Hydrogen-Bonding-Induced Heterogenization of Nickel and Palladium Catalysts for Copolymerization of Ethylene with Polar Monomers

The practical synthesis of polar-functionalized polyolefins using transition-metal-catalyzed copolymerization of olefins with polar monomers is a challenge; the use of heterogeneous catalysts is little explored. Herein, we report the synthesis of heterogeneous naphthoquinone-based nickel (Ni/SiO2) and palladium (Pd/SiO2) catalysts through hydrogen bonding interactions of the ligands with the silica surface. Ni/SiO2 exhibits high activities (up to 2.65x10(6) g mol(-1) h(-1)) during the copolymerization of ethylene with 5-hexene-1-yl-acetate, affording high-molecular-weight (M-n up to 630 000) polar-functionalized semicrystalline polyethylene (comonomer incorporation up to 2.8 mol %), along with great morphology control. The resulting copolymers possess improved surface properties and great mechanical properties. Pd/SiO2 can mediate ethylene copolymerization with polar monomers with moderate activity to produce high-molecular-weight copolymers with tunable comonomer incorporation.