Stereoregular and stereoirregular alternating ethylene-norbornene copolymers

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TRITTO, Incoronata, Catherine MARESTIN, Laura BOGGIONI, Maria Carmela SACCHI, Hans-Herbert BRINTZINGER, Dino R. FERRO, 2001. Stereoregular and stereoirregular alternating ethylene-norbornene copolymers. In: Macromolecules. 34(17), pp. 5770-5777. ISSN 0024-9297. eISSN 1369-9261. Available under: doi: 10.1021/ma010122r

@article{Tritto2001Stere-24063, title={Stereoregular and stereoirregular alternating ethylene-norbornene copolymers}, year={2001}, doi={10.1021/ma010122r}, number={17}, volume={34}, issn={0024-9297}, journal={Macromolecules}, pages={5770--5777}, author={Tritto, Incoronata and Marestin, Catherine and Boggioni, Laura and Sacchi, Maria Carmela and Brintzinger, Hans-Herbert and Ferro, Dino R.} }

Boggioni, Laura Stereoregular and stereoirregular alternating ethylene-norbornene copolymers 2013-07-12T09:33:14Z Sacchi, Maria Carmela Sacchi, Maria Carmela Brintzinger, Hans-Herbert Brintzinger, Hans-Herbert Ethylene−norbornene (E−N) copolymers were synthesized with the C<sub>2</sub> metallocene rac-Me<sub>2</sub>Si(2-Me-[e]-benzindenyl)<sub>2</sub>ZrCl<sub>2</sub> (3) and with the constrained geometry Me<sub>2</sub>Si(Me<sub>4</sub>Cp)(NtBu)TiCl<sub>2</sub> (4) in the presence of methylaluminoxane. The E−N copolymerizations were carried out using a variety of monomer feed compositions. Copolymers were fully characterized by <sup>13</sup>C NMR spectroscopy, gel permeation chromatography, and differential scanning calorimetry. Copolymer microstructures were analyzed in detail, through a procedure which accounts for the stoichiometric requirements of the copolymer chain as well as for the measured areas of <sup>13</sup>C NMR signals. This analysis, which quantifies the differences in sequence distribution and tacticity of the polymers, evidenced that mainly alternating stereoregular and stereoirregular copolymers were prepared with 3 and 4, respectively. The copolymer prepared with 4 contains both meso and racemic NEN sequences and small amounts of meso and racemic NN diads, while the alternating copolymer prepared with 3 contains only meso NEN sequences and small amounts of meso NN diads. The formation of NN diads is disfavored with both catalysts. Surprisingly, a significant amount of norbornene (up to 10%) belonging to NNN triads (T) is obtained with the C<sub>2</sub> catalyst. Ferro, Dino R. Marestin, Catherine Boggioni, Laura Ferro, Dino R. Tritto, Incoronata 2013-07-12T09:33:14Z Tritto, Incoronata Macromolecules ; 34 (2001), 17. - S. 5770-5777 eng 2001 Marestin, Catherine deposit-license

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