Cross-sectional images of as-spun
and drawn PTT fibers were obtained by field emission scanning electron microscopy (FE-SEM) measurements using a Hitachi electron microscope S-5000 operated at 18 keV, and were captured with 300, 1250, and 1500 magnification.
The value of 26.2 MG.Oe found for as-spun
[Pr.sub.8] [Fe.sub.75][Co.sub.10]N[b.sub.B5]C can be assumed to originate from the doped Pr, Co, Nb, and C elements and the homogeneous distribution of NbC phase at grain boundaries of the hard magnetic grains .
Figures 3 and 4 show SEM images and corresponding calculated particle size distribution of the as-spun
and calcined nanofibers.
As much solvent has been separated from the as-spun
gel fibers when quenched to room temperature, only residual PB in the gel fiber is extracted to obtain precursor fibers.
fibers were transferred to glass sides and dried for 24 hours in air before further investigation.
fluorescent PLA fibers were then drawn with a TF100 parallel drawing machine (Suzhou Tefa Electromechnical Technology Development, China).
Namely, centrifugal electrospinning combines the centrifugal force and electrical force into the process of spinning, and thus high alignment of the as-spun
fibers and higher production rate can be achieved at a lower working voltage or slower rotating velocity.
fibers were collected with a spin draw ratio of 3 using a methanol gelation bath maintained at -50[degrees]C.
nanofibrous membranes were collected on an aluminium roller with a diameter of 100 mm at a rotating speed of 1000 rpm.
 reported that the crystalline orientation factor of as-spun
fiber was 0.92 for PP resin with an MFI of 4.1 g/10 min when the take-up speed was fixed around 3000 m/min.
HDPE fibers were heat drawn through heated glycerol at 83 [+ or -] 2[degrees]C to a ratio of 18X.
Table 2 also shows the effect of drawing on the as-spun
treated and untreated yarns.