Abstract: Structures with multiple polymeric layers comprising a vinylidene fluoride polymer layer bonded to a polar polymer layer by the use of a polymeric adhesive comprising a vinyl acetate polymer. These structures are characterized in that the product of the weight content of vinyl acetate of the polymeric adhesive, expressed in percent, and its dynamic viscosity at 100.degree. C. and 1 s.sup.-1, expressed in kPa s, is greater than 1.4.times.10.sup.3. The structures with multiple polymeric layers can take the form of films, sheets, panels, tubes or hollow bodies which can be employed particularly in the field of protection against corrosion or ultraviolet rays.

Abstract: Process for the manufacture of vinylidene fluoride polymers by noncontinuous polymerization of vinylidene fluoride in an aqueous medium with the use of peroxydisulphates as initiators and in the absence of emulsifying agent, in which an alkyl acetate, employed as a chain-control agent, is introduced into the initial aqueous charge intended for the polymerization.Use of the resulting vinylidene fluoride polymers for the manufacture of paints and, more particularly, of paints intended for prelacquering metal sheets with improved gloss.

Abstract: A method for activating supported chromium oxide catalysts in which a chromium-containing catalyst on a silica-containing base is first heated in an oxidizing atmosphere at temperatures up to about 850.degree. C. and then cooled down. During the cooling step of the catalyst, the oxidizing atmosphere is replaced by a non-oxidizing one, leading to an activated catalyst. A process for the polymerization of alpha-olefins, especially ethylene, in which at least one alpha-olefin is contacted, under polymerization conditions, with the catalyst activated by the method described above.

Abstract: The invention relates to catalytic compositions for the hydrogenation of chlorofluoroalkenes to fluoroalkenes, comprising a porous carrier impregnated with metal of group VIII of the Periodic Table of the elements and with one or more compounds chosen from the salts of an alkali metal or alkaline-earth metal.The invention also relates to a process for obtaining these catalytic compositions and a process of hydrogenation by means of these catalytic compositions.

Abstract: The device which is used for recovering a fusible core employed for moulding a hollow plastic article includes a bath of a liquid heated to a temperature at least equal to the melting temperature of the metal constituting the fusible core, a handling mechanism for introducing and holding the hollow article in this bath and a mechanism for heating, using electrical induction, the fusible core of the hollow article, the liquid bath being contained in a leakproof enclosure (1) made of an electrically nonconductive material which withstands the temperature of the bath and the mechanism of heating using electrical induction (4) being arranged outside and around the enclosure (1).

Abstract: Process for the purification of an aqueous alkali metal chloride solution from iodine compounds and ammonium compounds, in which the operation is carried out in two successive stages comprising a first stage in which the iodine compounds are oxidized to molecular iodine which is removed from the solution on a halogenated basic anion exchange resin, and a second stage in which the ammonium compounds are oxidized to form nitrogen which is removed in a stream of inert gas.

Abstract: Process for the removal from vinyl chloride of compounds of ester type by an operation of treatment comprising an alkaline washing and a treatment with a hydride.

Abstract: Process for preparing a latex of polypyrrole in an aqueous reagent medium containing a ferric salt, a hydrolyzed polyvinyl acetate and a dodecyl sulphate.The films prepared with this conducting latex are homogeneous, adhere to metals and metallized glasses and have high conductivity.

Abstract: Process for the removal from vinyl chloride of compounds of the ester type by an operation of treatment comprising an alkaline washing and a treatment with a bisulphite.

Abstract: The invention relates to catalytic compositions for the hydrogenation of 1,1,2-trichloro-1,2,2-trifluoroethane to chlorotrifluoroethylene and trifluoroethylene comprising a porous oxygenated support impregnated with a metal of group VIII of the periodic table of the elements and one or more compounds chosen from the salts of an alkali or alkaline-earth metal.The invention also relates to a process for obtaining these catalytic compositions and a process of hydrogenation by means of these catalytic compositions.

Abstract: Slit film yarn based on propylene polymer, resistant to postfibrillation. The propylene polymer is a block copolymer of propylene and ethylene made up of chain segments consisting of propylene homopolymer and of chain segments consisting of random copolymer of propylene and ethylene.This slit film yarn is suitable for the manufacture of synthetic lawn.

Abstract: The present invention relates to a process for the treatment of heavy residues produced in the manufacture of chlorinated products, in which process a chemical compound chosen from certain fatty compounds is added to the heavy residues in order to form fluid and stable liquid suspensions.

Abstract: The invention concerns:a catalytic solid containing magnesium, a halogen, titanium and silicon, this catalytic solid also containing aluminium and being microporous;a process for preparing this catalytic solid;use of this catalytic solid for polymerizing alpha-olefines.

Abstract: An amorphous powder of titanium oxide and of barium and/or strontium oxide is precipitated by the hydrolysis of titanium alcoholate in the presence of barium oxide, hydroxide or alcoholate or strontium oxide, hydroxide or alcoholate and an acid organic compound containing more than 6 carbon atoms, and the amorphous powder is heated while being treated with a stream of gas containing water vapour, ammonia or CO.sub.2, to crystallize the barium or strontium titanate and distill off the acid organic compound. The barium or strontium titanate crystals are less than one micron in size and have an irregular, angular morphology.

Abstract: A purified antigenic protein has been obtained which is capable of inducing in a chicken an immune response conferring protection against infection by Eimeria necatrix or Eimeria tenella. The protein has a molecular weight of about 26,000 and is composed of two polypeptides joined by a disulfide bond. The two polypeptide subunits have molecular weights of about 18,000 and about 8,000, respectively. The gene encoding the protein has been sequenced and the amino acid sequence of the protein deduced therefrom.The protein and antigenic polypeptides having an amino acid sequence included within the protein may be incorporated into a vaccine for conferring upon a chicken active immunity against infection by E. necatrix or E. tenella.

Abstract: Biaxially oriented rigid thermoplastic structures with multiple coextruded polymeric layers comprising a layer of vinyl chloride polymer and a coating layer of polymethyl methacrylate containing products absorbing ultraviolet radiation. The content of products absorbing ultraviolet radiation is such that the glass transition temperature of the coating layer does not exceed 105.degree. C., thus permitting an orientation in the range 95.degree.-110.degree. C.

Abstract: 1-Chloro-1,1-difluoroethane is prepared by reacting hydrogen fluoride with vinylidene chloride, in a liquid medium containing preferably at least 40 mol % 1,1-dichloro-1-fluoroethane.

Abstract: Article made of lactic acid polymer capable of being employed particulaly as a biodegradable prosthesis exhibiting at 23.degree. C. a tensile regidity modulus higher than 5000 MPa and a tensile resilience higher than 500 kJ/m.sup.2 and a heat shrinkage of less than 50% at 130.degree. C.The article is produced by forging a blank at a temperature of between 80.degree. and 170.degree. C., with a draw ratio of 200 to 1000%.

Abstract: Compositions based on vinylidene fluoride polymers, which have a reduced smoke-producing capacity, comprising, as smoke-reducing agent, an effective amount of a dialkyltin dicarboxylate.The compositions are very particularly suitable for the manufacture of shaped articles in the building and the aeronautical industries.

Abstract: In a first stage, a lactone is polymerized by an ionic route in vinyl chloride with the aid of a catalyst consisting of the product, optionally complexed with tetrahydrofuran, of the reaction of an alkylmetal with ethylenically unsaturated alcohol, optionally in the presence of water and, in a second stage, the said vinyl chloride is polymerized by a radical route in an aqueous suspension and in the presence of the polymerization medium originating from the first stage, to which other unsaturated monomers are optionally added.The invention also relates to new modified vinyl chloride polymers consisting of lactone polymers whose number-average molecular weight is less than 5,000, grafted with vinyl chloride polymers.