Abstract: A method for preserving the porosity of porous materials is disclosed. In this method, the porous material is subjected to elevated temperature and vacuum conditions to thereby produce a dimensionally-stable, non-collapsible porous material.

Abstract: A process for producing a film-like or fibrous structure of an aromatic polyester, which comprises(1) forming an unstretched film-like or fibrous structure by melt-shaping a blend comprising 100 parts by weight of (A) an aromatic polyester having a high degree of polymerization derived from an aromatic dicarboxylic acid as a main acid component and an aliphatic diol and/or an alicyclic diol as a main glycol component and (B) 3 to 300 parts by weight of a low-molecular-weight compound being substantially non-reactive with the aromatic polyester (A) and having a boiling point of at least about 200.degree. C.

Abstract: The invention provides a method for producing permeable polymeric membranes comprising decomposing, in a polymeric matrix, molecular moieties, bound to the polymer or contained in compounds dispersed therein, into smaller, discrete, molecular units, whereby the smaller, discrete molecular units, which are formed, spontaneously leave the polymeric matrix and a membrane of defined permeation characteristics is obtained.

Abstract: There is disclosed a substantially skinless microporous polypropylene membrane characterized by having(a) a bubble point of about 25 to about 50 psi;(b) a thickness of about 3 to about 7 mils;(c) a nitrogen flow rate of at least 0.5 liters per square centimeter-minute;(d) a burst strength of at least 10 psi; and(e) an S value of about 15, or less.There is also disclosed a method of preparing a microporous polypropylene membrane comprising heating a mixture of about 30 percent polypropylene and about 70 percent, N,N-bis(2-hydroxyethyl)tallowamine, by weight, to a temperature and for a time sufficient to form a homogeneous solution, casting or extruding said solution at a thickness of about 3 to about 7 mils, onto a chill roll maintained at a temperature of from about 50.degree. to about 80.degree. C.

Abstract: Hollow water-absorbing polyester filaments each having a number of fine caves which are evenly distributed in at least a portion of the filament and through which the hollow is connected to the outside of the filament, are produced (1) by preparing hollow filaments from a blend of a principal polyester component and a cave-forming agent consisting of at least one member selected from:(i) copolyesters containing an additional divalent organic sulfonic acid compound moiety of the formula (II): ##STR1## wherein Z is a trivalent aromatic or aliphatic hydrocarbon radical, M.sup.1 is H or metal atom, R.sup.1 is an ester-forming organic radical and R.sup.2 is an H atom or ester-forming organic radical;(ii) phosphorus compounds of the formula (III): ##STR2## wherein R.sup.3 is a monovalent organic radical, X is --OR.sup.4, wherein R.sup.4 is an H atom or a monovalent organic radical, --OM.sup.3, wherein M.sup.3 is a metal atom, or a monovalent organic radical, M.sup.

Abstract: A dyed polyester fiber composite structure having an enhanced brilliance and/or color depth, comprises (A) a dyed porous polyester fiber which has been produced (1) by preparing a polyester resin from a dicarboxylic acid component and a glycol component in the presence of a pore-forming agent containing 0.3 to 3 molar % of at least one phosphorus compound based on the molar amount of the dicarboxylic acid component, (2) by converting the polyester resin to a polyester fiber in which fine particles of the pore-forming agent are dispersed, by treating the polyester fiber with an aqueous alkali solution so that at least 2% of the weight of the fiber is removed and a number of fine pores are formed in the fiber and (4) by dyeing the porous polyester fiber; and (B) a coating layer on the peripheral surface of the dyed porous polyester fiber, comprising a polymeric material having a smaller refractive index than that of the porous polyester fiber.

Abstract: The starting materials for the practice of the present invention are (1) one or more organic monomers or oligomers which upon irradiation very rapidly undergo a polymerization reaction to form a solid polymer; and (2) a liquid vehicle in which the one or more organic monomers or oligomers are soluble but in which the polymer formed is insoluble. For the manufacture of microporous membrane in accordance with the invention the monomers or oligomers are dissolved in the liquid vehicle, the resulting solution is formed into a thin layer, and the thin layer of the solution is then irradiated as with ultraviolet or electron beam radiation whereupon the rapid polymerization reaction immediately ensues and the polymer formed immediately segregates from the vehicle thereby resulting in microporous membrane from which the vehicle can be removed as by evaporation or washing.

Abstract: Novel cardiovascular prosthetic devices or implants having many useful cardiovascular applications comprise a porous surface and a network of interconnected interstitial pores below the surface in fluid flow communication with the surface pores. Tissue forms a smooth thin adherent coating of self-determining thickness on the porous surface making it resistant to the formation of the blood clots normally associated with the presence of foreign bodies in the blood stream. The device has particular utility in heart valves, pacemaker electrodes, blood pumps, blood stream filters, an artificial pancreas, vascular access tubes, small and large bore vascular grafts, blood pump diaphragms and vascular and intracardiac patches.

Abstract: Preparation of supported reverse osmosis membranes on a woven, unsized, porous support using dimethylacetamide solvent and a lithium nitrate or chloride or magnesium chloride salt.

Abstract: In the manufacture of cells, e.g. of the system Li-Al/LiCl-KCl/FeS.sub.x, the finely divided raw materials for the electrodes and for an included ceramic separator are respectively mixed individually with the electrolyte salt, as well as with a synthetic plastic which is decomposable without residue under heat. The mixtures are rolled into plates, and the plates are heated above the decomposition temperature of the plastic after assembly. The plastic is preferably a polyhydrocarbon such as polyisobutylene and is preferably introduced by means of a solvent. It makes the powder mixtures plastifiable and suitable for rolling. This makes it possible to produce ceramic separators, which are fundamentally composed only of loose particle accumulations, in the form of plates of uniform structure and strength and to handle these in the same way as electrode plates during cell assembly.

Abstract: A liquid composition for the manufacture of a membrane, comprising a reaction product a cuprammonium cellulose with an ammonium or alkali metal salt of a polymer containing 10 to 70 equivalent percent of a carboxyl group and having a number-averaged molecular weight in the range of from 500 to 200,000, and a membrane is obtained by molding the composition in the form of a film, immersing the shaped article thus obtained in a dilute sulfuric acid solution thereby coagulating and regenerating it, subsequently immersing the shaped article in an strong alkali solution thereby expelling said ammonium or alkali metal salt of the polymer therefrom and forming therein fine pores substantially corresponding to the molecular weight of said salt.

Abstract: Polymeric sheets having on one or both sides a fabric texture and, optionally, a network of elongated channels in the interior of the structural framework of the sheets are disclosed. The sheets are useful as burn coverings where they serve as synthetic, temporary replacements for damaged or missing skin. The sheets have physiologic properties similar to human skin, excellent drapability characteristics, recessed portions which provide a reservoir for wound debris and, in certain embodiments, a dermal surface which permits wound adherence by fibroblastic ingrowth.In one embodiment, laminated sheets in which only one side has a fabric texture are prepared by (1) applying one or more layers of polymer to a support surface, (2) partially embedding a sheet having a fabric texture in the layer of polymer, (3) curing or hardening the polymer to form a composite of the sheet and polymer, and (4) separating the composite from the forming surface.

Abstract: A method is shown for making porous thermoresin structures. By the method, the thermoresin is at least partially solvated, formed into a desired shape, and cooled until droplets of the solvent form by syneresis within the shape. Further cooling crystalizes the droplets. These crystalized droplets are subsequently removed to leave a porous structure.

Abstract: A process for the preparation of a porous membrane is provided which comprises the steps of preparing an aqueous dispersion system by dispersing a first material in water, said first material being selected from the group consisting of waxy substances, fatty substances and mixtures thereof and having a melting point of from the room temperature to 100.degree. C., admixing with said aqueous dispersion system an aqueous solution or aqueous dispersion of a second material selected from the group consisting of high polymers and compounds forming high polymers when irradiated by light rays, forming a membrane from the admixture, drying said membrane to evaporate water therefrom and removing said waxy substances and said fatty substances contained in the dried membrane by extracting the same by the use of a solvent.

Abstract: A microcellular low density foam of poly(4-methyl-1-pentene) which is particularly useful for forming targets for inertial confinement fusion has been developed. Articles made from the foam have been machined to tolerances of 0.0001 inch, although the densities of the fragile foam are low (about 10 to about 100 mg/cc) and the cell sizes are small (about 10 to about 30 .mu.m). Methods for forming the foam and articles are given; and the yield strength of the foam of the invention is higher than was obtained in other structures of this same material.

Abstract: A process for producing a porous, film-like or fibrous structure of an aromatic polyester, which comprises(1) forming a substantially non-oriented film-like or fibrous structure by melt-molding an aromatic polyester blend composed of(A) an aromatic polyester containing an aromatic dicarboxylic acid as a main acid component and an aliphatic diol and/or an alicyclic diol as a main glycol component, and(B) at least one low-molecular-weight compound selected from the group consisting of imide compounds and isocyanurate compounds being compatible, but substantially non-reactive, with the aromatic polyester and having a molecular weight of not more than 1,000,the amount of the low-molecular-weight compound being present in an amount of 10 to 300 parts by weight per 100 parts by weight of the aromatic polyester, and(2) extracting at least a major part of the low-molecular-weight compound from the resulting substantially non-oriented film-like or fibrous structure with an organic solvent which can dissolve the low-mo

Abstract: A woven or knitted polyester multifilament fabric having a silk-like appearance and touch, comprised of polyester multifilament yarns containing one or more types of porous polyester filaments each having an irregular cross-sectional profile, for example, C-, L- or V-shaped profile, and numerous fine linear concave parts formed on the peripheral surface thereof and extending along the longitudinal axis of each individual filaments, the fabric being characterized by a group of said concave parts corresponding to a half of the entire number of the concave parts, each having a length of 5 microns or more and a ratio of the length to the width of each concave part of 5 or more.

Abstract: A wholly aromatic polyester composition comprising(a) 100 parts by weight of a wholly aromatic polyester containing as a main component at least one compound selected from the group consisting of aromatic dicarboxylic acids, aromatic dihydroxy compounds and aromatic hydroxycarboxylic acids, and(b) from 5 to 300 parts by weight of a low-molecular-weight compound being substantially non-reactive with the wholly aromatic polyester and having a boiling point of at least about 200.degree. C. under atmospheric pressure and a molecular weight of not more than 1,000.The wholly aromatic polyester composition is produced advantageously by polycondensing in the molten state the polyester-forming starting mixture in the presence of the low-molecular-weight compound.A film-like or fibrous article of a wholly aromatic polyester may be produced by extracting the low-molecular-weight compound from a film-like or fibrous article of the wholly aromatic polyester composition.

Abstract: A process for making a porous dip tube for use in a pressurized container dispensing liquid material in which a mixture of polymers, one insoluble in the liquid material and a second soluble in a solvent, is extruded to form a tube and thereafter the second polymer is removed from the extruded tube to provide porosity in the wall of the tube. In use, the bulk of liquid material is forced from the bottom of the pressurized container through the tube longitudinally while gaseous matter passes through the wall of the tube to provide means to atomize the liquid material as it passes into the atmosphere.

Abstract: A load-bearing building panel capable of forming an external wall cladding or roof component has a solar heat collecting capacity in the form of channels for heat exchange fluid incorporated in the fabric of the panel. The panel is made of a structural plastics material, such as G.R.P. laminate, successive layers being moulded to simulate tiles. On the back or underside, longitudinal reinforcing beams are built in during laying up of the panel. Between the beams cores or formers defining a matrix or channels are encapsulated in layers of the G.R.P. Wax cores are melted or dissolved out after curing of the panel; metal formers remain embedded in the fabric of the panel. The matrix is connected by flow and return pipes to a heat exchange system within the building. Panels intended for roofing have ridge flanges and wall plates moulded into the substrate at the appropriate pitch angle, and a split capping tube embraces the ridge flanges. A pitched roof formed by oppositely sloping panels is self-supporting.

Abstract: A process is provided for forming a polymeric material which can be developed into a shaped polymeric structure comprising an active material encradled in a porous, fiber-containing polymeric composition. In the process, the active material is mixed with a tripartite system comprising a fibrillatable polymer, a support-contributing polymer and a pore-former. When such a system is mixed and developed with an active material, such as LaNi.sub.5, an active composition is produced which may be used, for example, as a hydrogen collecting or storing material.

Abstract: A respirator filter formed of a cast polymeric matrix having a controlled porosity and inclusion of toxic gas absorbing and/or neutralizing chemicals. The chemicals are introduced into the casting precursor or added after polymerization, e.g. by imbibition with a solvent carrier and deposition by solvent evaporation.

Abstract: This disclosure is directed to the preparation of cohesive, self-sustaining electrode backing layers by a method comprising mixing from about 20 to about 50 weight parts of polytetrafluoroethylene (PTFE) having a particle size ranging from 0.05 to 0.5 micron with from about 50 to about 80 weight parts of a partially fluorinated carbon black of the formula CF.sub.x, where x is from about 0.1 to about 0.18 and having particles of a size ranging from about 50 to about 3000 angstroms to produce an electrode backing layer having a combination of enhanced electrical conductivity and hydrophobicity.

Abstract: The method of the present invention produces a porous, electrolyte permeable polytetrafluoroethylene diaphragm with a thickness of about 5 to about 100 mils and an average pore size of about 0.1 to about 100 microns. This diaphragm is suitable for use in an electrolytic diaphragm cell adapted to electrolytically form chlorine and an alkali metal hydroxide from an aqueous alkali chloride solution.

Abstract: Porous toner comprises a coloring matter and a binder, said toner being formed by obtaining a powder through a step of mixing and kneading under heat a toner preparing material including a coloring matter, binder and elimination compound which neither softens or melts at a temperature at which said binder softens or melts, and by treating said powder with a solvent to remove said elimination compound.

Abstract: The present disclosure is directed to an electrode active layer or sheet containing from about 60 to about 85 wt. % active carbon in intimate admixture with 15 to 40 wt. % fibrillated PTFE. This electrode has improved strength and is capable of operation at high current density with resistance to mechanical failure due to blistering of the electrode, and to a process for producing same. The process is characterized by combining a dilute dispersion of smaller polytetrafluoroethylene particles with a suspension of catalyzed or uncatalyzed larger active carbon particles to discontinuously coat active carbon with PTFE; fibrillating same; comminuting said fibrillated PTFE/active carbon mix; and then rolling same into a self-sustaining, coherent sheet form. Alternatively, the sheet form can be provided by deposition of the heat treated polytetrafluoroethylenated active carbon on a filter paper or like medium.

Abstract: A new and useful hydrophilic polyester fiber and process of making same are disclosed; the fiber has a stable pore system exhibiting a moisture pickup (regain) of at least about 2 percent by weight at 40.degree. C. and a relative humidity of 92%. Our experiments indicate that the proportion of moisture regain is attributable to capillary condensation in an amount of at least 25%. The hydrophilic properties are the result of a certain pore system within the fiber which enables capilliary condensation to occur significantly. The invention describes one way to accomplish this, namely by the addition of a predetermined amount of a suitable oxalato-complex to a suitable polyester mass. Most preferably, about 10% by weight K.sub.3 Al(C.sub.2 O.sub.4).sub.3 is added to the polyester mass.

Abstract: Process for production of a hollow fiber semipermeable membrane which can selectively separate the components of solution or gas mixtures, which consists essentiallly of dissolving cellulose triacetate and an organic acid and optionally a polyether in N-methyl-2-pyrrolidone to give a spinning solution having fixed contents of cellulose triacetate and organic acid and polyether (if any), and extruding the spinning solution through a spinneret into a gaseous atmosphere and immersing the spun fibers in an aqueous coagulation bath. The hollow fiber semipermeable membrane has excellent permeability and excellent separation characteristics with good life and hence is useful for various techniques such as dialysis, ultrafiltration, reverse osmosis, and separation of gases.

Abstract: Hollow water-absorbing polyester filaments each having a number of fine caves which are evenly distributed in at least a portion of the filament and through which the hollow is connected to the outside of the filament, are produced (1) by preparing hollow filaments from a blend of a principal polyester component and a cave-forming agent consisting of at least one member selected from:(i) copolyesters containing an additional divalent organic sulfonic acid compound moiety of the formula (II): ##STR1## wherein Z is a trivalent aromatic or aliphatic hydrocarbon radical, M.sup.1 is H or metal atom, R.sup.1 is an ester-forming organic radical and R.sup.2 is an H atom or ester-forming organic radical;(ii) phosphorus compounds of the formula (III): ##STR2## wherein R.sup.3 is a monovalent organic radical, X is --OR.sup.4, wherein R.sup.4 is an H atom or a monovalent organic radical, --OM.sup.3, wherein M.sup.3 is a metal atom, or a monovalent organic radical, M.sup.

Abstract: In a method of making a biologically compatible, water-insoluble polymeric body for the controlled, prolonged release of a biologically active substance to a surrounding aqueous environment, the method including forming a liquid mixture containing the polymer, the active substance, and an organic solvent capable of dissolving the polymer, and solidifying the liquid mixture to form the polymeric body, the improvement wherein the liquid mixture further comprises water, the solidification is carried out by cooling the liquid mixture to a temperature sufficiently low to cause the water in the mixture to freeze, thereby creating channels in the body for the release of the active substance therefrom, and removing the organic solvent and the water from the body.

Abstract: The present disclosure is directed to a process for treating gas electrodes containing a wetproofing (backing) layer which contains a polytetrafluoroethylene (PTFE) in conjunction with a water-soluble pore-forming agent and a PTFE-containing active layer to preserve and enhance their structural integrity which comprises contacting the electrode first with an alkylene polyol, or other water-soluble organic material having a plurality of hydroxyl groups, at temperatures ranging from about 50.degree. to about 100.degree. C. for a sufficient period of time to thoroughly wet the PTFE-containing active layer thereof, and thereafter contacting the thus-treated electrode with water in one or more washing steps to substantially remove the pore-forming agent. Between the hot soak with the alkylene polyol, or equivalent material, and the water wash(es), the electrode can optionally be dried.

Abstract: The invention relates to a method of manufacturing supports for porous filters.Supports are placed in contact with a first slip coating liquid containing in suspension a mineral powder comprising agglomerates between 10 and 30 microns in diameter, the resulting deposited layer is dried by heating it to approximately 100.degree. C., the layer is brushed so as to remove particles of powder which have not penetrated inside the pores, the thus-treated supports are placed in contact with a second slip coating liquid containing in suspension a mineral powder having a particle size between 1 and 8 microns, and the products obtained are heat-treated at approximately 1500.degree. C.The resulting filters are used for separating isotopes.

Abstract: The invention relates to a process for the production of hydrophilic filaments and fibres from a filament-forming synthetic polymer by a wet- or dry-spinning process which comprises introducing into the spinning solvent from 5 to 50% by weight of a substance with special properties defined herein and from 0.05 to 5% by weight of at least one surface-active compound as well as to hydrophilic filaments and fibres produced by such process.

Abstract: A porous polyfluoroalkylene sheet, very preferably of polytetrafluoroethylene, which is suitable for use as a separator in an electrolytic cell, such as one used for the electrolysis of brine, has a porosity in the range of 70 to 90%, a thickness in the range of 0.2 to 3.5 mm. and at least one of (a) an A X-ray ratio in the range of 0.1 to 0.35 and (b) a B X-ray ratio in the range of 0.75 to 0.98. Preferably the A X-ray ratio is in the range of 0.1 to 0.3, the B.sub.2 X-ray ratio is in the range of 0.75 to 0.98 and the B.sub.1 X-ray ratio is in the range of 0.1 to 0.32. The porous sheets are incorporated in separators or diaphragms for electrolytic cells and the uses of such separators and cells in electrolysis processes, preferably in the electrolysis of brine, are described. Also shown in the specification are a method for the manufacture of the porous sheets and a method for ascertaining which milled, sintered and leached porous sheets are more suitable for use in electrolytic processes.

Abstract: Textile quality polymeric fibers and thin films that are highly sorbent for organic and other vapors, mists and solutes. The fibers and films comprise a polymeric matrix with a system of interconnecting micropores, and are highly loaded with particulate sorbents such as activated carbon. The fibers and films are manufactured by forming a melt blend of the sorbent particles, the polymer and a selected diluent, spinning or extruding and drawing down the fiber or film, and extracting the diluent. The diluent functions to permit a high spin or extrusion draw down, to permit the subsequent cold drawing of fibers highly-loaded with active carbon, and to permit the fiber or film to be porosified. Optionally, the diluent may be extracted after or before cold drawing, or without any cold drawing. The fibers and films are highly sorbent, are strong and durable and exhibit substantial strength over an appreciable degree of elongation.

Abstract: This disclosure is directed to a one pass process for forming a porous, uniaxially oriented polytetrafluoroethylene sheet which is coherent and suitable for utilization as an electrode backing (wetproofing) sheet and the resulting backing sheet. Particulate PTFE is blended in an organic liquid medium to form a dispersion to which a pore-forming agent is added. After mixing, the organic liquid is removed and the dry mix is fibrillated, chopped and formed into a sheet by passing it once through heated rollers.

Abstract: Hollow water-absorbing polyester filaments, each having fine pores evenly distributed throughout the filament and extending approximately in parallel to the filament axis, are produced by melt-spinning a blend of a polyester and a pore-forming agent consisting of at least one sulfonate compound of the formula:R'SO.sub.3 M'wherein R' is an alkyl radical having 3 to 30 carbon atoms or an aryl or alkylaryl radical having 7 to 40 carbon atoms and M' is an alkali or alkaline earth metal, and by removing at least a portion of the sulfonate compound from the hollow filaments by using an alkali aqueous solution so as to cause a number of fine pores to be formed in the hollow filaments and to cause each hollow to be connected to the outside of the filament through the fine pores.

Abstract: The invention relates to hygroscopic filaments and fibres of synthetic high polymers. The improved hygroscopicity compared with known synthetic fibres is due to the fact, that in a conventional dry-spun process a liquid is added to the spinning solvent which liquid has a higher boiling point than the spinning solvent used, which liquid is readily miscible both with the spinning solvent and water and which represents a non-solvent for the polymer to be spun.

Abstract: This invention is directed to a microporous film comprising a 40 to 90 volume percent polyolefin having a number average molecular weight of 15,000 or more and a weight average molecular weight of less than 300,000 and a 10 to 60 volume percent inorganic filler and having a void space rate or porosity of 30 to 75 volume percent based on the volume of the film. The microporous film of such specific composition and structure has a desired wettability and a much reduced electrical resistance. Said resistance being as low as 0.0006 .OMEGA.dm.sup.2 /sheet. Said film has sufficient flexibility and mechanical strength to make it useful in wide variety of applications, especially as separators in batteries or electrolytical apparatuses etc.

Abstract: A filled insoluble polymer containing one or more corrosion inhibitors and a slightly water soluble polymer is utilized to automatically and continuously add a corrosion inhibitor to a coolant solution passing through a heat exchanger. The corrosion inhibitor is gradually leached from the filled polymer supplying inhibitor to the coolant to protect the metallic parts of the coolant system that are subject to corrosive conditions.

Abstract: Textile-quality multifilament yarns that are highly sorptive for organic vapors, mists and solutes are described. Each filament comprises a microporous polymeric sheath filled with a core of sorptive material. In a multifilament spinneret having a hollow needle in each orifice, a slurry containing the sorptive material is supplied to each needle, and a blend of a polymeric material and a pore-forming material is supplied to the orifice externally of the needle. The spun composite fibers are drawn and subsequently extracted to porosify the sheath and to activate the sorptive property of the cores.

Abstract: Water absorbent articles, made from solutions of carboxylic polyelectrolytes, together with methods for their preparation, and a composition useful to make said articles are disclosed. The articles are cured and/or crosslinked with monomeric amine-epihalohydrin adducts by heating and/or removing substantially all of the solvent from the precursor composition.The absorbent articles are useful as surgical sponges, diapers, tampons, meat trays, bath mats and the like.

Abstract: Asymmetric reverse osmosis membranes are made from synthetic aromatic polyimides having a relatively high predominance of polar groups in the polymer backbone. A polar/non-polar group ratio of from 2:2 to 2:7 per imidized nitrogen link is required. Such membranes can be fabricated using conventional casting equipment by providing a solution of the polyimide in a good solvent and a poor solvent, the poor solvent being compatible with solution components at poor solvent/good solvent ratios of at least 1:1 up to about 7:1, casting a film of such solution, and partially evaporating the exposed surface of the cast film for 100.+-.30 seconds prior to gelation.

Abstract: A filtering medium having a large specific surface area is made by sintering basalt or lava powder with sodium or potassium metasilicate and borax. The powder before sintering and/or the sintered product after sintering is treated with inorganic acid and the extract may be processed to recover lanthanides.

Abstract: Tubular sheet material is produced by extruding a fluid polymer material through a hollow center die having an annularly extending extrusion orifice exit rotated about the die axis to form a continuous or discontinuous annular-form structure which is collected on a supported surface advancing through the hollow center of said die which surface at least in the zone of collection has a generally cylindrical shape concentric with the axis of die rotation. The collected structure undergoes attenuation because of the die exit rotation and, consequently, has a grain therein extending at an angle, e.g. helically, to the general extrusion direction. The collected structure may after solidification be slit and opened into sheet form or separated into filaments.

Abstract: Microporous membrane materials suitable for use in electrolytic cells, such as cells for the electrolysis of brine to produce chlorine, are formed from a mixture of polytetrafluoroethylene, a particulate pore forming material and an organic fluorinated lubricant. Such materials are preferably formed into a sheet, which is rolled to a desired thickness, sintered and subjected to leaching out of the pore forming material.

Abstract: A polyurethane gripping material for hand held implements. The material is an adhesive backed polyurethane sheet which includes a plurality of small pores on the surface of the sheet. The pores are formed by sprinkling salt on the surface of the sheet while it is in a softened state. The sheet is then cured and sanded down to expose and remove some of the salt granules. Many small pores are exposed by the removal of the salt. The pores act as suction cups to increase the performance of the grip.

Abstract: A polyvinyl alcohol (PVA) microporous membrane is disclosed which is prepared by a process which comprises forming a PVA membrane containing fine silica particles therein and substantially extracting said silica particles from said membrane, thereby forming a plurality of micropores therein with an average diameter of 0.01 to 50 microns and a porosity of at least 60%.

Abstract: A method and composition are described for the decomposition of sodium-mercury amalgam in a reactor containing solid packing particles to form hydrogen, sodium hydroxide, and denuded mercury. The novel packing particles are comprised of a heterogeneous solid mixture of a matrix of a thermally stable polymer having embedded therein discrete particles of a surface active element. Suitable thermally stable polymers include polyphenylene sulfide and suitable surface active elements include carbon, iron, nickel, cobalt, vanadium, and molybdenum. The proportion of polymer in the packing generally ranges from about 20 to about 80 percent by volume. Preferably, the matrix is prepared in porous form which may also be coated with a surface active metal.

Abstract: A method for the preparation of semipermeable membranes which comprises sulfonating porous membranes of acrylonitrile polymers containing acrylonitrile in an amount of 40% to 100% by mole.The resulting semipermeable membrane is very useful for separating substances by reverse osmosis or ultrafiltration.