Ethylene/Styrene Copolymerization by (Me3SiC5H4)TiCl2(O-2,6-iPr2-4-RC6H2) (R = H, SiEt3)-MAO Catalysts: Effect of SiMe3 group on Cp for Efficient Styrene Incorporation

Synthesis and structural analysis of (Me3SiC5H4)TiCl2(OAr) [OAr = O-2,6-iPr2-4-RC6H2; R = H, SiEt3] that exhibit higher catalytic activities than (tBuC5H4)TiCl2(OAr), Cp*TiCl2(OAr) with efficient comonomer incorporation in the ethylene/styrene copolymerization in the presence of methylaluminoxane (MAO) cocatalyst. The catalytic activity in the copolymerization increased upon increasing the styrene concentration charged along with increase in the styrene content in the copolymers, whereas the activities by other catalysts showed the opposite trend. (Me3SiC5H4)TiCl2(O-2,6-iPr2C6H3) displayed the most suitable catalyst performance in terms of the activity and the styrene incorporation to afford the amorphous copolymers with styrene contents higher than 50 mol% (up to 63.6 mol%) with random styrene incorporation confirmed by 13C-NMR spectra.