INFLUENCE OF POLYMERIZATION CONDITIONS ON MICROSTRUCTURE OF NORBORNENE-ETHYLENE COPOLYMERS MADE USING METALLOCENE CATALYSTS AND MAO

When characterized with C-13-NMR, it was found that norbornene-ethylen e copolymers had a more complicated microstructure when dimethylsilyl bis(indenyl) zirconium dichloride was used as the catalyst compared to ethylene bis(indenyl) zirconium dichloride. One could see more block sequences but less alternating sequences. For both catalysts the highe st amounts of block sequences were obtained for high norbornene concen trations, medium to high Al/Zr ratios, and low polymerization temperat ures. There were also more alternating sequences for high norbornene c oncentrations and high polymerization temperatures. The isolated norbo rnene units (separated by more than one ethylene unit) were all exocon figuration. No unsaturation was seen. (C) 1997 John Wiley & Sons, Inc.