The catalyst system which includes the boride hydrogen metallocene mixture and the said mixture of lanthanide, using polymerization method, and the said method of using the said catalyst, the ethylene - butadiene copolymer which can

摘要

A borohydride metallocene complex of a lanthanide, its process of preparation, a catalytic system incorporating it, a process for the copolymerization of olefins employing this catalytic system and an ethylene/butadiene copolymer obtained by this process, the butadiene units of which comprise 1,2-cyclohexane or 1,2- and 1,4-cyclohexane links. This complex corresponds to one or other of the following formulae A and B: where, in the formula A, two ligand molecules Cp1 and Cp2, each composed of a fluorenyl group, are connected to the lanthanide Ln, such as Nd, and where, in the formula B, a ligand molecule, composed of two fluorenyl groups Cp1 and Cp2 which are connected to one another via a bridge P of formula MR1R2, where M is an element from group IVa, such as Si, and where R1 and R2, which are identical or different, represent an alkyl group comprising from 1 to 20 carbon atoms, is connected to the lanthanide Ln, where L represents an alkali metal, such as Li, where N represents a molecule of a complexing solvent, such as THF, where x is an integral or non-integral number greater than 0 and where p is an integer equal to or greater than 1.