Two Catalyst Combo Builds Multiblock Copolymer

Significance

The Dow scientists describe an economical method to produce olefin multiblock copolymers using a mixture of two catalysts with different affinities for the two monomers and a chain-shuttling agent. The authors identify the ideal catalysts and chain-transfer agent by employing high-throughput screening; remarkably, 1600 distinct polymerizations were screened in three weeks by monitoring the polymer molecular weights and distributions. The resulting polymer microstructures are different from those obtained from conventional living copolymerizations, thus producing new materials with unique physical properties. Additionally, this two-catalyst system is highly tunable; for example, the relative amount of each catalyst or the chain-shuttling-agent-to-monomer concentration ratio can be changed.