cone-25,27-Dipropyloxy-26,28-dioxo-calix[4]arene titanium (IV) dichloride (1) has been assessed in the ring-opening polymerisation of rac-lactide (L,D-LA). The polymers formed (PLDA) turned out to display an isotactic stereoblock microstructure (determined by NMR) despite the fact that the catalyst has C2v symmetry. Two techniques were applied for initiating the polymerisation reaction, microwave irradiation, and conventional thermal treatment. The polymers obtained were all characterised by NMR, IR, HPLC-SEC, DSC, and MALDI-TOF analysis. The use of microwave irradiation, applied for the first time to calixarene-based catalysts in the presence of the rac-lactide monomer, increased the polymerisation rate compared with that obtained by the other method. On the other hand, standard thermal treatment enabled a slightly better control than microwave irradiation over the molecular weight and molecular weight distribution of the polylactides formed.
Ring Opening Polymerization of rac-Lactide using a calix[4]arene-based Titanium (IV) Complex / Marco Frediani; David Sémeril; Dominique Matt; Luca Rosi; Piero Frediani; Fabio Rizzolo; and Anna Maria Papini. - In: INTERNATIONAL JOURNAL OF POLYMER SCIENCE. - ISSN 1687-9422. - ELETTRONICO. - 2010:(2010), pp. 1-6. [10.1155/2010/490724]
Ring Opening Polymerization of rac-Lactide using a calix[4]arene-based Titanium (IV) Complex
FREDIANI, MARCO;ROSI, LUCA;FREDIANI, PIERO;PAPINI, ANNA MARIA
2010
Abstract
cone-25,27-Dipropyloxy-26,28-dioxo-calix[4]arene titanium (IV) dichloride (1) has been assessed in the ring-opening polymerisation of rac-lactide (L,D-LA). The polymers formed (PLDA) turned out to display an isotactic stereoblock microstructure (determined by NMR) despite the fact that the catalyst has C2v symmetry. Two techniques were applied for initiating the polymerisation reaction, microwave irradiation, and conventional thermal treatment. The polymers obtained were all characterised by NMR, IR, HPLC-SEC, DSC, and MALDI-TOF analysis. The use of microwave irradiation, applied for the first time to calixarene-based catalysts in the presence of the rac-lactide monomer, increased the polymerisation rate compared with that obtained by the other method. On the other hand, standard thermal treatment enabled a slightly better control than microwave irradiation over the molecular weight and molecular weight distribution of the polylactides formed.File | Dimensione | Formato | |
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