Highly stereoregular co:polymers of ethylene] and aromatic vinyl compounds, e.g. styrene]

摘要

Copolymers (I) of ethylene (II) and aromatic vinyl compounds (III), containing between 1 and less than 55 mol.% (III), in which the phenyl groups have a stereoregularity in the alternating (II)/(III) structure of formula (1) expressed by an isotactic symmetry (diad) index (m) of more than 0.75. The structure index ( lambda ) according to equation (i) is greater than 1 and less than 70 : lambda = A3/A2 x 100 (i) A3 = sum of area under peaks a, b and c obtained from a 13C-NMR spectrum for an alternating (II)/(III) structure according to formula (1`) ; and A2 = sum of area under the 13C-NMR spectra peaks for main chain methylene and methylene carbon within the 0-50 ppm range, using TMS as a standard. Ph = aromatic group, eg. phenyl ; and xa = at least 2. Also claimed are (i) the preparation of (I) and (ii) catalysts used for the preparation of stereoregular ethylene / aromatic compound copolymers, comprising transition metal compounds each containing one or two optionally substituted indenyl groups or an optionally substituted cyclopentadienyl group.