Abstract: Hollow synthetic fibers useful in reverse osmosis, ultrafiltration, gas separation and the like, having high hydraulic permeability to the solvent and capable of operation at pressures from 600 psi and up, are prepared by forming a solution of a fiber-forming polymer in a suitable solvent, adding to the solution a second polymer soluble in the solvent but with limited compatibility with the first polymer when their total concentration increases on coagulation, extruding the resulting solution through an orifice equipped for coaxial extrusion so that coagulating fluid within tube flow results, precipitating with a liquid which is miscible with the solvent for the fiber-forming material, is a non-solvent for the first polymer and a solvent for the second, contacting the extruded solution with the precipitating liquid either coaxially through the extrusion device or by passing the extrudate through the precipitating liquid, and finally washing the resulting hollow fiber free of residual solvents and non-solvents

Abstract: A porous film of polytetrafluoroethylene having an accurately controlled pore diameter and a superior pore diameter distribution, and a process for preparing the film.

Abstract: A semipermeable membrane is obtained by casting a cast solution comprising a mixture of a water-insoluble high polymer and a water-soluble high polymer, a mixture of a water-insoluble high polymer and a water-soluble surfactant or a mixture of a water-insoluble high polymer, a water-soluble high polymer and a water-soluble surfactant to form a shaped article, exposing the thus formed shaped article to a plasma to crosslink the surface thereof, and then washing the exposed article with water to remove uncrosslinked water-soluble high polymer or water-soluble surfactant. The membrane can be used for such substance separation methods as reverse osmosis, ultrafiltration and the like.

Abstract: Method of producing an entrainer for squeezing or dyeing textile fabric webs with the aid of a foulard which includes inserting a spread-out endless textile web into an annular mold both the web and the annular mold having a periphery and a width corresponding to the periphery and width of the entrainer to be formed and thereafter filling the annular mold with a material that hardens to form a sponge; and endless entrainer produced by the foregoing method.

Abstract: A continuous process for preparing particulate microporous, open-celled polymer structures in a co-rotating twin-screw processor comprising agitating normally solid organic polymer and chlorofluorocarbon in the melt zone of said processor, cooling the resulting solution under agitation in the cooling and milling zone, extruding a snow-like mass from the cooling and milling zone, and then removing the chlorofluorocarbon from the snow-like mass to leave the polymer structures.

Abstract: A dry-wet process for forming interiorally asymmetric hollow fiber cellulose acetate membranes is disclosed.

Abstract: A novel cloth comprising asbestos fibers, particularly in the form of a micro-porous membrane is provided and a method of obtaining this cloth. It is characterized in that said cloth is obtained by the dry mixing of asbestos fibers and at least one filler or charge substance, then working up by malaxation in the presence of a latex, forming the cloth and, optionally, elimination of the filler substance. The invention is particularly applicable in the production of a micro-porous membrane for use in electrolysis diaphragms.

Abstract: The present invention relates to blowing agent compositions, to foamable thermoplastic compositions, to a process for preparing articles obtained by foaming such compositions, and to the articles obtained by such a process.

Abstract: Coagulation apparatus for producing thick microporous polyurethane sheet material by passing a layer of polymer solvent composition beneath a close spaced plate with liquid non-solvent fed to the gap between the plate and the surface to produce controlled initiation of the coagulation.

Abstract: Dry semipermeable membranes of polyacrylonitrile or copolymers containing more than 65 wt. % of acrylonitrile are prepared by dissolving the polymer in a solvent in a solids concentration of 15-30% by weight; uniformly coating the solution onto a surface in a desired shape under an atmosphere whose relative humidity is 60-85% and dipping said coated surface into a non-solvent medium so as to remove the solvent which forms the membrane; heat-treating the membrane under moist conditions at 60.degree.-90.degree. C; and drying the membrane at a temperature less than the temperature of the heat treatment under conditions such that the coefficient of contraction is less than 1%, whereby a dried semi-permeable membrane having an open-celled structure with a pore size of a diameter less than 0.5 .mu. and a porosity of 0.40-0.7 is obtained.

Abstract: In accordance with a preferred embodiment of this invention, a family of alkylene-linked aromatic polyimides is synthesized. These polymers are thermally stable at a temperature of at least 400.degree. C. and processible in conventional thermoplastic processing equipment. Such new and useful polymers are produced by employing an alkylene-linked dixylene which is oxidized and dehydrated to form the corresponding dianhydride. This alkylene-linked dianhydride is then reacted, through a condensation polymerization reaction, with any of many known diamine terminated compounds to form the subject polyimide resins.

Abstract: Normally hydrophobic, polyethylene hollow fibers having contiguous microporosity are prepared by extruding a heated solution of a polyethylene and an ester from a hollow fiber spinnerette, simultaneously cooling and drawing the forming fibers to a ratio of up to 40 to 1, drawing the gelled fibers to an overall ratio of from about 1.5/1 to 800/1 and then removing the ester. The maximum pore radius ranges up to about 50A, and the fibers have gas permeabilities approaching 10.sup.-.sup.2 cc (STP) per cm.sup.2 per second per cm. Hg. transmembrane pressure differential. A significant increase in permeability over polyethylene hollow fibers made according to the teachings of the prior art is achieved.

Abstract: The preparation of three dimensional skeletal structures using the step of deforming rounded beads to form a mold or matrix is described. A filler material is introduced and then rigidified to form the skeletal structure. The deformable beads are composed of materials which deform upon compression or expansion due to pressure from adjacent beads and included, for instance, metals, waxes, salts, polymers, and ceramic compositions in their plasticly deformable states. The filler material which rigidifies to form the skeletal structure can be composed of solidifiable materials such as metals, polymers, or ceramic compositions. The solid material volume of the skeletal structure so formed upon removal of the beads is between about 2% to 20% of a corresponding volume of a non-skeletal solid material. The corresponding porosities representing the interconnected void volumes are between about 80% and 98% of a corresponding volume of a non-skeletal solid material.

Abstract: The preparation of three dimensional skeletal structures using the step of deforming rounded beads to form a mold or matrix is described. A filler material is introduced and then rigidified to form the skeletal structure. The deformable beads are composed of materials which deform upon compression or expansion due to pressure from adjacent beads and included, for instance, metals, waxes, salts, polymers, and ceramic compositions in their plasticly deformable states. The filler material which rigidifies to form the skeletal structure can be composed of solidifiable materials such as metals, polymers, or ceramic compositions. The solid material volume of the skeletal structure so formed upon removal of the beads is between about two percent (2%) to twenty percent (20%) of a corresponding volume of a non-skeletal solid material.

Abstract: The invention relates to polymerizing olefins in the presence of organic fibers and then removing the fibers to obtain hollow polyolefin resins.

Abstract: The manufacture of ion-exchanging shaped articles, in particular fibers, fabrics and membranes, by polymerization of the polymerizable monomers of a homogeneous mixture of a polyolefin, a vinylaromatic compound, an aromatic divinyl compound and a solvent of low volatility, converting said mixture to a shaped article, removing the said solvent and introducing ion-exchanging groups into the said shaped article.

Abstract: Polyester polymer is recovered from mixed collections of fibers in the form of fibers, filaments, or fabrics (including dyed or undyed fibers other than polyester fibers as well as dyed polyester fibers) and used in the production of new undyed fibers, films and other polymer products through the process of stripping the dye from the polyester fibers by contacting the fabrics with a dye stripping solvent for polyester polymer which is preferably not a solvent for fibers other than polyester fibers at a temperature below which the polyester fibers dissolve and above which the crystalline lattice of the polyester fibers swell so as to release the dye; then removing essentially all of the dye-containing dye-stripping solvent which is not absorbed by the fibers; then contacting the solvent-laden fibers (which may contain residual dye) with sufficient additional solvent under selective dissolution conditions for polyester fibers; then removing the undissolved fibers and any other undissolved impurities from the so

Abstract: Polyester polymer is recovered from polyester fibers (in the form of filaments, yarns or fabrics and the like, both dyed and undyed), and used in the production of new undyed fibers, films, and other polymer products through the process of: stripping the dye from the dyed polyester fibers by contacting the fibers with a dye-stripping solvent for polyester polymer at a temperature below which the polyester fibers dissolve and above which the crystalline lattice of the polyester fibers swell so as to release the dye; then removing essentially all of the dye-containing dye-stripping solvent which is not absorbed by the fibers and fabrics; then contacting the wet solvent-laden fibers, possibly containing residual dye, with sufficient addition of a dissolution solvent under dissolution conditions for polyester fibers; thereafter precipitating the polyester out of; and, separating the polyester from the solution.

Abstract: A method of obtaining a micro-porous membrane is provided as well as the improved membrane. Said method is characterized in that a homogeneous paste is prepared from a pore-forming filler substance and a latex, and said paste, which is reduced to powder form, is dried and a membrane is formed therefrom and then (fritted) sintered, and the pore-forming filler substance is then removed. The membrane thus obtained is particularly useful as a diaphragm for electrolysis cells.

Abstract: Polymeric bodies having selected morphological properties are prepared by effecting an apparent increase in the glass transition temperature of the polymer to cause it to become glassy and manipulating the polymer while it is in the glassy state. In the preferred practice of the invention, the apparent increase in the glass transition temperature is a reversible function so that after the morphological properties of the polymer have been developed, the normal glass transition temperature of the polymer may be restored.The process of this invention finds utility in the preparation and formulation of polymers in powdered form; it provides a practical method for the formation of powders in unusual size ranges, which, in turn, makes possible the formation of shaped articles by novel processes; and it provides a simple method for making products, such as open-cell foams and surfaces in relief, that have unique physical characteristics.

Abstract: A porous thermoplastic resin sheet is obtained by molding into a sheet a mixture comprising 100 parts by weight of a thermoplastic resin and 0.1 to 50 parts by weight of a pullulan powder, and then immersing the resulting thermoplastic resin sheet in water to dissolve-out and remove the said pullulan powder.

Abstract: Ultrathin membranes for separating substances are obtained by exposing shaped articles comprising a water-soluble polymer or a mixture of a water-soluble polymer and water-insoluble polymer to a plasma of a gas selected from helium, argon, nitrogen, hydrogen, oxygen, carbon monoxide, carbon dioxide, ammonia, a hydrocarbon having 1 to 10 carbon atoms, an epoxide having 2 to 10 carbon atoms, or an alkylamine, or a mixture of these substances to crosslink the surface layer, and then washing the exposed articles with water to remove the unreacted portions. The membrane exhibits outstanding performance characteristics when used in the processes for separating or concentrating substances, such as reverse osmosis, ultrafiltration, and the like.

Abstract: A shoe upper having in place of the upper leather thereof a fleeceless water vapor permeable microporous sheet of elastomeric polyurethane material having a thickness of about 0.8 - 1.8 mm. and having an extension at break of at least 200%.

Abstract: A uniform, porous, homogeneous diaphragm for use in electrolysis cells is provided by bringing together a homogeneous, stable suspension of asbestos fibers in water and a fluorinated polymeric resin latex with a pore-forming agent in the presence of a sulfonated anionic surfactant, the resulting suspension being shaped to the desired form of the diaphragm by filtration, the desired shape of the diaphragm then being dried and sintered at a temperature above the crystalline melting point of the fluorinated polymeric resin, the pore-forming agent finally being removed from the resulting diaphragm by decomposition or extraction.

Abstract: Hollow articles, in particular microballoons, hollow fibers and other shapes, are prepared by dispersing or dissolving a soluble film-forming solid in a core solvent which is normally solid but transformable slowly to gas, shaping the blend while molten, cooling to solidify and slowly removing the solid core material as a gas. The film-forming solid migrates to form a shell having the original core shape and a non-uniform cross-section of an outer skin and an inner sponge lining.

Abstract: There is disclosed a water vapor permeable shoe upper material having at least three layers, the density, thickness and structure of the layers having a defined novel relationship whereby an improved cut tear to stiffness relationship is achieved.

Abstract: A water vapor permeable artificial leather material is disclosed which consists essentially of tough microporous elastomeric polymer material free from fibrous reinforcement having a thickness of at least 0.8 mm and a microporous appearance modifying surface layer or finish.

Abstract: Microporous membrane filters composed of polyesters derived from aromatic dibasic acids and especially polytetramethylene terephthalate are produced. These membranes are produced by a polymer assisted phase inversion process involving casting a solution of the polyester and assisting polymer to form a film, evaporating the solvent to form a membrane having inchoate micropores filled with the assisting polymer and subsequently at least partially leaching out the assiting polymer.

Abstract: Solid, ultrafine porous polymer articles and processes of producing such polymer articles are described wherein a solid body of a crystalline thermoplastic polymer exhibiting at least 70 percent crystallinity or blends of such crystalline thermoplastic polymers and thermoplastic polymers exhibiting up to 65 percent crystallinity where the latter polymer is present in an amount up to 50 weight percent of the crystalline polymer is heated at a temperature of at least in its melting temperature range, a benzoate salt is incorporated therein forming a composite body, the composite body is shaped at a temperature in the range of the initial heating temperature of the polymer, the shaped composite body is cooled to room temperature forming a solid composite body, and the salt is dissolved from the solid composite body leaving the polymer as an ultrafine porous article.

Abstract: A method is disclosed for preparing a porous structure of ultra high molecular weight polyethylene. A heterogeneous composite of the polyethylene and a particular hydrocarbon is heated to a temperature above the melting point of the hydrocarbon but below the melting point of the polyethylene. The composite is then shaped. After such shaping the temperature is then raised to a temperature above the melting point of the polyethylene and maintained until complete fusion of the polyethylene particles occurs. Thereafter the hydrocarbon is extracted from the cooled shaped structure.

Abstract: A synthetic film which comprises at least two unmixed polymeric components, at least one of the components occurring in the form of substantially endless threads in the longitudinal direction of the film. The threads have transverse dimensions that are smaller than the thickness of the film and are embedded in a basic mass of a different polymeric component.The process for producing such synthetic films includes the steps of arranging at least two polymeric components, in the liquid state, side by side in a particular order to form a single main stream; repeatedly dividing and doubling the main stream into a multi-layer stream; temporarily dividing the multi-layer stream in a direction transverse to the direction of the layers at least once into sub-streams on the order of magnitude of the layer thicknesses in situ, while retaining the continuity of flow of the multi-layer stream and then extruding the resulting stream containing a plurality of the sub-streams through a casting slit to form said film.

Abstract: Electrode structures for fuel cells are made by blending noble metal black, dry polytetrafluoroethylene and a soluble bulking agent in a liquid, filtering liquid from the blend and rolling the remnant to form a sheet of fibrillated polytetrafluoroethylene containing noble metal black and bulking agent. The bulking agent may be leached from the sheet and the sheet then pressed or the sheet may be first pressed and the bulking agent then leached from the sheet.

Abstract: A composition for forming into a soft, pliable, leather-like material includes a polyolefine having from 50 to 90 weight percent of inorganic compounds. The inorganic compounds contain a substantial amount of calcium sulfite having crystal sizes of 1-100 .mu..

Abstract: An improved hydrophobic polymer matrix having preselected wettable characteristics.