Brill transition of nylon-6 in electrospun nanofibers

Chi Wang, Shih Yung Tsou, Hsuan Sheng Lin

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

Electrospun nylon-6 fibers were prepared from its polyelectrolyte solution in formic acid with different concentrtaions. In situ Fourier transform infrared (FTIR), wideangle X-ray diffraction and small-angle X-ray scattering (SAXS) were performed on the nylon-6 fibers heated to various temperatures until melting. For comparison, stepwise annealing of the solution-cast film having exclusively the α-form was also carried out to elucidate the structural evolution. Our results showed that Brill transition in the electrospun fibers occurs at a lower temperature than that in the solution-cast film due to the crystal size difference. Differential scanning calorimetry heating traces on the as-spun fibers exhibited a unique crystalline phase with a melting temperature of ~235 °C, higher than the equilibrium melting temperature of nylon-6. The content of high melting temperature (HMT) phase increased with increasing nylon-6 concentration; a maximum of 30 % of the fiber crystallinity was reached for fibers obtained from the 22 wt.% solution regardless of the heating rates used. Based on the SAXS and FTIR results, we speculated that the HMT phase is associated with thick α-form crystals developed from the highly oriented nylon-6 chains that are preserved in the skin layer of the as-spun fibers. A plausible mechanism for the formation of the skin/core fiber morphology during electrospinning was proposed.

Original languageEnglish
Pages (from-to)1799-1809
Number of pages11
JournalColloid and Polymer Science
Volume290
Issue number17
DOIs
Publication statusPublished - 2012 Nov 1

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Colloid and Surface Chemistry
  • Materials Chemistry

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