Abstract:
Provided herein are bimodal porous polymer microspheres comprising macropores and micropores. Also provided herein are methods and apparatus for fabrication such microspheres. Further provided herein are methods of using bimodal porous polymer microspheres.
Abstract:
The present invention relates to a method for preparing an open pourous polymer material, wherein said method comprises forming or a polymer solution, addition of a porogen to said polymer solution and precipitation with water of polymer from said polymer solution, and said method then comprises removal of solvent and porogen from said polymer material wherein said precipitation is homogenous through that said water is in form of crystal water and that said crystal water is bonded to said porogen, wherein said porogen is a sugar hydrate. It further relates to an open porous polymer material, a mixture comprising a sugar hydrate and a polymer solution. and a designed material, and uses thereof.
Abstract:
Provided is a porous para-oriented aromatic polyamide film which contains fine particles composed of a heat-resistant resin in an amount of 10 to 400 parts by weight based on 100 parts by weight of a pare-oriented aromatic polyamide and has a linear thermal expansion coefficient at 200 to 300° C. of from −50×10−6/° C. to +50×10−6/° C. The porous para-oriented aromatic polyamide film shows excellent tear propagation resistance and has light weight and low linear thermal expansion coefficient, and is suitable as a prepreg material used for a base substrate for printed circuit board.
Abstract:
Supercritical drying has distinct advantages in generating microcellular materials. The dimensional stability of the polymer is not affected on drying because the supercritical process does not go through the two phase path and therefore the effect of capillary forces is absent. This helps in maintaining the morphology of the final polymer structure and better control over cell size.Organic microcellular foams were prepared by polymerizing directly in a near-critical fluid and pursuing the supercritical drying in the same reactor. The critical variables are the choice of a diluent with a strong enough solvent power to stabilize the polymer matrix, but with a low enough critical temperature to permit critical point drying without damage to the polymer matrix.
Abstract:
A method of producing a plastic sheet with a porous surface layer suitable for use as, for example, a recording medium on which characters and images are printed by ink jet or thermal-transfer printing method. The method comprises preparing a solution by dissolving two or more kinds of plastics having low levels of miscibility to each other in a solvent, applying said solution to a substrate, passing said substrate with said solution applied thereto through a liquid which dissolves said solvent but does not dissolve said plastics thereby solidifying said plastics, and drying said substrate with the solidified plastic layer. Preferably, two or more kinds of plastics having low levels of miscibility to each other include mainly a material A which is vinyl chloride or its compolymer and a material B which is acrylonitrile or its copolymer.
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 PROCESS FOR PREPARING MICROPOROUS OPEN-CELLED CELLULAR POLYMERIC STRUCTURES WHICH COMPRISES (A) DISSOLVING THE STARTING POLYMER IN A MIXTURE COMPRISING CHLOROFLUOROCARBON SOLVENT AND A COSOLVENT SELECTED FROM METHANOL, ETHANOL, ISOPROPANOL, T-BUTANOL, DIMETHYLFORMAMIDE, DIMETHYLACETAMIDE, DIOXANE, TRIOXANE, DIMETHYLSULFOXIDE, TETRAHYDROFURAN, ACETONE, METHYLETHYL KETONE, HEXAMETHYL PHOAPHORAMIDE, ACETIC ACID, BUTYROLACTONE, N-METHYLPYRROLIDONE, PYRIDINE, MORPHOLINE, METHYL CELLOSOLVE, ETHYL CELLOSOLVE, PROPYL CELLOSOLVE AND A MIXTURE OF ANY OF SAID COSOLVENTS TO FORM A POLYMER SOLUTION; (B) ADDING WATER IN THE AMOUNT OF AT LEAST 10 VOLUME PERCENT OF THE POLYMER SOLUTION THERETO AT A TEMPERATURE BELOW THE ATMOSPHERIC BOILING POINT OF THE SOLVENTS BUT GREATER THAN 0*C.; (C) SEPARATING THE RESULTANT POLYMERCHLOROFLUOROCARBON PHASE; AND (D) REMOVING THE CHLOROFLUOROCARBON FROM THE SEPARATED POLYMER-CHLOROFLUOROCARBON PHASE.
Abstract:
In a method of making artificial leathers and other water vapor permeable flexible sheet materials, a layer of polymer-containing mixture adhering to a temporary support is coagulated by suitable liquid treatment, dried, and then stripped from the support.