Olefinic Block Copolymer Production Using Dow Chemical's Chain Shuttling Process

The Dow Chemical Company has recently developed a new process to produce olefin block copolymers (OBCs). The OBCs can be produced using a conventional continuous solution process with a mixture of metallocene catalysts. To produce the OBCs, a chain shuttling agent (CSA) is added to the polymerization mixture. The CSA is a metal alkyl complex such as diethyl zinc. The microstructures of the OBCs are controlled by manipulating the catalyst com-bination, CSA, and relative comonomer concentration in the reactor feed. In this review, the process to produce linear ethylene-based block copolymers via chain shuttling polymerization is examined.