Showing papers by "Rhône-Poulenc published in 1976"

Support for a natural human heart valve

Abstract: A support for a natural human heart valve is disclosed, said support consisting of an annular or part annular semi-rigid frame having the shape of at least a substantial portion of the periphery of said natural heart valve at the base of its cusps, the frame being completely or partly enclosed in a textile sheath, the frame and the sheath being formed of a bio-compatible material and being deformable after implantation. The frame and sheath may be flexurally deformable, and are extensible by 0.001 times to 0.3 times their length. Preferably, the frame has the same flexural elasticity as an annular bundle or 2 to 8 turns of a cylindrical bristle or poly(ethylene terephthalate) and having a circumference equal to 0.025 times the length of one turn. The frame may be formed of at least one strand of bristle. The frame and the sheath may be in the form of a portion of a convex curve.

Surface active composition

Abstract: A surface active composition which comprises by weight: A. 45 to 90% of at least one n-alkyl monoether of a polyethylene glycol, containing 4 to 9 --CH 2 CH 2 O-- units, the n-alkyl radicals containing 5 to 15 carbon atoms, B. 5 to 35% of a sodium dialkylsulphosuccinate, the linear or branched alkyl radicals containing 6 to 12 carbon atoms, C. 2 to 17% of at least one acid selected from oleic, linoleic, linolenic and ricinoleic acid and D. 1.5 to 12% of at least one amine selected from triethanolamine and N-hydroxyethylmorpholine; Is used as an emulsifier with diorganopolysiloxanes to form transparent micro-emulsions or transparent gels or to introduce silane cross-linking agents into catalyzed aqueous polysiloxane emulsions to cross-link the emulsion.

Bicomponent filaments with a special cross-section

Abstract: Side-by-side bicomponent polyester filaments, and process for making same, are disclosed, wherein the filaments are of polyethylene terephthalate and polybutylene terephthalate, with the polybutylene terephthalate being sparingly cross-linked by at least about 0.20 mole per cent of cross-linking agent. The sparingly cross-linked polybutylene terephthalate has a melted state viscosity VF of at least about 2000 poises at 260° C. The polyethylene terephthalate partly envelopes the sparingly cross-linked polybutylene terephthalate, in cross-section, so as to cover at least about 45% of the periphery of the sparingly cross-linked polybutylene terephthalate.

Peristaltic tube pump with means preventing complete occlusion of tube

Abstract: A peristaltic pump equipped with at least one peristaltic tube is disclosed characterized in that the said tube is associated with means which limit its occlusion, independently of the physical and/or mechanical stresses to which it may be subjected. The peristaltic tube is provided with at least one longitudinal groove or ridge on the internal surface of its wall. Alternatively, a strand may extend longitudinally inside the peristaltic tube, at least over the part subjected to the action of the pressing devices, and this strand is rigid or semi-rigid and has the shape of an arc of a circle. The strand may be flexible and may be firmly attached to the peristaltic tube at least at a point located upstream from the pressing devices. Various other geometrical arrangements are disclosed. The peristaltic pump is especially adapted to extracorporal blood circulation. The peristaltic tube is of such dimensions that when flattened transversely, there remains at least one passage, the ratio of the cross-section of the passage to the cross-section of the channel of the tube at rest being between 1/10 and 1/10,000. The peristaltic tube consists of a silicone elastomer and may be coated on the internal surface and/or the external surface with a thin layer of a silicone elastomer.

Catalytic hydroformylation of olefins

Abstract: Olefins are hydroformylated to aldehydes in the presence of a catalytic system comprising a rhodium containing, aqueous solution of certain sulfonated aryl phosphine compounds.

Stabilization of vinyl chloride polymers

Abstract: Vinyl chloride polymers are heat stabilized by formulating therewith minor amounts of [1] a divalent metal salt of an organic carboxylic acid and [2] either a β-diketone or a β-keto-aldehyde.

Hydrophilic polyurethanes and textiles treated therewith

Abstract: A hydrophilic polyurethane composition comprising a reaction product of: 1. 10 to 45 weight percent of an organic diisocyanate and, 2. 35 to 89 weight percent of a compound containing one or two active hydrogen atoms selected from: A. 75 to 100 weight percent of a compound of the general formula: R--(O--C.sub.x H.sub.x).sub.n -OH wherein R is hydrogen or a hydrocarbon radical containing from 1 to 20 carbon atoms; X is a number from 2 to 4; n is a number to indicate that the molecular weight is between 300 and 10,000; and, B. 0 to 25 weight percent of a diol and, 3. 1 to 25 weight percent of a nitrogen-containing compound of the general formula: ##STR1## wherein R' is an alkyl radical containing from 1 to 5 carbon atoms; X 1 and X 2 are hydroxyalkyl or amino alkyl radicals with the proviso that the overall ratio of NCO/active H is from about 0.7 to about 1. The composition when applied to textiles provides outstanding soil-release and anti-soil redeposition properties particularly with fibers and fabrics made of polyester and polyester blends.

Hydroxylation of aromatic compounds

Abstract: Phenols and phenol ethers are hydroxylated with hydrogen peroxide in the presence of sulphur, selenium, tellurium, phosphorus, arsenic or antimony High yields of dihydric materials are obtained by this process which avoids the need to use peracids or very strong acids

Method of separating proteins by ion exchange

Abstract: of the Disclosure A method of separating proteins by ion exchange comprising putting a solution of proteins into contact with an ion exchange resin consisting of a porous inorganic carrier coated with a cross-linked polymer containing or carrying anion exchanging groups - tertiary amines or salts of quaternary ammonium - or cation exchanging groups and application of the process to the food, pharmaceutical and veterinary field.

Polymeric compositions for membranes

Abstract: A mixture of at least one non-sulphonated polysulphone and at least one sulphonated polysulphone, this mixture consisting of 10 to 30% by weight of a sulphonated polysulphone which has a theoretical exchange capacity of from 500 to 1,200 meq/kg is provided. Such mixtures enable one to obtain semi-permeable membranes using relatively concentrated solutions of the mixtures. The resulting membranes are particularly suitable for use in ultrafiltration.

Uni- and biaxial stretching of chlorinated pvc sheets. A fundamental study of thermoformability

Abstract: Chlorinated PVC is superior to unmodified PVC as a thermoplastic for use in thermoforming, especially if improved heat resistance and dimensional stability are required. In the present report, results tire given of a fundamental experimental study on the thermoformability of CPVC sheets obtained by calendering various formulations based on CPVC resins with at least 65 percent chlorine content. Extensibility as well as the relationship between stress and strain in uni- and biaxial stretching have been determined as a function of temperature and rate of stretching by means of specially devised, highly instrumented laboratory equipment. Stress-strain relations under isothermal conditions and at constant strain rate are compared for the two modes of stretching, and the difference in behavior between PVC and CPVC, particularly with regard to the effect of temperature, is emphasized. Internal stresses frozen in during cooling, following rapid stretching at appropriate thermoforming temperatures, have been determined by means of a detailed analysis of retractive force measurements. The relationship between internal stress and molecular orientation is discussed as well as the effect of the latter parameters on various properties of technological interest: dimensional stability, impact resistance, and gas permeability.

Process for obtaining dimethyl terephthalate from polyester scrap

Abstract: A process is disclosed for converting a bis-(diol) terephthalate to dimethyl terephthalate, by interchange in a methanol medium in the presence of magnesium methylate as catalyst. In this way dimethyl terephthalate may be regenerated from scrap of polyterephthalate or copolyterephthalate filaments or films, for the purpose of manufacturing fresh polyterephthalates or copolyterephthalates which can then be used for the manufacture of, for example, filaments or films.

Alumina-based bodies obtained by agglomeration which are resistant to elevated temperatures

Abstract: Alumina based bodies having resistance to temperatures of up to 1200° C prepared by autoclaving alumina and at least one additive from the group of oxides of lanthanum, neodymium, praseodymium and thorium. Bodies of the alumina of this invention are useful in adsorption and catalysis.

Compositions intended for the flameproofing of plastics

Abstract: Compositions based on red phosphorus and epoxy resin for flame proofing plastics without the release of toxic products during use. The compositions consist of a pulverulent mixture containing from 50 to 95% by weight of red phosphorus and from 5 to 50% by weight of compounds having epoxy groups in their chain.

Process for the preparation of hydroxybenzaldehydes

Abstract: A process is provided for the production of hydroxybenzaldehydes, especially salicylaldehyde, from the oxidation of the corresponding hydroxybenzyl alcohol, especially orthohydroxybenzyl alcohol, with oxygen in an aqueous alkaline medium in the presence of a noble metal catalyst, such as platinum or palladium, and in the presence of a co-catalyst containing bismuth.

Selective diaphragm for electrolysis

Abstract: A selective composite diaphragm is provided comprising a ion-exchange membrane having at least one microporous layer joined to it, whereby the microporous layer is of high, homogeneous porosity and is preferably at least as thick as the membrane. Said diaphragm is particularly useful for electrolysis of sodium chloride, enabling pure concentrated alkaline solution to be obtained with a high yield.

Process for the manufacture of beta-methylthiopropionaldehyde

Abstract: Beta-methylthiopropionaldehyde is prepared from methylmercaptan and an acrolein-containing gaseous mixture derived as an off-gas from the catalytic oxidation of propylene.

Process for the carbonylation of aralkylhalides

Abstract: A process for the production of arylpyruvic acids which comprises reacting an arylmethylhalide in a liquid solvent medium with carbon monoxide at pressures of 5 to 200 bars in the presence of a catalytic amount of a metal carbonyl compound and an alkaline earth metal inorganic base.

Process for the treatment of gases containing various derivatives of sulphur

Abstract: Catalysts for Claus reaction treatment of industrial gases containing hydrogen sulphide and sulphur dioxide in which the catalyst has a specific surface area of at least 80 sqm/g and is composed of activated alumina and a compound of a metal of column III A of the periodic classification of elements which is present, when calculated as the oxide, in an amount within the range of 1-20% by weight of the catalyst

Recovery of acetic acid from dilute aqueous solutions thereof

Abstract: Acetic acid is recovered from its dilute aqueous solutions by extracting same with an organic solvent, neutralizing the acidic extract with aqueous ammonia, whereby there are separated an organic phase and an ammonium acetate containing aqueous phase, and thence thermally decomposing said ammonium acetate.

Nouvelle silice de synthese amorphe, procede pour son obtention et application de ladite silice dans les vulcanisats

Abstract: PRECIS DE LA DIVULGATION: Une silice synthetique amorphe presentant une surface CTAB comprise entre 80 et 125 m2/g et un indice de structure au moins egal a 0,80, est obtenue par action d'un acide fort sur une solution de silicate alcalin, l'acide etant ajoute a la solution de silicate alcalin a une vitesse variable, telle que l'alcalinite residuelle du milieu reste sensiblement constante en fonction du temps, l'addition de l'acide etant eventuellement interrompue au moins une fois, pendant un temps de 5 a 20 mn, lorsque le maximum de formation des polymeres est atteint. Ce procede est caracterise par le fait que le silicate est constitue par un silicate de sodium de rapport molaire SiO2/Na2O compris entre 2 et 4, la concentration initiale de silicate dans le milieu comprise entre 90 et 150 g/l de SiO2, ramenee a un rapport molaire SiO2/Na2O de 3,5, que la concentration finale en SiO2 est comprise entre 60 et 90 g/l, le temps de reaction total est compris entre 40 et 200 mn, non compris le temps des arrets eventuels, et la temperature de reaction est comprise entre 65 et 95°C. La silice synthetique amorphe ainsi obtenue trouve son application notamment comme charge de renforcement dans les vulca-nisats.

Polyurethanes for articles for medical usage

Abstract: A polyurethane is disclosed which can be used in particular for the production of articles intended to be in contact with blood, characterized in containing a macromolecular chain comprising nitrogen atoms in the form of quaternary ammonium groups, to which molecules of heparin are bonded, these nitrogen atoms originating from polymers consisting of q recurring units of the formula: --A--NH--CO--O--B--O--CO--NH-- (I) and t recurring units of the formula: --A--NH--CO--Z--NH-- (II), these units of the formula (I) and (II) being bonded to one another, and the various symbols of these units having the following meanings: A is a divalent organic radical consisting of a straight-chain or branched-chain alkylene radical containing from 3 to 10 carbon atoms, or a cycloalkylene radical having 5 or 6 carbon atoms in the ring or a phenylene radical which is optionally substituted by 1, 2 or 3 lower alkyl radicals (with at most 4 carbon atoms), or two alkylene or phenylene radicals linked to one another by a divalent hydrocarbon radical containing from 1 to 4 carbon atoms or by a hetero-atom chosen from amongst oxygen, sulphur and nitrogen, B represents a divalent organic radical obtained by removing the terminal hydroxyl groups from a macrodiol of the formula: ##STR1## in which: B 1 represents a linear or branched aliphatic radical having from 2 to 12 carbon atoms, R represents an alkylene radical of from 1 to 4 carbon atoms, R 1 represents an alkyl radical of from 1 to 20 carbon atoms which may contain functional groups, such as, for example, aldehyde, carboxylic acid or sulphonic acid groups, n, m and p are identical or different integers (or fractions in the case where (III) represents a mean formula) such that the molecular weight of B is between 300 and 10,000, and q and t are such that the polyurethane, before quaternization of the nitrogen atoms, has a specific viscosity, measured at 20° C on a solution of 2 g/l in dimethyl formamide, of greater than 0.05 and preferably between 0.1 and 0.9, the ratio q/t being between 0.5 and 10, Z is a single bond or a divalent radical chosen from amongst the radicals of the formulae: --NH--NH--CO--, --NH--CH 2 --CO--NH--NH--CO--, --NR 2 --D--NR 3 --CO--, and --O--M--O--CO--, in which R 2 and R 3 , which may be identical or different, are hydrogen atoms or lower alkyl radicals, D is a hydrogen chain containing from 2 to 12 carbon atoms, or a hydrocarbon ring with 5 or 6 carbon atoms or a nitrogen-containing heterocyclic ring with 5 or 6 chain members, containing 1 or 2 nitrogen atoms, all the hydrocarbon chains and rings being saturated or unsaturated, unsubstituted or substituted by one or two lower alkyl radicals or by a nitrogen-containing heterocyclic ring with 5 or 6 chain members, which is attached by a nitrogen atom, it being possible for two of the chains or rings to be linked to one another by an alkylamino group, and M is an aliphatic hydrocarbon radical containing from 2 to 12 carbon atoms, which is linear or branched, saturated or ethylenically unsaturated, unsubstituted or substituted by one or two lower alkyl radicals or by a dialkylamino radical, which is uninterrupted or interrupted by an alkylamino radical. The polyurethane may comprise t units of the formula (II) and q units of the formula ##STR2## in which R 4 represents a monovalent or polyvalent organic radical and if R is monovalent, it may represent an alkyl, cycloalkyl or aralkyl radical which may possess functional groups and preferably containing fewer than 15 carbon atoms, these radicals being preferably the methyl, ethyl, propyl, cyclohexyl, benzyl and formylmethyl radicals, while if R is polyvalent it may represent an alkylene or alkenylene or cycloalkylene or aralkylene radical and then links different atoms or different macromolecular chains, and X- is an anion, which anion may be replaced by another anion in accordance with the usual ion exchange techniques and is preferably an anion such as a halide (chloride, bromide or iodide), nitrate, sulphate, sulphite, phosphate, sulphonate and hydroxyl. The polymer may contain from 0.1 to 30 parts by weight of heparin per 100 parts of polymer. Processess for making the polymer; and shaped articles comprising the polymer are also included.

Cathode for electrolytic cell

Abstract: A cathode for an electrolytic cell, providing a low overvoltage on contact with the electrolyte, having at least one surface of a compound comprising (a) a metal of the group comprising nickel, copper, iron and cobalt, and (b) another element of the group comprising any of the preceding metals, titanium, lanthanides, magnesium, boron, molybdenum, manganese, vanadium, niobium and tantalum and their hydrogenation products. The cathode is particularly useful in the electrolysis of alkali chlorides.

Apparatus for treating filamentary products

Abstract: Apparatus for treating filamentary products, such as yarn, includes advancing the yarn in a groove, which has orifices opening in the bottom thereof, and which communicate with a channel through which a fluid is expelled. The channel lies in the wall of a cylindrical static body and is tangent to the inner wall of said body. The fluid supports the strand so that the yarn does not touch the groove. In addition, the fluid treats the yarn and helps to advance the yarn.

The equivalent wavelength notion: Definition, properties, applications

Abstract: The subject of a monochromatic radiation strictly equivalent to a given polychromatic spectral distribution is developed in accordance with usual analytical practice (e.g. by referring to relative intensities) assuming that (1) the polychromatic distribution can be any one, i.e. a continuous or discontinuous white spectrum, possibly including characteristic lines or not; (2) the fluorescent element is engaged in a homogeneous sample and is subject only to pure absorption effects (whether positive or negative) on the part of its neighbour elements. Important conclusions can then be derived. These are (a) the existence for each composition of one, and only one, equivalent wavelength λe, the origin and mathematical determination of which are accurately described; (b) the fact that λe systematically decreases with increasing fluorescent element concentration in binary compositions, whatever the associate element, whether it be a positive or negative absorber. This property then clearly extends to any given matrix; (c) the existence of a simple relation of equivalence between absorbers, enabling us to consider any absorber and then any absorbing matrix in terms of ‘equivalents’ if we so choose; (d) as a consequence of (b) and (c), a novel description of influence coefficients for the absorption case, accounting for their systematic variation with fluorescent element concentration and introducing a definite correlation between coefficients belonging to different absorbers; (e) further interesting properties such as the effect of the ‘geometry’, as well as the effect of dilution, on the situation of equivalent wavelengths and the values of influence coefficients. In so far as absorption effects are considered all the facts of X-ray fluorescence as induced by polychromatic excitation are covered by the present theory.

Solid, non-corrosive detergent compositions

Abstract: A non-corrosive detergent cleaning composition adapted primarily for cleaning dishes and textiles formulated to contain a mixture of detergent agents, oxidizing or disinfecting agents, non-ionic or a mixture of non-ionic and anionic agents, and which may include filling agents, the improvement wherein the composition is formulated to contain a sodium silico-aluminate which inhibits coloring, corrosion and degradation of chlorine derivatives, with or without a silico-aluminate to inhibit tarnishing of aluminum.

Copolymers of butadiene and carboxylated styrene

Abstract: A coated substrate for photogravure printing in which the substrate is coated with an aqueous latex containing as an essential film forming component particles of a copolymer of butadiene and carboxylated styrene having a particle size within the range of 0.08-0.14 microns and consisting essentially of 41-45% by weight butadiene, 45-57% by weight styrene and 2-10% by weight of at least one unsaturated carboxylic ethylenic acid.