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Homo and copolymerization of ethylene: improvement of supported vanadium catalysts performance by halocarbons
Author(s) -
Ribeiro M. Rośario,
Deffieux Alain,
Fontanille Michel,
Portela Manuel F.
Publication year - 1995
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1995.021961133
Subject(s) - comonomer , copolymer , ethylene , vanadium , catalysis , chemistry , polymer chemistry , organic chemistry , polymer
The effect and the role of halogenated molecules as additives for supported vanadium catalytic systems has been investigated both in high temperature ethylene homopolymerization and in its copolymerization with 1‐hexene. Addition of CH 3 CCI 3 to the {VCl 3 , x AICI 3 } or {VCl 3 , x CrCI 3 } system, leads to a strong productivity improvement. The intensity of the activating effect depends on the nature of the support. Results suggest that the activation involves both oxidation of V(II) deactivated species into potentially active trivalent ones, and generation of new active sites. Studies on the structure of ethylene/1‐hexene copolymers show that the addition of halocarbons leads to copolymers with a higher comonomer content (SCB) and a better homogeneity in composition.