A polyimide precursor includes a repeating unit of formulae (I) and (II):

##STR00001## where R1 and R3 are each a tetravalent group of a tetracarboxylic dianhydride residue, and R2 and R4 are respectively a divalent group of a residue of a first-type diamine and a divalent group of a residue of a second-type diamine. The first-type diamine is represented by formula (III), and the second-type diamine is represented by formula (IV). A resin composition including the polyimide precursor, a polyimide formed from the polyimide precursor, and use of the polyimide are also disclosed.

The present invention relates to the production of a polyimide precursor, whereby, by using an amide-based organic solvent having a positive-number partition coefficient (Log P) and a density of at most 1 g/cm3, an interaction between the organic solvent and polyamic acid, which is a polyimide precursor, may be mitigated, thereby enabling the decrease of the viscosity of a polyimide precursor solution, and thus enabling a polyimide precursor solution having high solid content and low viscosity to be obtained.

A method of preparing a thermoplastic composition is provided. The method includes the following steps. A polyetherimide or a polyphenylene sulfide is provided. A polyimide is provided, wherein the glass transition temperature of the polyimide is between 128° C. and 169° C., the 10% thermogravimetric loss temperature of the polyimide is between 490° C. and 534° C., and when the polyimide is dissolved in N-methyl-2-pyrrolidone and the solid content of the polyimide is 30 wt %, the viscosity of the polyimide is between 100 cP and 250 cP. A melt process is performed to mix the polyetherimide and the polyimide or mix the polyphenylene sulfide and the polyimide to form a thermoplastic composition. Further, a thermoplastic composition is also provided.

The present technology relates to a sulfur-containing polymer or organic compound for use in a positive electrode material, especially in lithium batteries. More specifically, the use of this sulfur-containing polymer or compound as an active electrode material makes it possible to combine sulfur and an active organic cathode material. The present technology also relates to the use of the sulfur-containing polymer or organic compound as defined herein as a solid polymer electrolyte (SPE) or as an additive for electrolyte, especially in lithium batteries.

Provided are a polyimide compound including a repeating unit having an aromatic diamine component having a specific structure in which a side-chain benzylic position is regioselectively brominated, a gas separation membrane having a gas separation layer containing the polyimide compound, and a gas separation module and a gas separation apparatus each having the gas separation membrane.

A method of making diimide and dianhydride that includes contacting a nitro or halo N-substituted phthalimide with bisphenol in polar aprotic solvents, such as dimethylsulfoxide and sodium hydride to provide high conversion to a diimide; precipitating the product in acetic acid solution and filtration; treating the resulting solid, N-substituted diimide with a carboxylic acid and substituted or unsubstituted dimethyl sulfoxide in an aqueous medium to provide a reaction mixture including tetra acid, triacid, imide diacid and diimide along with substituted or unsubstituted acetic acid, dimethyl sulfoxide and their derivatives. The method includes the isolation of tetra acid by precipitation in water followed by centrifuge or filtration. The tetra acid is converted into the corresponding dianhydride. The dianhydride prepared by the method are also described as precursor to make polyetherimide.

The present technology relates to a sulfur-containing polymer or organic compound for use in a positive electrode material, especially in lithium batteries. More specifically, the use of this sulfur-containing polymer or compound as an active electrode material makes it possible to combine sulfur and an active organic cathode material. The present technology also relates to the use of the sulfur-containing polymer or organic compound as defined herein as a solid polymer electrolyte (SPE) or as an additive for electrolyte, especially in lithium batteries.

A polyimide resin composition containing a polyimide resin (A) and a polyetherimide sulfone resin (B), wherein the polyimide resin (A) contains a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), and a content ratio of the repeating structural unit of the formula (1) with respect to the total of the repeating structural unit of the formula (1) and the repeating structural unit of the formula (2) is 20 to 70 mol %; and a molded article containing the same.

##STR00001##

(R.sub.1 represents a divalent group having from 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure; R.sub.2 represents a divalent chain aliphatic group having from 5 to 16 carbon atoms; and X.sub.1 and X.sub.2 each independently represent a tetravalent group having from 6 to 22 carbon atoms containing at least one aromatic ring.)

A transparent polyimide mixture is disclosed. The transparent polyimide mixture includes a transparent polyimide, an additive, and a solvent. A molecular chain of the transparent polyimide includes an active hydrogen atom. The additive includes a carbodiimide group. An equivalent ratio of the active hydrogen atom and the carbodiimide group is in a range of 1:0.8 to 1:1.2. A method for preparing the transparent polyimide mixture, a transparent polyimide film, and a method for preparing a transparent polyimide film are also disclosed.

Provided is a polyimide excellent in heat resistance and colorless transparency and also excellent in flexibility and ultraviolet ray transmittance. The polyimide includes a structural unit represented by Formula (1a) and a structural unit represented by Formula (1b) wherein R is a specific aromatic group. ##STR00001##