Crystal Structure of Stereocomplex of Poly(L-lactide) and Poly(D-lactide)

Takumi Okihara, Masaki Tsuji, Akiyoshi Kawaguchi, Ken Ichi Katayama, Hideto Tsuji, Suong Hyu Hyon, Yoshito Ikada

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359 Citations (Scopus)


An equimolar mixture of poly (L-lactide) and poly(D-lactide) was crystallized into a stereocomplex whose crystal system is triclinic (P1) with cell dimensions: a = 0.916 nm, b = 0.916 mm, c (chain axis) = 0.870 nm, a = 109.2°, β = 109.2°, and y = 109.8°. In the unit cell, a poly(L-lactide) segment and a poly (D-lactide) segment are contained as a pair and packed laterally in parallel fashion. The L- and D-poly(Iactides) in the complex take a 31helical conformation, which is a little extended from a 103 helix in the homopolymer crystal with the α-form. Homopolymers are also able to take the 31helical conformation and form the β-form crystal. The 31helix in the homopolymer crystal is less stable than the 103one, and hence the β-form is easily transformed to the a-form by annealing.

Original languageEnglish
Pages (from-to)119-140
Number of pages22
JournalJournal of Macromolecular Science, Part B
Issue number1-2
Publication statusPublished - Mar 1 1991
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Polymers and Plastics
  • Materials Chemistry


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