Effect of Loading Concentration on the Electrical and Hardness Properties of MWCNT/Epoxy Nanocomposites

Abstract

Carbon nanotubes have excellent mechanical and electrical properties, and are also a good reinforcement material for composites than conventional materials. The matrix used in this study was epoxy and reinforcement filler in multi-walled carbon nanotubes (MWCNTs). The different MWCNTs loading concentrations (0 ~ 10 wt. %) were added into the epoxy resin. The dispersion of MWCNTs in epoxy resin was conducted using high speed mixer through mechanical shearing mechanism. The mixture of epoxy/MWNTs suspension was poured into the mold and compression molding was conducted for fabrication of MWCNTs/epoxy nanocomposites. The electrical conductivity of nanocomposite by variation of CNTs concentration was measured by the four point probe. Dispersion state of CNTs in epoxy matrix was observed on fractured surface by scanning electron microscopic. Hardness of the composite was tested using the Dinamic Ultra Micro Hardness machine. Non conductive epoxy polymer becomes conductor as addition of CNTs.. Electrical conductivity of nanocomposite plates increased with increasing CNTs concentration. Agglomerations of CNTs were observed on fractured surfaces. This phenomenon due to CNTs which used in this study was at as produced state where no modification is being done on it. Long and entanglement of individual CNTs easily lead to agglomerations. Van de Wall’s force interactions between CNTs also contribute to the agglomerations of CNTs. Hardness of the composite increases with the CNTs loading concentrations until it reaches a maximum peak at the composition of 5wt% of CNTs but the hardness decreases rapidly with loading greater than 5wt% of CNTs.