Crystallization and structure formation of poly(L-lactide-co-meso-lactide) random copolymers

A time-resolved wide- and small-angle X-ray scattering study

Jaedong Cho, Stephen Baratian, Jangsoon Kim, Fengji Yeh, Benjamin S. Hsiao, James Patrick Runt

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

Time-resolved synchrotron simultaneous wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) experiments were used to investigate the crystallization behavior and microstructure development of poly(L-lactide), PLLA, and two random copolymers containing L-lactide (predominately) and randomly placed R stereochemical defects. The general features of crystallization of PLLA and the copolymers are similar except that the copolymers crystallize much more slowly and to a lesser extent than PLLA, as expected. Lamellar thicknesses derived from SAXS experiments are in very good agreement with mean thicknesses determined in a tapping mode AFM study of the same materials. The reduction in lamellar thickness and crystallinity with increasing meso-lactide content supports significant exclusion of the R stereoisomer from crystalline lamellae. In a separate series of time-resolved WAXD/SAXS experiments, each (co)polymer was crystallized for a fixed time, then heated to above its melting point. The observed behavior suggests a model for crystallization of the copolymers in which thinner lamellae form between 'primary' lamellar stacks during crystallization, with an average lamellar thickness that decreases with increasing R stereoisomer content.

Original languageEnglish (US)
Pages (from-to)711-717
Number of pages7
JournalPolymer
Volume44
Issue number3
DOIs
StatePublished - Dec 20 2002

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Crystallization
X ray scattering
Copolymers
Stereoisomerism
X ray diffraction
Experiments
Synchrotrons
Melting point
Polymers
Crystalline materials
Defects
Microstructure
dilactide
poly(lactide)

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

Cite this

Cho, Jaedong ; Baratian, Stephen ; Kim, Jangsoon ; Yeh, Fengji ; Hsiao, Benjamin S. ; Runt, James Patrick. / Crystallization and structure formation of poly(L-lactide-co-meso-lactide) random copolymers : A time-resolved wide- and small-angle X-ray scattering study. In: Polymer. 2002 ; Vol. 44, No. 3. pp. 711-717.
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abstract = "Time-resolved synchrotron simultaneous wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) experiments were used to investigate the crystallization behavior and microstructure development of poly(L-lactide), PLLA, and two random copolymers containing L-lactide (predominately) and randomly placed R stereochemical defects. The general features of crystallization of PLLA and the copolymers are similar except that the copolymers crystallize much more slowly and to a lesser extent than PLLA, as expected. Lamellar thicknesses derived from SAXS experiments are in very good agreement with mean thicknesses determined in a tapping mode AFM study of the same materials. The reduction in lamellar thickness and crystallinity with increasing meso-lactide content supports significant exclusion of the R stereoisomer from crystalline lamellae. In a separate series of time-resolved WAXD/SAXS experiments, each (co)polymer was crystallized for a fixed time, then heated to above its melting point. The observed behavior suggests a model for crystallization of the copolymers in which thinner lamellae form between 'primary' lamellar stacks during crystallization, with an average lamellar thickness that decreases with increasing R stereoisomer content.",
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Crystallization and structure formation of poly(L-lactide-co-meso-lactide) random copolymers : A time-resolved wide- and small-angle X-ray scattering study. / Cho, Jaedong; Baratian, Stephen; Kim, Jangsoon; Yeh, Fengji; Hsiao, Benjamin S.; Runt, James Patrick.

In: Polymer, Vol. 44, No. 3, 20.12.2002, p. 711-717.

Research output: Contribution to journalArticle

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