Polymer precursor-based preparation of carbon nanotube-silicon carbide nanocomposites

Michael D. Clark, Luke S. Walker, Viktor G. Hadjiev, Valery Khabashesku, Erica L Corral, Ramanan Krishnamoorti

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Multiwalled carbon nanotubes were dispersed in a silicon carbide matrix to examine nanotube influence on mechanical properties of the resulting composite. The ceramic matrix was generated through high temperature conversion of poly(methylsilyne), a preceramic polymeric precursor. Nanotube alkylation was explored using two functionalization schemes: organic peroxide workup and alkyllithium displacement of fluorinated nanotubes, which promoted extensive mixing within precursor solutions, thereby ensuring nanotube dispersion within the polymer matrix while facilitating interfacial bonding. The former scheme was less effective at displacing inner nanotube shell bound fluorine and resulted in lower alkyl chain grafting density on the outer shell. Polymer nanocomposites were pyrolyzed and consolidated using an optimized spark plasma sintering scheme to generate fully densified ceramics. The pure polymer-derived ceramic displayed exceptional Young's modulus and Vickers microhardness of 126 ± 12 and 9.6 ± 0.5 GPa, respectively, while maintaining a fracture toughness of 2.8 ± 0.3 MPa·m 1/2. Increased sintering time further augmented the fracture toughness to 3.6 ± 0.4 MPa·m 1/2, approaching the 4 MPa·m 1/2 that characterizes pure silicon carbide, while maintaining both Young's modulus and microhardness. Nanotube addition resulted in some loss of the intrinsic mechanical properties, but enhanced monolith damage tolerance behavior, raising the Vickers indent force needed to induce cracks to an excess of 98.1 N in contrast to the pure polymer-derived sample, which began crack propagation below 49.0 N.

Original languageEnglish (US)
Pages (from-to)328-337
Number of pages10
JournalJournal of the American Ceramic Society
Volume95
Issue number1
DOIs
StatePublished - Jan 2012

Fingerprint

Carbon Nanotubes
Silicon carbide
Nanotubes
Carbon nanotubes
Nanocomposites
Polymers
Microhardness
Fracture toughness
Elastic moduli
Mechanical properties
Damage tolerance
Spark plasma sintering
Fluorine
Multiwalled carbon nanotubes (MWCN)
Peroxides
Alkylation
Polymer matrix
silicon carbide
Crack propagation
Sintering

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

Cite this

Polymer precursor-based preparation of carbon nanotube-silicon carbide nanocomposites. / Clark, Michael D.; Walker, Luke S.; Hadjiev, Viktor G.; Khabashesku, Valery; Corral, Erica L; Krishnamoorti, Ramanan.

In: Journal of the American Ceramic Society, Vol. 95, No. 1, 01.2012, p. 328-337.

Research output: Contribution to journalArticle

Clark, Michael D. ; Walker, Luke S. ; Hadjiev, Viktor G. ; Khabashesku, Valery ; Corral, Erica L ; Krishnamoorti, Ramanan. / Polymer precursor-based preparation of carbon nanotube-silicon carbide nanocomposites. In: Journal of the American Ceramic Society. 2012 ; Vol. 95, No. 1. pp. 328-337.
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