Isotactic and Syndiotactic Ethylene-alt-alfa-Olefin Copolymers from Highly Stereoregular Iso- and Syndiotactic cis-1,4 Poly(1,3-Diene)s

The stereospecific polymerization of 1,3-dienes with transition metal and lanthanide catalysts can give polymers with different structure (cis-1,4; trans-1,4; 1,2; 3,4; iso- and syndiotactic) from different monomers. The great availability of all these highly stereoregular polydienes may represent an outstanding source of highly stereoregular olefin copolymers, hardly obtainable through the simple and common stereospecific polymerization of the corresponding monomers. Thus for example, the hydrogenation of isotactic and syndiotactic cis-1,4 polydienes can give perfectly alternating isotactic and syndiotactic ethylene/alfa-olefin copolymers. On the synthesis and characterization of isotactic and syndiotactic perfectly alternating ethylene/2-butene and ethylene/propylene copolymers, we have already reported. In the present communication we are now describing the synthesis and characterization of i) perfectly alternating isotactic ethylene/1-butene copolymers, obtained by hydrogenation of isotactic cis-1,4 poly(1,3-hexadiene); ii) perfectly alternating ethylene/1-pentene copolymers, iso- and syndiotactic, obtained by hydrogenation of cis-1,4 poly(1,3-heptadiene)s, iso- and syndiotactic ; iii) perfectly alternating ethylene/1-hexene copolymers, iso- and syndiotactic, obtained by hydrogenation of cis-1,4 poly(1,3-octadiene)s, iso- and syndiotactic.