Electrical Conductivity and Linear Rheology of Multiwalled Carbon Nanotube/Acrylonitrile Butadiene Styrene Polymer Nanocomposites Prepared by Melt Mixing and Solution Casting

Abstract

Polymer nanocomposites are potential materials for three dimensional (3d) printing of functional components. For effective 3d printing, besides ensuring high conductivity of the nanocomposites, their flow characteristics also need careful adjustment. To satisfy the contradictory requirements, multiwalled carbon nanotubes (MWCNT) have emerged as an attractive option. As the dispersion of the MWCNT is believed to strongly influence the properties of the nanocomposites, we compared nanocomposites prepared using melt mixing and solution casting. The MWCNT endow the nanocomposites with appreciable conductivity even at relatively low loadings. At these loadings, the low frequency storage modulus indicates that the MWCNT impart solid-like character to the nanocomposites. While the conductivity percolation threshold of the nanocomposites prepared by melt mixing was lower, at higher loadings the conductivity of the nanocomposites prepared by the two methods were similar. Fitting the electrical conductivity and the linear viscoelastic storage modulus to power-laws, the obtained critical exponents for the two methods were close to each other and to the percolation theory predictions for the conductivity exponent. Our findings suggest that for MWCNT/ABS polymer nanocomposites, simple melt mixing can yield conductivities that are similar to that obtained by solution casting and close to the highest values reported in the literature.