title: Ring-opening homo- and co-polymerization of lactides and ε-caprolactone by salalen aluminum complexes.
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 allowed controlled random copolymerization of ε-caprolactone and l-lactide.
authors.affiliation: Dipartimento di Chimica e Biologia, Università di Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy. mlamberti@unisa.it.
authors.forename: Alessia
authors.initials: A
authors.lastname: Pilone
authors.forename: Nicolina
authors.initials: N
authors.lastname: De Maio
authors.forename: Konstantin
authors.initials: K
authors.lastname: Press
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Venditto
authors.forename: Daniela
authors.initials: D
authors.lastname: Pappalardo
authors.forename: Mina
authors.initials: M
authors.lastname: Mazzeo
authors.forename: Claudio
authors.initials: C
authors.lastname: Pellecchia
authors.forename: Moshe
authors.initials: M
authors.lastname: Kol
authors.forename: Marina
authors.initials: M
authors.lastname: Lamberti