The effects of melt annealing and counterpart's molecular weight on the thermal properties and phase morphology of poly(L-lactide)-based blends

Fang Chyou Chiu, Chin Yu Kan, Jen Chang Yang

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10 Citations (Scopus)

Abstract

The thermal properties and phase morphology of poly(L-lactide) (PLLA)-based blends have been studied. Two poly(ethylene glycol)s (PEGs) with molecular weight (MW) of about 1,500 (1.5k) g/mol and 2,000,000 (2M) g/mol, respectively, wereused as counterparts. The blends were annealed at a preselected temperature of 200 °C for either 2 min or 30 min before the characterizations. Both PEGs were determined to enhance the crystallizability of PLLA. After a 2-min process of annealing, the PEG(1.5k)'s crystallization efficiency on PLLA has been noted to increase withthe increase of its content. Conversely, PEG(2M) 'scrystallization efficiency declined with the increase of its content. Extending the annealing time has evidently changed the PEGs' crystallization effect on PLLA. Moreover, the PEG(1.5k) has, to a greater extent, brought about the depression of PLLA's melting temperature by increasing its content, and this depression increased with the annealing time. The blends exhibited lower thermal stability than those of the parent components, particularly for the PEG(1.5k)-included system with a higher PEG content. Regardless of the annealing time, the PEG(1.5k)-included blends have shown homogeneous melt morphology under light microscope, whereas the PEG(2M)-included blends have displayed phaseseparated melt morphology. In addition to the composition, PEG's MW and annealing time influence the crystalline morphology of the blends. The ringed PLLA spherulites have appeared mostly in the 2-min annealed PEG(1.5k)-included blends.

Original languageEnglish
Pages (from-to)1497-1510
Number of pages14
JournalJournal of Polymer Science, Part B: Polymer Physics
Volume47
Issue number15
DOIs
Publication statusPublished - Aug 1 2009

Fingerprint

Polyethylene glycols
molecular weight
Thermodynamic properties
thermodynamic properties
Molecular weight
Annealing
annealing
crystallization
spherulites
Crystallization
poly(lactide)
glycols
ethylene
thermal stability
microscopes
melting
temperature
Melting point
Microscopes
Thermodynamic stability

Keywords

  • Blends
  • Crystallization
  • Morphology
  • PEG
  • PLLA

ASJC Scopus subject areas

  • Materials Chemistry
  • Polymers and Plastics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

Cite this

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title = "The effects of melt annealing and counterpart's molecular weight on the thermal properties and phase morphology of poly(L-lactide)-based blends",
abstract = "The thermal properties and phase morphology of poly(L-lactide) (PLLA)-based blends have been studied. Two poly(ethylene glycol)s (PEGs) with molecular weight (MW) of about 1,500 (1.5k) g/mol and 2,000,000 (2M) g/mol, respectively, wereused as counterparts. The blends were annealed at a preselected temperature of 200 °C for either 2 min or 30 min before the characterizations. Both PEGs were determined to enhance the crystallizability of PLLA. After a 2-min process of annealing, the PEG(1.5k)'s crystallization efficiency on PLLA has been noted to increase withthe increase of its content. Conversely, PEG(2M) 'scrystallization efficiency declined with the increase of its content. Extending the annealing time has evidently changed the PEGs' crystallization effect on PLLA. Moreover, the PEG(1.5k) has, to a greater extent, brought about the depression of PLLA's melting temperature by increasing its content, and this depression increased with the annealing time. The blends exhibited lower thermal stability than those of the parent components, particularly for the PEG(1.5k)-included system with a higher PEG content. Regardless of the annealing time, the PEG(1.5k)-included blends have shown homogeneous melt morphology under light microscope, whereas the PEG(2M)-included blends have displayed phaseseparated melt morphology. In addition to the composition, PEG's MW and annealing time influence the crystalline morphology of the blends. The ringed PLLA spherulites have appeared mostly in the 2-min annealed PEG(1.5k)-included blends.",
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author = "Chiu, {Fang Chyou} and Kan, {Chin Yu} and Yang, {Jen Chang}",
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T1 - The effects of melt annealing and counterpart's molecular weight on the thermal properties and phase morphology of poly(L-lactide)-based blends

AU - Chiu, Fang Chyou

AU - Kan, Chin Yu

AU - Yang, Jen Chang

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Y1 - 2009/8/1

N2 - The thermal properties and phase morphology of poly(L-lactide) (PLLA)-based blends have been studied. Two poly(ethylene glycol)s (PEGs) with molecular weight (MW) of about 1,500 (1.5k) g/mol and 2,000,000 (2M) g/mol, respectively, wereused as counterparts. The blends were annealed at a preselected temperature of 200 °C for either 2 min or 30 min before the characterizations. Both PEGs were determined to enhance the crystallizability of PLLA. After a 2-min process of annealing, the PEG(1.5k)'s crystallization efficiency on PLLA has been noted to increase withthe increase of its content. Conversely, PEG(2M) 'scrystallization efficiency declined with the increase of its content. Extending the annealing time has evidently changed the PEGs' crystallization effect on PLLA. Moreover, the PEG(1.5k) has, to a greater extent, brought about the depression of PLLA's melting temperature by increasing its content, and this depression increased with the annealing time. The blends exhibited lower thermal stability than those of the parent components, particularly for the PEG(1.5k)-included system with a higher PEG content. Regardless of the annealing time, the PEG(1.5k)-included blends have shown homogeneous melt morphology under light microscope, whereas the PEG(2M)-included blends have displayed phaseseparated melt morphology. In addition to the composition, PEG's MW and annealing time influence the crystalline morphology of the blends. The ringed PLLA spherulites have appeared mostly in the 2-min annealed PEG(1.5k)-included blends.

AB - The thermal properties and phase morphology of poly(L-lactide) (PLLA)-based blends have been studied. Two poly(ethylene glycol)s (PEGs) with molecular weight (MW) of about 1,500 (1.5k) g/mol and 2,000,000 (2M) g/mol, respectively, wereused as counterparts. The blends were annealed at a preselected temperature of 200 °C for either 2 min or 30 min before the characterizations. Both PEGs were determined to enhance the crystallizability of PLLA. After a 2-min process of annealing, the PEG(1.5k)'s crystallization efficiency on PLLA has been noted to increase withthe increase of its content. Conversely, PEG(2M) 'scrystallization efficiency declined with the increase of its content. Extending the annealing time has evidently changed the PEGs' crystallization effect on PLLA. Moreover, the PEG(1.5k) has, to a greater extent, brought about the depression of PLLA's melting temperature by increasing its content, and this depression increased with the annealing time. The blends exhibited lower thermal stability than those of the parent components, particularly for the PEG(1.5k)-included system with a higher PEG content. Regardless of the annealing time, the PEG(1.5k)-included blends have shown homogeneous melt morphology under light microscope, whereas the PEG(2M)-included blends have displayed phaseseparated melt morphology. In addition to the composition, PEG's MW and annealing time influence the crystalline morphology of the blends. The ringed PLLA spherulites have appeared mostly in the 2-min annealed PEG(1.5k)-included blends.

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