A polyimide material includes a polyimide of Formula (I)

##STR00001##

wherein A.sub.1 and A.sub.2 for each occasion independently are selected from a group of tetravalent moieties and B for each occasion independently is selected from a group of divalent moieties, wherein x is an integer greater than 1. The polyimide material has desirable optical, structural, thermal, mechanical properties, or combination thereof.

The present invention provides a method of manufacturing a polyimide film including unit polymers that are omnidirectionally distributed, and a polyimide film. The present invention also provides a graphite sheet having good quality manufactured using the polyimide film.

A gas separation membrane is provided. The gas separation membrane includes a poly(imide-oxadiazole) polymer including an oligomer having a structure comprising: ##STR00001##
In this structure, Ar.sub.1, Ar.sub.2, and Ar.sub.3 include aromatic moieties, and wherein Ar.sub.1, Ar.sub.2, and Ar.sub.3 are each independently selected.

A method of manufacture of a polyetherimide composition includes contacting a substituted phthalic anhydride and an organic diamine in the presence of diphenyl sulfone, sulfolane, or a combination comprising at least one of the foregoing solvents at a temperature of greater than 130 C. to provide a bis(phthalimide) composition comprising diphenyl sulfone, sulfolane, or a combination comprising at least one of the foregoing solvents and a bis(phthalimide); and polymerizing the bis(phthalimide) and an alkali metal salt of a dihydroxy aromatic compound in the presence of diphenyl sulfone, sulfolane, or a combination comprising at least one of the foregoing to form a polyetherimide. The method does not require any catalyst either for the imidization or the polymerization.

The present invention relates to a resin composition comprising a maleimide compound having a saturated or unsaturated divalent hydrocarbon group and a divalent group having at least two imido bonds; and a catalyst comprising at least one selected from the group consisting of an imidazole compound, a phosphorus compound, an azo compound and an organic peroxide.

A process for the purification of an oxydiphthalic anhydride includes contacting a mixture of an oxydiphthalic anhydride and at least one of the corresponding oxydiphthalic diacid, a corresponding oxydiphthalic tetraacid, a halophthalic anhydride, and a catalyst with a solvent to provide a slurry. The solvent is capable of solubilizing the corresponding oxydiphthalic diacid, the corresponding oxydiphthalic tetraacid, the halophthalic anhydride, and the catalyst at a temperature of 15 to 50 C., and the oxydiphthalic anhydride is substantially insoluble in the solvent at this temperature. The oxydiphthalic anhydride can be isolated from the slurry. A purified oxydiphthalic anhydride and a polyetherimide prepared therefrom are also disclosed.

Provided are a polyamic acid resin, a polyamideimide film, and a method for preparing the same. More specifically, provided are a polyamic acid resin derived from a combination of specific components, and a polyamideimide film capable of implementing high modulus and excellent optical properties.

Provided are a polyamic acid resin, a polyamideimide film, and a method for preparing the same. More specifically, provided are a polyamic acid resin derived from a combination of specific components, a polyamideimide film capable of implementing high modulus and excellent optical properties while implementing excellent mechanical properties, heat properties, and electrical properties, and a method for preparing the same.

The present invention relates to a method for preparing poly(carbonate-etherimide) compound comprising polycarbonate segment as shown in the structure (A) and polyetherimide segment as shown in the structure (B). Said method does not contain a highly toxic phosgene in its operation, can be performed easily, and can be operated at not high temperature. wherein R.sub.1 represents aromatic with 6 to 30 carbon atoms or, optionally said aromatic is bonded with heteroatom; R.sub.2 represents aromatic with 6 to 30 carbon atoms or, optionally said aromatic is bonded with heteroatom; m is an integer from 1 to 15; and n is an integer from 1 to 10.

##STR00001##

A polyimide resin including a structural unit A derived from a tetracarboxylic dianhydride and a structural unit B derived from a diamine compound, wherein the structural unit A includes at least one of a structural unit (A-1) derived from a compound represented by the following formula (a-1), a structural unit (A-2) derived from a compound represented by the following formula (a-2), and a structural unit (A-3) derived from a compound represented by the following formula (a-3), the structural unit B comprises a structural unit (B-1) derived from a compound represented by the following formula (b-1), a proportion of the structural unit (B-1) in the structural unit B is 60 mol % or more, and the polyimide resin has a glass transition temperature of higher than 410 C.:

##STR00001## wherein X and Y in the formula (b-1) each independently are a hydrogen atom, a methyl group, a chlorine atom, or a fluorine atom.