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Employing (half-)titanocene complexes as initiators for the synthesis of end-functionalized polylactides by coordination polymerization
Authors:Georgios Patias  Ioannis Choinopoulos  Spyros Koinis  Marinos Pitsikalis
Affiliation:1. Industrial Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, 15771 Panepistimiopolis Zografou, Athens, Greece;2. Laboratory of Inorganic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, 15771 Panepistimiopolis Zografou, Athens, Greece
Abstract:Seven (half-)titanocene alkoxide complexes, [Cp2TiCl(OEt)], [Cp2TiCl(O-2-Bu)], [Cp2TiCl(OCH2CF2CF2H)], [CpTiCl2(OEt)], [CpTiCl2(O-(S)-2-Bu)], [CpTiCl2(OCH2CF3)], and [Cp2TiCl(OCH2CF3)], were synthesized and employed in lactide coordination polymerization. These organotitanium (IV) compounds proved to be very efficient initiators for the ring-opening polymerization of enantiomeric l -lactide and racemic mixture of rac-lactide, leading to end-functionalized polymers. Kinetic studies illustrated that these compounds produce well-defined polymers in a controlled manner. This was further demonstrated by synthesizing poly(l -lactide-b-hexyl isocyanate) diblock copolymer. The effect of the alkoxy end groups on the thermal behavior of the polymers was also studied by thermogravimetric analysis and differential scanning calorimetry. The polymers were characterized using size exclusion chromatography and proton nuclear magnetic resonance spectroscopy. The optical properties of the diblock copolymer were also investigated. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2192–2202
Keywords:(half)-titanocenes  coordination polymerization  polyisocyanates  polylactides
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