Homopolymerization of higher 1-olefins with metallocene/MAO catalysts

Linear 1-olefins from 1-pentene to 1-octadecene are polymerized by non-stereospecific Cp2HfCl2 (1), syndiospecific Me2C(Cp)(9-fluorenyl)ZrCl2 (2) and iso-specific Et(Ind)(2)ZrCl2 (3) catalysts in the presence of MAO. The molecular weight of the resulting polymers (GPC) is highly dependent on the nature of the catalyst, but more or less independent of the monomer chain length. The stereoregularity of the poly(1-olefins) obtained with 2 and 3 as determined by NMR spectroscopy decreases linearly with increasing monomer chain length. A decrease in isotacticity occurs for the poly(1-oletins) synthesized with 3 when increasing the catalyst concentration. Vinylidene, 1,2-disubstituted and 1,1,2-trisubstituted double bonds attributed to different chain termination mechanisms are generated during the polymerization processes.