The present invention provides a polyimide comprising a structural unit, which comprises a first structural unit represented by formula (1) and a second structural unit represented by formula (2), wherein A, D and E are defined herein. A polyimide film formed by the polyimide has a low linear thermal expansion coefficient.

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The invention pertains to a multi-step process for making polyfunctional aromatic compounds comprising two phenyl rings bearing reactive groups susceptible of polycondensation reaction to provide polycondensed polymers, said method using economic raw materials, and possessing high selectivity and overall yield.

The present disclosure is directed to methods of forming polyimide gels. The methods generally include forming a polyamic acid and dehydrating the polyamic acid with a dehydrating agent in the presence of water. The resulting polyimide gels may be converted to polyimide or carbon xerogels or aerogels. The methods are advantageous in providing rapid or even instantaneous gelation, which may be particularly useful in formation of beads comprising the polyimide gels. Polyimide or carbon gel materials prepared according to the disclosed method are suitable for use in environments containing electrochemical reactions, for example as an electrode material within a lithium-ion battery.

Provided are a polyimide film, preparation method, and application thereof. The polyimide film is a colorless transparent film with low thermal expansion. The polyimide film is obtained by taking a mixture of rigid aromatic diamine and fluorine-containing aromatic diamine, a mixture of rigid aromatic tetracarboxylic dianhydride and fluorine-containing aromatic tetracarboxylic dianhydride as raw materials, mixing the raw materials to obtain a resin solution, and then conducting imidizing and post-treating. The polyimide film not only has excellent transparency, but also has the advantages of low thermal expansion, high modulus, high glass transition temperature, and so on, and can be well applied to a flexible optoelectronic display substrate, a flexible printed circuit board, or an electronic packaging substrate.

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.

A polyimide-based binder for power storage device having a repeated breaking energy retention ratio of 70% or more. The use of the binder enables improvement of a power storage device having a high capacity.

Embodiments provide a polyamide-imide polymer film, which comprises a polyamide-imide polymer formed by polymerizing a diamine compound, a dianhydride compound, and a dicarbonyl compound; and silica particles, wherein the number of aggregates having an average diameter of 150 to 200 nm observed in a cross-section cut in the thickness direction of the polyamide-imide film is less than 0.5/μm.sup.2, and a process for preparing the same.

There are provided a method of manufacturing a cured film, including a first exposure step of exposing a part of a photocurable film formed from a photocurable resin composition, a development step of developing the photocurable film after the exposure with a developing solution to obtain a pattern, and a second exposure step of exposing the pattern with light including light having a wavelength different from a wavelength of light used in the first exposure step, where the photocurable resin composition has a specific constitution, a photocurable resin composition that is used in the method of manufacturing the cured film, a method of manufacturing a laminate including the method of manufacturing a cured film, and a method of manufacturing an electronic device, which includes the method of manufacturing the cured film.

A method for manufacturing a thick polyimide film includes providing a first and second laminated structures. The first and second laminated structures are heated, and the heated first and second laminated structures are wound together to form a third laminated structure. The first polyamic acid gel film of the heated first laminated structure and the second polyamic acid gel film of the heated second laminated structure are overlapped and bonded together to form a third polyamic acid gel film. Two third laminated structures are wound together to form a fourth polyamic acid gel film. A dehydration ring-closure imidization reaction is applied to the fourth polyamic acid gel film by heating to obtain the thick polyimide film. A thick polyimide film manufactured by the method is also disclosed.

A curable epoxy composition, comprising: an epoxy resin composition comprising one or more epoxy resins, each independently having at least two epoxy groups per molecule; an epoxy resin curing agent; optionally a curing catalyst; and a functionalized polyetherimide prepared from a substituted or unsubstituted C.sub.4-40 bisanhydride, a substituted or unsubstituted C.sub.1-40 organic diamine, and optionally an organic compound, wherein the functionalized polyetherimide includes a reactive end group of the formula (C.sub.1-40 hydrocarbylene)-NH.sub.2, (C.sub.1-40 hydrocarbylene)-OH, (C.sub.1-40 hydrocarbylene)-SH, (C.sub.4-40 hydrocarbylene)-G, wherein G is an anhydride group, a carboxylic acid, a carboxylic ester, or a combination thereof, wherein the functionalized polyetherimide has a total reactive end group concentration of 50-1,500 μeq/g and 0.05-1,000 ppm by weight of residual organic diamine, wherein the functionalized polyetherimide is obtained by precipitation from a solution using an organic anti-solvent, or by devolatilization, and the organic compound comprises at least two functional groups/molecule.