Ni(II) α-Diimine-Catalyzed α-Olefins Polymerization: Thermoplastic Elastomers of Block Copolymers

Abstract

The polymerization of ethylene with late transition metal complexes typically provides highly branched amourphous poly(ethylene)s through a chain-walking mechanism, while the chain-straightening polymerization of α-olefins gives semicrystalline polymers. Herein, we report the polymerization of 1-hexene, 1-octene, and 1-dodecene catalyzed by an α-diimine Ni(II) complex in combination with diethylaluminum chloride. The effect of monomer chain length and monomer concentration on the productivity, polymerization “livingness”, selectivity of monomer insertion, and polymer structure/properties is investigated. The polymerization results indicate the possibility of precise microstructure control, depending on the monomer employed and monomer feedstock concentration, which in turn strongly affects the physical polymer properties. Additionally, di- and triblock copolymers were successfully fabricated in an easy, high-yielding route, at room temperature. The synthesis was accomplished through the sequential monomer...