Characterization of poly(L-lactic acid) fibers produced by melt spinning

Xiaoyan Yuan, Arthur F.T. Mak, Kin Wing Kwok, Brian K.O. Yung, Kangde Yao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

121 Citations (Scopus)


Biodegradable poly(L-lactic acid) (PLLA) fibers were processed by a two-step melt-spinning method (melt extrusion and hot draw) from PLLA with three different viscosity-average molecular weights (494,600, 304,700, and 262,800). Before spinning, the polymer flakes were first milled into powders and dried under vacuum. Viscosity-average molecular weight of PLLA following the fabrication process was monitored. Tensile properties of as-spun and hot-drawn fibers were investigated. Morphology of the PLLA fibers was viewed under a scanning electron microscope. Crystallinity of these fibers was assessed by thermogram analysis of differential scanning calorimetry. Results showed that the extent of decrease in the viscosity-average molecular weight of PLLA dropped sharply by 13.1-19.5% during pulverization and by 39.0-69.0% during melt-extrusion. The hot-draw process in this study had a little effect on the viscosity-average molecular weight of PLLA. Smoother fibers could be obtained for the die temperature at least 230°C for raw materials with higher crystallinity (more than 75%) and at least 220°C for raw materials with lower crystallinity (about 60%). The as-spun fibers showed crystallinity of 16.5-22.8% and the value increased to 50.3-63.7% after hot draw. Tensile moduli of the as-spun fibers were in the range of 1.2-2.4 GPa, which were raised to 3.6-5.4 GPa after hot draw. The final PLLA fibers with 110-160 μm diameters showed tensile strengths of 300-600 MPa.
Original languageEnglish
Pages (from-to)251-260
Number of pages10
JournalJournal of Applied Polymer Science
Issue number1
Publication statusPublished - 5 Jul 2001


  • Biodegradable fibers
  • Melt spinning
  • Poly(L-lactic acid)
  • Tensile properties
  • Viscosity-average molecular weight

ASJC Scopus subject areas

  • Chemistry(all)
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Materials Chemistry


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