High-yield production of lactide isomers from depolymerization of polylactic acid in supercritical carbon dioxide

SİVRİ S., SEZGİ N. A., DİLEK HACIHABİBOĞLU Ç.

Journal of Supercritical Fluids, cilt.217, 2025 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 217
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1016/j.supflu.2024.106473
  • Dergi Adı: Journal of Supercritical Fluids
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, Food Science & Technology Abstracts, INSPEC, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: Depolymerization, Lactic acid, Lactide, PLA, Recycling
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

Chemical depolymerization of polylactic acid (PLA) was demonstrated in supercritical carbon dioxide medium. No catalyst, organic solvent or water was employed in the reaction. The primary feedstocks used in ring opening polymerization of PLA, lactide isomers, were produced with high yield. More specifically, lactides were produced as the sole nongaseous products with a 93 % yield based on the initial polymer mass at 200 °C and 310 bar in 120 min. The influences of the reaction temperature, time, and pressure on PLA depolymerization products were investigated. While the lactide yield and distribution were highly influenced by the reaction temperature and time, further improvement was attained with an increase in the pressure. The results demonstrate that supercritical CO2 can be applied as a promising reaction medium for PLA degradation, providing a high-yield production of its feedstock. The process can enable green depolymerization of polylactic acid and promote its circular economy with a closed loop production.