Mechanical and electrical properties of injection-molded mwcnt-reinforced polyamide 66 hybrid composites

The addition of fillers or reinforcements has a direct influence on the mechanical and electrical properties of polymers. Such properties are a function of the morphology and the distribution of fillers in the polymer base. Each feature may have contrasting effects on mechanical and electrical properties. In this study, chopped carbon fiber of different lengths and multiwalled carbon nanotubes (MWCNTs) were added to nylon 6,6. Specimens were manufactured by injection molding of a polyamide/MWCNT masterbatch with the addition of loose chopped carbon fiber. Tensile testing of dogbone specimens was conducted to obtain Young’s modulus, ultimate tensile strength, and elongation. Electrical conductivity testing was conducted on the same specimens prior to mechanical testing. To evaluate the morphology of fillers, scanning electron micrographs were evaluated. Micrographs show the presence of a skin layer close to the surface of the specimens. For this reason, core and surface conductivities were compared. The results show that while promising electrical properties can be achieved by the addition of fillers, the improvement in mechanical properties is minimal.