Ring-opening copolymerization of L-lactide and ε-caprolactone in supercritical carbon dioxide using triblock oligomers of caprolactone and PEG as stabilizers

Creative Commons License

YILMAZ M., Eǧri S., YILDIZ N., Çalimli A., Pişkin E.

Polymer Journal, cilt.43, sa.9, ss.785-791, 2011 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 43 Sayı: 9
  • Basım Tarihi: 2011
  • Doi Numarası: 10.1038/pj.2011.70
  • Dergi Adı: Polymer Journal
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.785-791
  • Anahtar Kelimeler: (A-B-A) copolymer of ε-CL (A) and PEG400 (B), L-lactide and ε-caprolactone copolymers, ring-opening polymerization, supercritical carbon dioxide, triblock stabilizer
  • Ankara Üniversitesi Adresli: Evet

Özet

In this study, the use of triblock (A-B-A) oligomers of ε-caprolactone (ε-CL) (A) and PEG400 (B) as stabilizers (SB) for the copolymerization of L-lactide (LLA) and ε-CL in supercritical carbon dioxide (scCO2) was investigated. To determine the effect of CO2-philic and polymer-philic segments on copolymerization, oligomers with three different average molecular weights (Mw = 2000-6000 Da) were synthesized by changing the PEG400/ε-CL ratio. Copolymerizations were confirmed by 1H-nuclear magnetic resonance (NMR), 13C-NMR and differential scanning calorimeter data. It was possible to copolymerize LLA and ε-CL in scCO2 without any SB; however, the polymerization yields and average molecular weights were low, and significant aggregate formations were detected. Recipes featuring only 5% SB were successfully applied to reach high polymerization yields of ∼85% and polymers with average molecular weights greater than 20 kDa. When the polymer-philic segment of the SB increased, both the yield and molecular weight of the copolymer also increased significantly, resulting in white powdery products. © The Society of Polymer Science, Japan (SPSJ) All rights reserved.