Abstract: A method of making a novel composition of a porous medium comprising volume elements of both voids and pores wherein the voids are much larger than the mean size of the pores. The method includes a first step of preparation of a porous medium comprising solid particles the approximate size selected for the voids and pores as volume elements and a second step of removing the particles by etching out with hydrofluoric acid or other means to form a porous medium comprising both voids and pores. In another embodiment, the voids are prepared from Bow etching out of a polymeric hydrogel silica particles which were allowed to self-assemble as a crystalline colloidal array prior to formation of the polymeric hydrogel around them, thereby forming a porous medium containing a crystalline colloidal array of voids containing aqueous solution. In another embodiment, a method of partitioning macromolecules between a solution comprising the macromolecules, and the voids and pores of a porous medium.

Abstract: Porous polyimide dielectric materials having low dielectric constants useful in electronic component manufacture are disclosed along with methods of preparing the porous polyimide dielectric materials. Also disclosed are methods of forming integrated circuits containing such porous polyimide dielectric material.

Abstract: Methods and compositions are described that provide three dimensional porous matrices as structural templates for cells. The porous matrices of the present invention have desirable mechanical properties suitable to a variety of applications, including platforms for in vitro cell cultivation, implants for tissue and organ engineering, and materials suitable for chromatography and filtration.

Abstract: A porous article having excellent heat resistance, a finely cellular structure, and a low dielectric constant; and a process for producing the porous article which comprises subjecting a polymer composition having a micro-domain structure comprising a continuous polymer phase and dispersed therein a discontinuous phase having an average diameter smaller than 10 &mgr;m to a treatment for removing the ingredient constituting the discontinuous phase by at least one operation selected from vaporization and decomposition and by an extraction operation to thereby make the polymer porous. The ingredient constituting the discontinuous phase has a weight average molecular weight of, e.g., 10,000 or lower. Liquefied carbon dioxide, supercritical carbon dioxide, or the like can be used as an extraction solvent for the ingredient constituting the discontinuous phase.

Abstract: The invention is directed to a process for preparing porous polymer materials by a combination of gas foaming and particulate leaching steps. The invention is also directed to porous polymer material prepared by the process, particularly having a characteristic interconnected pore structure, and to methods for using such porous polymer material, particularly for tissue engineering.

Abstract: A porous polyimide having a finely cellular structure and having a low dielectric constant and heat resistance. The porous polyimide can be produced by a process comprising adding a dispersible compound to a polyimide precursor to form a micro-domain structure in which the dispersible compound is dispersed in the polymer so as to have a size smaller than 10 &mgr;m and then removing the dispersible compound by extraction with supercritical carbon dioxide to thereby make the precursor porous, wherein the interaction parameter &khgr;AB between the polyimide precursor A and the dispersible compound B is larger than 3. This porous polyimide has an average cell diameter smaller than 5 &mgr;m and a dielectric constant of 3 or lower.

Abstract: The present invention provides an improved lyophilization process for forming biocompatible foam structures. The process allows the foam structures to be tailored for specific end uses. The foams formed by this process are well suited to be used in medical applications such as tissue engineering.

Abstract: The present invention provides a process for producing porous polymer materials. In the present invention, a polymer material and a soluble material are mixed in their solid states. The surface of the polymer material is partially dissolved and fused by introducing a solvent. The present invention makes use of a pressure difference while introducing a non-solvent into the polymer material to solidify and resolve the solved polymer material. Then, a substantial amount of water is used to wash the inside soluble material out. Therefore, the porous polymer materials with high porosity and interconnecting pores inside the materials are produced massively and rapidly.

Abstract: A durable, conformable, absorbent, hydrophilic, polymeric latex foam composition having a free absorbent capacity of at least 5 grams of a 0.9 weight percent aqueous saline solution per gram of foam and capable of vertically wicking said aqueous saline solution to a height of greater than about 5 cm. In a preferred embodiment, after compression, the latex foam composition remains thin until wet, whereupon it expands and exhibits a high free absorbent capacity and high vertical wicking height.

Abstract: A composition comprising aqueous fluid absorbent polymer particles which have been heat-treated at temperatures greater than 170° C. for more than 10 minutes, wherein the composition has been remoisturized, after the heat-treatment, with an aqueous additive solution, in the absence of an organic solvent or water-insoluble, non-swellable powder, and comprises 1 to 10 percent by weight, based on the total weight of the composition, water and wherein the composition is characterized by the ability to absorb at least 20 grams of a 0.9 weight percent aqueous saline solution under a pressure of 0.3 psi (21,000 dynes/cm2), that is, a 60 minute 0.3 psi (21,000 dynes/cm2) AUL greater than 20 grams/gram. A process for preparing such a composition.

Abstract: The invention is directed to a process for preparing porous polymer materials by a combination of gas forming and particulate leaching steps. The invention is also directed to porous polymer material prepared by the process, particularly having a characteristic interconnected pore structure, and to methods for using such porous polymer material, particularly for tissue engineering.

Abstract: Methods and compositions are described that provide three dimensional porous matrices as structural templates for cells. The porous matrices of the present invention have desirable mechanical properties suitable to a variety of applications, including platforms for in vitro cell cultivation, implants for tissue and organ engineering, and materials suitable for chromatography and filtration.

Abstract: Porous organo polysilica dielectric materials having low dielectric constants useful in electronic component manufacture are disclosed along with methods of preparing the porous organo polysilica dielectric materials. Also disclosed are methods of forming integrated circuits containing such porous organo polysilica dielectric materials.

Abstract: The present invention involves compositions having variable permeation and/or porosity and objects made therefrom. The compositions are prepared by dispersing a pore-forming agent in a polymer matrix by agitation. The composition is density developed resulting in a variable concentration in pore-forming agent throughout the mixture through application of an external force on the mixture with or without continued agitation. The pore-forming agent is then leached from the mixture to form a polymer matrix having variable permeability and/or porosity.

Abstract: Oxyhalopolymer composites which include an oxyhalopolymer having free volume therein and an inorganic or organic material disposed in the free volume of the oxyhalopolymer are disclosed. Also disclosed is a surface-oxyhalogenated non-halopolymer composite. The composite includes a surface-oxyhalogenated non-halopolymer having free volume therein and an inorganic or organic material disposed in the free volume of the surface-oxyhalogenated non-halopolymer. Methods for making and using these composites are also described.

Abstract: A process for producing poromeric synthetic leather comprises I. producing an essentially nonporous impregnate by impregnating a textile sheet material with an aqueous polyurethane dispersion and drying, and II. producing a poromeric synthetic leather from the impregnate by subjecting the impregnate to the action of an aqueous solution of a Brønsted base.

Abstract: A method of forming a porous insulating composition comprising the steps of (A) providing at least one organic sacrificial material/dielectric material composition comprising at least one organic sacrificial material and at least one dielectric material; and (B) removing the at least one organic sacrificial material in the at least one organic sacrificial material/dielectric material composition, in order to generate pores in the at least one dielectric material. Also disclosed is a composition useful in making a porous insulator, comprising a heat-activated, pore-forming, sacrificial material; and a dielectric material. Alternatively, the composition useful in making a porous insulator, comprises at least one pore-forming, organic sacrificial material; and at least one dielectric material, wherein the at least one pore-forming, material is a norbornene-type polymer.

Abstract: High internal phase emulsions (HIPEs), porous polymeric materials made therefrom, and methods for making and using the same. Specific embodiments of the invention include water-in-oil high internal phase emulsions having at least 70 volume percent of an internal aqueous phase and less than 30 volume percent of an external oil phase wherein the oil phase comprises a vinyl polymerizable monomer and a surfactant effective to stabilize the emulsion. The subject surfactants are oil soluble and preferably include an oxyalkylene component.

Abstract: Water-absorbing, expanded, crosslinked polymers obtainable by(I) foaming a polymerizable aqueous mixture which comprises(a) monoethylenically unsaturated monomers which contain acidic groups and are at least 50 mol % neutralized,(b) with or without other monoethylenically unsaturated monomers,(c) crosslinkers,(d) initiators,(e) 0.1-20% by weight of at least one surfactant,(f) with or without at least one solubilizer and(g) with or without thickeners, foam stabilizers, polymerization regulators, fillers and/or cell nucleating agents,where the foaming takes place by dispersing fine bubbles of a gas which is inert to free radicals, and(II) polymerizing the foamed mixture to form an expanded hydrogel and adjusting the water content of the expanded polymer to 1-45% by weight, a process for their production and their use in hygiene articles employed to absorb body fluids and in dressing material for covering wounds.

Abstract: The present invention is a freeze-dried polystyrene-polysiloxane foam having a density of 0.05 to 0.8 grams per cubic centimeter and a void volume of 20 to 99 percent. These foams exhibit good compressibility and rebound and are useful in insulation and sound-deadening applications.

Abstract: Biodegradable and biocompatible porous scaffolds characterized by a substantially continuous polymer phase, having a highly interconnected bimodal distribution of open pore sizes with rounded large pores of about 50 to about 500 microns in diameter and rounded small pores less than 20 microns in diameter, wherein the small pores are aligned in an orderly linear fashion within the walls of the large pores. Methods of preparing polymeric tissue scaffolds are also disclosed.

Abstract: The present invention relates to porous crosslinked polymeric microbeads having cavities joined by interconnecting pores wherein at least some of the cavities at the interior of each microbead communicate with the surface of the microbead. The present invention also relates to a process for producing a porous, crosslinked polymeric microbead as well as the product of this process. This process involves combining an oil phase with an aqueous discontinuous phase to form an emulsion, adding the emulsion to an aqueous suspension medium to form an oil-in-water suspension of dispersed emulsion droplets, and polymerizing the emulsion droplets to form microbeads. At least 10% of the microbeads produced in accordance with the present invention are substantially spherical or substantially ellipsoidal or a combination of the two.

Abstract: Insecticides, and particularly termiticides, may be dissolved in monomers polymerized to form foamable polymers, such as polystyrene. The resulting monomer and insecticide may then be polymerized in a conventional manner and either impregnated with a blowing agent or expanded using an extrusion process to produce polymeric foam having insecticidal properties. The polymer may also contain a flame retardant. Such polymers and the foam made therefrom may be used in the construction industry, particularly where insect infestation is a concern.

Abstract: Stable high internal phase water-in-oil emulsions containing polymerizable vinyl monomers, crosslinking monomers and initiators are obtained, useful in producing low density porous crosslinked polymeric materials by using a surfactant system containing (a) an anionic surfactant, the anionic surfactant having an oil soluble tail and an anionic functional group and (b) one or more quatemary salts having one or more hydrocarbon groups having greater than or equal to 8 carbon atoms. A water-in-oil emulsion can be formed with lower surfactant concentration than sorbitan fatty acid ester alone and improved surfactant performance at elevated temperatures is obtained.

Abstract: The present invention relates to a porous or microporous film of a high molecular weight polyolefin excellent in strength and air-permeability and suitable for use in filtering materials, separators for aqueous electrolyte batteries, separator films for batteries, separator films for electrolytic capacitors, and air-permeable films; for moisture-permeable water-proof use such as paper diapers and house-wrapping films; and for other uses such as cloths, package and printing, as well as a process for producing same. The feature of the present invention resides in an aspect that the film is composed of fibrils comprising extended-chain crystals and lamellar crystals and/or fibrils comprising helicoidal crystals.This porous film of a high molecular weight polyolefin is produced by subjecting an air-impermeable film of a high molecular weight polyolefin to thermal treatment followed by, if necessary, a stretching treatment and/or a thermosetting treatment.

Abstract: Chemically resistant, strong fluorinated copolymer adsorbent particles for use in carrying out chromatographic separations are prepared by high shear, anaerobic reaction of a di-unsaturated crosslinking agent with a polyfluorinated monomer in the presence of poly(vinyl alcohol) and a porogen.

Abstract: The invention relates to a composite foam comprising from 10 to 90% by volume of SiO.sub.2 aerogel particles and from 90 to 10% by volume of a foam, preferably a polyurethane and/or polyolefin foam, a process for its preparation and its use.

Abstract: Microporous materials formed by thermally induced phase transition from a crosslinkable oil in combination with a thermoplastic polymer providing covalent bonding and immobilization of the oil diluent. Such materials are useful in graphic imaging substrates and fluid-repellent diapers and garments.

Abstract: Rapidly dissolving/absorbing free-flowing powders of hydrophilic/superabsorbent (co)polymers, having irregular nonspherical morphology and a particle size distribution ranging from 100 .mu.m to 800 .mu.

Abstract: Process for making polyisocyanate based aerogels by trimerisation of an organic polyisocyanate in an organic solvent in the presence of a (co)polymer containing an isocyanate-reactive group, gellation and supercritically drying of the obtained sol-gel.

Abstract: The present invention is embodied in a ceramic foam made by mixing a liquid pre-ceramic resin and a liquid phenolic resin, allowing the resultant mixture to chemically foam, curing the mixture for a time and at a temperature sufficiently to convert the mixture to a polymeric foam, and then heating the resultant polymeric foam for a time and at a temperature sufficient to break-down polymers of the polymeric foam and convert the polymeric foam to a ceramic foam. The ceramic foam of the present invention contains residual decomposed components of the liquid phenolic resin and/or liquid pre-ceramic resin.

Abstract: High internal phase emulsions having an internal aqueous phase of greater than 70 percent by volume and an external oil phase comprising a vinyl polymerizable monomer contain a surfactant capable of chemically binding to the polymerizable monomer. Polymeric foams having a high internal phase emulsion stabilizing surfactant chemically bound to the polymeric material and a liquid capacity of from about 70 to 99 percent of its saturated volume can be prepared from such emulsions.

Abstract: Highly uniform microporous foam suitable for medical applications and methods for preparing these foams. The highly uniform microporous foams are of controlled pore size that may be utilized in a variety of applications. In preparing the foams, an organic crystalline polymer is melted and combined with a selected solid crystalline fugitive compound to produce a substantially isotropic solution. The solution is cooled under controlled conditions, which foster solid-solid phase separation by the simultaneous crystallization of the fugitive compound and the polymer, to produce a foam precursor containing the solidified fugitive compound dispersed through a matrix of the organic polymer. Crystals of fugitive compound are then removed by solvent extraction and/or sublimation, or like process to produce microcellular foams having a continuous, open-cell structure.

Abstract: A process for obtaining an aerogel from a polymeric material that is in the form a sol-gel in an organic solvent, by exchanging the organic solvent for a fluid having a critical temperature below a temperature of polymer decomposition, and supercritically drying the fluid/sol-gel. The process is carried out in a semi-continuous mode that includes the steps of contacting the initial sol-gel with a stream of the fluid at different pressures and temperatures through n+1 pressure vessels A.sub.0 to A.sub.n that each have an inlet for fluid VI.sub.i and an outlet for effluent VO.sub.i wherein the n+1 pressure vessels are operated dependently on each other through a joint fluid supply system and a joint effluent treatment system so that the respective product in each of the pressure vessels A.sub.0 to A.sub.n is submitted to the fluid in successive steps with pressure and temperature following a curve that never cuts the vaporization curve in the pressure-temperature diagram of FIG. 1.

Abstract: A microporous shaped article is provided. The article comprises ethylene-vinyl alcohol copolymer which has an internal structure of a multiplicity of spaced, randomly dispersed, non-uniform shaped particles of ethylene-vinyl alcohol copolymer.

Abstract: This invention relates to porous polyfluoroethylene (PTFE), shaped articles prepared therefrom, and to methods of preparing said articles.

Abstract: There is provided a cord of twisted polybenzazole fibers, which has a tenacity of 35 g/d or higher and an elastic modulus of 800 g/d or higher. The cord has not only remarkably improved fatigue resistance but also excellent mechanical characteristics at a high level that has not been achieved so far. Therefore, it can attain the weight reduction of composite materials, particularly in the field of reinforced rubber materials, and can also make a great contribution to the energy saving.

Abstract: Highly uniform microporous foam suitable for medical applications and methods for preparing these foams. The highly uniform microporous foams are of controlled pore size that may be utilized in a variety of applications. In preparing the foams, an organic crystalline polymer is melted and combined with a selected solid crystalline fugitive compound to produce a substantially isotropic solution. The solution is cooled under controlled conditions, which foster solid-solid phase separation by the simultaneous crystallization of the fugitive compound and the polymer, to produce a foam precursor containing the solidified fugitive compound dispersed through a matrix of the organic polymer. Crystals of fugitive compound are then removed by solvent extraction and/or sublimation, or like process to produce microcellular foams having a continuous, open-cell structure.

Abstract: The present invention relates to porous crosslinked polymeric microbeads having cavities joined by interconnecting pores wherein at least some of the cavities at the interior of each microbead communicate with the surface of the microbead. The present invention also relates to a process for producing a porous, crosslinked polymeric microbead as well as the product of this process. This process involves combining an oil phase with an aqueous discontinuous phase to form an emulsion, adding the emulsion to an aqueous suspension medium to form an oil-in-water suspension of dispersed emulsion droplets, and polymerizing the emulsion droplets to form microbeads. At least 10% of the microbeads produced in accordance with the present invention are substantially spherical or substantially ellipsoidal or a combination of the two.

Abstract: A method for altering a macroporous cross-linked hydrophobic copolymeric lattice produced by precipitation polymerization in a solvent of at least one monounsaturated ester monomer and at least one polyunsaturated ester monomer soluble therein, in order to render the hydrophobic copolymeric lattice hydrophilic. The method involves saponifying the hydrophobic copolymeric lattice by reacting the surface of the hydrophobic copolymeric lattice with an aqueous alkali. The surface can also be rendered hydrophilic by polymerizing an acrylate monomer onto the lattice in order to form a surface containing carboxylic acid sites. The carboxylic acid sites formed on the surface of the lattice are converted to carboxylate anions.

Abstract: Highly uniform microporous foam suitable for medical applications and methods for preparing these foams. The highly uniform microporous foams are of controlled pore size that may be utilized in a variety of applications. In preparing the foams, an organic crystalline polymer is melted and combined with a selected solid crystalline fugitive compound to produce a substantially isotropic solution. The solution is cooled under controlled conditions, which foster solid--solid phase separation by the simultaneous crystallization of the fugitive compound and the polymer, to produce a foam precursor containing the solidified fugitive compound dispersed through a matrix of the organic polymer. Crystals of fugitive compound are then removed by solvent extraction and/or sublimation, or like process to produce microcellular foams having a continuous, open-cell structure.

Abstract: This invention relates to porous polyfluoroethylene (PTFE), shaped articles prepared therefrom, and to methods of preparing said articles.

Abstract: The disclosed invention is a crystalline microporous polymer and process for preparing a low density microporous polymer comprising, providing a mixture of a polymer and a polymer solvent, the mixture capable of achieving a supercritical condition; applying pressure, at a temperature sufficient for the mixture to attain a super critical condition; cooling the supercritical solution that results and precipitating a microporous crystalline polymer product.

Abstract: The present invention relates to a process for forming a foamed elastomeric polymer. The process involves forming a reverse emulsion of liquid droplets in a continuous liquid phase of polymer precursor and then polymerizing the precursor to entrap uniformly distributed droplets of the liquid in pores formed in the polymer bulk. The liquid in the pores is then removed under supercritical conditions.

Abstract: A structure of a microporous resin bonded to metal is prepared by a method, comprising, molding a resin composition comprising a polymer alloy consisting of polyether imide and polyphenylene ether and particles of aluminum borate or amorphous silica filler, wherein the particles of aluminum borate and amorphous silica have an aspect ratio of 10 or less and an average diameter of 0.01-100 .mu.m, the aluminum borate having the formula: nAl.sub.2 O.sub.3.mB.sub.2 O.sub.3, wherein n and m individually represent an integer of 1-100, and the amorphous silica having the formula: SiO.sub.2, into a shaped object, treating the molded resin composition with an aqueous alkaline solution to remove the filler, thereby creating micropores within the resin object, and depositing a metal film on a surface of the treated resin object.

Abstract: The present invention relates to porous crosslinked polymeric microbeads having cavities joined by interconnecting pores wherein at least some of the cavities at the interior of each microbead communicate with the surface of the microbead. The present invention also relates to a process for producing a porous, crosslinked polymeric microbead as well as the product of this process. This process involves combining an oil phase with an aqueous discontinuous phase to form an emulsion, adding the emulsion to an aqueous suspension medium to form an oil-in-water suspension of dispersed emulsion droplets, and polymerizing the emulsion droplets to form microbeads. At least 10% of the microbeads produced in accordance with the present invention are substantially spherical or substantially ellipsoidal or a combination of the two.

Abstract: The present invention relates to a process for forming a foamed elastomeric polymer. The process involves forming a reverse emulsion of liquid droplets in a continuous liquid phase of polymer precursor and then polymerizing the precursor to entrap uniformly distributed droplets of the liquid in pores formed in the polymer bulk. The liquid in the pores is then removed under supercritical conditions.

Abstract: Scaffold bodies and methods for their fabrication are disclosed, and, more particularly, fabrication of scaffold bodies by freeze-drying emulsion of polymer solutions are disclosed.

Abstract: This invention relates to porous polyfluoroethylene (PTFE), shaped articles prepared therefrom, and to methods of preparing said articles.

Abstract: A polymeric reticulated structure is prepared by mixing an ethylene-propylene copolymer having an ethylene content of at least 60% by weight or a thermoplastic block copolymer terminated with a crystalline ethylene block with a low molecular weight material. The low molecular weight material is trapped in the three-dimensional continuous network the copolymer forms.