Different experimental procedures were investigated for incorporating Multi Walled Carbon nano-tubes (MWCNT) into epoxy diglycidil-ether bisphenol-A(DGEBA), cured with 4,4 diamine-dibenzyl-sulfone (DDS): (i) mechanical mixing; (ii) high energy ball milling; (iii) ultrasonication. The mechanical properties of the obtained samples were monitored and used in order to guide the selection of the most promising composite system. The best results were obtained by using, as method of incorporation of CNT in the resin, sonication for 20 minutes. Resins with increasing MWCNT concentration were prepared and the thermal properties analyzed, showing a slight improvement in either the glass transition or the degradation temperature. The electrical conductivity of the selected composite system is characterised by a percolation threshold (lower than 0.1%) comparable to that found for similar systems, but beyond threshold it assumes greater values. The conductivity is characterised by only a slight increase with temperature in the range 30–90 C. The positive temperature coefficient can be related to a decrease of the small gaps separating the CNTs clusters. A simple power law describes the relation between the composite conductivity and CNT concentration near the percolation threshold. A dependence of all the parameters of the power law on the temperature has also been evidenced, and it should be properly considered and indicated when using such a model in describing the behaviour of composites near the percolation threshold.

Cure Behavior and Physical Properties of Epoxy Resin—Filled with Multiwalled Carbon Nanotubes

GUADAGNO, Liberata;NADDEO, Carlo;VITTORIA, Vittoria;SORRENTINO, Andrea;VERTUCCIO, LUIGI;RAIMONDO, MARIALUIGIA;TUCCI, Vincenzo;DE VIVO, BIAGIO;LAMBERTI, PATRIZIA;
2010

Abstract

Different experimental procedures were investigated for incorporating Multi Walled Carbon nano-tubes (MWCNT) into epoxy diglycidil-ether bisphenol-A(DGEBA), cured with 4,4 diamine-dibenzyl-sulfone (DDS): (i) mechanical mixing; (ii) high energy ball milling; (iii) ultrasonication. The mechanical properties of the obtained samples were monitored and used in order to guide the selection of the most promising composite system. The best results were obtained by using, as method of incorporation of CNT in the resin, sonication for 20 minutes. Resins with increasing MWCNT concentration were prepared and the thermal properties analyzed, showing a slight improvement in either the glass transition or the degradation temperature. The electrical conductivity of the selected composite system is characterised by a percolation threshold (lower than 0.1%) comparable to that found for similar systems, but beyond threshold it assumes greater values. The conductivity is characterised by only a slight increase with temperature in the range 30–90 C. The positive temperature coefficient can be related to a decrease of the small gaps separating the CNTs clusters. A simple power law describes the relation between the composite conductivity and CNT concentration near the percolation threshold. A dependence of all the parameters of the power law on the temperature has also been evidenced, and it should be properly considered and indicated when using such a model in describing the behaviour of composites near the percolation threshold.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11386/2261777
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