A polyetherimide of improved color and processes for preparing the polyetherimide are disclosed.

A method for producing polyimide microparticles may comprise: combining a diamine and a dianhydride in a first dry, high boiling point solvent; reacting the diamine and the dianhydride to produce a mixture comprising poly(amic acid) (PAA) and the first dry, high boiling point solvent; emulsifying the mixture in a matrix fluid that is immiscible with the first dry, high boiling point solvent using an emulsion stabilizer to form a precursor emulsion that is an oil-in-oil emulsion; and heating the precursor emulsion during and/or after formation to a temperature sufficient to polymerize the PAA to form the polyimide microparticles.

A method for predicting the material performance of a polyimide, the method comprising: dissolving a sample of the polyimide in a solvent to form a polyimide solution; determining a transmittance of the polyimide solution at a wavelength of 400 to 800 nm, preferably at a wavelength of 450 to 600 nm to obtain a test value; inputting the test value into a predetermined prediction equation to obtain a predicted material performance value; and determining if the predicted material performance value is within a desired range of material performance.

A resin composition comprises a modified polyimide compound, an epoxy resin, and a solvent. The modified polyimide compound has a chemical structural formula of

##STR00001##

the Ar represents a group selected from a group consisting of phenyl having a chemical structural formula of

##STR00002##

diphenyl ether having a chemical structural formula of

##STR00003##

biphenyl having a chemical structural formula of

##STR00004##

hexafluoro-2,2-diphenylpropane having a chemical structural formula of

##STR00005##

benzophenone having a chemical structural formula of

##STR00006##

and diphenyl sulfone having a chemical structural formula of

##STR00007##

and any combination thereof, the modified polyimide compound has a degree of polymerization n of about 1 to about 50, the epoxy resin and the modified polyimide compound are in a molar ratio of about 0.1:1 to about 1:1. A modified polyimide compound and a polyimide film are also provided.

A method for producing a reactive intermediate composition, including: reacting a substituted phthalic anhydride of the formula (I) with a diamine of the formula H.sub.2NRNH.sub.2 in the presence of an aromatic dianhydride in an amount of 10 to 50 mole percent based on the total moles of anhydride functionality in the reaction; wherein the reacting is conducted in an aprotic solvent in a reactor, under conditions effective to produce the reactive intermediate composition; and wherein X comprises a halogen or a nitro group, and R comprises a C.sub.6-36 aromatic hydrocarbon group or a halogenated derivative thereof, a straight or branched chain C.sub.2-20 alkylene or a halogenated derivative thereof, or a C.sub.3-8 cycloalkylene or a halogenated derivative thereof.

A resin composition comprises a modified polyimide compound, an epoxy resin, and a solvent. The modified polyimide compound has a chemical structural formula of ##STR00001##
the Ar represents a group selected from a group consisting of phenyl having a chemical structural formula of ##STR00002##
diphenyl ether having a chemical structural formula of ##STR00003##
biphenyl having a chemical structural formula ##STR00004##
hexafluoro-2,2-diphenylpropane having a chemical structural formula of ##STR00005##
benzophenone having a chemical structural formula of ##STR00006##
and diphenyl sulfone having a chemical structural formula of ##STR00007##
and any combination thereof, the epoxy resin and the modified polyimide compound are in a molar ratio of about 0.1:1 to about 1:1. A polyimide film and a method for manufacturing the polyimide film using the resin composition are also provided.

A method of making a polyetherimide comprises: combining a bisphenol A dianhydride, p-phenylene diamine and a halogenated aromatic solvent to form a reactant solution; heating the reactant solution to a temperature of 205 C. to 330 C. at a pressure sufficient to prevent boiling to afford a reaction solution; removing water from the reaction solution; maintaining the reaction solution at a temperature of 205 C. to 330 C. and a pressure sufficient to prevent boiling for 10 minutes to 5 hours to form a product mixture comprising the polyetherimide and solvent; and isolating the polyetherimide.

Boron nitride nanotube (BNNT)-polyimide (PI) and poly-xylene (PX) nano-composites, in the form of thin films, powder, and mats may be useful as layers in electronic circuits, windows, membranes, and coatings. The processes described chemical vapor deposition (CVD) processes for coating the BNNTs with polymeric material, specifically PI and PX. The processes rely on surface adsorption of polymeric material onto BNNTs as to modify their surface properties or create a uniform dispersion of polymer around nanotubes. The resulting functionalized BNNTs have numerous valuable applications.

A polyimide-forming composition includes a particulate polyimide precursor composition having an average particle size of 0.1 to 100 micrometers wherein the polyimide precursor composition comprises a substituted or unsubstituted C.sub.4-40 bisanhydride, and a substituted or unsubstituted divalent C.sub.1-20 diamine; an aqueous carrier; and a surfactant. A method of manufacturing an article including a polyimide includes the steps of forming a preform comprising the polyimide-forming composition; and heating the preform at a temperature and for a period of time effective to imidize the polyimide precursor composition and form the polyimide. An article prepared by the method, and a layer or coating including a polyimide and a surfactant are also described.

Novel aromatic polyimides are disclosed with sufficient physical properties to be useful in 3D printing.