Thermal Behavior of Poly(L-lactide) Having Low L-Isomer Content of 94% after Compressed CO2 Treatment

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The effect of compressed CO2 treatment on the thermal behavior of poly(L-lactide) (PLLA) with low L-isomer content of 94% was studied by using differential scanning calorimetry (DSC) and temperature modulated DSC. It was shown that the treated samples displayed rich thermal transition signals during DSC heating, which is differ from the PLLA having high L-isomer content, including enthalpy relaxation, endothermic annealing, melting-recrystallization process, and cold crystallization. The results suggested that the crystalline phase obtained has less perfection and low crystallinity regardless of the treatment conditions because of the low crystallizability of the PLLA. This PLLA was induced to crystallize after treatment under CO2 at 2 MPa and temperature >= 65 degrees C and at pressures of 4-16 MPa and temperatures as low as 0 degrees C. At 2 MPa, the alpha crystal form is formed predominantly in the crystallized samples. The results also indicated that the ELLA-CO2 system exhibited the property of retrograde vitrification.


  • Qiaofeng Lan
  • Jian Yu
  • Jiasong He
  • Frans Maurer
  • Jun Zhang
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Chemical Sciences
Original languageEnglish
Pages (from-to)8602-8609
Issue number20
Publication statusPublished - 2010
Publication categoryResearch

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Polymer and Materials Chemistry (LTH) (011001041)