Direct Synthesis of Polar Polyolefin Elastomers Enabled by Neutral Nickel-Catalyzed High Temperature Solution Copolymerization.

Copolymerization of olefin and polar monomer to produce the desired polar polyolefin materials is a longstanding challenge, which becomes much more difficult when carried out at industrially preferred high temperatures due to both catalyst deactivation and rapid chain transfer reactions. Here, we report for the first time the direct synthesis of high-molecular-weight polar polyolefin elastomers (P-POEs) from high-temperature solution copolymerization of ethylene and biomass-derived polar monomer at above 130°C. The key lies in the discovery of highly thermostable α-ketocarboxamide nickel catalysts, which are not only neutral catalysts that do not require excess alkyl aluminum as an activator/scavenge/protecting agent but also in situ generate desired branches (36.8-70.6/1000C) through chain walking reaction that circumvents the need of α-olefins. Molecular weights of P-POEs with ester incorporations of 0.6-8.7 mol% produced at 130°C-170°C, which is also the preferred temperature for the synthesis of commercially non-polar polyolefin elastomer (POE), reach 59-276 kDa that are 2-9 times higher than those obtained previously at high temperatures. Both high-molecular-weights and polar functional characteristics enable P-POE as attractive materials, endowing them with desired properties, including tensile strength, strain recovery, melt flowability, hydrophilicity, dyeability, adhesion, and compatibilization properties.