Polyolefins by Single-Site Catalysts

ii Developments in single-site catalysts for olefin polymerization have offered unprecedented freedom in designing new polyolefins, controlling polyolefin structure, and tailoring materials properties. The main theme of this sandwich-style thesis is the synthesis, characterization, and properties of a novel series of polyolefin materials that have unique chain structures and superior materials properties. These polyolefin materials were respectively prepared with a variety of recently developed single-site catalysts. High-strength polyethylene fibers were in situ synthesized Via nano-extrusion polymerization of ethylene with a mesoporous particle (MCM-41) supported titanocene catalyst, Cp2TiCh. The unique nanotube structure prevented the conventional folding of growing polymer chains inside the nanotubes and thus led to the formation of polyethylene nanofibrils with unique extended chain crystalline structure. Further aggregation of nanofibrils resulted in macro-scale