Copolymerization of propylene with 1-hexene and 4-methyl-1-pentene in liquid propylene medium. Synthesis and characterization of random metallocene copolymers with isotactic propylene sequences

SummaryPropylene copolymerization with 1-hexene and 4-methyl-1-pentene in liquid propylene medium in presence of MAO-activated C2-symmetry ansa-zirconocene rac-Me2Si(4-Ph-2-MeInd)2ZrCl2 was studied. Random copolymers of propylene with 1-hexene and 4-methyl-1-pentene content up to 7 mol % were obtained at 60 °C. General kinetic characteristics of propylene/higher α-olefin copolymerization were evaluated. The distinct feature of propylene copolymerization with 1-hexene and 4-methyl-1-pentene in liquid propylene medium – the proximity of comonomer relative reactivity ratios (r1∼r2∼1) that indicates azeotropic nature of copolymerization processes in studied conditions. Synthesized copolymers were characterized with the use of IR, 13C NMR, GPC, WAXD, DSC techniques, and uniaxial tensile testing.