Elf Atochem S.a.

Atofina

Manuel Hidalgo

Christian Collette

Andre Kowalik

Emmanuel Puchois

Philippe Bonnet

Paul Mallo

Michel Devic

Christophe Navarro

Beatrice Boussand

Jean-Marc Corpart

Francois Court

Fabienne Lebendenko

Shu-Rong Rebre

Use is made, for selectively hydrogenating the olefinic double bonds of block copolymers, at least one block of which comprises olefinic double bonds, using a catalyst based on a metal from Group VIII in a medium comprising an organic solvent for the copolymer and an ionic liquid as solvent for the catalyst, of a water-immiscible ionic liquid, preferably an ionic liquid for which the anion is the hexafluorophosphate anion and the cation is the 1-butyl-3-methylimidazolium (bmim) or 1-ethyl-3-methylimidazolium (emim) cation. Applied to poly(styrene)-b-poly(butadiene)-b-poly(methyl methacrylate) block copolymers, the poly(butadiene) block of which predominantly possesses a 1,4-microstructure, this process results in copolymers for which the degree of hydrogenation is at least equal to 50% and which exhibit a melting point of greater than 30 &#xb0;C.

Hydrogenation method for unsaturated block copolymers and hydrogenated unsaturated block copolymers

Certain mixtures of two superabsorbent powders having very different capillary suctions exhibit a resulting capillary suction which approaches the higher value. The resulting mixtures simultaneously exhibit a high capillary suction and a high intrinsic absorption capacity.

Superabsorbent powders of high absorption and high capillary suction

Rapidly dissolving/absorbing free-flowing powders of hydrophilic/superabsorbent (co)polymers, having irregular nonspherical morphology and a particle size distribution ranging from 100 .mu.m to 800 .mu.m, are prepared by (a) phase inversion (co)polymerizing stirred admixture of (i) a hydrocarbonic solution of at least one surfactant having an HBL ranging from 8 to 12 and (ii) an aqueous solution of at least one hydrophilic unsaturated monomer, in the presence of an effective amount of a radical polymerization initiator and at a predetermined temperature of (co)polymerization, (b) next introducing into the medium of (co)polymerization, after (co)polymerization of the at least one hydrophilic unsaturated monomer, a second aqueous solution of at least one hydrophilic unsaturated monomer, (c) then (co)polymerizing the second aqueous solution, and (d) thence extracting the hydrocarbonic phase and water from the resulting (co)polymerizate and drying same, with the proviso (e) that the second aqueous monomer solution is introduced at a temperature of about the predetermined temperature of (co)polymerization and the volumetric ratio of aqueous phase to hydrocarbonic phase ranges from 0.6 to 1.2.

Preparation of rapidly dissolving/absorbing powders of hydrophilic/super

Shell/core distortion-resistant particulates of a partially crosslinked superabsorbent polymer, the gradient of partial crosslinking of which being to such extent that the shells are harder and less flexible than the cores thereof, have a capacity to absorb 0.9% saline water of at least 50 g/g and the modulus of which is at least 35,000 Pa; a bed of a saline water gel of the subject particulates has a saline water absorption of at least 20 g/g and a porosity of at least 500 g.

Shell/core particulates of superabsorbent polymers

The process consists in the agglomeration of fine particles of superabsorbent polymer, carried out by introducing an aqueous solution of monomer into a slurry of aqueous polymer dispersed within a hydrocarbon liquid, this introduction being performed directly at the temperature and in conditions of polymerization of the monomer. A superabsorbent product is thus obtained in a very good yield, in the form of aggregates of particles such that the fraction passing through a 100-micron screen is less than 1%.

Process for obtaining polymers which are superabsorbent for water and

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Bois-Colombes, France

Manuel Hidalgo