Edmund M. Carnahan

Supported metallocene catalysts

Single-site olefin polymerization catalysts have been researched extensively and are now achieving wide acceptance in the polyolefin industry. To achieve commercial significance in the majority of todays commercial processes, these soluble catalysts must be immobilized on a carrier. The challenges of supporting metallocene catalysts have been addressed in many creative ways and are the topic of this paper.

Chain Shuttling Catalysis and Olefin Block Copolymers (OBCs)

Olefin block copolymers (OBCs) with new-to-the-world properties have recently been made via a process called chain shuttling polymerization. These systems comprise two or more catalysts with differing affinities for comonomer combined with a chain shuttling agent (CSA), which distributes the growing polymer chains among the various catalysts. The result is a unique block copolymer, with statistically distributed block sizes and numbers of blocks per chain. A unique property of the materials is that the melting temperature is nearly independent of the comonomer incorporation, which breaks a seemingly immutable relationship that was long held to be true.