Aluminum complexes of non-chiral-salalen ligands were investigated in the catalysis of ring-opening polymerization (ROP) of lactide and ε-caprolactone and in their copolymerization. The aluminum-salalen complexes were found to polymerize all varieties of lactide, namely: L-, D-, rac- and meso-lactide, and showed moderate productivities. rac-LA gave rise to isotactic polylactides (with Pm up to 72%), while meso-LA gave rise to heterotactic polylactides (with a Pm of 79%). An experiment was designed for distinguishing between chain-end control and enantiomorphic-site control combined with polymeryl exchange for the isotactic stereoblock microstructure observed for the PLA produced from rac-LA; it gave strong evidence for polymeryl exchange between propagating species. Finally, this class of catalysts promoted the copolymerization of ε-caprolactone and lactides. In particular, compound 2b allowed controlled random copolymerization of ε-caprolactone and L-lactide.

Ring-opening homo- and co-polymerization of ε-caprolactone and lactides by salalen aluminum complexes

PILONE, ALESSIA;VENDITTO, Vincenzo;MAZZEO, Mina;PELLECCHIA, Claudio;LAMBERTI, Marina
2015

Abstract

Aluminum complexes of non-chiral-salalen ligands were investigated in the catalysis of ring-opening polymerization (ROP) of lactide and ε-caprolactone and in their copolymerization. The aluminum-salalen complexes were found to polymerize all varieties of lactide, namely: L-, D-, rac- and meso-lactide, and showed moderate productivities. rac-LA gave rise to isotactic polylactides (with Pm up to 72%), while meso-LA gave rise to heterotactic polylactides (with a Pm of 79%). An experiment was designed for distinguishing between chain-end control and enantiomorphic-site control combined with polymeryl exchange for the isotactic stereoblock microstructure observed for the PLA produced from rac-LA; it gave strong evidence for polymeryl exchange between propagating species. Finally, this class of catalysts promoted the copolymerization of ε-caprolactone and lactides. In particular, compound 2b allowed controlled random copolymerization of ε-caprolactone and L-lactide.
File in questo prodotto:
File Dimensione Formato  
Salalen-Al ROP submitted Dalton Trans.pdf

accesso aperto

Descrizione: Articolo principale
Tipologia: Documento in Pre-print (manoscritto inviato all'editore, precedente alla peer review)
Licenza: Creative commons
Dimensione 1.35 MB
Formato Adobe PDF
1.35 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11386/4591857
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 69
  • ???jsp.display-item.citation.isi??? 67
social impact