Abstract: Polyimide soluble in an organic polar solvent was prepared by heating the solution in the presence of a binary catalyst having low boiling point. Block copolyimides consisting of more than three components were prepared by the sequential addition process in the presence of the binary catalyst. Polyimide resins were prepared without the separation of polyimides and catalysts because of evaporating consequently catalysts and solvent. The binary catalyst comprise one compound selected from .gamma.-valerolactone and crotonic acid, and one compound selected from pyridine and N-methylpyrrolidone.

Abstract: A copolyimide was prepared by reacting 3,4'-oxydianiline (3,4'-ODA) with a dianhydride blend comprising, based on the total amount of the dianhydride blend, about 67 to 80 mole percent of 4,4'-oxydiphthalic anhydride (ODPA) and about 20 to 33 mole percent of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA). The copolyimide may be endcapped with up to about 10 mole percent of a monofunctional aromatic anhydride and has unbalanced stoichiometry such that a molar deficit in the dianhydride blend is compensated with twice the molar amount of the monofunctional aromatic anhydride. The copolyimide was used to prepare composites, films and adhesives. The film and adhesive properties were significantly better than those of LaRC.TM.-IA.

Abstract: A polyimide represented by the general formula (1): ##STR1## wherein Y represents a hydrocarbon group having 4 to 20 carbon atoms or a sulfur atom; each of R.sub.1 to R.sub.4, R.sub.i and R.sub.j represents a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms or a halogen-containing hydrocarbon group having 1 to 6 carbon atoms; each of a, b, c, d, e and f represents an integer of 0 to 4 satisfying a+b.ltoreq.4, c+d.ltoreq.4 and e+f.ltoreq.4; and X represents a tetravalent organic group having 2 or more carbon atoms.

Abstract: A negative birefringent film, useful in liquid crystal displays, and a method for controlling the negative birefringence of a polyimide film is disclosed which allows the matching of an application to a targeted amount of birefringence by controlling the degree of in-plane orientation of the polyimide by the selection of functional groups within both the diamine and dianhydride segments of the polyimide which affect the polyimide backbone chain rigidity, linearity, and symmetry. The higher the rigidity, linearity and symmetry of the polyimide backbone, the larger the value of the negative birefringence of the polyimide film.

Abstract: A solvent resistant copolyimide was prepared by reacting 4,4'-oxydiphthalic anhydride with a diaimine blend comprising, based on the total amount of the diamine blend, about 75 to 90 mole percent of 3,4'-oxydianiline and about 10 to 25 mole percent p-phenylene diamine. The solvent resistant copolyimide had a higher glass transition temperature when cured at 350.degree. , 371.degree. and 400.degree. C. than LaRC.TM.-IA. The composite prepared from the copolyimide had similar mechanical properties to LaRC.TM.-IA. Films prepared from the copolyimide were resistant to immediate breakage when exposed to solvents such as dimethylacetamide and chloroform. The adhesive properties of the copolyimide were maintained even after testing at 23.degree., 150.degree., 177.degree. and 204.degree. C.

Abstract: A polyimide precursor composition solution includes a tetracarboxylic acid component containing not less than 70 mol % of at least one selected from the group consisting of benzenetetracarboxylic acid and its reactive derivatives; a maleimide compound; and a diamine component containing not less than 70 mol % of 2,2'-substituted-4,4'-benzidine represented by the general formula (I) and siloxydiamine amounting to from 1 to 10 mol %. The tetracarboxylic acid component, the maleimide compound and the diamine component are dissolved in a solvent which is consisting essentially of .gamma.-butyrolactone. The amount of the tetracarboxylic acid component is substantially equivalent to that of the diamine component. The amount of the maleimide compound is from 5 to 30 wt % of the total weight of the tetracarboxylic acid and the diamine component.

Abstract: A photosensitive resin composition comprising, as its main ingredient, a poly(amic acid) resin constituted of a diamino compound represented by formula: ##STR1## and optionally used other diamino compound and a tetracarboxylic acid dianhydride as its constituent monomers and/or a poly(amic acid) ester resin obtained by esterifying said poly(amic acid) resin and/or a polyimide resin obtained by a dehydrating or alcohol-eliminating ring-closure reaction of said poly(amic acid) resin or poly(amic acid) ester resin has an excellent developability and a high film strength and can form a relief patter of low thermal expansion.

Abstract: The invention is a direct process for preparing semi-crystalline polyimides. This process comprises the steps of: providing a polar aprotic solvent, adding a dianhydride and a diamine to the solvent to form a mixture, stirring the mixture at ambient temperature, and adding glacial acetic acid to the mixture to provide a ratio of polar aprotic solvent to glacial acetic acid which ranges from about 90 to 10 to about 75 to 25 by volume to form a solution. The solution was heated to a range from about 110.degree. C. to about 140.degree. C. to form a polyimide precipitate. The polyimide precipitate was recovered as a semi-crystalline polyimide powder.

Abstract: A method for forming a homogeneous, concentrated, prepolymer composition, and a method of using the concentrated prepolymer composition to uniformly coat fibers is described. The prepolymer mixture is formed by dissolving a dialkyl, trialkyl, or tetraalkylester of biphenyltetracarboxylic acid in a solvent comprising ethyl acetate and methanol in a molar ratio of from about 1:3 to about 1:60, to form an ester solution. Diamine and end cap compound are added to the ester solution to form a monomer mixture solution. The end cap compound is a divalent compound characterized by (i) at least one unsaturated moiety, (ii) capable of reacting with the diamine or the ester to form an end cap radical that precludes further reaction of the diamine with the ester, and (iii) capable of undergoing addition polymerization. A portion of the solvent is evaporated from the monomer solution to form the substantially homogeneous, concentrated, prepolymer composition.

Abstract: A method for forming a homogeneous, concentrated, prepolymer composition, and a method of using the concentrated prepolymer composition to uniformly coat fibers is described. The prepolymer mixture is formed by dissolving a dialkyl, trialkyl, or tetraalkylester of biphenyltetracarboxylic acid in a solvent comprising ethyl acetate and methanol in a molar ratio of from about 1:3 to about 1:60, to form an ester solution. Diamine and end cap compound are added to the ester solution to form a monomer mixture solution. The end cap compound is a divalent compound characterized by (i) at least one unsaturated moiety, (ii) capable of reacting with the diamine or the ester to form an end cap radical that precludes further reaction of the diamine with the ester, and (iii) capable of undergoing addition polymerization. A portion of the solvent is evaporated from the monomer solution to form the substantially homogeneous, concentrated, prepolymer composition.

Abstract: A polyimide varnish which is a solution having a polyimide and/or a polyimide precursor dissolved in an organic solvent and which is useful for forming a polyimide coating film on a substrate by coating the solution on the substrate followed by heat treatment, wherein from 5 wt % to 60 wt % of the organic solvent is a lactic acid derivative of the formula (I): ##STR1## wherein each of R.sup.1 and R.sup.2 which are independent of each other, is hydrogen, a C.sub.1-5 alkyl group or a C.sub.1-5 alkenyl group.

Abstract: Novel compounds having use as contrast agents in magnetic resonance imaging, as well as other uses, are described. The compounds are comprised of a copolymer which comprises at least two of a first monomer of the formula X.sub.1 --(CHR.sub.2 CHR.sub.2 -Y).sub.n -(CHR.sub.2).sub.m --CHR.sub.2 CHR.sub.2 13 X.sub.2, wherein X.sub.1 and X.sub.2 are, independently, OH, NH.sub.2, NHR.sub.1, COOH, COOR.sub.1, SH, or Z, Y is O, NH, NR.sub.1, S, or CO, n is 0-10,000, m is 0 or 1, each Z is, independently, Cl, Br, or I, each R.sub.1 is, independently, a C.sub.1 -C.sub.20 substituted alkyl or cycloalkyl, and each R.sub.2 is, independently, H or OH, and at least one of a second monomer which is a polynitrilo chelating agent having at least two COOH, COOR.sub.1, or COZ groups, the first and second monomers being bound to one another to form a copolymer through an ester, amide, or carboxylic thioester linkage of at least one of the OH, NH.sub.2, NHR.sub.1, COOH, COOR.sub.

Abstract: A diamine compound of the general formula ##STR1## wherein the arrows denote isomerism, R.sub.1 is a divalent aromatic group selected from the group consisting of ##STR2## R.sub.2 is a tetravalent aromatic group selected from the group consisting of ##STR3## and R.sub.4 is a monovalent aliphatic group selected from the group consisting of ethyl and isopropyl; and, a process for preparing same.

Abstract: A method for forming a homogeneous, concentrated, prepolymer composition, and a method of using the concentrated prepolymer composition to uniformly coat fibers is described. The prepolymer mixture is formed by dissolving a dialkyl, trialkyl, or tetraalkylester of biphenyltetracarboxylic acid in a solvent comprising ethyl acetate and methanol in a molar ratio of from about 1:3 to about 1:60, to form an ester solution. Diamine and end cap compound are added to the ester solution to form a monomer mixture solution. The end cap compound is a divalent compound characterized by (i) at least one unsaturated moiety, (ii) capable of reacting with the diamine or the ester to form an end cap radical that precludes further reaction of the diamine with the ester, and (iii) capable of undergoing addition polymerization. A portion of the solvent is evaporated from the monomer solution to form the substantially homogeneous, concentrated, prepolymer composition.

Abstract: An agent for alignment treatment for a liquid crystal cell, which comprises an organic solvent-soluble polyimide obtained by reacting and polymerizing a tetracarboxylic acid component with a diamine component and a dicarboxylic acid component containing a long chain alkyl group and/or a monoamine component containing a long chain alkyl group, followed by imide-formation.

Abstract: The present invention relates to an improved process for making polyamic ester comprising reacting an aromatic diester diacid halide with the monohydrohalide salt of an aromatic diamine in the presence of a base. The polyamic ester can be imidized to form a polyimide suitable for use in electronic components.

Abstract: The invention describes new biphenyl dianhydrides, and new polyimides and copolyimides made from the dianhydrides. The synthesized polyimides exhibit significantly enhanced solubility when the biphenyl dianhydrides are substituted, particularly at the 2 and 2' positions on the phenyl rings.

Abstract: A random polyimide copolymer, based on a rigid dianhydride, a rigid diamine and an additional diamine and/or dianhydride containing one or more flexibilizing linkages. Soft-baked coatings of the poly(amic acid) precursor are readily processed using conventional aqueous base developers, such as tetramethylammonium hydroxide. The polyimide and soft-baked coatings are useful as a dielectric layer In multichip module applications or as a stress buffer coating.

Abstract: Novel compounds having use as contrast agents in magnetic resonance imaging, as well as other uses, are described. The compounds are comprised of a copolymer which comprises at least two of a first monomer of the formula X.sub.1 --(CHR.sub.2 CHR.sub.2 --Y).sub.n --(CHR.sub.2).sub.m --CHR.sub.2 CHR.sub.2 --X.sub.2, wherein X.sub.1 and X.sub.2 are, independently, OH, NH.sub.2, NHR.sub.1, COOH, COOR.sub.1, SH, or Z, Y is O, NH, NR.sub.1, S, or CO, n is 0-10,000, m is 0 or 1, each Z is, independently, Cl, Br, or I, each R.sub.1 is, independently, a C.sub.1 -C.sub.20 substituted alkyl or cycloalkyl, and each R.sub.2 is, independently, H or OH, and at least one of a second monomer which is a polynitrilo chelating agent having at least two COOH, COOR.sub.1, or COZ groups, the first and second monomers being bound to one another to form a copolymer through an ester, amide, or carboxylic thioester linkage of at least one of the OH, NH.sub.2, NHR.sub.1, COOH, COOR.sub.

Abstract: A process for preparing polyimide fibers involves the preparation of a polymer in p-chlorophenol from reactants comprising 2,2'-dimethyl-4,4'-diaminobiphenyl and a tetracarboxylic anhydride. Following its preparation, the polyimide fibers can be spun directly from the reaction mixture. In a preferred embodiment, the dianhydride comprises 3,3',4,4'-biphenyltetracarboxylic dianhydride.

Abstract: Amorphous polyimide powder which has recurring structural units of the formula (I): ##STR1## as a fundamental skeleton, is blocked at the polymer chain end with dicarboxylic anhydride represented by the formula (II) ##STR2## wherein Z is a divalent radical having from 6 to 27 carbon atoms and selected from the group consisting of a monoaromatic radical, condensed polyaromatic radical and noncondensed aromatic radical connected to each other with a direct bond or a bridge member, and essentially has no reactive radical at the polymer chain end, preparation process of the amorphous polyimide powder, heat-resistant adhesive comprising the polyimide, and bonding method using the adhesive.

Abstract: A diamine compound of the general formula ##STR1## wherein the arrows denote isomerism, R.sub.1 is a divalent aromatic group selected from the group consisting of ##STR2## R.sub.2 is a tetravalent aromatic group selected from the group consisting of ##STR3## and R.sub.4 is a monovalent aliphatic group selected from the group consisting of ethyl and isopropyl; and, a process for preparing same.

Abstract: A polyimide comprising a requisite structural unit having one or more recurring structural units of the formula: ##STR1## such as the structural units of the formula ##STR2## The polyimide can have an extremely low dielectric constant and is colorless, transparent and excellent in processability and heat resistance, and also provides an aromatic diamine which is useful as a raw material monomer of the polyimide or a raw material of other various engineering plastics.

Abstract: Functional-amine polyesters have at least a first residue of a first monomer, a second residue of a second monomer and from about 0.1 to about 3.0 mole percent of a functional-amine residue of a functional amine prepared by reacting the first and second monomers and the functional amine in an inert atmosphere. The functional amine has a functional group which facilitates polymerizing the amine and the first and second monomers. The amine residue facilitates reaction of the functional-amine polyester in an organic peroxide cross-linking reaction system.

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: Copolyimide compositions and methods for their preparation which are melt-processible at relative low pressures, i.e. less than 1000 psi, and are suited for laminating and molding, are described. The invention additionally encompasses copolyimide precursors, reinforced polyimide composites and laminates made from said polyimides where the composite is reinforced by fibrous materials. This is achieved by reacting at least one aromatic dianhydride where each anhydride group is located on an aromatic ring with the carbonyl units in an ortho orientation relative to one another, with at least one diamine which is capable of a transmidization reaction upon incorporation into the polyimide backbone, and with at least one other diamine which is not capable of undergoing such reaction, the diamine which is capable of undergoing the transimidization reaction being present in an amount of from about 1-50 mole percent in relation to the diamine that is not susceptable to transimidization.

Abstract: Addition polyimide resins having improved thermo-oxidative stability and enhanced processability are prepared by the reaction of a mixture of monomers comprising a non-planar polyphenyl diamine (a), a diester of tetracarboxylic acid or the corresponding dianhydride (b) and an end-capping agent (c), or a diamine (d), a non-planar polyphenyl diester or dianhydride of a tetracarboxylic acid (e) and an end-capping agent (c).

Abstract: A thermoplastic resin composition comprise 99.9.about.50 parts by weight of one or more thermoplastic resin selected from the group consisting of aromatic polyimide, aromatic polyetherimide, aromatic polyamideimide, aromatic polyethersulfone and aromatic polyether ketone and 0.1.about.50 parts by weight of one or more liquid crystal type aromatic polyimide having recurring structural units represented by the formula (1): ##STR1## wherein R.sub.1 .about.R.sub.5 is a hydrogen atom, fluorine atom, trifluoromethyl, methyl, ethyl or cyano and may be the same or different, and R is a tetravalent radical having 6.about.27 carbon atoms and being selected from the group consisting of a monoaromatic radical, condensed polyaromatic radical and noncondensed aromatic radical connected each other with a direct bond or a bridge member.

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: Polyimide optical waveguide structures comprising a core within a cladding wherein at least one of the core and the cladding is a polyimide containing 6FDA, BTDA, an aromatic diamine having bulky methyl groups ortho to the amine, and a co-diamine wherein the polyimides have the properties of low optical loss, low optical absorbance, controllable refractive index, and high thermal stability, and wherein the polyimides are photosensitive and solvent resistant.

Abstract: A photosensitive polyimide precursor composition containing as main ingredients a poly(amic acid) wherein at least one molecular end is esterified with an alcohol, a compound containing carbon-carbon unsaturation having photoreactivity, and a photopolymerization initiator.The photosensitive polyimide precursor composition of the present invention can be prepared without the formation of any harmful by-product. When film formed from this composition is masked for patterning and then subjected to exposure and development using a developer, the amount of exposed portion dissolved in the developer until unexposed portion is dissolved off by the developer, is small and so it is possible to obtain a thick pattern. Further, by heat-treating this pattern, there can be obtained a thick polyimide pattern.

Abstract: An improved method of laminating a metal foil or sheet to a polyimide material is provided. A solution of a precursor of an intractable (i.e. thermosetting) polyimide is applied to a substrate and the solvent is removed to form a dry tack-free film. Thereafter, a solution of a precursor of a thermoplastic polyimide is applied onto the first film of polyimide and the solvent is removed to form a dry tack-free second film. Both films are then cured concomitantly at a sufficiently rapid rate and low temperature to effect substantial imidization of the polyimide precursors of both films without substantial crosslinking or densification of the polyimides in either of the films. Thereafter, a metal sheet or foil is laminated onto the thermoplastic polyimide film according to the following process. The thermoplastic film is contacted with the sheet or foil of metal to be laminated thereto.

Abstract: Novel polyimides containing pendent siloxane groups (PISOX) were prepared by the reaction of functionalized siloxane compounds with hydroxy containing polyimides (PIOH). The pendent siloxane groups on the polyimide backbone offer distinct advantages such as lowering the dielectric constant and moisture resistance and enhanced atomic oxygen resistance. The siloxane containing polyimides are potentially useful as protective silicon oxide coatings and are useful for a variety of applications where atomic oxygen resistance is needed.

Abstract: A silicon-modified, adhesive polyimide film composed mainly of the repetition units of the formula (I) and a process for producing a polyimide film composite product using the above film are provided, the formula (I) being ##STR1## the above process for producing a polyimide film composite product comprising subjecting the above-silicon-modified polyimide film to contact-bonding on heating to a material to be adhered, at an ultimate curing temperature of 130.degree.-230.degree. C.The above polyimide film is highly adhesive and heat-resistant in spite of heating at a relatively low temperature.

Abstract: The present invention relates to a liquid crystal alignment treating agent which comprises a polyimide resin prepared from a diamine including an aromatic diamine having at least one linear alkyl group of at least 6 carbon atoms per benzene ring as the essential component and a tetracarboxylic acid and its derivative.The liquid crystal alignment treating agent obtained in accordance with the present invention comprises a polyimide resin having an alkyl group on a side chain, and accordingly provides a liquid crystal-aligned film containing liquid crystal molecules stably having an enhanced inclined alignment angle (tilt angle) to a substrate.

Abstract: The present invention provides a dehydrating agent which is less poisonous and which can be easily handled in producing a polyisoimide by dehydrating a polyamic acid. A process is also provided for producing a polyisoimide without requiring the separation of by-products.That is, the process for producing the polyisoimide of the present invention includes the step of using a dihyroquinoline derivative represented by the formula ##STR1## (wherein each R.sup.1 and R.sup.2 is independently a monovalent organic group having 1 to 8 carbon atoms) as the dehydrating agent in producing the polyisoimide by dehydrating the polyamic acid.

Abstract: Aromatic polyimides with acetylenic end groups are cured by coupling together thermally or catalytically using cuprous salts as catalysts to increase molecular weight with little or no by-product formation. These polyimides can be shaped and formed prior to the coupling.The acetylenic end-capped aromatic polyimides are formed by the reaction of an aromatic dianhydride, an acetylenic organic monoamine compound which will provide the reactive end groups and optionally an aromatic diamine.

Abstract: A method of producing a multiphase polymer is disclosed whereby the phases have the same chemical structure but have different morphological states and thus different properties. This is achieved by forming a mixture of precursors of the polymer, at least one of the precursors having a reaction rate higher than the other precursor or precursors in the mixture. The precursor having the highest reaction rate is then converted to obtain a composite of a polymer and the precursors that are not polymerized. This mixture might also be formed by mixing a soluble polymer with its precursor.

Abstract: In one aspect, the present invention relates to polyimides having excellent thermal resistance and process for preparing the same comprising carrying out condensation of 4,4'-bis(3-aminophenoxy)biphenyl with pyromellitic dianhydride in the presence of a different diamine compound and optionally with a different tetracarboxylic acid dianhydride.In a second aspect, the present invention relates to a heat resistant resin composition consisting essentially of an aromatic polyetherimide and a defined polyimide.In a third aspect, the present invention relates to a polyimide resin composition comprised on a defined polyimide and a separate high-temperature engineering polymer.In a fourth aspect, the present invention relates to a resin composition comprised of a defined polyimide and an aromatic polyamideimide.

Abstract: A thermally stable polyimide which is blocked at the polymer terminal with a dicarboxylic acid anhydride represented by the formula (III): ##STR1## wherein Z is a divalent radical selected from the group consisting of a monoaromatic radical which is substantially unsubstituted or substituted with a radical having no reactivity with amine or dicarboxylic acid anhydride and has from 6 to 15 carbon atoms, a condensed polyaromatic radical or a noncondensed aromatic radical connected each other with a direct bond or a bridge member, and has a fundamental skeleton represented by recurring structural units of the formula (IV): ##STR2## and a process of preparing the polyimide.

Abstract: A readily processable polyimide being blocked at the terminal of a polymer molecule with a divalent radical derived from dicarboxylic acid anhydride represented by the formula (IV): ##STR1## wherein Z is a divalent radical selected from the group consisting of a monoaromatic radical which is substantially unsubstituted or substituted with a radical having no reactivity with amine or carboxylic acid anhydride and has from 5 to 15 carbons atoms, condensed polyaromatic radical or noncondensed aromatic radical connected each other with a direct bond or a bridge member, and having a fundamental skeleton represented by recurring structural units of the formula (III): wherein X and Y are --O-- or --CO-- and differ each other; preparation process of the polyimide; and resin composition containing the polyimide and fibrous reinforcement.

Abstract: Heat-resistant bonding materials are composed of a polyimide precursor end-capped at molecule ends thereof and/or an imide compound formed from the polyimide precursor. They may also contain fine particles of at least one material selected from metals, metal oxides, metal carbides and metal nitrides.

Abstract: A liquid crystal aligning agent containing a polymer selected from the group consisting of a polyamic acid having a steroidal skeleton and an imidized product thereof; and a liquid crystal display device to which the liquid crystal aligning agent is applied.

Abstract: The present invention provides a polyimide having all of small dielectric constant, small thermal expansion coefficient, high heat resistance, high glass transition temperature and high mechanical properties, a precursor of the polyimide, and processes for producing them. A polyimide precursor whose molecular chain comprises repeating units represented by the following general formula (1) and repeating units represented by the following general formula (2): ##STR1## wherein R.sup.1 is at least one kind of tetravalent organic group selected from the group consisting of ##STR2## R.sup.2 is at least one kind of divalent organic group having a linear structure which is selected from the group consisting of ##STR3## m is an integer of 1 to 4, and R.sup.3 is a divalent organic group having a non-linear structure which contains at least two aromatic rings.

Abstract: A readily melt-processable polyimide obtained by reacting diamino-diphenyl ether with 3,3',4,4'-biphenyltetracarboxylic dianhydride in the presence of phthalic anhydride and thermally or chemically imidizing the resultant polyamic acid.

Abstract: Processes for producing oriented films of semicrystalline thermoplastic polymers, such as polyimides, and films produced thereby are disclosed. One process includes partial crystallization or imidization, orientation and further crystallization or imidization. Another process includes rendering a film of semicrystalline thermoplastic polymer amorphous, orienting the film and introducing crystallinity.

Abstract: A process for preparing a polyetherimide-polyimide copolymer by (a) reacting a bis (ether anhydride) with a stoichiometric excess of an organic diamine in an inert, non-polar solvent to form an amine-terminated oligomer-solvent mixture; (b) removing unreacted organic diamine from the oligomer-solvent mixture; and (c) reacting the oligomer with an aromatic dianhydride.

Abstract: A terminal-modified imide oligomer composition, comprising(A) 100 parts by weight of a terminal-modified imide oligomer obtained by a reaction in a solvent of a biphenyltetracarboxylic acid compound with an aromatic diamine compound and a monoamine compound containing a carbon-carbon triple bond, and having an unsaturated terminal group at the terminal of the oligomer and an imide bond in the oligomer, and having a logarithmic viscosity number at 30.degree. C., as determined at a concentration of 0.5 g/100 ml of N-methyl-2-pyrrolidone as a solvent, of from 0.1 to 1 and;(B) 5 to 180 parts by weight of an unsaturated imide compound obtained by a reaction in a solvent of a substituent-containing nadic anhydride with a monoamine compound having a carbon-carbon triple bond in an equimolar ratio, and having an unsaturated terminal group at the terminal thereof and an imide bond therein.

Abstract: Polyetherketoneimides and copolymers thereof having an imide repeat unit of formula ##STR1## wherein Ri is ##STR2## in which A is a direct bond or --O--or another substantially non-electron-withdrawing group, and/or Ra is an at least partly arylene moiety other than m- or P-phonylene.These polymers tend to have improved melt stability and other properties, especially when made from a pre-existing imide monomer, instead of by the known amic acid route which results in uncyclised amic acid residues in the polymer.

Abstract: A composition for the application of a planar polymide coating having a glass transition temperature above 300.degree. C. comprises a solution in an anhydrous, aprotic solvent of .Iadd.the reaction product .Iaddend.of an aromatic diamine and a .[.dialkyldihydrogen.]. .Iadd.dialkyl .Iaddend.pyromellitate .Iadd.diacyl chloride .Iaddend.which .[.is more than.]. .Iadd.comprises about .Iaddend.90% .Iadd.or more .Iaddend.meta isomer.