Increasing mechanical resilience and enhanced electrical conductivity through the incorporation of CNF reinforcing additives in PA6 nanocomposites

Abstract

In pursuit of strong, tough, and functional advanced composite materials, a series of polymer nanocomposite blends were prepared from the engineering thermoplastic polyamide 6 (PA6) and increasing admixtures of carbon nanofibers (CNF) up to 8 wt%. The combination of high sheer mixing and solvent processing techniques employed produced free-standing films of 40–60-μm thickness, which were characterized for mechanical performance, dispersion, thermal behavior, and electrical conductivity. The combination of XRD, FTIR, Raman, and SEM analysis supported a dominant α-phase PA6 and good dispersion of the CNF. CNF:PA6 composite films yield an impressive ~ 500% elongation at break for 2 wt% CNF, with more modest increases in tensile strength and elastic modulus over the unmodified PA6. DSC analysis suggests strong interfacial forces between additive and polymer, with a nucleating effect on the formation of crystallites. Increasing CNF loading leads to enhanced thermal stability, and a significant increase in electrical conductivity was observed at low loadings of CNF. These materials show great promise for use in advanced composites applications.