On the elongated domains in electrospun nanofibers of polyamide-6 blends

Wereport analysis of electrospun polymer nanofibers fabricated from blends of semicrystalline polyamide-6 (PA-6) and fully amorphous polyamide-6 (PA-6I) in the narrow diameter range of 200.250 nm. The combined differential scanning calorimetry and wide angle x-ray scattering results show the presence of α-and γ-phase crystals in PA-6 nanofibers. Simultaneous small-and wide-angle x-ray scattering investigations confirmed the existence of small elongated domains which were formed during the electrospinning process due to stretching of polymer chains. The Debye. Bueche analysis determined a cross-sectional width of elongated domains in the range of 10.8.16 A. Additionally, analysis by Ruland's method revealed a decrease in the length of elongated domains with increasing crystalline phase content in the blends. Evaluation of Herman's orientation function suggested that the domains possessed higher molecular anisotropy along the c-axis in PA-6I compared to PA-6 nanofibers. These investigations and the suggested role of the amorphous phase in molecular stretching of polymer chains in electrospun nanofibers, may have broad implications for the sizedependent mechanical properties.