Abstract: An expansible macromolecular material is produced by a method which comprises mixing an aqueous polyvinyl alcohol solution, an acidic aqueous macromolecular electrolyte solution, and a basic aqueous macromolecular electrolyte solution thereby preparing a composite polymer and subjecting this composite polymer to at least one cycle of alternate freezing and defrosting treatments. A macromolecular membrane constituted of said expansible macromolecular material and containing numerous through holes is obtained by mixing, freezing, and defrosting the aforementioned three mixed aqueous solutions under specific conditions.

Abstract: A porous polymer article for use as a filter medium or battery separator is prepared by admixing a cellulosic compound and a thermoplastic polymer, both usually in powder form, forming the article under pressure and heat to melt and flow the thermoplastic polymer into a continuous phase and after cooling to set the polymer matrix, contacting the set admixture with a solvent, e.g. water, for the cellulosic compound which will not also dissolve the polymer matrix to produce a porous polymer which has a predetermined degree of porosity and is free from residual salt. The article so produced is also disclosed.

Abstract: A microporous biocompatible material is formed by preparing a segmented polyether urethane urea solution containing 25%.+-.1.5% solids dissolved in a solvent. The solution has sufficient viscosity to be preshaped and formed into the desired thickness of the finished article, then immediately immersed into a precipitation bath in which the solvent in the solution is miscible for a time interval sufficient to cause the solution to set up into an opaque elastomeric article. The article is immediately removed from the bath, any excess solvent extracted and then dried at a temperature on the order of 35.degree. C. to 70.degree. C. followed by heat treating by annealing for approximately sixty minutes at a temperature at 100.degree. C. to 130.degree. C. The void volume of the membrane solution is controlled to within the 50% to 80% range and the pore size from ca <0.1 to several mms.

Abstract: The invention relates to a porous membrane made of a particular fluorine resin, having excellent chemical resistance, excellent thermal resistance, excellent filtration performance and excellent mechanical properties, and having uniform porous structure comprising minute pores, and also relates to a process for preparing the same. In particular, the invention relates to a porous membrane suited for a microfilter having excellent thermal resistance and excellent filtration performance, especially a porous membrane suited for a microfilter for use in purification of chemicals such as strong acid and strong alkali by utilizing the excellent chemical resistance, and also a process for preparing the same.

Abstract: The present invention discloses a hydrophilized porous polyolefin membrane with a polymer of a monomer, which has an HLB value of 2-20, held on at least a part of the pore walls of a porous polyolefin membrane as well as its production process. This hydrophilized porous polyolefin membrane has long-lasting hydrophilicity and good mechanical strength.

Abstract: Low density, microporous polymer foams are provided by a process which comprises forming a solution of polymer and a suitable solvent followed by rapid cooling of the solution to form a phase-separated system and freeze the phase-separated system. The phase-separated system comprises a polymer phase and a solvent phase, each of which is substantially continuous within the other. The morphology of the polymer phase prior to and subsequent to freezing determine the morphology of the resultant foam.Both isotropic and anisotropic foams can be produced. If isotropic foams are produced, the polymer and solvent are tailored such that the solution spontaneously phase-separates prior to the point at which any component freezes. The morphology of the resultant polymer phase determines the morphology of the resultant foam and the morphology of the polymer phase is retained by cooling the system at a rate sufficient to freeze one or both components of the system before a change in morphology can occur.

Abstract: A porous and transparent hydrated gel is prepared from a poly(vinyl alcohol) solution in a mixed solvent consisting of water and an water-miscible organic solvent. Upon cooling the poly(vinyl alcohol) solution below room temperature, a gel is formed as a consequence of crystallization of poly(vinyl alcohol) molecules. Exchange of the organic solvent included in the gel with water produces a hydrated gel of poly(vinyl alcohol) which has a high tensile strength, a high water content, and a high light transmittance.

Abstract: A polymeric porous membrane having a matrix made from an aliphatic thermoplastic polyamide or from an aliphatic thermoplastic polyamide/polyimide copolymer which has both relatively non-crystalline and relatively crystalline portions. The pores in the membrane are defined by spaces between the relatively crystalline portions and at least some of the relatively crystalline portions are linked together by the reaction of a bis-aldehyde with the membrane matrix.

Abstract: Composite materials useful as hard tissue prosthetics comprising synthetic biodegradable polymers and unsintered calcium phosphate biomaterials optionally porositized by pore-forming agents are described. The composite materials may be ground and blended with a compatible water soluble pore-forming agent and then molded to form dense, shaped objects which may be made porous by leaching out said water soluble pore-forming agent. The composites may be used as hard tissue prosthetics either alone or in conjunction with conventional prostheses.

Abstract: An in situ polymerization process is disclosed whereby an .alpha.-amino acid N-carboxyanhydride is blended intimately and efficiently with one or more calcium phosphate biomaterials. The polymerization proceeds at ambient temperature and pressure without the need for initiators or surface modification of the calcium phosphate biomaterials. The resulting composite material may subsequently be ground and blended with a compatible water soluble pore-forming agent and then molded to form dense, shaped objects which may be made porous be leaching out said water soluble pore-forming agent. The resulting shaped objects may then be used as hard tissue prosthetics either alone or in conjunction with conventional prostheses.

Abstract: A wound dressing material comprising a sheet of a synthetic plastics material which is permeable to water vapour and to air, having on one side a surface for application to a wound, and immediately behind the said surface a cellular region having a structure of collapsed, open cells which intercommunicate with one another, and a more dense region behind the cellular region, and an intermediate region in which there is a gradual transition from the cellular region to the more dense region, so that on contact with liquid exudate from a wound, the dressing material will absorb a limited amount of exudate into the cellular region but prevent it from passing right through the dressing material.

Abstract: The invention relates to a porous membrane made of a particular fluorine resin, having excellent chemical resistance, excellent thermal resistance, excellent filtration performance and excellent mechanical properties, and having uniform porous structure comprising minute pores, and also relates to a process for preparing the same. In particular, the invention relates to a porous membrane suited for a microfilter having excellent thermal resistance and excellent filtration performance, especially a porous membrane suited for a microfilter for use in purification of chemicals such as strong acid and strong alkali by utilizing the excellent chemical resistance, and also a process for preparing the same.

Abstract: A polyethylene microporous membrane having a thickness of at most 10 .mu.m, a breaking strength of at least 200 kg/cm.sup.2 and a porosity of at least 30% is produced by heating and dissolving polyethylene having a weight average molecular weight of at least 5.times.10.sup.5 in a solvent, forming a gel sheet from the resulting solution, subjecting the gel sheet to a solvent removal treatment to adjust the amount of the solvent in the gel sheet to 10 to 80% by weight, heating and stretching the sheet and then removing the residual solvent therefrom.

Abstract: Miscible blends of poly-2-oxazolines and thermoplastic polymers are disclosed herein. These blends exhibit a single glass transition point indicative of a miscible blend. The blends of this invention are useful as membranes, particularly separation membranes for mixtures of organic compounds or organic compounds and water and a perevaporation process.

Abstract: The present invention relates to molded articles of an open-cell structure, containing a copolymer which is comprised of copolymerized, fluorinated olefin, copolymerized vinyl acetate and optionally copolymerized olefin, the acetate groups of the copolymer being optionally saponified into OH groups. The molded articles possess an inherent latent structural convertibility and have effective pores of a diameter in the range from 0.002 to 10 .mu.m. The invention further includes processes for the preparation of the specified molded articles and processes for converting their structure. The invention also relates to several uses of molded articles according to the invention.

Abstract: Cross-linked homogenous porous polymeric materials are prepared by polymerization of monomers as the continuous phase in a high internal phase emulsion having above a critical limit of surfactant to ensure adequate absorbtivity. The porous materials may be dried and refilled with selected liquids and act as a high capacity reservoir.

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: A receptacle for handling contaminated waste for sterilization and subsequent disposal which is a pore forming sterilization bag made from a thermoplastic resin which has been embedded with either soluble materials or melt materials which respond to the temperature and moisture of steam sterilization to form pores in the bag, thus permitting the entrance of sterilant and the exit of air for sterilization of the waste. The melt materials are low molecular weight polymers such as carbowaxes. The soluble materials can be either organic or inorganic materials such as polyvinyl alcohol, polyvinyl acetate, polyvinyl pyrrolidone and various inorganic salts, such as sodium chloride.

Abstract: A porous aromatic imide polymer membrane usable as a gas or liquid separator or concentrator is prepared by a process comprising the steps of:(1) dissolving 3 to 30% by weight of an aromatic imide polymer which comprises at least 80 molar % of a recurring unit selected from those of the formulae (I) and (II): ##STR1## wherein R represents a divalent aromatic or heterocyclic radical in 70 to 97% by weight of a solvent consisting essentially of a homogeneous mixture of:(A) 100 parts by weight of a base solvent which consists essentially of at least one polar organic compound and is capable of dissolving therein said aromatic imide polymer in a concentration of 5% by weight or more therein and of evaporating at a temperature of from 50.degree. to 400.degree. C.

Abstract: The present invention relates to molded articles of an open-cell structure, containing a copolymer which is comprised of copolymerized, fluorinated olefin, copolymerized vinyl acetate and optionally copolymerized olefin, the acetate groups of the copolymer being optionally saponified into OH groups. The molded articles possess an inherent latent structural convertibility and have effective pores of a diameter in the range from 0.002 to 10 .mu.m. The invention further includes processes for the preparation of the specified molded articles and processes for converting their structure. The invention also relates to several uses of molded articles according to the invention.

Abstract: An aromatic polyimide membrane having an excellent gas-separating property comprises (A) a substrate consisting of a porous membrane comprising at least one aromatic polyimide having at least 80 molar % of at least one type of recurring unit of the formula (I): ##STR1## wherein R is a tetravalent aromatic radical and R.sup.1 is a divalent aromatic radical, the porous membrane exhibiting a hydrogen gas permeability (PH.sub.2) of 1.times.10.sup.-5 to 5.times.10.sup.-1 cm.sup.3 /cm.sup.2.sec.cmHg and a ratio of hydrogen gas permeability (PH.sub.2) to carbon monoxide gas permeability (PCO) of 2 to 5; and (B) 50% or more, based on the weight of the porous membrane substrate, of a gas-separating liquid contained in the porous membrane substrate, the gas-separating liquid being substantially incapable of dissolving therein the porous membrane substrate and having a boiling point of 180.degree. C. or more.

Abstract: Porous, powdery polypropylene is disclosed, obtained by providing a hot solution of polypropylene in pentaerythrol ester as solvent, slowly cooling said solution down to approximately room temperature to provide a solidified mass with or without affecting mechanical size reduction of said solidified mass, and extracting said solidified mass with an extractant in which pentaerythrol is soluble, with or without subsequently removing said solvent to a high degree.

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: The invention relates to a process producing porous powdery polymer particles. A homogeneous mixture having two components minimum, one a meltable polymer, the other fluid inert to the polymer, both forming a system having a range of complete miscibility and a miscibility gap are introduced to a bed of solid-substance particles, then cooling the mixture to below solidification of the polymer and comminuting the obtained cake-like mass. The polymer is separated then from the inert fluid and solid-like substance particles.

Abstract: Process for the production of porous, powdery polypropylene, and utilization thereof. Hot solutions of polypropylene in pentaerythrol ester are slowly cooled down to approximately room temperature, forming a solidified mass, after which it is extracted with an extractant in which pentaerythrol is soluble. Before extracting, the size of the solidified mass may be reduced mechanically. After extracting, the pentaerythrol may be removed from the extractant to a high degree. Preferred embodiments include using solutions of polypropylene in pentaerythrol esters of fatty acids, more specifically, of synthetic fatty acids with 8-10 carbon atoms; using ethanol for the extraction; using solutions with a weight ratio of polypropylene to pentaerythrol ester of 30:70 to 10:90; having cooling of the solutions within the range of 260.degree. to 120.degree. C. proceed at an average rate of 1.degree. to 20.degree. C. per minute; using polypropylene with an admixture of up to 10% by weight of polyethylene.

Abstract: Crystalline adducts of the polyamides: poly-e-caproamide, poly(hexamethylene adipamide), poly-p-benzamide, poly(p-benzanilidene terephthalamide), and mixtures thereof; with the perfluorinated diacids: perfluorosuccinic acid, perfluoroglutaric acid, perfluoroadipic acid, and mixtures thereof. The polyamide components of the adducts contain at least 25 about amide groups in the polymer chain, preferably at least 75 amide groups for aliphatic polyamides and at least 50 amide groups for aromatic polyamides. The adducts can be formed into shaped objects from which diacid can be leached to produce a porous object useful for example as a filtration device.

Abstract: There are disclosed monofunctional and polyfunctional aliphatic oxycarbonylsulfenyl chlorides having general utility as crosslinking, coupling and chemical modification agents for olefin containing polymers, particularly unsaturated rubber hydrocarbon elastomers.

Abstract: Organic foams having a low density and very small cell size and method for producing same in either a metal-loaded or unloaded (nonmetal loaded) form are described. Metal-doped foams are produced by soaking a polymer gel in an aqueous solution of desired metal salt, soaking the gel successively in a solvent series of decreasing polarity to remove water from the gel and replace it with a solvent of lower polarity with each successive solvent in the series being miscible with the solvents on each side and being saturated with the desired metal salt, and removing the last of the solvents from the gel to produce the desired metal-doped foam having desired density cell size, and metal loading. The unloaded or metal-doped foams can be utilized in a variety of applications requiring low density, small cell size foam. For example, rubidium-doped foam made in accordance with the invention has utility in special applications, such as in x-ray lasers.

Abstract: A method for preparing macroporous aminotriazine-aldehyde resins by reaction in the presence of an acid catalyst and a miscible porogen. The resin product has high surface area and porosity and displays excellent sorption capacity.

Abstract: The preparation of flexible polyurethane foam micro-bits by the comminution of a flexible polyurethane foam in the presence of a compatible protective cooling fluid under specific comminuting steps and conditions.

Abstract: Hydrophilic polymeric chambers for encapsulating biologically active tissue and methods for their preparation. The tissue refers to those essential cellular components of a particular organ that is capable of receiving, modifying or secreting hormones. A device comprising such chamber and such tissue is fabricated and implanted in a living body so that said tissue is permitted normal function without being rejected by the host's immunological system. The viability of the tissue in the device is maintained by a correlation of factors including pore size and membrane thickness of the hydrophilic chamber. To maintain the viability of the tissue, the implanted device allows the inflow of essential nutrients and gases, and outflow of metabolites and products while simultaneously excluding the ingress of cellular components of the host's immunological system.

Abstract: Organic amides, solutions of polymers thereof, which polymers are subject to hydrolysis and degradation in the presence of amines, and polymers isolated therefrom are stabilized by the presence of aromatic sulfonic acid esters of aliphatic, arylaliphatic and alicyclic alcohols and polyols.

Abstract: Highly useful novel microcellular polymeric structures, especially films and fibers, are prepared from certain solid polymers. Aromatic polysulfones, polyimides, polyhydantoins, polyamides and polyparabanic acid are the preferred ones for the novel structures of the invention.

Abstract: A porous thermoplastic sheet is formed by adding a material to a polymer latex to passivate the aqueous phase of the latex. An additional material of a preselected particle size, corresponding to the desired pore size of the final product is then added. The latex composition is gelled and is then formed into a sheet. The sheet is dried and cured or sintered and the solubles are extracted therefrom with a solvent. A preferred polymer latex is PTFE.

Abstract: A textile or textile-like polyester element having improved adhesion to rubber and being characterized by a high surface energy, a chemically unmodified surface and a coating which is a crystallizing agent for the polyester substrate.

Abstract: An improved microporous polymer material is made by coagulating, e.g. in water, a polymer solution containing dispersed microscopic particles of a removable filler soluble in a coagulating liquid.

Abstract: This invention relates to light sensitive photoresist materials which are used in the photo-engraving process or in the production of the phosphor screens of color picture tubes. The light sensitive photoresist materials of this invention are novel, water-soluble azide materials.

Abstract: The invention concerns a membrane filtration type hollow fiber. It is composed of a single material phase which material is a chain high polymer such as cellulose acetate and capable of forming fibers by the spinning of the high polymer. The cylindrical wall defining the hollow fiber represents a three-dimensional net-like structure of fine filtering passages. This structure occupies substantially the whole mass of the tubular wall or a closed ring band zone when seen in any cross-section of the wall, providing thus an effective and active filtering zone. The pore rate amounts to at least 55%, and active points of the filtering passages for governing minimum passable sizes of the passages for solids included in a filtering liquor to be treated upon are distributed at random throughout at least the active zone. These sizes are nearly uniform.

Abstract: Novel, macroreticular cross-linked anion exchange and adsorbent copolymers of at least one monovinylidene ring-containing nitrogen heterocyclic monomer are prepared. Preferred monovinylidene ring-containing heterocyclic monomers are the various vinylpyridines.

Abstract: A membrane made of a composition containing essentially two kinds of ethylene-vinyl alcohol copolymers with different ethylene unit contents and the membrane has such a microstructure that there are at least one active layer and a porous layer thereunder, the porous layer comprises mono- or multi-layer of a plurality of cylindrical voids and a plurality of spherical voids therein and the membrane is of a porosity of 70 to 95%.

Abstract: A printing material composed of an open-cell sponge rubber capable of including therein a colored ink, which does not necessitate a stamp pad for the stamping operation, is disclosed. This printing material is prepared by adding appropriate amounts of soluble starch and a fine powder of an easily water-soluble salt which does not decompose or gasify at a curing temperature to a mixture of a starting rubber, a curing agent and a filler, kneading and milling the mixture, introducing the mixture into a mold, heating the mixture to effect curing, removing said starch and salt by washing, and drying the resulting product.

Abstract: A porous, hydrophilic, assimilable prosthesis is formed by the removal of solvent, without substantial dimensional change, from a solution of (a), an assimilable polymer composed primarily of polymerized units of an alpha or beta hydroxy carboxylic acid, preferably but not necessarily those having 1 to 4 carbon atoms, and (b), a small amount of a physiologically acceptable wetting agent that is sufficient to impart hydrophilicity to the prosthesis. The preferred assimilable polymer is a polylactic acid. The preferred process for making the prosthesis involves the lyophilization of a solution of polylactic acid having a molecular weight of at least 100,000, weight average, at a concentration of at least 31/2% by weight of the solution of the polylactic acid. A variety of physiologically acceptable wetting agents is useful, a preferred class being the alkali metal soaps of fatty acids or of alkyl aryl sulfonic acids.

Abstract: An improved microporous polymer material is made by coagulating, e.g. in water, a polymer solution containing dispersed microscopic particles of a removable filler soluble in a coagulating liquid.

Abstract: A composition of material suitable for in vivo implantation to provide an environment in which normal tissue growth is fostered which composition is a porous fibrous structure in which the critical surface tension of the fibers is 35 dynes per centimeter or higher. This composition in the preferred form is a porous structure of carbon or graphite fibers bonded together by sintered polytetrafluoroethylene in a manner to expose a maximum amount of fiber surface.Another composition of material suitable for implantation for wear surfaces includes carbon fibers and polytetrafluoroethylene resin and is processed to align the carbon fibers with the wear surfaces. The method of preparing both material includes the step of mixing, filtering, compressing, rolling, sintering and drying. The method of stabilizing appliances or implants includes bonding the ingrowth material to the appliance or implant.

Abstract: The method of fabrication of porous macromolecular materials which are primarily intended for use as ion-exchange membranes and selective semi-permeable membranes consists in subjecting a polymer to irradiation with heavy nuclear particles, in chemically fixing a monomer having at least one ethylene double bond in the zones which are modified by irradiation and localized around the locus of passage of each particle and in forming the pore structure by means of a chemical attacking agent which is specific to the starting polymer.

Abstract: Asymmetric polyimide membranes are prepared from tetracarboxylic acid dianhydrides and diamines. They are semipermeable and useful in the separation of different chemical species by osmosis, dialysis, electrodialysis and reverse osmosis.

Abstract: A non-swellable three-dimensional polymer having a component which is a residue of an optically active compound, which residue is chemically removable from said polymer to leave behind in the physical structure of said polymer a void corresponding to the size and shape of said residue of optically active compound, and a particular steric arrangement of functional groups within the void of said polymer corresponding to the chemical structure of said residue of optically active compound, the original polymer having recurring units of the formulas ##STR1## wherein A, C and D are residues bonded to B of compounds which residues are polymerizable or polycondensable and B is a residue of an optically active compound; a process for preparing such polymer and the form of such polymer containing such void and free of the residue of optically active compounds.

Abstract: There is described the preparation of hydrophilic, semi-permeable film membranes having an increase in pores and containing complex-forming metals. The films can be formed from solutions having film-forming material and pore-forming material dissolved in a solvent. The films can be useful for separating a component, e.g. an aliphatically-unsaturated hydrocarbon, from mixtures by the combined use of liquid barrier permeation and metal complexing techniques. The liquid barrier is at least partially within the hydrophilic film membrane during use, and the barrier contains complex-forming metal ions in aqueous solution. The metal ions may be, for example, noble metal, nickel, mercurous, cuprous or other metal ions, and mixtures of these metal ions, and the aqueous solution may contain other cations. The separation of ethylene from ethane and methane is of particular interest.

Abstract: A process for preparing permeable membranes which comprises kneading in the molten state two different kinds of thermoplastic synthetic resins which are partly compatible with each other, fabricating the molten mixture into a sheet, film or hollow article, treating the fabricated article with a solvent which is a good solvent for one of the component resins but is a poor solvent for the other to dissolve and remove the former resin, drying the fabricated article, and then stretching it. In place of the resin to be removed by the solvent, rubbers or oligomers having partial compatibility with the resin which remains undissolved can be used.