Kevin White - Electrical conductivity and fracture behavior of epoxy/polyamide-12/multi-walled carbon nanotube composites

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      Publication Details (including relevant citation   information):

      Kevin L White and Hung-Jue Sue, Polym Eng Sci, In Press.


      Untreated multi-walled carbon nanotubes (MWCNTs) were   incorporated into a brittle epoxy matrix at 1 wt.% by solvent   evaporation and showed significant gains in tensile strength,   strain at break, and electrical conductivity.  However, only   fractional improvement in fracture toughness was observed.    In order to improve fracture toughness, 10 µm polyamide-12 (PA)   preformed particles were added at 20 wt.% loading.  The PA   particles were observed to aid in the dispersion of MWCNTs,   reducing most of the large MWCNT clusters to sub-micron   sizes.  The epoxy/PA/MWCNT ternary composite exhibits an   increased electrical percolation threshold, but nearly identical   electrical scaling behavior as the epoxy/MWCNT composite.    The similarity in percolation parameters suggest conduction   occurs by efficient electron transport through MWCNT clusters,   rather than pathways composed of individual tubes.  The   ternary composite also shows significant improvements in strain   at break and fracture toughness due to synergistic interaction   between filler phases.  The usefulness of this ternary   composite approach in vacuum-assisted resin transfer molding for   advanced composite applications is discussed.

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