Abstract: Disclosed is a polyimide ammonium salt comprising the reaction product of an ethylenically unsaturated amine with an aromatic polyimide having pendant carboxylic acid groups, said polyimide comprising the reaction product of diamine and aromatic dianhydride, where the diamine comprises an aromatic carboxylic acid diamine having at least one carboxylic acid. A substrate can be coated with the polyimide ammonium salt by forming a composition of a crosslinking agent and a solution of the polyimide salt in an organic solvent, spreading the composition on the substrate, evaporating the solvent to form a coating, exposing at least some of the coating to actinic radiation to crosslink and insolubilize the exposed portions of the coating, and washing the unexposed portions away by dissolving them in an organic solvent.

Abstract: A method and apparatus are disclosed for conducting a physical process and a chemical reaction by exposing a material containing a volatile substance to microwave radiation where the morphology of said material will change when exposed to such radiation. The power of said radiation is adjusted over time as the morphology of the material changes to maximize the effect of the radiation in order to produce a product in a minimum amount of time that is substantially free of said volatile substance.The method and apparatus can also be used to conduct such a process or reaction with materials that do not contain a volatile material.In one embodiment a method and apparatus are disclosed for manufacturing a polyimide from a precursor in a solvent by exposing the precursor to microwave radiation in a tuneable microwave resonant cavity that is tuned during imidization to achieve critical coupling of the system. Microwave power is controlled to remove the solvent and obtain the desired level of reaction.

Abstract: The terminal-modified imide oligomer composition capable of being cured within a short time and of being converted to a shaped, cured resin article having a high mechanical strength, heat resistance and elastic modulus, comprises a rigid, high molecular weight aromatic polyimide (I) produced by polymerizing and imidizing a tetracarboxylic acid component comprising at least one biphenyltetracarboxylic acid compound with an amine component comprising at least one aromatic diamine compound (a) having at least one cyclic structure and two amino groups directly attached to the cyclic structure; a flexible imide oligomer (II) produced by polymerizing and imidizing the tetracarboxylic acid component, with a diamine component comprising at least one aromatic diamine compound (b) having at least two cyclic structures and two amino groups attached directly or through a divalent bonding member to the cyclic structures and a monoamine component comprising at least one monoamine compound (c) having an unsaturated hydrocar

Abstract: Poly(dianhydride) compounds having formulae (I) and (II): ##STR1## where m is 0 to 50. ##STR2## wherein n is 0 to 20 and X is bond junction, oxygen atom, sulfur atom, SO.sub.2, C(CF.sub.3), CO, C(CH.sub.3).sub.2, CF.sub.2 --O--CF.sub.2, CH.sub.2, and CHOH.

Abstract: Sizing for carbon fibers with uncapped or capped linear polyamideimides.The uncapped linear polyamideimides useful as carbon fiber sizings generally contain repeating units having the general formula: ##STR1## Wherein R.sub.2 =a trivalent organic radical and generally benzenetriyl;R.sub.3 =a divalent organic radical; andn=an integer sufficiently large to provide a strong, tough coating.Useful capped, linear polyamideimide oligomers may be formed by including end caps with an unsaturated functionality (Y) containing a residue selected from the group consisting of: ##STR2## wherein R.sub.1 =lower alkoxy, aryl, aryloxy, substituted alkyl, substituted aryl, halogen, or mixtures thereof;j=0, 1, or 2;i=1 or 2;G=--CH.sub.2 --, --O--, --S--, --SO.sub.2 --, --SO--, --CO--, --CHR--, or --CR.sub.2 --;T=methallyl or allyl;Me=methyl; andR=hydrogen, lower alkyl, or phenyl.Prepregs and composites having carbon fibers sized with such polyamideimides are also described.

Abstract: Polyimide sheets having excellent thermal resistance and good surface appearance of the resultant sheets are obtained by a melt-extrusion process from a specific polyimide in the temperature range of 300.degree. C. to 450.degree. C. and a moisture content of 200 ppm or less.

Abstract: Polymerization or cure of di-phthalonitrile monomers or prepolymers by a curing agent selected from (a) an acid and an amine, (b) a salt of an acid and an amine, and (c) mixtures of (a) and (b). In a preferred embodiment, the curing agents are amine salts which are reaction products of an aromatic amine and an aromatic sulfonic acid. The use of the novel curing agents enhances curing rates and results in polymers which have high Tg.

Abstract: Novel polyimide and polyamide-imide gas separation membranes and the process of using such membranes to separate one or more gases from a gaseous mixture is disclosed. The polyimides and polyamide-imides are formed from a blend of diamines containing the ester derived from 1,3-diamino-2-hydroxypropane.

Abstract: A perfluorinated polyimide comprising a repeating unit represented by general formula (1): ##STR1## and a perfluorinated poly(amic acid) comprising a repeating unit represented by general formula (6): ##STR2## wherein R.sub.1 is a tetravalent organic group; and R.sub.2 is a divalent organic group, provided that chemical bonds between carbon atoms and monovalent elements contained in R.sub.1 and R.sub.2 are exclusively carbon-to-fluorine bonds; methods for preparing them; and optical material including the perfluorinated polyimide. 1,4-Bis(3,4-dicarboxytrifluorophenoxy)tetrafluorobenzene dianhydride, 1,4-difluoropyromellitic anhydride, 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrafluorobenzene, 1,4-difluoropyromellitic acid, and 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrafluorobenzene as well as methods preparing them. The perfluorinated polyimide has a thermal stability and has a low optical loss in an optical communication wavelength region (0.8 to 1.7 .mu.m).

Abstract: A novel aromatic diamine; a polyimide comprising 1,3-bis(3-aminobenzoyl)benzene or 4,4'-bis(3-aminobenzoyl)biphenyl as a diamine component and having recurring structural units represented by the formula (III): ##STR1## wherein R is a tetravalent radical selected from the group consisting of an aliphatic radical having from 2 to 27 carbon atoms, alicyclic radical, monoaromatic radical, condensed polyaromatic radical, and noncondensed aromatic radical connected each other with a direct bond or a bridge member, and X is a divalent radical of ##STR2## and a polyimide having a terminal aromatic group which is essentially unsubstituted or substituted with a radical having no reactivity with amines or dicarboxylic acid anhydrides or a composition comprising said polyimide.

Abstract: A polyamic acid having a three-dimensional network molecular structure produced by a gel forming ring-opening polyaddition reaction in an organic solvent of the reaction components comprising:(A) an acid component consisting of at least one tetracarboxylic acid dianhydride selected from the group consisting of a tetracarboxy benzene dianhydride, a tetracarboxy dianhydride of a compound having 2 to 5 condensed benzene rings, and compounds represented by formula (III), and substituted compounds thereof: ##STR1## wherein R.sub.1 represents --O--, --CO--, --SO.sub.2 --, --SO--, an alkylene group, an alkylene bicarbonyloxy group, an alkylene bioxycarbonyl group, a phenylene group, a phenylene alkylene group, or a phenylene dialkylene group, n.sub.4 is 0 or 1, n.sub.5 is 0 or 1; and n.sub.6 is 1 or 2, provided that the sum of n.sub.5 and n.sub.

Abstract: The present invention relates in general to color liquid crystal displays and more particularly to color liquid crystal displays in which the color filter functions as the orientation layer. A film which functions as both an orientation layer controlling the orientation of liquid crystal molecules and as a color filter is described. A process for producing the combination film is also described. The process comprises synthesizing a polyimide precursor by the ring-opening polyaddition reaction of a diamine component and an acid anhydride component in a solvent. Wherein the diamine component has a predetermined structure. Further, the acid anhydride component has a predetermined structure. Finally, the process includes the step of dispersing coloring materials in the polyimide precursor to form the filter.

Abstract: The invention relates to soluble homo- or copolyimides of formula I ##STR1## wherein Y is hydrogen or the substituents Y, together with the linking N atom, are a divalent radical of of formulae IIa to IIc ##STR2## and X is the radical of of an aromatic amine after removal of the amino end groups, and n is an integer from 5 to 150.The compounds of the invention are readily soluble in organic solvents and are suitable tougheners for epoxy, bismaleimide and triazine resin systems.

Abstract: Polyimides having high glass transition temperature prepared from 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride and 1,5-, 1,6-, 2,6- or 2,7-bis(4-aminophenoxy)napthalene.

Abstract: High performance, thermooxidatively stable polyimides are prepared by reacting aromatic diamines with pendant trifluoromethyl groups and dianhydrides in an amide solvent to form a poly(amic acid), followed by cyclizing the poly(amic acid) to form the corresponding polyimide, which has the following general structure: ##STR1##

Abstract: The invention is a process for making novel branched polybenzazole polymers and the polymers formed thereby. Novel compounds are also disclosed that are useful as branching agents in making the branched polybenzazole polymers. The branched polymers synthesized by the process can be formed into strong, light articles such as fibers and films.

Abstract: A high-temperature stable, highly optically transparent-to-colorless, low dielectric linear aromatic polyimide is prepared by reacting an aromatic diamine with 3,3'bis(3,4-dicarboxyphenoxy)diphenylmethane dianhydride in an amide solvent to form a linear aromatic polyamic acid. This polyamic acid is then cyclized to form the corresponding polyimide, which has the following general structural formula: ##STR1## wherein Ar is any aromatic or substituted aromatic group, and n is 10-100.

Abstract: Azole rings, such as oxazole and thiazole rings, can activate an aromatic ring bonded to a leaving group such as a halogen atom so that the aromatic ring will undergo aromatic nucleophilic substitution. The reaction is useful for making ethers, thioethers and amines containing azole rings. In particular, monomers having azole rings, activated aromatic rings with leaving groups and nucleophilic moieties can react under conditions of aromatic nucleophilic displacement to form non-rigid rod PBZ polymers. The non-rigid rod PBZ polymers can be used to form molecular composites with rigid rod PBZ polymers which molecular composites are not substantially phase separated.

Abstract: The solvent-resistance and thermal stability of polyamideimides of the general formulae: ##STR1## is improved by capping the amideimides with a crosslinking functionality (Y) containing a residue selected from the group of: ##STR2## wherein R.sub.1 =lower alkyl, lower alkoxy, aryl, aryloxy, substituted alkyl, substituted aryl (either including hydroxyl or halo-substituents), halogen, or mixtures thereof;j= 0, 1, or 2;G=--CH.sub.2 --, --O--, --S--, --SO.sub.2 --, --SO--, --CO--, --CHR--, or --CR.sub.2 --;R=hydrogen, lower alkyl, or phenyl;T=methallyl or allyl;Me=methyl;R.sub.2 =a trivalent organic radical; andR.sub.3 =a divalent organic radical.The amideimide oligomers may be linear or multidimensional, and can be processed into blends, prepregs, or composites. Methods of making these amideimides and intermediates useful in the syntheses are also described.

Abstract: The present invention relates to new polyetherimideimides having imideimide group with the following structural formula(I) and inherent viscosity of 0.27.about.0.71 dl/g, which can be made by effecting reaction between an aromatic bis(ether anhydride) and an organic diamine or an aromatic bis(nitro imideimide) and a metal salt of diol.

Abstract: Linear aromatic polyimides containing the cyclobutene-3,4-dione moiety were produced by reacting 1,2-bis(4-aminoanilino)cyclobutene-3,4-dione with several aromatic dianhydrides. The resulting polymers exhibited glass transition temperatures greater than 500.degree. C., adhered tenaciously to glass, and became more flexible after heating for 1 hour at 300.degree. C.

Abstract: The semicrystalline polyimide prepared by reaction of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and 1,3-bis(4-aminophenoxy-4'-benzoyl)benzene (1,3-BABB) is modified so that it can be more readily processed to form adhesive bonds, moldings and composites. The stoichiometric ratio of the two monomers, BTDA and 1,3-BABB is controlled so that the intermediate polyamide acid is of a calculated molecular weight. A polyamide acid with excess anhydride groups is then reacted with the stoichiometrically required amount of monofunctional aromatic or aliphatic amine required for complete endcapping. A polyamide acid with excess amino groups is reacted with the stoichiometrically required amount of monofunctional aromatic anhydride required for complete endcapping. The stoichiometrically offset, endcapped polyimide is processed at lower temperatures and pressures than the unmodified high molecular weight polyimide with the same repeat unit, and exhibits an improved melt stability.

Abstract: A hot-melt adhesive comprising a special polyamideimide or polyamide is excellent in heat resistance and adhesive strength and usable for providing substrates for printed circuit boards.

Abstract: In a process for the preparation of polyimide by reacting a diamine compound with tetracarboxylic dianhydride in a phenol based solvent, an improved process for reacting the diamine compound with tetracarboxylic dianhydride in a solution by forming separate solutions of the tetracarboxylic dianhydride and the diamine compound and mixing the solutions and/or by dissolving tetracarboxylic dianhydride in the phenol-based solvent containing an organic base.

Abstract: Phosphazene-containing amines having at least one amine or substituted amine moiety reactive with nitrile groups of the phthalonitrile monomers or oligomeric resins are useful curing agents for phthalonitriles. Typically, the phosphazene-containing amines useful as curing agents in the present invention have the formula: ##STR1## wherein each of X.sub.1-6 is a hydrogen, an unsubstituted amine group, or an amine group substituted with C.sub.1 -C.sub.12 alkyl groups or aromatic groups, at least one of X.sub.1-6 includes an amine group, and each of R'.sub.1-6 is an alkyl, aromatic, or alkyl-substituted aromatic moiety, or a linear polymer of the phosphazene-based amine monomer. The curing agents enhance the speed of cure and also add flame retardancy to the cured polymers.

Abstract: Integrated circuit sockets for use in a burn-in test are disclosed. The IC sockets are produced by injection molding of a specific polyimide having an inherent viscosity of 0.35 to 0.65 dl/g and essentially consisting of recurring units represented by the formula (I): ##STR1## wherein X is a radical selected from the group consisting of a bond, divalent hydrocarbon having from 1 to 10 carbon atoms, etc. and R is a tetravalent radical selected from the group consisting of an aliphatic radical having two or more carbon atoms, cycloaliphatic radical, monoaromatic radical etc.

Abstract: Polyimide which is obtained by polymerization and consists essentially of recurring structural units of the formula (I): ##STR1## wherein X is a single bond or a hexafluoroisopropylidene group, is processed to a form of pellet, followed by heat-treating to obtain crystallinity of 5% or more, and fed to an extruder to obtain articles.

Abstract: Certain substituted benzidines enable the preparation of linear chain, high molecular weight polyimides based on benzidine.

Abstract: A tri-component polyimide copolymer and the process of preparing the copolymer are disclosed. A mixed reaction medium or solvent system comprising phenol and at least one compound of resorcinol, 1,6-dimethyl phenol and 4-methoxy phenol is used to produce the copolymer by direct imidization without isolating or purifying the imide oligomer as an intermediate.

Abstract: In one embodiment this invention provides polymalonamide polymers with side chains which exhibit nonlinear optical response.

Abstract: Tetrapolyimide films derived from 3,3',4,4'-benzophenone tetracarboxylic dianhydride, pyromellitic acid dianhydride, p-phenylene diamine and 4,4'-diaminodiphenyl ether, and their preparation, are described. The tetrapolymer films have low water absorption, low coefficients of thermal and hygroscopic expansion, high modulus and are caustic etachable and can be used in flexible printed circuit and tape automated bonding applications.

Abstract: A polyimide having a high heat-resistance good processability and recurring structural units of the formula (I): ##STR1## wherein R is a tetravalent radical selected from the group consisting of an aliphatic radical having at least two carbon atoms, alicyclic radical, monocyclic aromatic radical, fused polycyclic aromatic radical and polycyclic aromatic radical bonded through a direct bond or a bridge member.

Abstract: Azole rings, such as oxazole and thiazole rings, can activate an aromatic ring bonded to a leaving group such as a halogen atom so that the aromatic ring will undergo aromatic nucleophilic substitution. The reaction is useful for making ethers, thioethers and amines containing azole rings. In particular, monomers having azole rings, activated aromatic rings with leaving groups and nucleophilic moieties can react under conditions of aromatic nucleophilic displacement to form non-rigid rob PBZ polymers. The non-rigid rod PBZ polymers can be used to form molecular composites with rigid rod PBZ polymers which molecular composites are not substantially phase separated.

Abstract: It is advantageous to prepare oligomers of polybenzazole polymers by reaction of AA-PBZ monomer with an excess of BB-PBZ monomer. The resulting oligomer dopes may be stored at a temperature at which they remain pumpable until such time as the dope can be advanced to higher molecular weight by adding additional AA-PBZ monomer. The molecular weight of the polymer may be adjusted by controlling the amount of chain extender and/or chain terminator added to oligomer mixtures as they are advanced to final molecular weight.

Abstract: A method for preparing high molecular weight polyethermide polymers in a dual solvent system is disclosed. The inventive method provides for polymerizing a diamine monomer and a dianhydride monomer in a solvent system comprised of at least two solvents, a first solvent is selected for its solubility characteristics such that the polyethermide polymer is highly soluble therein and a second solvent is selected for its relatively high boiling point characteristics such that when the second solvent and first solvent are mixed together, the boiling point of the dual solvent system is at least as high as the temperature at which polymerization of said monomers occurs. In one embodiment, a diamine monomer of 4,4'-sulfonyl dianiline (SDAN) is reacted with a dianhydride monomer of bisphenol A dianhydride (BPADA) in the presence of a catalyst and a chain stopper in a dual solvent system comprised of chloroform and ortho-dichlorobenzene. The resulting polyethermide has an intrinsic viscosity exceeding 0.

Abstract: Rigid fluorine-containing compounds, monomers, and polymers based on pentacyclic core systems, such as 12H,14H-5, 7-dioxapentacene with perfluoroalkyl and/or aryl groups in the 12, 14 positions, and 5H,12H-7, 14-dioxapentacene, with perfluoroalkyl and/or aryl groups in the 5,12 positions. These monomers have utility in the preparation of advanced high-performance polymers, particularly polyimides. The rigid pentacyclic core decreases the coefficient of thermal expansion of the polymers, while the fluorinated substituents improve the dielectric constant and water absorption properties. Each monomer unit contains within its pentacyclic core two-O-bridges, and two --CRR.sub.f bridges (where R is aryl, substituted aryl or perfluoroalkyl, and R.sub.f is perfluoroalkyl).

Abstract: Polyimide compositions, films, and electronic devices using polyimides, based on 9-aryl-9(perfluoroalkyl)-xanthene-2,3,6,7-dianhydride and one or more diamines from a selected group, which offers to the polyimides a combination of desirable properties including solubility, pseudo rod-like structure, low linear coefficient of thermal expansion, high glass transition temperature, low dielectric constant, and high modulus.

Abstract: Polyimide intercondensation products are prepared from mixed dianhydrides and aromatic diamines. One of the mixed dianhydrides must be 2,2-bis(3,4-dicarboxyphenyl)-hexafluoropropane dianhydride (6FDA) and the other dianhydride may be oxydiphthalic anhydride (ODPA) or biphenyl dianhydride (BPDA) or mixtures thereof. Preferred aromatic diamines are p-phenylenediamine (PPD) and/or m-phenylenediamine (MPD). The polyimide products have increased glass transition temperatures (Tg), frequently higher than 400.degree. C. Composites made from the polyimides have high thermal and oxidative stability and may be used in aircraft engine hardware.

Abstract: Disclosed is an aromatic diamine having the general formula ##STR1## where A is a group containing at least one aromatic ring, each Y is independently selected from ##STR2## R is a group containing at least one olefinically unsaturated group, R' is hydrogen, alkyl to C.sub.25, aryl, or R, n is 1 to 4, and the number of olefinic groups in Y is at least 3 when each Y is ##STR3## and otherwise is at least 2. Photosensitive polyamic acids and polyimides can be prepared from the aromatic diamines which can be crosslinked with light to a mask to form patterns on a substrate.

Abstract: A new class of soluble phenylated polyimides made from 3,6-diarypyromellitic dianhydride and process for the manufacture of the 3,6-diarypyromellitic dianhydride starting material. The polyimides obtained with said dianhydride are readily soluble in appropriate organic solvents and are distinguished by excellent thermal, electrical and/or mechanical properties making the polyimides ideally suited as coating materials for microelectronic apparatii, as membranes for selective molecular separation or permeation or selective gas separation or permeation, or as reinforcing fibers in molecular composites, or as high modulus, high tensile strength fibers.

Abstract: Polyimide resins, which have reduced anhydride content when molded, are prepared by a novel reaction process that includes reacting an esterified aromatic tetracarboxylic acid or anhydride monomer with a primary aromatic diamine until substantially no free monomer remains to form a polyamide-acid (the molar ratio of esterified monomer to diamine ranging from 1:1 to 1:2); reacting the polyamide-acid with a low molecular weight end-capping agent to form an end-capped polyamide-acid; and heating the end-capped polyamide-acid to form the polyimide.

Abstract: Aromatic homopolyimide and copolyimide films derived from an aromatic dianhydride and a chlorinated aromatic diamine such as 2-chloro-p-phenylene diamine and 2,2'-dichloro-4,4'-diaminodiphenyl ether are described. The films have low water absorption, high elastic modulus and elongation and can be heat-processed without embrittlement.

Abstract: Polyimide oligomers include (1) linear, monofunctional crosslinking oligomers prepared by condensing a monoanhydride end cap with a diamine that includes alternating ether and "Sulfone" (--SO.sub.2 --, --S--, --CO--, --(CF.sub.3).sub.2 C--, or --(CH.sub.3).sub.2 C--) linkages connecting alternating aromatic radicals and with a dianhydride (or dianhydride mixture), particularly the unsaturated, aliphatic dianhydride commonly known as MCTC; (2) linear, mono- or difunctional crosslinking oligomers prepared by condensing an amine end cap with a diamine and a dianhydride; and (3) multidimensional, crosslinking oligomers having an aromatic hub and at least three radiating arms connected to the hub, each arm including a crosslinking end cap at its distal end and at least one imide linkage.Blends, prepregs, and composites can be prepared from the oligomers.

Abstract: The present invention relates to a novel class of aromatic diamine monomers, benzoxazole polymers made from said class of monomers, and polymer-matrix composites which may be produced therefrom. The present invention also relates to methods of producing said polymers and said polymer-matrix composites. The polymer-matrix composites have as one advantage high strength and temperature resistance.

Abstract: Polyimide copolymers are disclosed having the recurring structure ##STR1## wherein AR is AR.sub.1 or AR.sub.2, wherein AR.sub.1 is ##STR2## and wherein AR.sub.2 is ##STR3## provided that the molar ratio of AR.sub.1 to AR.sub.2 is 3:1 to 1:3, and wherein AR.sub.3 is ##STR4## These polyimides have unexpected properties which are useful in various electronic applications.

Abstract: A copolymeric amphiphilic polyimide precursor having the recurring unit of the formula (1): ##STR1## wherein R.sup.1 is a tetravalent group having at least 2 carbon atoms, R.sup.2 is a bivalent group having at least 2 carbon atoms, and R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are hydrogen atom or a monovalent group having 1 to 30 carbon atoms selected from the group consisting of an aliphatic group, an alicyclic group, an aromatic group, a group in which an aliphatic group is combined with an aromatic group, or an alicyclic group, and their groups substituted by a halogen atom, nitro group, amino group, cyano group, methoxy group or acetoxyl group, provided that at least one of R.sup.3, R.sup.4, R.sup.5 and R.sup.6 is neither hydrogen atom nor the above-mentioned group which has 1 to 11 carbon atoms; a part of at least one of said R.sup.1 and said R.sup.2 being substituted with a group having a valence different therefrom.

Abstract: An improved low toxicity polymerization of monomer reactants (PMR) system has 3,4'-oxydianiline as the key monomer reactant. One variation of this system, LaRC-RP46, is prepared by reacting together monomethyl ester or 5-norbornene-2,3-dicarboxylic acid (NE), 3,4'-oxydianiline (3,4'-ODA), and dimethyl ester of 3,3',4,4'-benzophenonetetracarboxylic acid (BTDE); this combination is then treated with heat. This new matrix resin is readily processed into a high quality graphite fiber reinforced composite with excellent reproducibility. The flexibility of the ether linkage in 3,4'-ODA provides high toughness. The composite retains excellent mechanical properties both at 316.degree. C. and at 371.degree. C. The development of LaRC-RP46 will significantly extend the applications of PMR type polyimides.

Abstract: Disclosed is an aromatic copolyimide film prepared by chemical conversion of a copolyamide acid solution obtained by copolymerization of an aromatic tetracarboxylic acid component comprising from 30 to 50 mole % of biphenyltetracarboxylic acid dianhydride, 50 to 70 mole % of pyromellitic acid dianhydride, 60 to 80 mole % of p-phenylenediamine and 20 to 40 mole % of 4,4'-diaminodiphenyl ether. The aromatic copolyimide film has a low coefficient of thermal expansion, low water absorption, a low coefficient of hygroscopic expansion, high mechanical strength and is readily etchable making it suitable for use an advanced electronic substrate.

Abstract: Soluble and/or fusible polyimides or polyamidoimides of the general formula I ##STR1## in which R denotes a divalent radical of the formula II ##STR2## Ar denotes trivalent or tetravalent aromatic radicals or mixtures thereof, X denotes the amide radical, if Ar is trivalent, and if Ar is tetravalent denotes the imide radical and R.sub.1 denotes divalent aromatic radicals, and a process for their preparation.

Abstract: Melt moldable polyamide-imide resins are disclosed which have a glass transition temperature ranging from 120.degree. to 300.degree. C. and have molecule ends blocked with an unsubstituted aromatic group or an aromatic group having a substituent not reactive with amines, isocyanates, carboxylic acids and dicarboxylic acid anhydrides.