Mechanical and Electrical Characterization of Polymer Nanocomposites with Carbon Nanotubes

This work has concerned the study of mechanical and electrical properties, carried out on epossidic nanostructured materials, which have the function of coatings for electronic circuits against possible troubles of electromagnetic nature. The effects of concentration and dispersion's degree of carbon nanotubes (Cnts in short) on the tensile strength and electrical conductivity of the nanocomposites were studied. In order to realize these materials we used an epoxy resin (EPIKOTE 828) as matrix, loaded with conductive nanofillers such as Cnts, synthesized with the arc discharge method. We have considered different percentages of the fillers, namely 0.25%, 0.5%, 0.75% and 1% wt (percentages valued in comparison to the weight of the resin). With the increase of Cnts, the electrical conductivity of composites increases, while the tensile strength values are higher when the content of Cnts is 0.50% and 1% wt; hence for these concentrations we considered appropriate to estimate also the values of resilience and Young's modulus. It was observed that for all the mechanical tests, the percentage that gave satisfactory results was 0.50% wt. At this point, in order to evaluate the efficiency of this concentration, graphite and carbon black were taken as referencing fillers, on which both mechanical and electrical tests were carried out. The results of mechanical tests have showed that, although the introduction of fillers inside the matrix, of whatever nature (Cnts, carbon black, graphite), does not improve its mechanical properties, at equal concentrations composites loaded with Cnts gave better results. Moreover, as regards the results obtained from electrical tests in direct current, we can observe that, also in this case, at equal concentrations of 0.5% wt. our nanotubes endow the composite with larger values of the electrical conductivity, in comparison with carbon black and graphite.