Rhone-Poulenc Chimie

Flamel Technologies

Frederic Leising

Jean-Marc Frances

Ghislaine Torres

Gerard Mignani

Bernard Chauvel

Remi Meyrueix

Patricia Fompeyrine

Loic Doguet

Etienne Foucher

The invention relates to a process for the preparation of polyorganosiloxanes by hydrolysis of organohalosilanes of formula (I) R.sub.a R.sup.1.sub.b SiX.sub.c, wherein R and R.sup.1 identical or different, are an hydrogen atom or a linear or branched C.sub.1 -C.sub.6 alkyl, aryl, alkylaryl or aralkyl group; X is a halogen atom; and a+b+c=4 and 0&lt;c&lt;4; said process comprising the steps of carrying out three or more successive hydrolysis steps (1), (2), (3), in which the reaction medium is capable of exerting an increasing hydrolysing force on the organohalosilanes (I), wherein step (1) is a hydrolysis under pressure in the presence of an aqueous solution S.sub.1 of saturated hydrogen halide, at the pressure and temperature of the reaction medium; and, optionally, carrying out one or more coalescence step (4).

Process for the preparation of polyorganosiloxanes by hydrolysis of

Cyclopentadienyl and/or cyclopentadienylene and/or dicyclopentadienylene-substituted polyorganosiloxanes that are crosslinkable into elastomeric state on exposure to atmospheric oxygen and/or to moisture are well suited, e.g., for adhesive applications in the construction industry and for diverse insulating/coating applications.

Cyclopentadienyl and/or cyclopentadienylene and/or dicyclopentadienylene

The present invention relates to an organopolysiloxane composition, containing a cyclopentenyl radical, which is stable on storage in the absence of gaseous oxygen, in particular in the absence of atmospheric oxygen, and is crosslinkable to an elastomer in the presence of gaseous oxygen, originating in particular from the atmosphere, characterized in that it comprises:

Organopolysiloxane composition containing a cyclopentenyl radical and

The present invention relates to new thiphene-related compounds of the general formula (I): ##STR1## in which: n is an integer between 1 and 10, advantageously between 1 and 4;

Thiophene-related compounds active in nonlinear optics, materials and

The present invention proposes a silane and an organopolysiloxane containing a cyclopentenyl radical, characterized in that the silane or the organopolysiloxane has a radical Y of the formula: ##STR1## directly linked to the silicon atom. The silanes according to the invention can be used as coupling and crosslinking agents, in particular in the compositions of acrylic paints. The diorganopolysiloxanes according to the invention can be used as base polymer of a silicone composition which is crosslinkable to an elastomer, in particular by exposure to atmospheric oxygen.

Silane and organopolysiloxane containing a cyclopentenyl radical and

Magnetizable composite particles, optionally in aqueous dispersion, consisting of a matrix based on a crosslinked organopolysiloxane, optionally bearing nonvinyl reactive and/or ionic units and magnetizable components less than 300 angstroms in diameter encapsulated in the matrix. The magnetizable composite particles are prepared by homogenizing a solution of the organopolysiloxane, an organohydrogenopolysiloxane optionally bearing ionic and/or reactive units, and a magnetic fluid, in the presence of water and a surfactant, performing a hydrosilylation in an aqueous emulsion, removing the organic solvents and the organic carrier liquid, and at least partially removing the water. The magnetizable composite particles are useful in biological applications.

Magnetizable composite particles based on crosslinked

Magnetizable microspheres, optionally in aqueous dispersion, consisting of a matrix of at least one organopolysiloxane optionally bearing Si-vinyl groups or reactive and/or ionic units and magnetizable particles less than 300 angstroms in diameter encapsulated in the matrix. The magnetizable microspheres are prepared by homogenizing a solution of the organopolysiloxane and a magnetic fluid in the presence of water and a surfactant, removing the solvent for the organopolysiloxane and the carrier liquid of the magnetic fluid, and at least partially removing the water. The magnetizable microspheres are useful in biological applications as active supports.

Process for the preparation of magnetizable microspheres based on

Magnetizable composite particles, optionally in aqueous dispersion, consisting of a matrix based on a crosslinked organopolysiloxane, optionally bearing nonvinyl reactive and/or ionic units and magnetizable components less than 300 angstroms in diameter encapsulated in the matrix. The magnetizable composite particles are prepared by homogenizing a solution of the organopolysiloxane, an organohydrogenpolysilioxane optionally bearing ionic and/or reactive units, and a magnetic fluid, in the presence of water and a surfactant, performing a hydrosilylation in an aqueous emulsion, removing the organic solvents and the organic carrier liquid, and at least partially removing the water. The magnetizable composite particles are useful in biological applications.

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Mornant, France

Frederic Leising