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 polyimide precursor solution contains a polyimide precursor, wherein in the case where the polyimide precursor is analyzed by gel permeation chromatography, the elution curve of the polyimide precursor has a region A including a higher-molecular-weight peak and a region B including a lower-molecular-weight peak; a weight average molecular weight determined from the region A in terms of polystyrene is approximately 10,000 or more, and a weight average molecular weight determined from the region B in terms of polystyrene is approximately less than 10,000; and when the area of the region A is a and the area of the region B is b, the polyimide precursor satisfies Equation (1)

a/(a+b)=approximately from 0.70 to 0.98.Equation 1:

A method for producing a polyimide film includes: obtaining a polyamic acid solution having a viscosity of 5 to 150 cps by preparing a raw material mixture liquid containing a solvent, a tetracarboxylic dianhydride represented by a specific general formula, and an aromatic diamine represented by a specific general formula, and has a total content of the tetracarboxylic dianhydride and aromatic diamine of 15% by mass or less, and reacting the tetracarboxylic dianhydride and aromatic diamine with each other in the raw material mixture liquid forming a polyamic acid having a repeating unit represented by a specific general formula; obtaining a polyimide-forming mixture liquid by adding a compound represented by a specific general formula to the polyamic acid solution; and obtaining a polyimide film represented by a specific general formula by forming a film made of the polyimide-forming mixture liquid, followed by imidization of the polyamic acid in the film.

A method of producing a polyimide resin that produces a polyimide resin having excellent heat resistance and mechanical properties, and having a low dielectric constant even when heat-treated at a lower temperature. The method includes heating at 120 C. to 350 C. a polyamic acid resulting from the reaction of a tetracarboxylic acid dianhydride component and a diamine component in a solvent including at least a compound represented by the general formula (1), in which R.sup.1 represents a hydrogen atom or a hydroxyl group, R.sup.2 and R.sup.3 independently represent a hydrogen atom or a C.sub.1 to C.sub.3 alkyl group, and R.sup.4 and R.sup.5 independently represent a C.sub.1 to C.sub.3 alkyl group. ##STR00001##

Provided are: a transparent polyimide copolymer which satisfies solvent solubility, storage stability, heat resistance, mechanical strength and thermal yellowing resistance at high levels and has excellent utility; a polyimide resin composition; a molded article; and a production method of the copolymer. The transparent polyimide copolymer is obtained by copolymerizing: (A) 4,4-oxydiphthalic dianhydride and/or 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride; and (B) at least one diamine and/or diisocyanate represented by the following Formulae (1) to (3): ##STR00001## (wherein, X represents an amino group or an isocyanate group; R.sup.1 to R.sup.8 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; and at least one of the R.sup.1 to R.sup.8 is not a hydrogen atom).

A method of making a polyetherimide comprising: reacting an aromatic bis(ether anhydride) with an aromatic diamine in a solvent to form a first solid/liquid mixture having a first solids content within 5% of a first target solids content; cooling the first solid/liquid mixture to a temperature within 5% of a target temperature; separating a portion of the liquid component from the cooled first solid/liquid mixture to form a second solid/liquid mixture having a second solids content within 10% of a second target solids content; and melt polymerizing the second solid/liquid mixture to form the polyetherimide.

Provided are methods for selecting a polymer for use as a flexible electronics substrate. An example method includes selecting a thermosetting polymer from a plurality of polymers, wherein the thermosetting polymer: undergoes a thermomechanical transition at a transition temperature between room temperature and the highest temperature observed during processing from the glassy to the rubbery regime; wherein the thermosetting polymer has a Young's modulus below 3 GPa in the glassy regime and wherein the thermosetting polymer has a Young's modulus above 0.3 MPa in the rubbery regime. The method further includes producing a flexible electronic substrate from the selected polymer.

The embodiments aim to provide a polyamide-imide-based film that has a TGA weight loss area value (TDA) of 0.01%.Math.min/? C. or less and is excellent in mechanical properties, optical properties, and the suitability for post-processing, a process for preparing the same, and a cover window and a display device comprising the same.

The present disclosure describes methods of polyimide synthesis and polyimides made therefore. The method includes placing a tetracarboxylic compound and a solvent in a reaction vessel and adding a first amount of a diamine. The first amount of the diamine is not more than 99.5 mol % of the tetracarboxylic compound inside the reaction vessel. The method can include agitating the mixture and determining a viscosity of the mixture. The method can further include adding a second amount of the diamine. The last steps can be repeated until the viscosity increases to a target value. The target viscosity can be correlated to a peak weight-averaged molecular weight of the polyimide.

A polyamic acid manufacturing system for manufacturing a polyamic acid is disclosed using, as raw materials, a first solution in which a polyaddition-type first polymerizable compound is dissolved and a second solution in which a polyaddition-type second polymerizable compound that reacts with the first polymerizable compound through polyaddition is dissolved. The polyamic acid manufacturing system may include: a first supply part for supplying the first solution; a second supply part for supplying the second solution; a first combining part; and a first reaction part, thereby producing a first polymerization solution in which the polyamic acid is dissolved. Further, the polyamic acid manufacturing system may include: a first supply step of supplying the first solution; a second supply step of supplying the second solution; a first combining step; and a first reaction step, thereby producing a first polymerization solution in which the polyamic acid is dissolved.