A process for preparing a polyamide-imide (PAI) polymer is provided. The process comprises the melt polymerization of a reaction mixture comprising at least one cycloaliphatic acid component comprising three carboxyl moieties, the carboxyl moieties selected from the group consisting of carboxylic acid, acid anhydride and ester functional groups, and at least one diamine component. The process comprises maintaining the reaction mixture in a liquid state and at a temperature of at least 200° C. during polymerization.

Compositions of and methods for producing a modified polyimide-containing compound with an alkyl or acyl group, one method including selecting and preparing a polyimide-containing compound to undergo a Friedel-Crafts alkylation or acylation reaction; carrying out the Friedel-Crafts alkylation or acylation reaction on the polyimide-containing compound to bond an alkyl group or acyl group to a reactive site on an aromatic compound of the polyimide-containing compound; cleaving the polyimide-containing compound to produce modified monomers comprising the alkyl group or the acyl group; and using the modified monomers in a reaction to produce the modified polyimide-containing compound, wherein the alkyl group or the acyl group is present in the modified polyimide-containing compound.

Provided is a curable resin composition having developability and resolution improved without degrading the heat resistance and the chemical resistance, furthermore, a curable resin composition that is useful as a PID material for optical uses or a material for optical sensor protective films and enables the formation of a cured product having both higher transparency and excellent heat resistance, a dry film containing the curable resin composition, a cured product thereof and a printed wiring board including the cured product. A curable resin composition containing (A) an amide-imide resin, (B) a compound having an ethylenic double bond and (C) a photopolymerization initiator, wherein the amide-imide resin (A) is a reaction product of an isocyanurate-type polyisocyanate synthesized from an isocyanate having an aliphatic structure and a tricarboxylic acid anhydride and has a number-average molecular weight of 500 to 1000.

A negative-type photosensitive resin composition that has a satisfactory imidization rate and can yield a resin layer with high chemical resistance, even under low-temperature curing conditions of 200° C. or below, the negative-type photosensitive resin composition containing a photopolymerization initiator (B) in a proportion of 0.1 part by mass to 20 parts by mass with respect to 100 parts by mass of a polyimide precursor (A), the polyimide precursor (A) being a polyamic acid ester or polyamic acid salt with a specific structure, and the weight-average molecular weight (Mw) of the polyimide precursor (A) being 3,000 or greater and less than 16,000, in terms of polystyrene, according to gel permeation chromatography (GPC).

A polyimide precursor solution is disclosed, and a colorless transparent polyimide film manufactured from the polyimide precursor solution. The polyimide precursor solution has diamines, a first dianhydride represented by biphenyl dianhydride, a second dianhydride represented by rigid alicyclic dianhydride, a third dianhydride represented by non-alicyclic dianhydrides and organic solvent. The colorless polyimide films have a modulus of 4.5 GPa or higher, a glass-transition temperature (T.sub.g) of 370° C. or higher, and a yellow index of 3.0 or lower. These polyimide films can be used as substrates for thin film transistor (TFT), touch sensor panel (TSP), and cover window applications in flexible display such as organic light-emitting diode (OLED), flexible liquid crystal display (LCD) and other fields.

A process for PAI-based coating compositions. An embodiment of a method includes manufacturing a coating composition, the manufacturing of the coating composition including mixing a first solvent, the first being solvent being N-formyl morpholine (NFM), with a second solvent to form a first solution; dissolving polyamideimide or polyamide amic acid resin polymer (PAI) in the first solution; precipitating a PAI compound from a mixture of MEK and the first solution; and dissolving the PAI compound in a second solution to generate a coating solution.

A manufacturing method for a transparent fiber is provided. The method includes forming a spinning solution containing a polyimide polymer in an organic solvent. The polydispersity index (PDI) of the polyimide polymer is 1.3˜2.6. The spinning solution is used to perform a dry-jet wet spinning step to form a plurality of fibers. Furthermore, the plurality of fibers are subjected to a thermal drawing step to form a plurality of transparent fibers, wherein the temperature of the thermal drawing step is controlled from 215° C. to 350° C. The manufacturing method for a transparent fiber provided in the present invention makes use of a polyimide polymer material and utilizes a dry-jet wet spinning step and a thermal drawing step, which allows the formation of a transparent and high strength polyimide fiber.

A polyimide and a method for manufacturing the polyimide are provided. The method for manufacturing the polyimide includes: mixing a diamine compound with a substance and an organic solvent, wherein the diamine compound includes an amide bond, and a molecular structure of the substance includes an ether dianhydride; and forming the polyimide by a cross-linking and curing process. A regular molecular chain arrangement, wherein the regular molecular chain arrangement has highly oriented in-plane crystallization and low free volume; a simple rigid planar structure; and intramolecular hydrogen bonds are introduced to prepare the polyimide that has high barrier performance, excellent heat resistance, and a low thermal expansion coefficient.

A varnish includes an isolated as-synthesized polyetherimide having a glass transition temperature of 180° C. or more, a solvent in an amount effective for the polyetherimide to remain in solution at a selected temperature, and an inorganic particulate composition wherein the amount of polyetherimide, inorganic particulate composition, and solvent total 100 wt %. Also disclosed is a method of manufacturing the varnish, articles prepared from the varnish, and methods of manufacturing such articles.

Porous three-dimensional networks of polyimide and porous three-dimensional networks of carbon and methods of their manufacture are described. For example, polyimide aerogels are prepared by mixing a dianhydride and a diisocyanate in a solvent comprising a pyrrolidone and acetonitrile at room temperature to form a sol-gel material and supercritically drying the sol-gel material to form the polyimide aerogel. Porous three-dimensional polyimide networks, such as polyimide aerogels, may also exhibit a fibrous morphology. Having a porous three-dimensional polyimide network undergo an additional step of pyrolysis may result in the three dimensional network being converted to a purely carbon skeleton, yielding a porous three-dimensional carbon network. The carbon network, having been derived from a fibrous polyimide network, may also exhibit a fibrous morphology.