Pack, JW Kim, SH Park, SY Lee, YW Kim, YH 2024-01-21T07:15:08Z 2024-01-21T07:15:08Z 2021-09-02 2004-03-15 1616-5187 https://pubs.kist.re.kr/handle/201004/137757 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 I It. 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 130degreesC 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 I-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. English WILEY-V C H VERLAG GMBH DISPERSION POLYMERIZATION CARBON-DIOXIDE SUSPENSION POLYMERIZATION EPSILON-CAPROLACTONE METHYL-METHACRYLATE TIN(II) OCTOATE MECHANISM KINETICS CO2 MONOMER Ring-opening polymerization of L-lactide and preparation of its microsphere in supercritical fluids Article 10.1002/mabi.200300089 1 MACROMOLECULAR BIOSCIENCE, v.4, no.3, pp.340 - 345 MACROMOLECULAR BIOSCIENCE 4 3 340 345 scie scopus 000220770100023 2-s2.0-4544236834 Biochemistry & Molecular Biology Materials Science, Biomaterials Polymer Science Biochemistry & Molecular Biology Materials Science Polymer Science Article; Proceedings Paper DISPERSION POLYMERIZATION CARBON-DIOXIDE SUSPENSION POLYMERIZATION EPSILON-CAPROLACTONE METHYL-METHACRYLATE TIN(II) OCTOATE MECHANISM KINETICS CO2 MONOMER biodegradable microsphere poly(L-lactide) ring-opening polymerization supercritical fluid