Ethylene-Norbornene Copolymerization by Rare-Earth Metal Complexes and by Carbon Nanotube-Supported Metallocene Catalysis

• Published in: Macromolecular symposia 2008-01, Vol.260 (1), p.114-121
• Main Authors: Tritto, I, Boggioni, L, Ravasio, A, Zampa, C, Hitzbleck, J, Okuda, J, Bredeau, S, Dubois, P
• Format: Article
• Language: English
• Subjects: Applied sciences; Catalysis; Copolymerization; Copolymers; ethylene-norbornene copolymers; Exact sciences and technology; living polymerization; metallocene catalysts; Nanocomposites; Nanomaterials; Nanostructure; Organic polymers; Physicochemistry of polymers; polymer nanocomposites; Preparation, kinetics, thermodynamics, mechanism and catalysts; Rare earth compounds; rare earth metal catalysts; Rare earth metals
• ISSN: 1022-1360; 1521-3900
• DOI: 10.1002/masy.200751416

E-N copolymerization with a number of half-sandwich rare-earth metal compounds [M(η5-C₅Me₄SiMe₂R)(η1-CH₂SiMe₃)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(η5-C₅Me₄SiMe₂C₆F₅)(η¹-CH₂SiMe₃)₂(THF)]/[/[Ph₃C][B(C₆F₅)₄] possess narrower molar mass distributions than those from [Sc(η⁵-C₅Me₄SiMe₃)(η¹-CH₂SiMe₃)₂(THF)]/[Ph₃C][B(C₆F₅)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)₂ZrCl₂/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.