Ethylene norbornene copolymerization by rare-earth metal complexes and by carbon nanotube-supported metallocene catalysis

E-N copolymerization with a number of half-sandwich rare-earth metal compounds [M(eta 5-C(5)Me(4)SiMe(2)R)(eta 1-CH(2)SiMe(3))(2)(L)] (M = Sc, Y, Lu) has been achieved. Mainly atactic alternating E-N copolymers are obtained with all catalytic systems. Interestingly, copolymers arising from [Sc(eta 5-C(5)Me(4)SiMe(2)C(6)F(5))(eta(1)-CH(2)SiMe(3))(2)(THF)]/[/ [Ph(3)C][B(C(6)F(5))(4)] possess narrower molar mass distributions than those from [SC(eta(5)-C(5)Me(4)SiMe(3))(eta(1)-CH(2)SiMe(3))(2)(THF)]/[Ph(3)C][B(C(6)F(5))(4)]. In addition, homogeneous surface coating of multi-walled carbon nanotubes is accomplished for the first time by in situ E-N copolymerization as catalyzed by rac-Et(Ind)(2)ZrCl(2)/MMAO-3A anchored onto the carbon nanotube surface. The copolymerization reaction allows for the destructuration of the native nanotube bundles. The relative quantity of E-N copolymer can be tuned up as well as the norbornene content in the formed copolymers and accordingly their glass transition temperature. By melt blending with an ethylene-vinyl-co-acetate copolymer (27 wt.-% vinyl acetate comonomer) matrix, high performance polyolefinic nanocomposites are obtained.