| 摘要 |
<p>An improved process for ethylene (co)polymerization is carried out in the presence of a catalyst obtained by reacting a Ziegler-Natta catalyst, or a component thereof, wherein at least a transition metal is pi -bonded to an organic residue, with an alpha-olefin having the following general formula (II): <CHEM> wherein R<4> and R<5> are two substituents selected, independently, from linear, cyclic or branched aliphatic or aromatic hydrocarbon groups having from 1 to 12 carbon atoms, or they are linked to each other to form a substituted or non-substituted cyclic compound, comprising the vinyl carbon atom in a ring of from 3 to 8 carbon atoms. The polymerization process allows productivity values to be obtained which are higher than those obtained with an analogous process carried out without the preliminary interaction with the above said alpha-olefin, while simultaneously allowing a complete freedom with regard to the choice of the monomer composition.</p> |
