A bimetallic salen aluminum complex (1), where salen is N,N-bis(4,6-di-tert-butyl salicylaldimine)-1,3-propylendiamine, was tested as a catalyst for the ring opening polymerization (ROP) and copolymerization (ROCOP) of cyclic esters, such as l-lactide (L-LA), ϵ-caprolactone (ϵ-CL), and β-butyrolactone (β-BL) with different heterocyclic substrates, such as cyclohexene oxide (CHO) and succinic anhydride (SA). Copolymers ranging from gradient to blocky structures were obtained from the copolymerization of the different couples of lactones. In the copolymerization of CHO with a cyclic ester, block polyether-co-polyesters were prepared by sequential monomer addition while polyesters were obtained, as exclusive products, when both monomers were simultaneously present in the reaction medium. From a mixture of three different monomers: CHO, SA and a cyclic ester, block copolyesters derived from two different catalytic processes, ROCOP of CHO/SA followed by ROP of the lactone, were instead produced. Surprisingly, a perfect selectivity was observed in the CHO/SA copolymerization without any addition of a cocatalyst; this suggested that the lactone comonomer could act as an endogen cocatalyst.

Copolymerization of cyclic esters, epoxides and anhydrides: Evidence of the dual role of the monomers in the reaction mixture

Isnard, Florence;Carratu, Mario;Lamberti, Marina;Venditto, Vincenzo;Mazzeo, Mina
2018-01-01

Abstract

A bimetallic salen aluminum complex (1), where salen is N,N-bis(4,6-di-tert-butyl salicylaldimine)-1,3-propylendiamine, was tested as a catalyst for the ring opening polymerization (ROP) and copolymerization (ROCOP) of cyclic esters, such as l-lactide (L-LA), ϵ-caprolactone (ϵ-CL), and β-butyrolactone (β-BL) with different heterocyclic substrates, such as cyclohexene oxide (CHO) and succinic anhydride (SA). Copolymers ranging from gradient to blocky structures were obtained from the copolymerization of the different couples of lactones. In the copolymerization of CHO with a cyclic ester, block polyether-co-polyesters were prepared by sequential monomer addition while polyesters were obtained, as exclusive products, when both monomers were simultaneously present in the reaction medium. From a mixture of three different monomers: CHO, SA and a cyclic ester, block copolyesters derived from two different catalytic processes, ROCOP of CHO/SA followed by ROP of the lactone, were instead produced. Surprisingly, a perfect selectivity was observed in the CHO/SA copolymerization without any addition of a cocatalyst; this suggested that the lactone comonomer could act as an endogen cocatalyst.
File in questo prodotto:
File Dimensione Formato  
2018 Cat. Sci and tech.pdf

accesso aperto

Descrizione: Articolo principale
Tipologia: Documento in Pre-print (manoscritto inviato all'editore, precedente alla peer review)
Licenza: Creative commons
Dimensione 499.8 kB
Formato Adobe PDF
499.8 kB 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/11386/4721084
 Attenzione

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

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 41
  • ???jsp.display-item.citation.isi??? 41
social impact