Melt‐spinning of carboxylated MWNTs‐reinforced polyamide 6 fibers with solid mixing nanocomposites

Nanocomposite fibers of carboxylated multiwalled carbon nanotubes (MWNTs-COOH)-reinforced polyamide 6 (PA6), which have good mechanical properties, were fabricated by a ball-milling and melt spinning process. The ball-milling method was used to prepare PA6/MWNTs-COOH nanocomposite powders to address the key issue of dispersing MWNTs-COOH into the PA6 matrix uniformly. The effects of both the milling time and MWNTs-COOH loading on the mechanical properties of PA6/MWNTs-COOH nanocomposite fibers were investigated. Transmission electron microscopy, Raman spectroscopy, and X-ray diffraction were used to study the morphology and microstructure of MWNTs-COOH in compound powders after ball-milling. Scanning electron microscopy micrographs indicated that secondary agglomeration of MWNTs-COOH occurred after ball-milling for 5 h, and the best dispersing time was 3 h. The mechanical properties of the nanocomposite fibers fabricated by ball-milling were much higher than those of the control and composites fabricated by conventional melt mixing. The results of the differential scanning calorimetry revealed the close relationship between the dispersibility and crystallinity. This method, which does not require the use of solvent, has great potential for industrial application. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers