Ethylene1,3-butadiene cyclocopolymerization catalyzed by zirconocene systems》.pdf

European Polymer Journal 58 (2014) 157–163 Contents lists available at ScienceDirect European Polymer Journal journal homepage: www.elsevi /locate/europolj Ethylene/1,3-butadiene cyclocopolymerization catalyzed by zirconocene systems Stefania Pragliola ⇑, Chiara Costabile, Vincenzo Venditto Dipartimento di Chimica e Biologia, Università degli Studi di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano, SA, Italy a r t i c l e i n f o a b s t r a c t Article history: Copolymerizations of ethylene with 1,3-butadiene in the presence of catalytic systems based Received 23 January 2014 0 on C -symmetric zirconocenes rac-(CH ) Si(2-R-4-R -1-indenyl) ZrCl (where R = CH – or H 2 3 2 2 2 3 Received in revised form 3 June 2014 0 and R = C H – or H) are compared. The chemical nature and the relative amount of constitu- 6 5 Accepted 23 June 2014 tional comonomer units from butadiene (1,4-trans, methylene-1,2-cyclopentane and Available online 1 July 2014 methylene-1,2-cyclopropane) are strongly affected by the bulkiness of the substituent on the indenyl ligands. The unsubstitute