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The suitability of the (n‐butCp)2ZrCl2/methylaluminoxane (MAO) catalyst system for the copolymerization of ethene with propene, hexene, and hexadecene was studied and Ind2ZrCl2/MAO was tested as a catalyst for ethene/propene and ethene/hexene copolymerizations. The synergistic effect of longer α‐olefin on propene incorporation in ethene/propene/hexene and ethene/propene/hexadecene terpolymerizations was investigated with Et(Ind)2ZrCl2MAO and (n‐butCp)2ZrCl2/MAO catalyst systems. The molar masses, molar mass distributions, melting points, and densities of the products were measured. The incorporation of comonomer in the chain was further studied by segregation fractionation techniques (SFT), by differential scanning calorimetry (DSC), studying the β relaxations by dynamic mechanical analysis (DMA) and by studying the microstructure of some copolymers by 13C‐NMR. In this study (n‐butCp)2ZrCl2 and Ind2ZrCl2 exhibited equal response in copolymerization of ethene and propene and both catalysts were more active towards propene than longer α‐olefins. A nearly identical incorporation of propene in the chain was found for the two catalysts when a higher propene feed was used. A lower hexene feed gave a more homogeneous comonomer distribution curve than a higher hexene feed and also showed the presence of branching. In terpolymerizations catalyzed with (n‐butCp)2ZrCl2, the hexadecene concentrations of the ethene/propene/hexadecene terpolymers were always very low, and only traces of hexene were detected in ethene/propene/hexene terpolymers. With hexene no clear synergistic effect on the propene incorporation in the terpolymer was detected and with hexadecene the effect of the longer α‐olefin was even slightly negative. With an Et(Ind)2ZrCl2/MAO catalyst system both hexene and hexadecene were incorporated in the chain in the terpolymerizations. © 1997 John Wiley & Sons, Inc.

Ethylene/propylene (EP) and ethylene/l -octene (E/O) copolymers were polymerized with two bridged metallocene catalyst systems, Et(Ind)2ZrC12/MA0 and Et(Ind),HfCI,/MAO, respectively. The copolymers produced and some commercial reference copolymers were characterized by DSC, SEC, DMA and 13C NMR.The Hf-catalysed E P polymerizations showed much lower activities than the corresponding Zr-catalysed polymerizations but gave polymers with high molar mass. The Hf-based copolymers also showed two melting peaks which may be indicative of several active sites of the catalyst. A comparison of E P copolymers, containing about 20 mol-% propylene and produced with Zr, Hf and homogeneous V-catalysts, respectively, indicated that the Hf and V-catalysts gave material more similar to each other.The E/O copolymers produced with Zr-catalysts gave very low molar masses and the reactivity ratios, calculated from the NMR data, indicated that the Hf-catalyst has a slightly higher reactivity for 1-octene and the Zr-catalyst some better reactivity for ethylene. Segregation fractionation studies by DSC indicated that a lower l-octene feed gives more heterogeneous copolymers and the DMA measurements reveal the existence of a linear correlation between the 1-octene content and the intensity of the tan 6 , , ,ZUSAMMENFASSUNG: Ethylen/Propylen(E/P)-und Ethylerdl -octen(E/O)-Copolymere wurden mit zwei verschiedenen Katalysatorsystemen, Et(Ind)2ZrC12/MA0 und Et(Ind)2HfC12/MA0, hergestellt und mittels DSC, SEC, DMA und 13C-NMR charakterisiert. Die E P -Polymerisationen mit Hf ergaben niedrigere Katalysatoraktivitaten, jedoch zeigten die erhaltenen Polymeren eine hohere Molmasse und zwei verschiedene Schmelzpunkte, was auf unterschiedliche aktive Zentren des Katalysators hindeutet. E/O-Copolymere mit sehr niedrigen Molmassen wurden mit dem Zr-Katalysator hergestellt. Die Hf-Katalysatoren ergaben Copolymere mit hoheren Molmassen, je-