Loading…

Evidence for Ester-Exchange Reactions and Cyclic Oligomer Formation in the Ring-Opening Polymerization of Lactide with Aluminum Complex Initiators

Four polylactide samples, obtained by ring-opening polymerization with an aluminum alkoxide initiator derived from a Schiff's base, were characterized by MALDI-TOF mass spectrometry. The MALDI mass spectra of these polylactides show well-resolved signals that can be reliably assigned to polylac...

Full description

Saved in:
Bibliographic Details
Published in:Macromolecules 1996-09, Vol.29 (20), p.6461-6465
Main Authors: Montaudo, Giorgio, Montaudo, Maurizio S, Puglisi, Concetto, Samperi, Filippo, Spassky, N, LeBorgne, Alain, Wisniewski, Muriel
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Four polylactide samples, obtained by ring-opening polymerization with an aluminum alkoxide initiator derived from a Schiff's base, were characterized by MALDI-TOF mass spectrometry. The MALDI mass spectra of these polylactides show well-resolved signals that can be reliably assigned to polylactide oligomers. Remarkably, both even-membered and odd-membered oligomers are present in these MALDI spectra. The presence of odd-membered oligomers cannot be explained on the basis of the lactide ring-opening polymerization, and one must admit that ester-exchange reactions do occur parallel to the polymerization process, causing a random cleavage of the polylactide chain. Furthermore, evidence for the presence of cyclic lactides was found in the MALDI-TOF spectrum of a low molecular weight polylactide fraction, indicating that ester exchange occurs also in polylactides by intramolecular end-biting reactions (ring−chain equilibration), with formation of cyclic oligomers.
ISSN:0024-9297
1520-5835
DOI:10.1021/ma960538i