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Sacrificial bonds in stacked-cup carbon nanofibers: biomimetic toughening mechanisms for composite systems.

Publication ,  Journal Article
Palmeri, MJ; Putz, KW; Brinson, LC
Published in: ACS nano
July 2010

Many natural composites, such as nacre or bone, achieve exceptional toughening enhancements through the rupture of noncovalent secondary bonds between chain segments in the organic phase. This "sacrificial bond" rupture dissipates enormous amounts of energy and reveals significant hidden lengths due to unraveling of the highly coiled macromolecules, leaving the structural integrity of their covalent backbones intact to large extensions. In this work, we present the first evidence of similar sacrificial bond mechanisms in the inorganic phase of composites using inexpensive stacked-cup carbon nanofibers (CNF), which are composed of helically coiled graphene sheets with graphitic spacing between adjacent layers. These CNFs are dispersed in a series of high-performance epoxy systems containing trifunctional and tetrafunctional resins, which are traditionally difficult to toughen in light of their highly cross-linked networks. Nonetheless, the addition of only 0.68 wt % CNF yields toughness enhancements of 43-112% for the various blends. Analysis of the relevant toughening mechanisms reveals two heretofore unseen mechanisms using sacrificial bonds that complement the observed crack deflection, rupture, and debonding/pullout that are common to many composite systems. First, embedded nanofibers can splay discretely between adjacent graphitic layers in the side walls; second, crack-bridging nanofibers can unravel continuously. Both of these mechanisms entail the dissipation of the pi-pi interactions between layers in the side walls without compromising the structural integrity of the graphene sheets. Moreover, increases in electrical conductivity of approximately 7-10 orders of magnitude were found, highlighting the multifunctionality of CNFs as reinforcements for the design of tough, inexpensive nanocomposites with improved electrical properties.

Duke Scholars

Published In

ACS nano

DOI

EISSN

1936-086X

ISSN

1936-0851

Publication Date

July 2010

Volume

4

Issue

7

Start / End Page

4256 / 4264

Related Subject Headings

  • Temperature
  • Surface Properties
  • Nanoscience & Nanotechnology
  • Nanocomposites
  • Mechanical Phenomena
  • Epoxy Resins
  • Carbon
  • Biomimetics
 

Citation

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MLA
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Palmeri, M. J., Putz, K. W., & Brinson, L. C. (2010). Sacrificial bonds in stacked-cup carbon nanofibers: biomimetic toughening mechanisms for composite systems. ACS Nano, 4(7), 4256–4264. https://doi.org/10.1021/nn100661a
Palmeri, Marc J., Karl W. Putz, and L Catherine Brinson. “Sacrificial bonds in stacked-cup carbon nanofibers: biomimetic toughening mechanisms for composite systems.ACS Nano 4, no. 7 (July 2010): 4256–64. https://doi.org/10.1021/nn100661a.
Palmeri, Marc J., et al. “Sacrificial bonds in stacked-cup carbon nanofibers: biomimetic toughening mechanisms for composite systems.ACS Nano, vol. 4, no. 7, July 2010, pp. 4256–64. Epmc, doi:10.1021/nn100661a.
Journal cover image

Published In

ACS nano

DOI

EISSN

1936-086X

ISSN

1936-0851

Publication Date

July 2010

Volume

4

Issue

7

Start / End Page

4256 / 4264

Related Subject Headings

  • Temperature
  • Surface Properties
  • Nanoscience & Nanotechnology
  • Nanocomposites
  • Mechanical Phenomena
  • Epoxy Resins
  • Carbon
  • Biomimetics