Influence of Melt Viscosity on the Structure and Properties of Electrically Conductive Nanocomposites Produced by Masterbatch Process

Electrically conductive polypropylene nanocomposites containing multi-walled carbon nanotubes were produced by melt blending by dilution of a concentrate masterbatch containing 10 wt.% of filler. In order to promote polymer infiltration within primary agglomerates a ultra-low melt viscosity polypropylene grade has been used for masterbatch production. Moreover, three polypropylenes with different melt viscosities have been used for successive dilutions. Filler dispersion has been assessed by both indirect macroscale analyses and direct morphological investigations. Characterization showed percolation thresholds occurring for very low filler contents. During dilution, lower polymer viscosities lead to more effective residue agglomerates dispersion, hence better electrical properties.