Investigation of phase transitional behavior of poly(L-lactide)/ poly(D-lactide) blend used to prepare the highly-oriented stereocomplex

Jianming Zhang, Kohji Tashiro, Hideto Tsuji, Abraham J. Domb

Research output: Contribution to journalArticlepeer-review

225 Scopus citations

Abstract

By using the highly oriented 1:1 stoichiometric blend of high-molecular-weight PLLA and middle-molecular-weight PDLA species and by choosing a suitable annealing condition, we have succeeded for the first time to observe the phase transition phenomenon in the heating and cooling processes by measuring the temperature dependence of the X-ray fiber diagram and polarized IR spectra. The as-drawn sample was found to consist of the two crystalline phases; disordered α form (α′) and stereocomplex (βc). In the heating process, the α′ form was found to be reorganized into the oriented α phase above 120°C, which melted around 180°C. However, by heating this sample some more, some parts of the molten chains are found to crystallize on the surface of the βc crystallites with high degree of chain orientation. In the subsequent cooling process from the βc phase, the unoriented α crystal appeared at around 120°C and coexisted with the highly oriented βc crystals.

Original languageEnglish
Pages (from-to)1049-1054
Number of pages6
JournalMacromolecules
Volume40
Issue number4
DOIs
StatePublished - 20 Feb 2007
Externally publishedYes

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