Copolymerization of L-Lactide and ε-Caprolactone promoted by zinc complexes with phosphorus based ligands

Ilaria D'Auria; Marina Lamberti; Raffaella Rescigno; Vincenzo Venditto; Mina Mazzeo

doi:10.1016/j.heliyon.2021.e07630

Copolymerization of L-Lactide and ε-Caprolactone promoted by zinc complexes with phosphorus based ligands

Heliyon. 2021 Jul 22;7(7):e07630. doi: 10.1016/j.heliyon.2021.e07630. eCollection 2021 Jul.

Authors

Ilaria D'Auria¹, Marina Lamberti¹, Raffaella Rescigno¹, Vincenzo Venditto^{1

2}, Mina Mazzeo¹

Affiliations

¹ Department of Chemistry and Biology "Adolfo Zambelli", University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Salerno, Italy.
² INSTM Research Unit, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.

Abstract

The zinc complexes 1 and 2 bearing chelating phosphorous based pincer ligands were found to catalyze the ring-opening copolymerization of L-lactide and ε-caprolactone in the melt at 110 °C to obtain a series of random copolymers in which the monomer distributions were coherent with the monomer ratio in the feed. All the obtained copolymers showed high molecular masses with monomodal and moderately narrow distributions. The thermal properties of the achieved copolymers (T_g, glass transition temperature, and T_m, melting temperature) were strongly dependent on their composition. A linear dependence of T_g with molar percentage of lactide in the copolymers was observed over a temperature range from -59 °C (pure polycaprolactone) to 55 °C (pure polylactide).

Keywords: Biodegradable; Copolymers; Polyesters; ROP; Zinc catalyst.