Abstract
Ultra-high molecular weight polyethylene (UHMWPE) possesses advantages over conventional polyolefins such as excellent mechanical properties. Recent progresses in transition-metal complexes have led to the discovery of highly active catalysts for the preparation of UHMWPE. In this study, Ti with bis(phenoxy-imine) ligand (FI catalyst) and Me2Si(C5Me4)(N-tBu)TiCl2 (CGC) were immobilized on silica and tested for the preparation of UHMWPE. Results revealed that soluble FI catalyst and CGC can produce polyethylene having relatively high molecular weight above 106 g/mol, which also can be successfully immobilized on carriers for better adaptability to production processes.
ACKNOWLEDGEMENTS
This research was kindly supported by a grant from the Fundamental R & D Program for Core Technology of Materials (10037176) funded by the Ministry of Knowledge Economy, Republic of Korea.
Notes
a Polymerization conditions: reactor = 250 mL round bottom flask; catalyst concentration = 3 × 10−5 mol/L; cocatalyst = MAO, 6 × 10−2 mol/L; [Al]/[cat] = 2000; pressure = 1 bar; temperature = 50°C.
a Polymerization condition: reactor = 250 mL round-bottom flask; catalyst = FI catalyst, 2.0 × 10−5 mol/L; MAO, 5.0 × 10−2 mol/L, [Al]/[FI] = 2500; Ph3CB(C6F5)4, 4.0 × 10−5 mol/L, [FI]:[Ph3CB(C6F5)4]:[TIBAL] = 1: 2: 500; toluene, 125 mL; pressure = 1 bar; time = 20 minutes.
a Polymerization condition: reactor = 250 mL round bottom flask or 100 mL autoclave; catalyst = FI catalyst, 2.0 × 10−5 mol/L; MAO, 5.0 × 10−2 mol/L, [Al]/[FI] = 2500; Ph3CB(C6F5)4, 4.0 × 10−5 mol/L, [FI]:[Ph3CB(C6F5)4]:[TIBAL] = 1: 2: 500; time = 20 minutes; temperature = 40°C.
b Temperature = 70°C; time = 10 minutes.
a Polymerization conditions: reactor = 1 L autoclave; temperature = 70°C; polymerization time = 90 minutes; solvent = isobutane, 400 mL.
b Polymerization temperature was 50°C and solvent was heptanes 100 mL, since isobutane is in gaseous phase at 1 bar.
c Not determined.
a Polymerization condition: reactor = 250 mL round-bottom flask; catalyst = immobilized FI catalyst (55 µmol-Ti/g-cat), 1.1 × 10−5 mol-Ti/L; toluene, 125 mL; pressure = 1 bar; time = 60 minutes; temperature = 70°C.
a Polymerization condition: reactor = 250 mL round-bottom flask or 100 mL autoclave; catalyst = immobilized FI catalyst (55 µmol-Ti/g-cat), 1.1 × 10−5 mol-Ti/L; scavenger, TIBAL 150 mg; solvent, 125 mL; time = 60 minutes.
b Solvent, 40 mL.