Characterization of polymer based nanocomposites with carbon nanotubes.

Abstract

The paper concerns investigation of the processing methods influence on the electrical, thermal and mechanical properties of the polymer matrix nanocomposites with carbon nanotubes (CNTs) as a filler. The focus is put on the relation between microstructure and properties dependently on the parameters of mixing, epoxy matrix curing parameters, neat epoxy resin viscosity, carbon nanotubes modified with different functional groups, as well as carbon nanotubes weight fraction. Nanocomposites with the CNTs varied from 0.05 to 5 wt.% were obtained by dispersion methods such as: mechanical stirring, ultrasonication and combination both of them, as well as calendaring. Three epoxy resin systems were tested, varied in viscosity and curing temperature. Also CNTs nonmodified and modified with amino, carboxyl and hydroxyl groups were used. The choice of the best epoxy resin system and kind of CNTs for fabrication of conductive nanocomposites was done. The lower neat epoxy resin viscosity the better dispersion of CNTs can be achieved. The distribution of CNTs in the epoxy matrix was evaluated using high resolution scanning electron microscopy, supported by image analysis. Electrical conductivity, as well as thermal stability and thermodynamic properties of polymers filled with CNTs were determined. Activation energy of decomposition process was calculated from thermogravimetric curves by Flynn-Wall-Ozawa method. The deterioration of thermal stability was obtained, while mechanical properties increase with the CNTs weight fraction growth up to 0.1%. Calendaring was found as the best method of CNTs dispersion in the polymer matrix.