Elf Atochem S.a.

Atofina

Other

Koch Materials Company

Koch Material Company

Elf Exploaration Production

Pascal Nicol

Laurent Germanaud

Bruno Vuillemin

Philippe Heim

Jean-Pascal Planche

David H Rein

Paul Rempp

Pierre Lutz

Bernard Boutevin

Denis Bertin

Muriel Plechot

Francedillaois Travers

Paul Tordo

Patrick Turello

Yves Gnanou

Jean-Pierre Bernard Finet

Fran&ccedil;ois Lemoigne

Laurence Orozco

Herve Nabet

Robert Jerome

Philippe Teyssie

Claude Granel

Polymerization in the presence of a stable free radical and of a free radical initiator

The present invention relates to a process for the manufacture of a composition comprising a vinylaromatic polymer and a rubber, wherein the polymerization stage is carried out in the presence of a stable free radical in a polymerization mixture. The presence of the stable free radical in the polymerization mixture makes its possible to increase the melt index and to influence the size of the rubber nodules in the final composition by generally increasing the fraction, by volume, of the rubbery phase and by widening the distribution of the size of these nodules. This is reflected by an improvement both in the melt index and in the impact strength of the final composition, which makes the latter an ideal composition for injection molding.

Process for the manufacture of a composition comprising a vinylaromatic polymer and a rubber by polymerization in the presence of a stable free radical

The invention relates to a process for the polymerization or copolymerization of at least one monomer which is polymerizable by the radical route in the presence of a stable free radical from the nitroxide family. The stable free radical is &bgr;-substituted and provides excellent control of polydispersity while ensuring a better rate of polymerization or copolymerization, if they are compared with the stable free radicals used in the prior art.

Polymerization in the presence of a &bgr;-substituted nitroxide radical

Polymerization in the presence of a stable free radical and of an iniferter

The present invention relates to the stabilization of a polymer by a stable free radical and in particular to the use of a stable free radical for inhibiting the degradation of a polymer by a mechanism which does not involve oxygen. This use can be carried out when the polymer is in the presence or in the absence of oxygen. The degradation which can be inhibited can be a depolymerization or a crosslinking.

Stabilization of a polymer by a stable free radical

A process is provided for the preparation of a bitumen-polymer composition which comprises

Process for the preparation of bitumen-polymer compositions, application

The process for the controlled radical (co)polymerization of (meth)acrylic and/or vinyl monomers is characterized in that the bulk, solution, emulsion or suspension polymerization or copolymerization is carried out, at a temperature at which can fall to 0.degree. C., of at least one of the said monomers in the presence of an initiating system comprising a radical-generating compound and at least one catalyst composed of a metal complex containing a ligand of the type

Process for the controlled polymerization or copolymerization of

A multifunctional anionic polymerization initiator which is in the form of a star-shaped polymer, and which is soluble in a nonpolar medium and is substantially free of residual double bonds. The initiator is denoted by the general formula (PA).sub.a N.sup.n- nLi.sup.+. PA is a polymer block of a vinylaromatic or diene monomer A. The variable 'a' is the number of branches in the block PA. N is a crosslinked core comprising no or practically no residual double bonds and has the formula (PMc)(RLi).sub.p. Mc is a monomer containing at least two polymerizable double bonds per molecule. PMc is a crosslinked core of at least one polymerized monomer Mc, containing 3 to 30% of residual double bonds in relation to the initial double bonds originating from the monomer Mc. R is an alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl, or alkenyl. The variable 'p' is the number of residual double bonds in PMc which are neutralized by RLi. The variable 'n' is the number of anionic sites present in the crosslinked core N. A process of making and using the initiator to prepare star-shaped polymers.

Multifunctional initiator for obtaining star-shaped polymers by an

Elastomer functionalized by grafted carboxyl or ester groups and its

The invention relates to a star block copolymer of the formula [S.sub.1 -S.sub.2 -(B.sub.1 /S.sub.3)-B.sub.2 ].sub.m -X-[B.sub.2 (B.sub.1 /S.sub.3)-S.sub.2 ].sub.n in which X represents a polyfunctional radical resulting from a coupling agent, m and n represent non-zero integers such that m+n is equal to 3 or 4, S.sub.1 and S.sub.2 each represent a block of a polymer containing at least one vinylaromatic monomer, B.sub.2 represents a block of a polymer containing at least one conjugated diene, (B.sub.1 /S.sub.3) represents a block of a statistical copolymer containing at least one vinylaromatic monomer and at least one conjugated diene, 40 to 75% by weight of (B.sub.1 /S.sub.3) consisting of resulting from vinylaromatic monomer, characterized in that the sum of the mass of the blocks B.sub.2 contains more than 40% by weight and less than 90% by weight of the total mass of the conjugated diene contained in the said star block copolymer. The invention also relates to the process for obtaining this copolymer. The compositions comprising this copolymer and crystal polystyrene have noteworthy mechanical properties and transparencies.

Star block copolymer of vinylaromatic monomer and of conjugated diene

A multifunctional anionic polymerization initiator which is in the form of a star-shaped polymer soluble in an apolar medium and substantially free of residual double bonds. The initiator is denoted by the general formula (PA).sub.a N.sup.n- nLi.sup.+. PA is a polymer block of a vinylaromatic or diene monomer A. The variable 'a' is the number of branches in the block PA. N is a crosslinked core comprising no or practically no residual double bonds and has the formula (PMc)(RLi).sub.p. Mc is a monomer containing at least two polymerizable double bonds per molecule. PMc is a crosslinked core of at least one polymerized monomer Mc, containing 3 to 30% of residual double bonds in relation to the initial double bonds originating from the monomer Mc. R is an alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl, or alkenyl. The variable 'p' is the number of residual double bonds in PMc which are neutralized by RLi. The variable 'n' is the number of anionic sites present in the crosslinked core N. A process of making and using the initiator to prepare star-shaped polymers.

A process for manufacturing block copolymers comprising anionically polymerizing a vinyl aromatic hydrocarbon mononer in solution in an aromatic hydrocarbon solvent capable of giving a homogeneous medium until attaining a homogeneous medium with a viscosity greater than 300 Pa.s at 20.degree. C. for a concentration of polymer in the aromatic hydrocarbon solvent between 60 and 90% by weight and then, after introduction of a conjugated diene, carrying out a copolymerization until a homogeneous medium is attained have a viscosity greater than 300 Pa.s at 90.degree. C. for a concentration of copolymer in the aromatic hydrocarbon solvent between 70 and 90% by weight, without the viscosity exceeding 3,000 Pa.s in either of the two polymerization steps.

Procedure for manufacturing transparent, impact-resistant styrene resin

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Pau, France

Pascal Nicol