Processing and characterization of thermoplastic nanocomposite fibers of hot melt copolyamide and carbon nanotubes

In this study, thermoplastic nanocomposite fibers based on hot melt copolyamide and multi-walled carbon nanotubes (MWCTs) were fabricated with a two-step approach. In the first step, a masterbatch containing 20 wt% MWCTs was diluted by pure hot melts to produce nanocomposite pellets with 2, 4, and 6 wt% MWCTs. In the second step, nanocomposite fibers were extruded and drawn from the fabricated pellets. The selected processing conditions resulted in fibers with an average diameter of 80 m. Rheological behavior of hot melt copolyamide changes dramatically after the addition of carbon nanotubes (CNTs). Crystallinity content expressed by enthalpy of melting is higher in the fibers than in the pellets. Microscopic examination shows that MWCTs are randomly oriented in the direction of the extrusion. The mechanical performance of the fibers shows decreased elongation at break for fibers with MWCTs and an increase in Young's modulus. A strong influence of fiber surface quality on mechanical properties was also indicated. Thermoplastic nanocomposites fibers with MWCTs, based on hot melt copolyamide, are a new group of materials that can be applied as multifunctional composites for aviation, automotive, military, medical and electronic industries due to their adhesive properties, low melting range as well as electrical properties.