Studies on chain shuttling polymerization reaction of nonbridged half-titanocene and bis(phenoxy-imine) Zr binary catalyst system

Abstract

In this contribution, olefin block copolymers were produced via chain shuttling polymerization (CSP), using a new combination of catalysts and a chain shuttling agent (CSA) diethylzinc (ZnEt2). The binary catalyst system included nonbridged half-titanocene catalyst, Cp*TiCl2(O-2,6-iPr2C6H3) (Cat A) and bis(phenoxy-imine) zirconium, {η2-1-[C(H)=NC6H11]-2-O-3-tBu-C6H3}2ZrCl2 (Cat B), as well as co-catalyst methylaluminoxane (MAO). In contrast to dual-catalyst system in the absence of CSA, the blocky structure was obtained in the presence of CSA and rationalized from rheological studies. The binary catalyst system could cause the CSP reaction to occur in the presence of CSA ZnEt2, which yielded broad distribution ethylene/1-octene copolymers (Mw/Mn: 35.86) containing block polymer chains with high Mw. The presented dual-catalytic system was applied for the first time in CSP and has a potential to be extended to produce a library of olefin block copolymers that can be used as advanced additives for thermoplastics.