| 摘要 |
<p>Ethylene-propylene-diene terpolymers are prepared by the polymerization of mixtures of the three monomers, carried out in the presence of catalysts comprising: A) A solid catalytic component containing at least on its surface compounds or mixtures of compounds comprising Mg, Ti, halogens and an electron-donor compound, characterized in that at least 50% by weight of Ti compounds present in it are insoluble in Ti tetrachloride at 80 DEG C, and that the surface area after extraction by TiCl4 is greater than 40 m<2>/g, and B) an organometallic compound of aluminium. In particular, the component A) comprises a titanium tetrahalide and an electron-donor compound, supported on anhydrous MgCl2 or MgBr2 in active form, the X-ray diffraction spectrum of which shows, in lieu of the highestintensity line appearing in the normal dihalide spectrum, a halo having an intensity maximum shifted relatively to the d distance of such line.</p> |
