TY - JOUR
T1 - Phase transition of poly(ethylene terephthalate) in nanofibers electrospun from phenol-based solution
AU - Wang, Chi
AU - Lee, Ming Feng
AU - Jao, Chuan Hsin
N1 - Funding Information:
We gratefully acknowledge financial support received from the National Science Council of Taiwan (NSC 98-2221-E-006-005-MY3) and National Synchrotron Radiation Research Center (NSRRC, 2009-2-047-5). The assistance of 2D SAXS and 2D WAXS experiments from Drs. U-Ser Jeng and Jey-Jau Lee, respectively, in NSRRC is highly appreciated.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 2014/3
Y1 - 2014/3
N2 - Poly(ethylene terephthalate) (PET) fibers were prepared from entangled solutions through high-temperature electrospinning using phenol as the solvent (melting point, 40.5 C). A continuous process of producing bead-free fibers can be obtained at the lowest spinning temperature of 80 C and the maximum electrospinning concentration of 36 wt.%. Fiber diameter decreased with increasing spinning temperature, but increased with increasing PET concentration. However, the limited processing window at high temperatures only exerted minimal effects. The differential scanning calorimetry heating trace of the as-spun fibers showed the existence of crystallization exotherm with an enthalpy much lower than that of the subsequent melting endotherm. This result suggested that the as-spun fibers were not in the amorphous state. Aligned fibers with a smaller diameter than random fibers collected by a stationary plate were obtained using a rotating disc collector. Structural characterization of the aligned fibers was performed using 2D wide-angle (WAXS) and small-angle X-ray scattering (SAXS) with synchrotron radiation sources. Aside from the isotropic amorphous phase, the as-spun fibers possessed a major oriented non-crystalline (ON) phase together with a trace of triclinic crystallites as revealed by the weak 1st layer (0 1̄ 1) reflection. The radial average intensity profile showed that the amount of amorphous phase was approximately 91%. The meridional SAXS slice showed no scattering peak, whereas an equatorial streak was observed. The aligned fibers were subjected to stepwise annealing up to a temperature of 270 C. The structural evolution of the unconstrained PET fibers was investigated. A three-phase model consisting of amorphous and non-amorphous (ON and triclinic) phases was used to account for the structural variation.
AB - Poly(ethylene terephthalate) (PET) fibers were prepared from entangled solutions through high-temperature electrospinning using phenol as the solvent (melting point, 40.5 C). A continuous process of producing bead-free fibers can be obtained at the lowest spinning temperature of 80 C and the maximum electrospinning concentration of 36 wt.%. Fiber diameter decreased with increasing spinning temperature, but increased with increasing PET concentration. However, the limited processing window at high temperatures only exerted minimal effects. The differential scanning calorimetry heating trace of the as-spun fibers showed the existence of crystallization exotherm with an enthalpy much lower than that of the subsequent melting endotherm. This result suggested that the as-spun fibers were not in the amorphous state. Aligned fibers with a smaller diameter than random fibers collected by a stationary plate were obtained using a rotating disc collector. Structural characterization of the aligned fibers was performed using 2D wide-angle (WAXS) and small-angle X-ray scattering (SAXS) with synchrotron radiation sources. Aside from the isotropic amorphous phase, the as-spun fibers possessed a major oriented non-crystalline (ON) phase together with a trace of triclinic crystallites as revealed by the weak 1st layer (0 1̄ 1) reflection. The radial average intensity profile showed that the amount of amorphous phase was approximately 91%. The meridional SAXS slice showed no scattering peak, whereas an equatorial streak was observed. The aligned fibers were subjected to stepwise annealing up to a temperature of 270 C. The structural evolution of the unconstrained PET fibers was investigated. A three-phase model consisting of amorphous and non-amorphous (ON and triclinic) phases was used to account for the structural variation.
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U2 - 10.1016/j.eurpolymj.2013.12.013
DO - 10.1016/j.eurpolymj.2013.12.013
M3 - Article
AN - SCOPUS:84893137296
VL - 52
SP - 127
EP - 136
JO - European Polymer Journal
JF - European Polymer Journal
SN - 0014-3057
IS - 1
ER -