Abstract: A method of continuous application of a graded index plastics optical fiber in which the refractive index is highest in the center and decreases progressively towards the periphery, said fiber having a plurality of layers of resin deposited concentrically, the method comprising making a plurality of mixtures, each mixture comprising at least one polymer P and a reactive diluting agent including at least two monomers, then depositing said mixtures in the form of coaxial layers, allowing interdiffusing to take place between the layers, and finally crosslinking the polymer P and/or the reactive diluting agent.

Abstract: The invention relates to a process comprising a stage of polymerization or copolymerization of at least one polymerizable or copolymerizable monomer by a radical mechanism in the presence of a stable free radical and of an initiator of formula: R1—O—O—R2 wherein R1 and R2, which can be identical or different, represent an alkyl, aryl, alkylaryl or aralkyl radical comprising, for example, from 1 to 20 carbon atoms. The process is fast, allows the initiator to act more efficiently and results in polymers or copolymers exhibiting a low yellowing index.

Abstract: The present invention relates to a grafted copolymer bearing grafts of formula (I): —O—PM1—(PM2)—T  (I) in which: PM1 represents a polymer block obtained by (co)polymerization of at least one monomer M1 via a radical route; and PM2, which is optionally present, represents a polymer block obtained by (co)polymerization of at least one monomer M2 via a radical route; and T represents the residue of a stable radical T•.

Abstract: The invention relates to a process for the polymerization or copolymerization of at least one monomer which can be polymerized or copolymerized by the radical route in the presence of a stable free radical and of an iniferter. The presence of the stable free radical greatly modifies the behavior of the iniferter during the polymerization or copolymerization, so that undesirable reactions are much reduced. It is possible, rapidly and with a high yield, to polymerize or copolymerize in the presence of an iniferter in order to result in a polymer or copolymer with a reduced polydispersity and with a monomodal molecular mass distribution.

Abstract: The invention relates to a process for the polymerization or copolymerization of at least one monomer which can be polymerized or copolymerized by the radical route in the presence of a stable free radical and of an iniferter.

Abstract: This invention relates to copolymers of molecular mass of between 5,000 and 300,000, consisting of a hydrophilic central portion, for example a polyacrylamide chain, and of hydrophobic ends the hydrophobicity of which is comparable with that of alkyl groups containing 4-20 carbons. They are produced by polymerization of hydrophilic monomers with the aid of initiators, for example of azo type, the hydrophobic residues of which will constitute the hydrophobic ends of the final copolymer.These copolymers are useful for rheological control of aqueous and/or pigmented compositions, like paints.

Abstract: A product for forming a coating on a support, in particular a protective coating against corrosion, photonic degradation and/or against gas penetration, comprising a halogenated polymer and/or copolymer activated by at least one peroxide and/or hydroperoxide function to which at least one phosphonated chain is attached.

Abstract: This photopolymerizable composition includes an grafted reactive telomer containing trifluoroethyl methacrylate units, a reactive diluent and a photopolymerization initiator. It gives hydrophobic transparent coatings.

Abstract: The invention relates to a crosslinkable material containing a polymer onto which chromophores are laterally grafted, characterized in that each chromophore is within a polymer unit which corresponds to the following formula (I): ##STR1## in which: X represents a part of the polymer chain,A is a group --NO.sub.2, --CN, --C(CN).dbd.C(CN).sub.2 or --SO.sub.2 R.sub.4, R.sub.4 being a C.sub.1 to C.sub.6 alkyl,D is a nitrogen, sulphur or oxygen atom,R.sub.1 is a hydrogen atom or a C.sub.1 to C.sub.6 alkyl if D is a nitrogen atom, or nothing if D is a sulphur or oxygen atom,R.sub.2 is a C.sub.1 to C.sub.6 aliphatic alkyl group,and E is a group chosen from --OH, --O--CO--(CH.sub.2).sub.n --COOH, --O--W, --O--CO--R.sub.3 O--W and --O--R.sub.3 --O--W, n being an integer between 2 and 6, W being a photodimerizable group and R.sub.3 being a C.sub.1 to C.sub.6 alkyl,and the said material additionally containing complementary anchoring functional groups capable of attaching themselves to E during the crosslinking.

Abstract: A polymer material of the fluorine-containing polyurethane acrylate type for coating an optical fiber or for an optical fiber tape, the material being based on at least a diol, a diisocyanate, and an acrylate, and being characterized by the fact that at least one of the above compounds contains fluorine and that at least one of the above compounds contains sulfur.

Abstract: There is disclosed an improved method for preparing a hybrid organodisilanol compound having the formulaHO--R.sup.1 R.sup.2 SiC.sub.n H.sub.2n RC.sub.n H.sub.2n SiR.sup.1 R.sup.2 --OH (I)said method comprising:(A) reacting a dihydridosilane of the formulaR.sup.1 R.sup.2 SiH.sub.2 (II)with a diene of the formulaC.sub.n H.sub.2n-1 RC.sub.n H.sub.2n-1 (III)to provide a dihydrido compound of the formulaH--R.sup.1 R.sup.2 SiC.sub.n H.sub.2n RC.sub.n H.sub.2n SiR.sup.1 R.sup.2 --H (IV); and(B) reacting said dihydrido compound (IV) with a buffered water solution in the presence of a palladium catalyst.

Abstract: The invention relates to a crosslinkable material that is active in non-linear optics, containing a polymer which carries chromophores each included in a polymer unit of formula: ##STR1## in which: T is part of the polymer chain,A is an --NO.sub.2, --CN or --C(CN).dbd.C(CN).sub.2 group,R.sub.1 is a hydrogen atom or a methyl or ethyl group,R.sub.2 is a CH.sub.2, C.sub.2 H.sub.4, C.sub.3 H.sub.6 or C.sub.4 H.sub.8 group, and:either X=Y is an azo group, F being a hydrogen atom and G being a group --C(O)--O--W or a group --C(O)--O--(CH.sub.2).sub.n --O--W, n being an integer between 2 and 6 and W being a hydrogen atom or a dimerizable group,or X=Y is an azomethine group, one of the groups F and G being a group --O--W or --R.sub.3 --O--W, R.sub.3 being a group --O--C(O)--R.sub.4 -- or --O--R.sub.4 --, where R.sub.4 is a C.sub.1 to C.sub.6 alkyl, the other of the groups F and G being a hydrogen atom and W being a hydrogen atom or a dimerizable group.

Abstract: The present invention relates to an improved method for preparing a fluorinated silane having the formulaR.sup.1.sub.4 Si (I)or the formulaR.sup.2.sub.3 Si(R.sup.3 SiR.sup.4.sub.2).sub.z R.sup.3 SiR.sup.2.sub.3(II)said method comprising reacting the corresponding halide-functional or alkoxy-functional silane with lithium aluminum hydride or sodium borohydride to form a hydride-functional silane and then reacting the latter with a vinyl-terminated fluorotelomer or an allyl-terminated fluorotelomer, wherein at least three R.sub.1 of said silane (I), at least two of the R.sup.2 and at least one R.sup.4 of said silane (II) are selected from derivatives of fluorotelomers or fluorocotelomers, z has an average value of 0 to 4 and R.sup.3 is a derivative of an alkylene-terminated telechelic divalent telomer or cotelomer.

Abstract: (Meth)acrylic/glutarimide copolymers, well suited, e.g., for optical applications, having enhanced glass transition temperatures (Tg), are prepared by salifying the acid functions of (meth)acrylic ester/(meth)acrylic acid copolymers, and then imidifying such "intermediate" salified copolymers into the subject (meth)acrylic/glutarimide polymers.

Abstract: Oligomers with polydiene sequences and crosslinkable grafts are useful as coatings for protecting metal surfaces as well as inking buffers. The oligomers contain a polydiene sequence of 1-100 diene links, from 1 to 20 polar functional groups, and from 1-20 acrylic or methacrylic groups.

Abstract: This invention relates to an improved method of preparing the active telogen CF.sub.3 CFClI. The process comprises reacting chlorotrifluoroethylene, iodine, and iodine pentafluoride in the presence of an aluminum bromide catalyst at a temperature above about 25.degree. C.

Abstract: The present invention relates to a novel, catalyst-free method for preparing brominated telomers of chlorotrifluoroethylene. The process comprises reacting chlorotrifluoroethylene with a brominated telogen at a temperature in excess of 200.degree. C. for a time sufficient to produce the telomer.

Abstract: According to the invention, the reactive lubricating product of carbon fibres for embedding in a resin which can be hardened by X or beta radiation according to a radical mechanism is constituted by a monomer having at least one functional group (F.sub.1) able to form a covalent chemical bond with the hydroxyl sites of the carbon fibres and an ethylene unsaturation (F.sub.2) able to crosslink with the resin during its hardening under irradiation.

Abstract: The invention relates to the preparation of mortars and concretes in the presence of a water-reducing plasticizer. The plasticizer used is a surface-active compound containing at least one perfluoro group and at least one ionic or nonionic hydrophilic group. It is possible for these groups to be linked directly or via one or more divalent chain links.

Abstract: Novel perchlorofluorinated hydrocarbons of the general formula:Cl-(CFX-CF.sub.2).sub.m -CCl.sub.2 -(CF.sub.2 -CFY).sub.n -Clwherein X and Y represent chlorine or fluorine atoms, and m and n are integers from 1 to 5, together with a process for preparing such perchlorofluorocarbons by reacting chlorotrifluoroethylene or tetrafluoroethylene with carbon tetrachloride or a telomer having the formula Cl.sub.3 C-(CF.sub.2 -CFX).sub.m -Cl in a polar solvent at a temperature of at least 120.degree. C. in the presence of copper or a copper salt.