Abstract: A synthetic vascular prosthesis comprises a hollow tubular base member having a multitude of continuous pores and formed of an elastomer material, and a hydrogel layer formed on the inner surface of the base member. The hydrogel layer is partly embedded in the inner portion of the base member at the pores, thereby permitting anchoring adhesion between the hydrogel layer and the base member. A method for manufacturing the synthetic vascular prosthesis is also disclosed, in which the formation of pores in the base member is effected by two separate steps and the hydrogel layer is formed after formation of an inner porous portion of the base member.

Abstract: A method of manufacture of flat permeable membrane comprises the steps of mixing a polyolefin, an organic filler uniformly dispersible in the polyolefin in the molten state, and crystal seed forming agent for the polyolefin; discharging the resultant mixture in the molten state through a die; bringing one surface of the discharged molten membrane into contact with a cooling roll; placine the cooled and solidified flat membrane into contact with an extractant capable of dissolving and extracting the organic filler and capable of dissolving the polyolefin; and subjecting the cooled and solidified flat membrane in a fixed state in longitudinal and lateral directions to a heat treatment at a temperature 20.degree. to 50.degree. C. lower than the melting point of the polyolefin.

Abstract: A process for producing an acoustic diaphragm of carbonaceous material including the steps of impregnating nonwoven fabric or woven fabric of carbon fiber having a high degree of elasticity with a thermosetting resin, thermally molding it into a diaphragm shape, calcining the shaped fabric in an inert gas atmosphere to obtain a porous carbon molding, heating the porous molding to a uniform temperature, and depositing vapor phase, thermally decomposed carbon upon a surface of the porous molding. The deposited carbon is generated by thermal decomposition of a hydrocarbon-containing material introduced together with a carrier gas. The process produces an acoustic diaphragm having a dense surface layer of carbonized fiber-carbonized thermosetting resin-thermally decomposed carbon, and a porous interior of carbonized fiber bonded together by carbonized resin and the thermally decomposed carbon.

Abstract: The preparation of a novel class of thin film membranes by interfacial polymerization is disclosed, said membranes incorporating as part of their polymeric structure the functionality of monomeric or oligomeric precursors. Specific embodiments include porphyrin and phthalocyanine derivatives that are photochemically or electrochemically active, as well as chemically asymmetric membranes.

Abstract: A granular water treatment material and a process for the production thereof, the material being in the form of spherical granules, each having a thermoplastic polymeric matrix (1) and a more dense adjuvant in the form of micro-grains (3) dispersed in the matrix; each granule has on the surface a porosity in the form of micro-cavities (4) and cationic hydrophilic sites distributed on the surface; the process includes providing a mixture of an oxidizable thermoplastic resin and an adjuvant in powdered form, heating the mixture to make it plastic, extruding the plastic material to a diameter corresponding to the size of the granules to be obtained and cutting the extrusions to a length equal to this diameter, achieving a beading of the extruded pieces, oxidizing the surface of the spherical granules thus obtained, then ionically grafting a cationic polyelectrolyte to the surface of said granules.

Abstract: Disclosed herein is a process for producing a polyhalogenated microporous film having a very narrow pore size distribution and good temperature and chemical resistance. The process involves blending a polyhalogenated copolymer having a very small particle size with a binder polymer utilizing a solvent which is a nonsolvent for the polyhalogenated copolymer but a solvent for the binder polymer, forming a film from the blend, drying the film, heating the film to a temperature at or above the melting point of the polyhalogenated copolymer and under conditions such that the microparticulate particles at their points of mutual contact will neck together to form a relatively continuous matrix and extracting the binder polymer from the film utilizing a solvent for the binder particle to form a microporous film.

Abstract: An asymmetric microporous hollow fiber for hemodialysis is made up of 90 to 99% by weight of a first hydrophobic polymer and 10 to 1% by weight of a second hydrophilic polymer. The fiber has a water adsorbing capacity of 3 to 10% and is produced by extruding a solution containing 12 to 20% by weight of the first polymer and 2 to 10% by weight of the second polymer, the rest being a solvent to give a continuous hollow structure with a wall, causing a precipitation liquor to act on said structure in an outward direction through the wall thereof with the full precipitation thereof and the concurrent dissolution and washing out of a part of said first polymer from said extruded structure and then washing out the dissolved out part of the pore-forming substance and the other organic components. Thereafter the fiber so produced is fixed in a washing bath.

Abstract: Fully aromatic polyamide (aramid) resins can be cast into ultraporous and microporous membranes by forming a solution of the resin in an amount sufficient to cast a coherent membrane, diluting the solution with a liquid pore modifier which is a nonsolvent for the resin so as to produce a metastable dispersion of the resin, adding a precipitant to form a turbid casting dope, casting the dope onto a surface, and gelling the so-cast film.

Abstract: A method of forming hollow, porous elastomeric bodies and hollow, duo-layered elastomeric bodies wherein one layer is porous and contiguous with the other layer which is solid by (a) coating a surface of a mandrel with a coating liquid, (b) adhering a layer of water-elutable particles onto the coated mandrel surface, (c) applying a layer of fluid elastomer composition to the particle-coated mandrel surface wherein the elastomeric composition is capable of forming a water-insoluble elastomer, (d) causing said elastomeric composition to form a cohesive mass while in contact with the particle-coated mandrel surface, (e) dissolving said elutable particles from the cohesvie mass with a water-based solvent, and (f) removing the cohesive mass from the mandrel. The coating liquid comprises water and may also further comprise a wetting agent and/or a sugar. The invention also relates to the method wherein the water-elutable particles are adhered to the mandrel surface by heating the mandrel surface.

Abstract: Medical devices for the sutureless repair of lacerated, severed, or grafted nerves comprising longitudinally-openable, porous, rough-surfaced tubes of a body-absorbable polymer are disclosed. The tubular devices of the invention are prepared by sintering or otherwise bonding together granules or fibers, or melt processing suitable polymers in the form of the desired device.

Abstract: The present invention provides a method for preparing a molded article of an ultra-high molecular weight polyethylene which is characterized by compression-molding, or heating and pressurizing a porous sheet of said ultra-high molecular weight polyethylene. The porous sheet may be superposed with a substrate, and may be wrapped around a deformable member of a mold and densified by deformation of said member.

Abstract: A method for preparing porous membranes containing a homogeneous microporous structure and narrow pore size distribution which are useful for ultrafiltration, distillation and substrates for composite membranes, including preparing films, pellets or sheets containing alternating microlayers of high density polyethylene and polystyrene, recoextruding these films, pellets or sheets, pulverizing into fine granules or powder, compression molding or sintering into thin films, immersing these films in a solvent bath into which one component is selectively dissolved and separating the resultant porous membrane from the solvent.

Abstract: A process for producing a filter including a microporous membrane and a supporting structure connected thereto, including producing a mold for the membrane and the supporting structure, filling the mold with a molding material whose solubility can be changed by high energy radiation, and forming the micropores by partial irradiation of the membrane with high energy radiation and removal of the regions having increased solubility. The filter produced according to the above method is a unitary structure with the supporting structure integrally connected to the membrane.

Abstract: A method for preparing an asymmetric, semi-permeable membrane containing a uniform microporous structure for gas and liquid separation, including forming a dense separation on one major surface of a microporous support structure. The microporous support structure is initially formed as a solid unitary film, fiber or sheet by the simultaneous extrusion of at least two streams of heat-plastified polymeric materials including at least two differentially soluble polymeric materials. The separation layer can be formed on the support structure prior to or after the soluble polymeric material has been dissolved out of, as by leaching from the solid support structure to form the microporous support for the separation layer. Preparation in this manner greatly reduces the tendency to form undesiralbe pinholes in the membrane.

Abstract: A mold (1) for cast-molding a slip is provided, which comprises a divsible casting mold including a plurality of mold portions to form a mold cavity (4) when mated together; each mold portion including an air-tight housing (2), an intermediate layer (5) of coarsely porous structure adjacent to the air-tight housing (2), and a solid synthetic resin filter layer (3) of fine open-cell structure; a slip supply duct (8) being connected with said mold cavity (4) and communicated with the outside of the air-tight housing (2); a fluid-flowing duct (9) being connected with said coarse intermediate layer (5) and communicated with the outside of the air-tight housing (2); said filter layer (3) being permeably joined to the coarse intermediate layer (5), and having substantially precise shape and dimension of substantially uniform fine open-cell structure.

Abstract: Novel microporous, asymmetric, integral, composite piolyfluorocarbon, e.g., polytetrafluoroethylene, membranes are disclosed. These membranes are made up of two or more sheets of microporous fluorocarbon polymer having different average pore sizes, arranged to provide an increasing gradations in average pore size from one surface of the membrane to the other, and are useful as microfilters for removing fine particle contaminants, including bacteria, from fluids such as those encountered in the electronics and pharmaceutical industries.

Abstract: A polarizable electrode for an electric double layer capacitor, composed of a continuously micro-porous structure of a fluorine-containing polymer resin with a fine carbon powder incorporated therein, wherein said structure includes a numerous fine nodes of the resin and fine fibers of the resin three dimensionally connecting the nodes so that the nodes are partially in contact with or connected to one another, and the fine carbon powder is contained substantially in the nodes.

Abstract: A composite self-supporting flexible agglomerated macrostructure is described which includes (1) a matrix of unfibrillated polytetrafluoroethylene resin and addition curable silicone and (2) particulate material including hydroxyapatite and/or tricalcium phosphate uniformly distributed throughout said matrix, the macrostructure being uniformly permeated by a network of open pores formed in the process of manufacture by intimately blending particulate sodium chloride and subsequently leaching the sodium chloride particles.

Abstract: The method of preparing dried asymmetric cellulose acetate blend membranes through the use of at least one drying agent which is a hydrophobic organic compound, such as polysiloxanes, hydrocarbons, ethers, ketones, chlorohydrocarbons or nitrohydrocarbons. The membranes are dried from their aqueous state by direct evaporation of water. The resulting air dried membranes are suitable for the desalination of water by reverse osmosis, non-aqueous liquid separation, ultrafiltration, pervaporation, and for the separation of various gaseous mixtures into their constituent parts.

Abstract: A polymeric component, for use as a separator in an electrochemical device in which the anode comprises metallic lithium, comprises a thermoplastic polymer, a tertiary plasticizer and a filler that comprises a lithium compound which is substantially insoluble in both the polymer and the plasticizer. The component is rendered porous by deformation which increases its surface area. The porosity can be enhanced by extracting one or both of the plasticizer and the filler.

Abstract: Precursor microporous material comprising a matrix consisting essentially of linear ultrahigh molecular weight polyolefin, a large proportion of finely divided water-insoluble siliceous filler, and interconnecting pores is stretched to increase the porosity and provide regions of stretch-induced molecularly oriented polymer in the matrix.

Abstract: A method for making an ink-impregnated material includes steps of mixing from a plastic powder, a water-soluble salt and a water-soluble, polar organic liquid to form a mixture, heating the mixture to a temperature sufficient to melt the plastic and form a cohesive structure, leaching the salt and polar organic liquid from the structure, drying the structure, and impregnating the structure with an ink. The resulting microporous material has an open-celled network of micropores extending therethrough, which micropores have smooth, rounded internal walls free of fibrous projections. An ink roll made of this material is suitable for use in an apparatus for printing coded images such as bar codes.

Abstract: A process for producing potassium hexatitanate fibers having a tunnel structure, which comprises mixing a titanium component represented by the general formula (Ti, M)O.sub.2 where M is metal impurities with a potassium component selected from the group consisting of potassium oxide, potassium compounds capable of forming potassium oxide when heated and a mixture thereof, to obtain a mixture represented by the general formula K.sub.2 O.n(Ti, N)O.sub.2 where n is from 1.5 to 2.5 and M is as defined above; heating the mixture to obtain a melt; forming from the melt a fibrous material having a layered crystalline structure corresponding to potassium dititanate (K.sub.2 O.2TiO.sub.2); leaching a part of K.sub.2 O from the fibrous material; and heating the fibrous material at a temperature of at least 800.degree. C. and lower than the melting point of the fibrous material.

Abstract: A process for preparing assymetric polyvinylidene fluoride microporous membranes using novel pore forming agents of an ammonium salt which is a non-solvent for the polymeric casting solution; such agents for example being ammonium hydroxide, ammonium chloride and the like.

Abstract: Disclosed is a microporous polyproplene film comprising a propylene homopolymer, a copolymer of propylene with other copolymerizable monomer or a blend thereof, which has an intrinsic viscosity (.eta.) of 1.9 to 3.0 dl/g, especially 2.0 to 3.0 dl/g, as measured at 135.degree. C. in tetralin, said microporous film having a network structure comprising intercommunicating pores having a maximum pore size smaller than 1.mu. and an average pore size of 0.005 to 0.6.mu. and having a porosity of 30 to 90%, an air permeability of 5 to 500 sec/100 cc and a thickness of 5 to 200.mu., said microporous film being molecularly oriented by stretching.

Abstract: A process for preparing a porous random fiber polymeric composite sheet through the addition of a cellulose ether which is selectively soluble or insoluble to a random fiber composite slurry under conditions such that the cellulose ether is insoluble, forming the slurry into a sheet, fusing the organic polymer component of the sheet and heating the sheet to solubilize the cellulose ether whereby voids are formed in the sheet. Before the sheet is treated to remove the cellulose ether, it may be combined with other sheets and densified under heat and pressure. Before removing the cellulose ether, the densified sheet may be heated under reduced pressure to expand or loft the sheet in a direciton normal to the plane of the sheet. A random fiber polymeric composite sheet, a densified sheet and a lofted sheet, each comprising a binder, fusable organic polymer, reinforcing material and a cellulose ether are also provided. The same sheets after removal of the cellulose ether are further provided.

Abstract: A precast composite plastic reinforcement insert, method of making the reinforcement insert and method of reinforcing a structural member. The insert includes pellets which are formed of a mixture of a thermoplastic polymeric resin and a blowing agent. Polymeric resins disclosed include a one-part epoxy with a thermal curing system or a thermoplastic polyester resin. The pellets in one embodiment are retained within a matrix of expanded polystyrene and in combination form the insert. The insert is formed in a mold cavity which receives the pellets and unexpanded polystyrene which is expanded during the process by heating the same within the mold cavity. The insert is used to reinforce a structural member by placing it in the structural member prior to a thermal paint curing operation.

Abstract: Novel porous fibers and filaments are prepared from normally solid, thermoplastic, orientable, organic polymers which have reactive or reactable groups pendent from the polymer chain, employing a process which involves reactions of said pendent groups while the polymer is in an oriented condition. One of the preferred polymers is a copolymer of ethylene/acrylic acid.

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 precast composite plastic reinforcement insert, method of making the reinforcement insert and method of reinforcing a structural member. The insert includes pellets which are formed of a mixture of a thermosetting polymeric resin and a blowing agent. Polymeric resins disclosed include a one-part epoxy with a thermal curing system or a thermoplastic polyester resin. The pellets in one embodiment are retained within a matrix of expanded polystyrene and in combination form the insert. The insert is formed in a mold cavity which receives the pellets and unexpanded polystyrene which is expanded during the process by heating the same within the mold cavity. The insert is used to reinforce a structural member by placing it in the structural member prior to a thermal paint curing operation.

Abstract: System for the artificial underground irrigation or watering of soil, with flexible tubing of a porous material, characterized by tubes with a non-expanded porous inside structure. The tubes are obtained through extrusion of a homogeneous mixture of at least two components, one component a meltable polymer and the other component a liquid inert in relation to the polymer. Both components forming a binary system displaying in liquid aggregate state a range of complete miscibility and a range with a miscibility gap. Preferred parameters include an inside tubing wall surface with open pores and an outer wall surface, the degree of openings of which, calculated as fraction of open area, is reduced at least 20% in relation to the inside wall surface; open pores in the outer wall surface for the most part of a pore diameter of less than 4 .mu.m; tubes with a pore cavity volume of from 50-90%; tubes made of polypropylene; tubes made of glass fiber-reinforced polypropylene; tubing wall thickness of about 0.5 to 2.

Abstract: A plastic foam is made by mixing a plastic material or its origin material with a blowing agent which does not react with the material, said agent having a maximum vapor pressure of 10 Pa at the highest permissible application temperature of the plastic foam and having a minimum vapor pressure of 600 Pa at a pressure at which said material is in plastic condition. A formed body of the mixture is then exposed to a pressure low enough to evaporate the blowing agent and form bubbles in the mixture, whereupon the body is cooled at low pressure to solidify the plastic material and substantially condense said agent, thereby providing said body with closed cells having a reduced internal pressure.

Abstract: A lysimeter for collecting soil water which is truly representative of the soil water contained in the soil at selected locations. The lysimeter contains a chamber and a filter section which is a rigid, porous fluoroplastic and through which moisture from the soil surrounding the lysimeter may pass into the chamber. The invention includes the rigid porous thermoplastic resin, a process for making the resin and a process for using the lysimeter to recover soil moisture in the lysimeter chamber.

Abstract: Disclosed herein is a process for producing a porous carbonaceous electrode substrate provided with elongated holes opening from one side to the opposite side of the electrode substrate through nearly the central region of the thickness of the substrate, for use in fuel cells, characterized by using high polymeric substance as a material for forming the elongated holes.

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 gas diffusion composite electrode is disclosed which is suitable for use in combination with an electrically conductive current collector. The electrode comprises an electrochemically active, porous and heterogeneous layer containing (1) an interconnected, hydrophilic island material comprising a blend of a major amount of an electrically conductive, particulate material, such as carbon black, in combination with an electrochemically active catalyst, and a minor amount of a hydrophobic polymer in combination with (2) a hydrophobic matrix material consisting essentially of a hydrophobic polymer rendered substantially porous by removal of a pore-forming ingredient. Methods of preparing the heterogeneous layer and the composite electrode are also disclosed.

Abstract: A surface-type microporous filter is prepared by embossing substantially uniform holes in an embossable polymer carried on a porous support wherein the pores are filled with a soluble filler. Subsequent to the embossing step, the filler is removed by dissolution.

Abstract: Processes for the production of filter elements based on aromatic polyamide in which a semi-finished filter element is produced from a solution of the polyamide in aprotic solvent and the polyamide is then coagulated by immersion in a liquid bath containing precipitating agent may be used for the production of filter elements with a pore size of from 0.05 .mu.m to 10 .mu.

Abstract: A method of improving the quality of hot pressed Si.sub.3 N.sub.4 bodies is disclosed. Unpurified silicon powder and admixed oxygen carrying agents are compacted to form a preform. The preform is nitrided, facilitated by the presence of certain impurities, to agglomerate the mixture to an increased density no greater than 2.7 gm/cm.sup.3. The nitrided preform is immersed in one or more stages in one or more leaching solutions of effective concentration to remove the selected impurities. The treated preform is then hot pressed to full density accompanied by a substantial reduction or absence of undesirable impurities such as iron silicide, which can conventionally form during hot pressing.

Abstract: This invention relates to a method of forming porous membranes from thermoplastic or polymeric materials and to membranes so formed.

Abstract: Stretched articles of ultrahigh-molecular-weight polyethylene are prepared by melt-kneading a mixture of ultrahigh-molecular-weight polyethylene with a paraffinic wax having a melting point of 40.degree. to 120.degree. C. and a weight average molecular weight of at least 230 but less than 2000 in a screw extruder while maintaining the temperature of the mixture at 180.degree. to 280.degree. C. The molten mixture is melt-extruded through a die at a temperature of 180.degree. to 300.degree. C. under a draft condition of a draft ratio of less than 2 or in the absence of a draft and the resulting unstretched extrudate is cooled to solidify it. The unstretched solidified extrudate is than subjected to a stretching treatment in a heated liquid medium which is a solvent for the paraffinic wax at a temperature of 60.degree. to 140.degree. C. at a particular stretch ratio.

Abstract: Polyester fibers containing one or more oxalate complexes of the general formulaMe.sub.n [Z(C.sub.2 O.sub.4).sub.m ]are drawn and subjected to a hydrosetting process at temperatures of 90.degree. to 170.degree. C. in the presence of liquid water, the water containing one or more of the following surfactants: salts of partial esters of phosphoric aid, sulfosuccinic aid esters, phosphonic acid esters as well as ethoxylated silicon compounds, ethoxylated fatty alcohols, polyglycol esters of fatty acids as well as various imidazole salts of partially or completely hydrogenated imidazoles. In this way the hydrosetting process is accelerated and a more stable pore structure is obtained. Water absorption and retention are also increased.

Abstract: A process of making a wound dressing is suggested, in which a technical conventional viscose solution is mixed with a polysaccharide derivative; the mixture is treated at increased temperatures such that it is thermally coagulated; the coagulate is wetted with a polyalkylene glycol and dried, whereby a particulate structure of the wound dressing is produced.

Abstract: Porous bodies, particularly membranes in the form of hollow filaments, are produced by heating a polymer above the upper critical temperature T.sub.c in a mixture of two compounds A and B, liquid and miscible at the dissolving temperature, whereby the employed mixture (polymer, compounds A and B) in liquid aggregate state displays a miscibility gap, the compound A is a solvent for the polymer and the compound B, which preferably is a non-solvent or a swelling agent for the polymer, raises the phase separation temperature of a solution composed of the polymer and compound A. After the dissociation, the components A and/or B if necessary are extracted. Through use of non-toxic substances such as e.g. edible oil as compound A and castor oil as compound B, bodies are obtained which are non-toxic and unobjectionable for use in medical areas and in the foods industry, among others.

Abstract: A moisture vapor permeable sheet material is comprised of a homogeneous admixture of a synthetic polymer material and a protein derivative. The sheet material is moisture vapor permeable and non-penetrable by liquid water. The sheet material additionally can have coated thereon a pressure sensitive adhesive which is comprised of a synthetic organic polymer adhesive and a soluble protein derivative in solid solution. Sheet material is formed by providing a homogeneous fluid solution of a soluble protein derivative and a synthetic organic polymer in a solvent. The protein derivative has a pH level compatible with the pH level of the organic polymer. Film is formed from the homogeneous fluid solution and the solvent is removed from the film to form the sheet material which is moisture vapor permeable. When the sheet material includes an adhesive, the adhesive is coated as a fluid solution in a solvent on one side of the sheet material.

Abstract: A process for the manufacture of porous sintered bodies with large open pore volume and defined pore diameter. A sinterable material in the form of finely ground powder is mixed with a leachable substance. The leachable substance is in the form of powder of a defined particle size. The mixture of sinterable material and leachable substance is heated to the sintering temperature and maintained there until the sinterable mass is sintered. The mass is then cooled and the leachable substance leached from the sintered mass.

Abstract: A method for producing .alpha.-silicon nitride whiskers. Silicon is blended with amorphous silicon nitride and a pore-forming composition particles able to be removed without leaving a residue, such as naphthalene particles. The mixture is compacted to a desired shape, after which the pore-forming particles are removed from the mixture to form a porous silicon precursor compact having the desired shape. The silicon precursor is reacted with a substance that releases free nitrogen, such as nitrogen or dry ammonia. The reaction is carried out at a temperature sufficiently high to form an identically shaped porous compact of .alpha.-silicon nitride whiskers but sufficiently low to avoid subliming substantially all of the formed whiskers. Preferably, the reaction is carried out in a range between about 1100.degree. C. and 1500.degree. C. The shaped porous compact of .alpha.

Abstract: The invention concerns porous fibers and membranes, methods for their preparation and for their use. The fibers are characterized by a smooth porous surface and an apparent density of between about 10 and 90% of the true density of the polymeric starting material employed. The process involves the formation of a homogeneous mixture of at least two components, one of which is a meltable polymer and another liquid inert with respect to the polymer. The mixture formed must be of a binary type, in which there is a temperature range of complete miscibility and a range in which there is a miscibility gap. The mixture is extruded at a temperature above the separation temperature into a bath containing at least some of the inert liquid which is at a temperature below the separation temperature. Upon introduction of the mixture into the bath, the fiber structure of the product is fixed.

Abstract: Porous silicon carbide bodies are obtained by starting with a powder of particle size falling within a single sieve mesh range fraction and consisting either entirely of carbon particles or a mixture of carbon and silicon carbide particles of the same mesh fraction is mixed or coated with 15 to 30% by weight of a binder, moulded to shape, warmed in the temperature range from 40.degree. to 200.degree. C. to vaporize volatile material and then coked at a temperature rising to 850.degree. C. Then it is siliconized by raising the temperature to the range from 1650.degree. to 1950.degree. C. with gaseous silicon or impregnated with silicon by dipping the body into a silicon melt and convert it to carbide, with the excess silicon thereafter being removed by vaporizing out or by boiling in lye. Sieve mesh fractions in the region of a few hundred .mu.m are preferred, and the density of the porous body after pressing but before siliconizing should lie in the neighborhood of 0.6 to 0.7 g/cm.sup.3.

Abstract: A method of making a microporous material is provided which comprises the steps of melt blending crystallizable thermoplastic polymer with a compound which is miscible with the thermoplastic polymer at the melting temperature of the polymer but phase separates on cooling at or below the crystallization temperature of the polymer, forming a shaped article of the melt blend, cooling the shaped article to a temperature at which the polymer crystallizes to cause phase separation to occur between the thermoplastic polymer and the compound to provide an article comprising a first phase comprising particles of crystallized thermoplastic polymer in a second phase of said compound, orienting the article in at least one direction to provide a network of interconnected micropores throughout. The microporous article comprises about 30 to 80 parts by weight crystallizable thermoplastic polymer and about 70 to 20 parts by weight of the compound.