was performed after exchanging the solvent (cyclohexane) with liquid CO 2 forming undamaged aerogels. A subsequent pyrolysis and heat treatment (up to 1500 °C) in argon flow converted the polymeric aerogel into a SiC/C‐based material with bulk density of 166 kg m −3 , SSA of 444 m 2 g −1 , a micro‐meso pore volume of 0.79 cm 3 g −1 , total porosity above 90 vol% and ultimate compressive strength of 1.6 MPa. The final product was compared to its cured gel and intermediates obtained during the pyrolysis process.