Elf Atochem S.a.

Centre National De La Recherche Scientifique

Paul Rempp

Bruno Vuillemin

Philippe Heim

Pascal Nicol

David H Rein

Pierre Lutz

Philippe Chaumont

Jean Herz

Gerard Beinert

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

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.

The invention relates to partially hydrophilic, non-ionic crosslinked copolymers. These copolymers consist of a crosslinked hydrophobic backbone having a high mechanical strength, and of non-ionic hydrophilic chains grafted selectively onto the backbone. The copolymers are useful for size exclusion chromatography in an aqueous medium.

Partially hydrophilic, non-ionic crosslinked copolymers and their

Growing community of inventors

Strasbourg, France

Paul Rempp