Metallocene catalysts ethylene homopolymerization

Jang Y-J, Nenov N, Klapper M, Mullen K (2003) Organic nanoparticles with polypropy-leneoxide chains as support for metallocene catalysts ethylene homopolymerization and ethylene/a-olefin copolymerization. Polym Bull 50 343-350... 

Besides the performance of metallocene catalysts in the homopolymerization of ethylene also their ability for copolymerization under high pressure was proofed. As comonomers a number of 1-olefins and dienes were used. In Figure 5 the change of the productivity with the concentration of the comonomer in the feed is shown for the copolymerization of ethylene with... 

Methylenecycloalkanes. Strained cycloalkanes with exo-methylene groups have been homopolymerized as well as copolymerized with ethylene by catalysts such as [(C5(CH3)5)2Zr(CH3)]+[(CH3)B(C6F5)3] and analogous Group IIIB and lanthanide metallocenes via the C—C bond migration mechanism shown in equation 30 (216). 

Koppl, A. Babel, A. L Alt, H. G. Homopolymerization of ethylene and copolymerization of ethylene and 1 -hexene with bridged metallocene/methylaluminoxane catalysts The influence of the bridging moiety. J. Mol. Catal. A Chem. 2000,153,109-119. 

While the copolymerization of norbornene and ethylene by vanadium and titanium catalysts had been investigated in the 1970s, it was not until the invention of metallocene/MAO catalysts and their application to the homopolymerization of norbornene and other cycloolefins by Kaminsky et ai.8,15,19 that the use of early transition metal catalysts for the addition polymerization of norbornene drew new attention. Nevertheless, the industrial relevance of E/NB copolymers, and the nature of the homopolymers, described in the first reports as insoluble in organic solvents, crystalline, and extremely high melting, focused further investigations on copolymers rather than on norbornene homopolymers. 

Single site catalysts, such as metallocene compounds, CGCs, and nickel or palladium diimine complexes, used in combination with MAO or borate cocatalysts, are highly active for the homopolymerization of norbornene and its copolymerization with ethylene. The structure of the norbornene homo- and copolymers can be widely influenced by the symmetry and structure of the ligands on the transition metal complexes. 

---