Mesoporous poly (aryl ether ketone) articles are formed from blends of poly (aryl ether ketones) with pore forming additives by melt processing, and can be in the form of a monofilament, disc, film, microcapillary or other complex shapes. The method of formation provides for preparation of poly (aryl ether ketone) articles with high degree of surface area and uniform nanometer pore size. The preferred poly (aryl ether ketone)s are poly (ether ketone) and poly (ether ether ketone). The mesoporous articles formed by the method of the present invention are useful for a broad range of applications, including molecular separations and organic solvent filtration.

Mesoporous poly (aryl ether ketone) articles are formed from blends of poly (aryl ether ketones) with pore forming additives by melt processing, and can be in the form of a monofilament, disc, film, microcapillary or other complex shapes. The method of formation provides for preparation of poly (aryl ether ketone) articles with high degree of surface area and uniform nanometer pore size. The preferred poly (aryl ether ketone)s are poly (ether ketone) and poly (ether ether ketone). The mesoporous articles formed by the method of the present invention are useful for a broad range of applications, including molecular separations and organic solvent filtration.

There is provided a porous polyimide film in which the pore distribution width A represented by the following formula is 1.15 or less, the average pore diameter is within a range of 0.50 μm to 3.0 μm, and the air permeation speed is 30 seconds or less:
A=(D.sub.84/D.sub.16).sup.1/2 wherein D.sub.16 is the pore diameter at 16% cumulation from the small diameter side of pores, and D.sub.84 is the pore diameter at 84% cumulation from the small diameter side of pores.

A method for preparing a durably hydrophilic and uniform-pore ultrafiltration membrane is disclosed herein. Chemical reactions between the functional groups and the active bonds of the molecular chains in the membrane materials are initiated perform the grafting of hydrophilic chains on the polymer chains under conventional dissolution conditions of the polymer membrane material (dissolution with synchronized hydrophilization), so as to realize durable hydrophilization of the membrane materials. The resulting hydrophilized polymer solution (a nascent-state membrane) is introduced into a coagulation bath to initiate a crosslinking reaction among the hydrophilic chains. The resulting crosslinking serves to synergistically regulate subsequent phase separation and membrane formation (phase separation under synergistic crosslinking).

A polyimide precursor solution includes: a polyimide precursor; polyester resin particles containing a polyester resin and having a volume average particle diameter of from 3 μm to 50 μm inclusive and an average circularity of 0.970 or more; and a solvent.

A composite material according to the present invention includes a solid portion including inorganic particles and a resin. The composite material has a porous structure including a plurality of voids surrounded by the solid portion. The composite material satisfies (i) and/or (ii). (i) P.sub.2 is 500 or more. (ii) The composite material has a heat conductivity of 0.5 W/(m.Math.K) or more and a thickness of 0.5 mm to 2.5 mm, the void have an average diameter of 50 μm to 1500 μm, and P.sub.3 is 70% to 90%. P.sub.2=the heat conductivity [W/(m.Math.K)] of the composite material×P.sub.3×100/an amount [volume %] of the inorganic particles P.sub.3 [%]=(F.sub.0−F.sub.1)×100/F.sub.0

Mesoporous poly (aryl ether ketone) articles are formed from blends of poly (aryl ether ketones) with pore forming additives by melt processing, and can be in the form of a monofilament, disc, film, microcapillary or other complex shapes. The method of formation provides for preparation of poly (aryl ether ketone) articles with high degree of surface area and uniform nanometer pore size. The preferred poly (aryl ether ketone)s are poly (ether ketone) and poly (ether ether ketone). The mesoporous articles formed by the method of the present invention are useful for a broad range of applications, including molecular separations and organic solvent filtration.

A composite material according to the present invention includes a solid portion including inorganic particles and a resin. The composite material has a porous structure including a plurality of voids surrounded by the solid portion. The composite material compressed by 10% has a reaction force of 0.1 kPa to 1000 kPa, and the composite material has a heat conductivity of 0.5 W/(m.Math.K) or more. The heat conductivity is a value measured for one test specimen in a symmetric configuration according to an American Society for Testing and Materials (ASTM) standard (ASTM) D5470-01.

A porous polyimide film is provided to suppress an increase in a dielectric loss tangent even when immersed in water. In the porous polyimide film, a difference between a dielectric loss tangent T1 after being left to stand for 24 hours under an atmosphere of 25° C. and relative humidity of 50% and a dielectric loss tangent T2 after immersion in water for 24 hours under an atmosphere of 25° C. is 0.0030 or less.

A composite material according to the present invention includes a solid portion including inorganic particles and a resin. The composite material has a porous structure including a plurality of voids surrounded by the solid portion. In the composite material, a ratio of a smallest heat conductivity of heat conductivities λ.sub.x, λ.sub.y, and λ.sub.z respectively in x-axis, y-axis, and z-axis directions perpendicular to each other to a largest heat conductivity of the heat conductivities λ.sub.x, λ.sub.y, and λ.sub.z is 0.8 or more.