Borohydride metallocene complex of a lanthanide, catalytic system including the said complex, polymerisation method using same and ethylene/butadiene copolymer obtained using said method
Borohydride metallocene complex of lanthanide, preparation process, catalytic system incorporating it, copolymerization of olefins employing catalytic system and ethylene/butadiene copolymer, the butadiene units comprise 1,2-cyclohexane or 1,2- and 1,4-cyclohexane links. The complex corresponds to of formulae A and/or B: where, in A two ligands Cp 1 and Cp 2 , each of a fluorenyl group, are connected to the lanthanide Ln, where, in B, a ligand molecule, composed of two fluorenyl groups Cp 1 and Cp 2 are connected via bridge P of formula MR 1 R 2 , is an element from group IVa, R 1 and R 2 , which are identical or different, represent an alkyl group comprising from 1 to 20 carbon atoms, connected to lanthanide Ln, L is alkali metal, N is molecule of a complexing solvent, x is integral or non-integral number ≧0 and p is integer ≧1.
1. A copolymer of ethylene and butadiene, that exhibits both:
a molar level of units resulting from butadiene which is equal to or greater than 25%, and
a molar level of 1,2-cyclohexane links in the units resulting from butadiene which is equal to or greater than 25%.
2. A copolymer of ethylene and butadiene according to claim 1 , that exhibits a number-average molecular weight Mn equal to or greater than 30 000 g/mol.
3. A copolymer of ethylene and butadiene obtained according to claim 1 , that exhibits units resulting from butadiene comprising links in the form of 1,4-cyclohexane.