Synthesis of Polyolefins with Combined Single-Site Catalysts



This manuscript shows how two single-site catalysts can be used to produce polyolefins with complex microstructures that cannot be made using conventional Ziegler-Natta or Phillips catalysts. In the first case study, thermoplastic polyolefins with heterogeneously branched structures are made by the copolymerization of ethylene, an α-olefin, and an α-ω diene using two metallocene catalysts in a two-stage solution polymerization process. In the second, metallocenes and late transition metal catalysts are co-supported on silica particles to produce ethylene/α-olefin copolymers with inverse comonomer distribution in a single slurry reactor, by manipulating the comonomer reactivity ratios and chain walking frequencies of the catalyst pair.