Ring-opening polymerization of L-lactide and preparation of its microsphere in supercritical fluids

Ji Won Pack, Sou Hyun Kim, Sou Young Park, Youn Woo Lee, Young Ha Kim

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


The ring-opening polymerization of L-lactide initiated by stannous octoate was carried out in supercritical chlorodifluoromethane (scR22) at various reaction conditions (time and temperature) and reactant concentrations (initiator, monomer, and solvent). The monomer conversion increased to ca. 70% on increasing the reaction time to 1 h. The molecular weight of the poly(L-lactide) (PLLA) product also increased to ca. 160 000 g · mol -1 over the same period. Increasing reaction temperature from 90 to 130 °C resulted in increased monomer conversion and PLLA molecular weight. A series of polymerizations conducted at various 1-dodecanol and stannous octoate concentrations suggested that stannous octoate does not act as an initiator by itself, and that the tin-alkoxide formed from 1-dodecanol and stannous octoate serves as the initiating species in scR22. While enhancements of the monomer conversion and PLLA molecular weight were observed with increasing monomer concentration, the chlorodifluoromethane concentration had the opposite on both. After the polymerization, PLLA microspheres were prepared in situ by using a continuous supercritical antisolvent process without residual organic solvent and monomer to yield highly purified microspheres for environmental and biomedical applications.

Original languageEnglish
Pages (from-to)340-345
Number of pages6
JournalMacromolecular Bioscience
Issue number3
Publication statusPublished - 2004 Mar 15


  • Biodegradable
  • Microsphere
  • Poly(L-lactide)
  • Ring-opening polymerization
  • Supercritical fluid

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biomaterials
  • Polymers and Plastics
  • Materials Chemistry


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