Synthesis of ultra-high molecular weight poly(ethylene)- co -(1-hexene) copolymers through high-throughput catalyst screening.

A family of permethylindenyl titanium constrained geometry complexes, Me 2 SB( R' N, 3-R I*)TiX 2 ((3-R-η 5 -C 9 Me 5 )Me 2 Si( R' TiX 2 )), supported on solid polymethylaluminoxane (sMAO) are investigated as slurry-phase catalysts for ethylene/H 2 homopolymerisation and ethylene/1-hexene copolymerisation by high-throughput catalyst screening. Me 2 SB( t Bu N,I*)TiCl 2 supported on sMAO [sMAO-Me 2 SB( t Bu N,I*)TiCl 2 ] is responsive to small quantities of H 2 (<1.6%), maintaining high polymerisation activities (up to 4900 kg PE mol Ti -1 h -1 bar -1 ) and yielding polyethylenes with significantly decreased molecular weight ( M w ) (from 2700 to 41 kDa with 1.6% H 2 ). In slurry-phase ethylene/1-hexene copolymerisation studies, a decrease in polymerisation activity and polymer molecular weights compared to ethylene homopolymerisation is observed. Compared to many solid supported system, these complexes all display high 1-hexene incorporation levels up to a maximum incorporation of 14.2 mol% for sMAO-Me 2 SB( iPr N,I*)TiCl 2 ). We observe a proportionate increase in 1-hexene incorporation with concentration, highlighting the ability of these catalysts to controllably tune the amount of 1-hexene incorporated into the polymer chain to produce linear low-density polyethylene (LLDPE) materials.