Copolymerization of ethylene and styrene in the presence of the catalytic system v5-C5Mej- Ti(CHzPh)3--B(CsF& has been investigated. Independently from the feed composition, basically alternating ethylene-styrene copolymers are obtained, together with some polyethylene and syndiotactic polystyrene, from which the former can be separated by solvent extraction. NMR analysis of suitably 13C-enriched end groups shows that the regiospeclficity of styrene insertion in the initiation step is largely secondary. A tentative explanation for the preferentially alternating comonomer incorporation is proposed.
Alternating ethylene-styrene copolymerization with a methylaluminoxane-free half-titanocene catalyst
PAPPALARDO D;
1996-01-01
Abstract
Copolymerization of ethylene and styrene in the presence of the catalytic system v5-C5Mej- Ti(CHzPh)3--B(CsF& has been investigated. Independently from the feed composition, basically alternating ethylene-styrene copolymers are obtained, together with some polyethylene and syndiotactic polystyrene, from which the former can be separated by solvent extraction. NMR analysis of suitably 13C-enriched end groups shows that the regiospeclficity of styrene insertion in the initiation step is largely secondary. A tentative explanation for the preferentially alternating comonomer incorporation is proposed.File in questo prodotto:
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