Abstract: A polyimide porous film obtained by drying and imidizing a polyimide precursor porous film which is substantially homogeneous on both sides, the polyimide porous film having pores on both sides wherein the pores all satisfy the conditions: 1) the difference in the mean pore size of both sides is less than 200% based on the smaller average value of the mean pore size, 2) the coefficient of variation for the pore size on each side is smaller than 70%, 3) the coefficient of variation for the pore centroid distance on each side is smaller than 50%, and 4) the mean pore size on each side is 0.05-5 &mgr;m.

Abstract: An electrode material for a secondary cell comprising as its essential component a powder of graphite having a crystallinity of 90% or more obtained by graphitizing a highly heat resistant polymer compact in an anaerobic atmosphere and crushing into a powder, and a process for the production of an electrode material for a secondary cell comprising heating and graphitizing a composition in which 0-10 wt % of a boron compound is added to a highly heat-resistant polymer to produce a powder of graphite having crystallinity of 90% or more contained as its essential component. An electrode material for a secondary cell having excellent charge/discharge cycle life and discharge voltage performance is provided.

Abstract: In a resin composite, polyolefine grains are dispersed in a polyamide matrix. Each of the polyolefine grains has a core made of an unmodified polyolefine and a shell made of another polyolefine that is modified. In one embodiment, the core is made of a crystalline polypropylene resin (C), and the shell is made of modified copolymer (B) having ethylene units and .alpha.-olefine units. The modified copolymer (B) may have the .alpha.-olefine units as a major component. The resin composite has 30 to 80 percents by weight of polyamide (A), 1 to 30 percents by weight of the modified copolymer (B), and 19 to 69 percents by weight of the crystalline polypropylene resin (C) wherein the sum of the polyamide, the modified copolymer, and the crystalline propylene resin is 100 percents by weight. In another embodiment, the core is made of an unmodified copolymer (E) having ethylene units and .alpha.-olefine units, and the shell is made of a modified crystalline polypropylene resin (D).

Abstract: A thermoplastic resin composition includes 40-75 parts by weight of a polyamide resin (A), 5-30 parts by weight of a modified polyphenylene ether (B) which is a polyphenylene ether modified with an .beta., .beta.-unsaturated carboxylic acid or a derivative thereof, 1-30 parts by weight of an aromatic vinyl compound-aliphatic hydrocarbon copolymer (C), and 1-30 parts by weight of an ethylene-.alpha.-olefin copolymer (D) or a polypropylene resin (E) with the total amount of the components (A), (B), (C), and (D) or (E) being 100 parts by weight. The polyamide resin (A) is present as a matrix phase and the other components (B), (C), and (D) or (E) are present as a disperse phase consisting of core-shell structure grains, in each of which grains the modified polyphenylene ether (B) forms a shell phase, the aromatic vinyl compound-aliphatic hydrocarbon copolymer (C) forms an intermediate phase and the ethylene-.alpha.-olefin copolymer(D) or the polypropylene resin (E) forms a core phase.

Abstract: A Xonotlite-reinforced organic polymer composition obtained by mixing (A) an organic polymer and (B) fibrous Xonotlite, in which the fibrous Xonotlite (1) satisfies conditions (a), (b), and (c):(a) 0.1 .mu.m.ltoreq.D.ltoreq.0.4 .mu.m(b) 1 .mu.m.ltoreq.L <5 .mu.m(c) 10.ltoreq.L/D .ltoreq.15wherein D and L represent an average fiber diameter and an average fiber length, respectively, of fibrous Xonotlite (B);(2) has a BET specific surface area of not less than 21 m.sup.2 /g as measured by nitrogen adsorption; (3) has had its surface treated with a surface active agent and/or a coupling agent; and (4) has been formed into granules. The composition exhibits improved mechanical characteristics and improved balance between heat resistance and impact resistance.