Multifunctional nanocomposites based on a polyamide 6/polyamide 12 blend and multi-walled carbon nanotubes

Nanocomposites based on an immiscible blend of polyamide 6 (PA6) and polyamide 12 (PA12) 50/50 wt.% with different contents of multi-walled carbon nanotubes (MWCNTs) were prepared by extrusion followed by compression molding. These materials have been proved to be electrically conductive in previous investigations for the range of filler content assayed. The morphology of the nanocomposites was analyzed using scanning electron microscopy, both on cryo-fractured and postmortem uniaxial tensile samples. Rheological measurements were performed along with differential scanning calorimetry, to assess the materials microstructure and thermal transitions. Furthermore, uniaxial tensile tests were carried out to determine mechanical properties such as stiffness, strength, and strain at break and to investigate the effect of MWCNTs on these properties. Finally, fracture tests were also conducted to evaluate how incorporating MWCNTs affected nanocomposites toughening capabilities. The obtained results suggest a notable improvement in the mechanical properties in the nanocomposites with low amounts of nanofiller. This expands their potential applications as conductive polymer composites (CPCs) and positions them as promising multifunctional materials. Highlights CPCs based on a PA blend and MWCNTs were successfully obtained. CNTs strongly affected the blend morphology and rheological properties. CNTs significantly modified the crystallization behavior of PA6. Ductility greatly improved at low CNT contents but decreased at high loadings. Stiffness increased steadily with increasing CNT content.