While our society is becoming more and more aware of the importance of sustainable development, green chemistry and renewability, poly(glycolide) (PGA), poly(lactide) (PLA) and their copolymers have already proven to be a valid, renewable alternative to the petrobased plastics in a wide range of applications. The most efficient way to obtain these polymers is via ring-opening polymerization (ROP) of their cyclic esters, and the most common initiator is tin octoate. Although it is FDA approved, its cytotoxicity raises several issues, along with the need of a more benign initiator. We have already reported the polymerization of ?-caprolactone promoted by sodium hydride (NaH). We now report on the use of NaH as initiator in the ROP of L-lactide, glycolide and in their copolymerization for the synthesis of poly[glycolide-co-(L-lactide)]s (PLGAs). NaH is not only a commercially available, cheap and easy-to-handle compound, but also a non-toxic initiator. Polymerization runs have been performed in bulk, without solvents, and random copolymers were obtained in the case of PLGAs. Their microstructure was characterized by nuclear magnetic resonance (1H and 13C NMR) and matrix assisted laser desorption time of flight mass spectrometry (MALDI MS). Thermal properties were studied via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Transport properties to water vapour were also evaluated and correlated to the copolymer composition.
NaH, a green initiator for renewable polymers: ROP of glycolide and lactide, and characterization of the obtained PLGAs
Paola Rizzarelli;Sabrina Carroccio;Giusy Curcuruto;
2016
Abstract
While our society is becoming more and more aware of the importance of sustainable development, green chemistry and renewability, poly(glycolide) (PGA), poly(lactide) (PLA) and their copolymers have already proven to be a valid, renewable alternative to the petrobased plastics in a wide range of applications. The most efficient way to obtain these polymers is via ring-opening polymerization (ROP) of their cyclic esters, and the most common initiator is tin octoate. Although it is FDA approved, its cytotoxicity raises several issues, along with the need of a more benign initiator. We have already reported the polymerization of ?-caprolactone promoted by sodium hydride (NaH). We now report on the use of NaH as initiator in the ROP of L-lactide, glycolide and in their copolymerization for the synthesis of poly[glycolide-co-(L-lactide)]s (PLGAs). NaH is not only a commercially available, cheap and easy-to-handle compound, but also a non-toxic initiator. Polymerization runs have been performed in bulk, without solvents, and random copolymers were obtained in the case of PLGAs. Their microstructure was characterized by nuclear magnetic resonance (1H and 13C NMR) and matrix assisted laser desorption time of flight mass spectrometry (MALDI MS). Thermal properties were studied via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Transport properties to water vapour were also evaluated and correlated to the copolymer composition.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
