Abstract:
Provided are: a polyetherimide porous body which has a low relative permittivity and is not easily cracked (or is excellent in cracking resistance) when folded, and a method for producing the porous body. This polyetherimide porous body comprises a polyetherimide crosslinked body and has a gel fraction of 10% or more, an average cell diameter of 8 μm or less, a volume porosity of 30% or more and an insulation breakdown voltage of 30 kV/mm or more.
Abstract:
Provided are porogen compositions and methods of using such porogen compositions in the manufacture of porous materials, for example, porous silicone elastomers. The porogens generally include comprising a core material and shell material different from the core material. The porogens can be used to form a scaffold for making a resulting porous elastomer when the scaffold is removed.
Abstract:
Disclosed is a process for production of a porous membrane that includes the steps of layering a film-forming dope that contains a polymer (A) that forms a membrane base, a polyvinylpyrrolidone (B) and a solvent (C) into a single layer or two or more layers; immersing the film-forming dope in a solidifying fluid that is a non-solvent with respect to the polymer (A) and is a good solvent with respect to the polyvinylpyrrolidone (B); and removing the polyvinylpyrrolidone (B), wherein the polyvinylpyrrolidone (B) has a K value of 50 to 80, a mass ratio r of the polyvinylpyrrolidone (B) to the polymer (A) is 0.5 or more and less than 1, and the viscosity of the film-forming dope at a membrane production temperature is 100 to 500 Pa·s. Accordingly, by using an appropriate amount of a low-molecular-weight hydrophilic polymer capable of being easily removed, it is possible to produce a porous membrane of a three-dimensional network structure in which macrovoids are suppressed, having high water permeability and superior filtration performance.
Abstract:
Provided are porogen compositions and methods of using such porogen compositions in the manufacture of porous materials, for example, porous silicone elastomers. The porogens generally include comprising a core material and shell material different from the core material. The porogens can be used to form a scaffold for making a resulting porous elastomer when the scaffold is removed.
Abstract:
Methods of forming a polymeric structure having a plurality of cells therein that include contacting a polymeric material that includes a first phase and a second phase with a composition comprising carbon dioxide to form the polymeric structure having a plurality of cells therein are described. Polymeric materials and microelectronic devices formed by such methods are also described.
Abstract:
A process for producing porous polymer material. The method combines a polymer and water-soluble granules to form a mixture. The mixture is placed into a mold; the surface of the polymer is dissolved to cause cohesion and form a polymer structure having water-soluble granules dispersed within, and water is introduced into the inner part of the polymer structure so that the polymer is solidified and water-soluble granules are washed out to obtain a porous polymer material. According to the invention, single or multiple layers of porous polymer material with different apertures, porosities, or made with different materials, are obtained by combining different polymer materials and water-soluble granules having different particle sizes in different weight ratios.
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 nullm and then removing the dispersible compound by extraction with supercritical carbon dioxide to thereby make the precursor porous, wherein the interaction parameter nullAB 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 nullm and a dielectric constant of 3 or lower.
Abstract:
A low density, open cell polymeric body is formed by coating or filling a reticulated polymeric foam with a liquid-form polymer which is resistant to high temperatures, curing the liquid form polymer in and on the foam and then removing the foam skeleton by dissolving and leaching the foam out of the solid polymeric body which remains.