Immobilization of pyridylamido hafnium catalyst on MgCl2-based support for slurry homo- and copolymerization of 4-methyl-1-pentene

Abstract

Heterogeneous catalysts have long dominated polyolefin production, the immobilization of a pyridylamido hafnium catalyst is highly challenging because of its unique in-situ ligand modification mechanism. Here, we report a heterogeneous pyridylamido hafnium catalyst immobilized on a dual MgCl₂/AlⁱBu_n(2-ethyl-1-hexoxide)_3-n activator/support for slurry homo- and copolymerization of 4-methyl-1-pentene (4MP). The supported pyridylamido hafnium catalyst shows enhanced catalytic activity and excellent polymer morphology control toward homopolymerization of 4-methyl-1-pentene. The produced poly(4-methyl-1-pentene)s show high isotacticity (>99 %) and high melting temperatures up to 230 °C, and have normal molecular weight distribution. The heterogeneous catalyst still remains the advantages of enhanced catalytic activity and excellent polymer morphology control during the copolymerization of 4MP and α-olefins. Both the incorporation of α-olefin and longer chain α-olefins can improve the resilience of PMP materials.