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Nanostructure and Energetics of Carbon-Rich SiCN Ceramics Derived from Polysilylcarbodiimides: Role of the Nanodomain Interfaces

Widgeon, S. ; Mera, G. ; Gao, Y. ; Stoyanov, E. ; Sen, S. ; Navrotsky, A. ; Riedel, R. (2012):
Nanostructure and Energetics of Carbon-Rich SiCN Ceramics Derived from Polysilylcarbodiimides: Role of the Nanodomain Interfaces.
In: Chemistry of Materials, 24 (6), pp. 1181-1191. ACS, ISSN 0897-4756,
[Article]

Abstract

SiCN polymer-derived ceramics (PDCs) with different carbon contents have been synthesized by pyrolysis of poly(phenylvinylsilylcarbodiimide) and of poly(phenylsilsesquicarbodiimide), and their structure and energetics have been studied using 29Si, 13C, 15N, and 1H solid state nuclear magnetic resonance (NMR) spectroscopy and oxide melt solution calorimetry. The structure of these PDCs at lower carbon content (35–40 wt %) and pyrolysis temperatures (800 °C) consists primarily of amorphous nanodomains of sp2 carbon and silicon nitride with an interfacial region characterized by mixed bonding between N, C, and Si atoms that is likely stabilized by the presence of hydrogen. The average size of the carbon domains increases with increasing carbon content, and a continuously connected amorphous carbon matrix is formed in PDCs with 55–60 wt % C. The interfacial silicon–carbon and nitrogen–carbon bonds are destroyed with concomitant hydrogen loss upon increasing the pyrolysis temperature to 1100 °C. Calorimetry results demonstrate that the mixed bonding between C, N, and Si atoms in the interfacial regions play a key role in the thermodynamic stabilization of these PDC. They become energetically less stable with increasing annealing temperature and concomitant decrease of mixed bonds and hydrogen loss.

Item Type: Article
Erschienen: 2012
Creators: Widgeon, S. ; Mera, G. ; Gao, Y. ; Stoyanov, E. ; Sen, S. ; Navrotsky, A. ; Riedel, R.
Title: Nanostructure and Energetics of Carbon-Rich SiCN Ceramics Derived from Polysilylcarbodiimides: Role of the Nanodomain Interfaces
Language: English
Abstract:

SiCN polymer-derived ceramics (PDCs) with different carbon contents have been synthesized by pyrolysis of poly(phenylvinylsilylcarbodiimide) and of poly(phenylsilsesquicarbodiimide), and their structure and energetics have been studied using 29Si, 13C, 15N, and 1H solid state nuclear magnetic resonance (NMR) spectroscopy and oxide melt solution calorimetry. The structure of these PDCs at lower carbon content (35–40 wt %) and pyrolysis temperatures (800 °C) consists primarily of amorphous nanodomains of sp2 carbon and silicon nitride with an interfacial region characterized by mixed bonding between N, C, and Si atoms that is likely stabilized by the presence of hydrogen. The average size of the carbon domains increases with increasing carbon content, and a continuously connected amorphous carbon matrix is formed in PDCs with 55–60 wt % C. The interfacial silicon–carbon and nitrogen–carbon bonds are destroyed with concomitant hydrogen loss upon increasing the pyrolysis temperature to 1100 °C. Calorimetry results demonstrate that the mixed bonding between C, N, and Si atoms in the interfacial regions play a key role in the thermodynamic stabilization of these PDC. They become energetically less stable with increasing annealing temperature and concomitant decrease of mixed bonds and hydrogen loss.

Journal or Publication Title: Chemistry of Materials
Journal volume: 24
Number: 6
Publisher: ACS
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 02 Apr 2012 08:41
Official URL: http://dx.doi.org/10.1021/cm2038238
Identification Number: doi:10.1021/cm2038238
Alternative keywords:
Alternative keywordsLanguage
polymer-derived ceramics; polysilylcarbodiimide; SiCN; NMR spectroscopy; calorimetry; interface; structure; energetics; nanodomainEnglish
Funders: National Science Foundation (NSF MWN-0906070)-Deutsche Forschungsgemeinschasft materials collaborative project “Nanostructure and thermodynamics of polymer-derived ceramics”, financial support by the Fonds der Chemischen Industrie, Frankfurt (Germany)
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