The efficacy of a metal-silsesquioxane, namely, hep- taisobutyl (isopropoxyde)titanium-polyhedral oligomeric silses- quioxanes (Ti-POSS), as initiator of the ring-opening polymerization of L-lactide (LLA) has been assessed. Indeed, as demonstrated by proton nuclear magnetic resonance (1H NMR) spectroscopy and gel permeation chromatography (GPC) measurements, a well-controlled polymerization occurs via a coordination-insertion mechanism. Moreover, the above reac- tion leads to the direct insertion of the silsesquioxane molecule into the polymer backbone, thus producing a hybrid system. Differential scanning calorimetry measurements demonstrated that in comparison with a commercial poly-L-lactide (PLLA), the polymers prepared with Ti-POSS exhibit a higher crystallinity. Indeed, the presence of silsesquioxane molecules, attached to one end of the polymer chains, has been found to appreciably affect the crystal nucleation density.

A Novel Use of Ti-POSS as Initiator of L-Lactide Ring-Opening Polymerization / O., Monticelli; D., Cavallo; Bocchini, Sergio; Frache, Alberto; F., Carniato; Tonelotto, Alessandro. - In: JOURNAL OF POLYMER SCIENCE. PART A, POLYMER CHEMISTRY. - ISSN 0887-624X. - STAMPA. - 49:22(2011), pp. 4794-4799. [10.1002/pola.24926]

A Novel Use of Ti-POSS as Initiator of L-Lactide Ring-Opening Polymerization

BOCCHINI, SERGIO;FRACHE, ALBERTO;TONELOTTO, ALESSANDRO
2011

Abstract

The efficacy of a metal-silsesquioxane, namely, hep- taisobutyl (isopropoxyde)titanium-polyhedral oligomeric silses- quioxanes (Ti-POSS), as initiator of the ring-opening polymerization of L-lactide (LLA) has been assessed. Indeed, as demonstrated by proton nuclear magnetic resonance (1H NMR) spectroscopy and gel permeation chromatography (GPC) measurements, a well-controlled polymerization occurs via a coordination-insertion mechanism. Moreover, the above reac- tion leads to the direct insertion of the silsesquioxane molecule into the polymer backbone, thus producing a hybrid system. Differential scanning calorimetry measurements demonstrated that in comparison with a commercial poly-L-lactide (PLLA), the polymers prepared with Ti-POSS exhibit a higher crystallinity. Indeed, the presence of silsesquioxane molecules, attached to one end of the polymer chains, has been found to appreciably affect the crystal nucleation density.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2464776
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