Provided is a porous low-dielectric polymer film which has a low dielectric constant at high millimeter-wave frequencies to fulfill utility as a sheet for a millimeter-wave antenna, and provides excellent circuit board processability. The porous low-dielectric polymer film is made of a polymer material and formed with fine pores dispersed therein, wherein the film has a porosity of 60% or more, and the pores have an average pore diameter of 50 m or less, and wherein a porous structure of the film is a closed-cell structure.

In an embodiment, a porous material comprises a base polymer having a continuous pore structure. In another embodiment, a method of making the porous material comprises reacting a base polymer with a degradable polymer with a crosslinker in the presence of a solvent and/or reacting a base polymer and a degradable polymer with a crosslinker in the presence of the solvent; removing the solvent to form a phase separated material; and removing the degradable polymer to form the porous material.

A polymer composition can be used for selective absorbing sintering, SAS, or selective inhibition sintering, SIS. The polymer has open mesopores and the cumulative pore volume distribution of the mesopores, measured to DIN 66134, is at least 0.01 cm.sup.3/g.

Halogen-free, microporous polyolefin membranes are disclosed herein. The halogen-free, microporous polyolefin membranes can be manufactured using an environmentally friendly manufacturing process that includes extrusion of polymer-plasticizer mixtures followed by sheet formation and extraction of the plasticizer with a halogen-free solvent. The halogen-free solvent has a flashpoint greater than about 23 C. and an initial boiling point at least about 50 C. lower than the flashpoint of the plasticizer. The process can further be a closed loop process in which the halogen-free solvent can be reused.

The present invention aims to provide a method for producing a porous tissue regeneration substrate that allows a wide choice of solvents and easy adjustment of the bulk density and pore size of the porous substrate. The present invention also aims to provide a method for producing an artificial blood vessel and an artificial blood vessel. The present invention relates a porous, tubular artificial blood vessel containing a bioabsorbable material, the artificial blood vessel including: a skin layer having a relatively small pore size as an innermost layer; and a porous layer positioned around the skin layer and having a relatively large pore size.

A nanoporous open-cell foam or wick structure and method for production are disclosed. The nanoporous foam or wick structures are produced from, for example, thermoplastic or thermoset polymer gels in which a gelation solvent is removed so as to preserve an expanded monolithic gel structure consisting of intertwined and or chemically crosslinked polymer molecular fibrils. The nanoporous foam or wick may encompass a stand-alone structure, or be incorporated in to microporous open cell foams or wick materials converting them in to nanoporous cellular materials having a bipore structure. Such produced nanoporous polymer materials have unique properties that may be exploited for making high performance capillary pump loop or heat pipe thermal management systems, low-boiloff slosh-less cryogen storage vessels and superior insulation materials for systems operating under ambient and elevated pressure conditions.

A method of synthesizing aerogels and cross-linked aerogels in a single step and in a single pot without requiring any solvent exchange is described. Porous matrices are synthesized through a modification of hydrolysis condensation of alkoxides in which addition of water is minimized. The reaction occurs in an ethanol-water azeotrope mixture; the water in the azeotrope slowly hydrolyzes the alkoxide. Additionally, after gelation, the porous matrix is dried in supercritical ethanol rather than liquid CO.sub.2, which allows for elimination of solvent exchange steps. These modifications allow for the preparation of aerogel monoliths in any size in one step and in one pot and much faster than conventional procedures. In addition, the method provides for custom aerogel parts with large dimensions, as well as high volume fabrication of aerogels. The custom aerogel parts may be used in a variety of thermal insulation applications.

Provided is a low-dielectric porous polymer film having a low dielectric constant at high millimeter-wave frequencies and thereby useful as a sheet for a millimeter-wave antenna. The low-dielectric porous polymer film is made of a polymer material and formed with fine pores dispersed therein, wherein the film has a porosity of 60% or more, and the pores have an average pore diameter of 10 m or less.

A polymer composition for producing gel extruded articles is described. The polymer composition contains polyethylene particles combined with a plasticizer and one or more strength enhancing additives. Polymer articles made in accordance with the present disclosure have enhanced strength properties. In one embodiment, the polymer composition is used to form a porous membrane for use as a separator in electronic devices.

A method of synthesizing aerogels and cross-linked aerogels in a single step and in a single pot without requiring any solvent exchange is described. Porous matrices are synthesized through a modification of hydrolysis condensation of alkoxides in which addition of water is minimized. The reaction occurs in an ethanol-water azeotrope mixture; the water in the azeotrope slowly hydrolyzes the alkoxide. Additionally, after gelation, the porous matrix is dried in supercritical ethanol rather than liquid CO.sub.2, which allows for elimination of solvent exchange steps. These modifications allow for the preparation of aerogel monoliths in any size in one step and in one pot and much faster than conventional procedures. In addition, the method provides for custom aerogel parts with large dimensions, as well as high volume fabrication of aerogels. The custom aerogel parts may be used in a variety of thermal insulation applications.