Basf Aktiengesellschaft

Ecp-enichem Polymeres France S.a.

Michel Fontanille

Alain Deffieux

Christian Schade

Philippe Desbois

Volker Warzelhan

Wolfgang Fischer

Hermann Gausepohl

Konrad Knoll

Karel Bujadoux

Wolfgang Loth

Stephan J&uuml;ngling

Rainer Klostermann

Emmanuel Adisson

Stefan L&auml;tsch

Stephane Menoret

In a process for the anionic polymerization of vinylaromatic monomers or dienes in the presence of a lithium organyl or lithium alcoholate and a magnesium and/or an aluminum compound, a sterically hindered phenol or amine is added.

Method for carrying out the anionic polymerization of vinylaromatic monomers

Anionic polymerization process

In a process for the homopolymerization of vinylaromatic monomers or the copolymerization of vinylaromatic monomers and dienes, the monomers are polymerized in the presence of at least one alkali metal organyl, at least one magnesium organyl and at least one aluminum organyl. The invention also provides an initiator composition for carrying out the process.

Method for retarded anionic polymerization

Disclosed are a process for the preparation of an initiator composition comprising an alkali metal organyl and an aluminum organyl and a process for the polymerization of anionically polymerizable monomers.

Method for the production of an initiator composition for retarded anionic polymerization

This catalyst has the general formula VX.sub.3, mAIX.sub.3, nZ, wherein X is a halogen atom, Z is at least one at least partially halogenated, branched or unbranched, saturated hydrocarbon, m is between 0.1 and 10, and n is between 1 and 300. To prepare it, a vanadium halide VX.sub.2 and/or VX.sub.3 is coground with an aluminum halide AlX.sub.3, and then at least one halogenated hydrocarbon Z is added to the mixture obtained in proportions corresponding to the chosen values of m and n. The invention also relates to the (co)polymerization of alpha-olefins at 20.degree.-350.degree. C. in the presence of a catalyst system comprising at least one catalyst as defined above and at least one organometallic activator.

Catalyst for the (co)polymerization of alpha-olefins, a process for its

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Talence, France

Michel Fontanille