A Self-Supporting Strategy for Gas-Phase and Slurry-Phase Ethylene Polymerization using Late-Transition-Metal Catalysts.

The polyolefin industry is dominated by gas-phase and slurry-phase polymerization techniques using heterogeneous catalysts. In contrast, the polyolefin academic research is extensively focused on homogeneous systems, especially for the field of late-transition-metal catalysts. The heterogenization of homogeneous catalysts represents a general strategy to provide "drop-in" catalyst solutions for existing industrial polyolefin synthetic strategies. In this paper, we report an alternative, potentially general strategy for the utilization of homogeneous late-transition-metal catalysts in gas-phase and slurry-phase polymerization techniques. In this self-supported strategy, catalysts with moderate chain walking capabilities produced porous polymer supports during gas-phase ethylene polymerization. The chain walking ability of the catalysts, in which the metal center can move up and down the polymer chain during polymerization, ensures that the metal center can travel along the polymer chain to find suitable sites for efficient ethylene enchainment. This strategy also enables simple heterogenization of catalysts on solid supports for slurry-phase polymerization which allows the polymer morphology to be controlled. Most importantly, various branched ultra-high-molecular-weight polyethylenes can be prepared under various polymerization conditions with proper catalyst selection.