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 Runt

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

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

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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