Ethylene/butadiene copolymers, catalytic system and process for the synthesis thereof

Abstract

Disclosed are ethylene and butadiene copolymers and a catalytic system usable for the synthesis of these copolymers. The copolymers have a molar content of units resulting from butadiene of ≧8%, said units comprising trans-1,2 cyclohexane linkages, and a number-average molecular mass Mn of ≧40,000 g/mol. The catalytic system includes: (i) an organometallic complex represented by one of the following formulae A or B: where Ln represents a lanthanide and X a halogen, where, in the formula A, two ligand molecules Cp1 and Cp2 each consisting of a fluorenyl group, are attached to Ln, where, in the formula B, a ligand molecule consisting of two fluorenyl groups Cp1 and Cp2, joined together by a bridge P of formula MR2, where M is an element of column IVa and R is an alkyl with 1 to 20 carbon atoms, is attached to Ln, and (ii) a co-catalyst selected from an alkylmagnesium, an alkyllithium, an alkylaluminium, a Grignard reagent, or a mixture of these constituents. The (co-catalyst/organometallic complex) molar ratio falls within a range of from 1 to 8.

Dependencies are inferred from the claim text.