Ring-opening polymerization of D,L-lactide by rare earth 2,6-dimethylaryloxide

Ring‐opening polymerization of D,L‐lactide (LA) has been successfully carried out by using rare earth 2,6‐dimethylaryloxide (Ln(ODMP)3) as single component catalyst or initiator for the first time. The effects of different rare earth elements, solvents, monomers and catalyst concentration as well as...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Polymer international 2004-08, Vol.53 (8), p.1013-1016
Hauptverfasser: Zhang, Lifang, Shen, Zhiquan, Yu, Cuiping, Fan, Ling
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Ring‐opening polymerization of D,L‐lactide (LA) has been successfully carried out by using rare earth 2,6‐dimethylaryloxide (Ln(ODMP)3) as single component catalyst or initiator for the first time. The effects of different rare earth elements, solvents, monomers and catalyst concentration as well as polymerization temperature and time on the polymerization were investigated. The results show that La(ODMP)3 exhibits higher activity to prepare poly(D,L‐lactide) (PLA) with a viscosity molecular weight of 4.5 × 104 g mol−1 and the conversion of 97 % at 100 °C in 45 min. The catalytic activity of Ln(ODMP)3 has following sequence: La > Nd > Sm > Gd > Er > Y. A kinetic study has indicated that the polymerization is first order with respect to both monomer and catalyst concentration. The apparent activation energy of the polymerization of LA with La(ODMP)3 is 69.6 kJ mol−1. The analyses of polymer ends indicate that the LA polymerization proceeds according to ‘coordination–insertion’ mechanism with selective cleavage of the acyl–oxygen bond of the monomer. Copyright © 2004 Society of Chemical Industry
ISSN:0959-8103
1097-0126
DOI:10.1002/pi.1585