Group 10 Metal Catalytic Olefin Polymerization and Synthesis of Ethylene/Acrylate Block Copolymers

Date

2022-07-08

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Abstract

The functionalized polyolefin materials are considered economical and high performance materials used in a wide range of applications, such as upcycling polymers, elastomers, membranes, and compatibilizers. This dissertation focuses on developing group 10 metal catalysts for olefin polymerization and synthesis of ethylene/acrylates block copolymers. The distorted sandwich α-diimine Pd catalyst development exhibited high catalytic activity and living ethylene polymerization at low-pressure conditions. The resulted PEs are not only a low branching density (<17/1000 C) but also consist of methyl branches exclusively. The ethylene/acrylate block copolymers were synthesized through coordination and photo-induced radical polymerization, and a series of high molecular weight (~500 kDa) block copolymers were generated. The post-functionalization of ethylene/acrylate block copolymers is practicable by incorporating NAS ester groups, demonstrated with 1 pyrenemethylamine dye. The acrylate block can significantly modify the mechanical properties of olefin-polar block copolymers, which can be hard plastics, elastomers, or even semi-amorphous polymers. The PE-b-PBzA and PE-b-PMA exhibited excellent elastomeric properties with high strain break values and elastic recovery. To further evolve the late-transition metal catalysts for olefin and photo-induced radical polymerization, a series of novel iminopyridyl Ni complexes were developed. Compared with the common aluminum activation, the iminopyridyl Ni catalysts with borate activation can generate higher molecular weight polymers with lower dispersity. The iminopyridyl Ni catalysts exhibited a unique property for the regulation of branching by temperature control. The resulted PE could be either a HDPE, LDPE, amorphous PE, or even oil in the temperature range from 0 to 80 oC. In addition, the Ni catalysts were able to copolymerize ethylene with polar vinyl monomers or α-olefins with high incorporation. Lastly, the ethylene/acrylate block copolymers were successfully synthesized by the iminopyridyl Ni complexes via photo-induced radical polymerization. The development of cheaper and less toxic Ni complexes makes the replacement of expensive Pd catalysts with Ni possible, making this novel block copolymerization technique get to the first step of industrial manufacture.

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Keywords

Palladium catalysis, Nickel catalysis, Polyolefins, Olefin polymerization, Copolymerization, Block copolymers, Elastomers, Borate activation, Photo-induced radical polymerization

Citation

Portions of this document appear in: Liu, Yu‐Sheng, and Eva Harth. "Distorted Sandwich α‐Diimine PdII Catalyst: Linear Polyethylene and Synthesis of Ethylene/Acrylate Elastomers." Angewandte Chemie 133, no. 45 (2021): 24309-24317.