Single-site and dual-site metallocene ethene/propene copolymerizations : experimental and theoretical investigations

Three series of ethylene-propylene copolymers are made using the catalysts (1) rac-[Me2Si(2-Me-4-(1-Naph)Ind)2]ZrCl2/MAO, (2) [Me2Si(Ind)(Flu)]ZrCl2/MAO, and (3) a 1:5 mixt. of 1 and 2, all with a broad range of (co)monomer mole fractions in the reactor and copolymers. All three series are analyzed by 13C NMR, DSC, and SEC. The 13C NMR spectra of the single-site series are the input of the direct peak method to det. the second-order Markov reactivity ratios of the catalysts used. The activities and reactivity ratios of the catalysts in the single-site expts. are used to model the dual-site series based on 13C NMR data. The results of this modeling are used to interpretate the DSC and SEC data of the dual-site series: most of the melting peak temps. and molar masses of the dual- site can be attributed to one of the two catalysts