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 process for producing a nanoporous polymer film of no greater than 10 micron thickness having low dielectric constant value, including the steps of: (a) providing a polymer in a solution with at least two solvents for the polymer in which a lowest boiling solvent and a highest boiling solvent have a difference in their respective boiling points of approximately 50° C. or greater; (b) forming a film of the polymer in solution with at least the two solvents on a substrate; (c) removing a predominant amount of the lowest boiling solvent; (d) contacting the film with a fluid which is a non-solvent for the polymer, but which is miscible with the at least two solvents to induce phase inversion in the film; (e) forming an average pore size in the film in the range of less than 30 nanometers. The present invention is also nanoporous films made by the above process.
Abstract:
A process for forming polymer powders by dissolving one or more polymers in a suitable solvent, followed by atomizing the solution into a droplet atmosphere of a non-solvent to precipitate polymer particles. The particles are separated from the non-solvent, washed and dried to produce a powder with a rounded particle morphology, high internal porosity and surface area, and high apparent density.Polymer powders with these properties can be pressed to dense shaped articles suitable for sintering in automated presses because the powders have good low and compressibility characteristics. The process if particularly useful when applied to soluble polymners that are not readily shaped by melt processing means.
Abstract:
Microporous polypropylene membrane or hollow fibers is formed from a melt blend of 5 to 20 weight percent polypropylene and a solvent. The melt blend is shaped and cooled to effect solid phase separation of the polypropylene from the blend. The solvent is separated from the polypropylene by extraction and the porous polypropylene is dried under restraint to prevent shrinkage.
Abstract:
A basic copolymer whose main chain is cross-linked which comprises about 6 to about 98% by weight of recurring units of Formula (A) or (B), ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3, which may be the same or different, each represents a hydrogen atom or a hydrocarbon group selected from the group consisting of C.sub.1-20 alkyl groups, C.sub.3-10 cycloalkyl groups, C.sub.3-8 alkenyl groups, C.sub.6-15 aryl groups, C.sub.7-12 arylalkyl groups and C.sub.1-15 aminoalkyl groups; and X is an acid radical, and about 2 to about 94% by weight of cross-linked units based on the total weight of the recurring units of Formula (A) or (B) and the cross-linked units and, if desired, up to about 92% by weight of units of a monoethylenically unsaturated monomer or a conjugated monomer based on the total weight of the recurring units of Formula (A) or (B), the cross-linked units and the units of the monoethylenically unsaturated monomer or the conjugated monomer.
Abstract:
A porous ultra-thin polymer film has a film thickness of 10 nm-1000 nm. A method of producing the porous ultra-thin polymer film includes dissolving two types of mutually-immiscible polymers in a first solvent in an arbitrary proportion to obtain a solution; applying the solution onto a substrate and then removing the first solvent from the solution applied onto the substrate to obtain a phase-separated ultra-thin polymer film that has been phase-separated into a sea-island structure; and immersing the ultra-thin polymer film in a second solvent which is a good solvent for the polymer of the island parts but a poor solvent for a polymer other than the island parts to remove the island parts, thereby obtaining a porous ultra-thin polymer film.
Abstract:
A process for producing porous structures from polyamide by dissolving the polyamide in an ionic liquid and precipitating or coagulating the dissolved polyamide by contacting the solution with a liquid precipitant medium. Fibers are produced from the dissolved polyamide in a wet-spinning process by precipitation in protic solvents, in particular water, a C1-4-alkanol or mixtures thereof, and subsequent freeze-drying. Foils, films or coatings are produced by blade coating the dissolved polyamide onto a substrate surface, optionally spraying with protic solvent, in particular water, a C1-4-alcohol or mixtures thereof, dipping into a precipitation or coagulation bath, freeze-drying of the resulting foil, of the film or of the coated substrate. Molded parts are prepared by extracting the dissolved polyamide with protic solvents, preferably water, a C1-4-alcohol or mixtures thereof, wherein the dissolved polymer is transformed to a solid or wax-like state by cooling and extracted after subsequent molding.
Abstract:
Porous cross-linked polyimide-urea networks are provided. The networks comprise a subunit comprising two anhydride end-capped polyamic acid oligomers in direct connection via a urea linkage. The oligomers (a) each comprise a repeating unit of a dianhydride and a diamine and a terminal anhydride group and (b) are formulated with 2 to 15 of the repeating units. The subunit was formed by reaction of the diamine and a diisocyanate to form a diamine-urea linkage-diamine group, followed by reaction of the diamine-urea linkage-diamine group with the dianhydride and the diamine to form the subunit. The subunit has been cross-linked via a cross-linking agent, comprising three or more amine groups, at a balanced stoichiometry of the amine groups to the terminal anhydride groups. The subunit has been chemically imidized to yield the porous cross-linked polyimide-urea network. Also provided are wet gels, aerogels, and thin films comprising the networks, and methods of making the networks.