Abstract: The present invention provides novel one-step processes for preparing highly branched macromolecule polymers that have highly controlled molecular architectures. The process comprises the reaction of a branching monomer such as a substituted phenyl compound having the formula: ##STR1## wherein R.sub.1, R.sub.2, and R.sub.3 are defined herein, with a core monomer and an end-capping monomer, such as a phenolic ester, for a sufficient period of time and at a sufficient temperature to directly produce the highly branched polymer, in a single processing step.

Abstract: A process for preparing molded articles of a polyimide is provided the steps of melting and extruding, at 50.degree. to 100.degree. C., a polyimide precursor composition for extrusion molding of a polyimide which includes 30 to 60% by weight of a polyimide precursor (c) obtained by reacting an aromatic tetracarboxylic dianhydride or its derivative (a) with an aromatic diamine or its derivative (b) in a good solvent of the polyimide precursor and then depositing the resultant polyimide precursor solution in a poor solvent of the polyimide precursor, 0.1 to 5% by weight of the poor solvent, and 35 to 69.9% by weight of the good solvent, and then heating the molded composition at 250.degree. to 500.degree. C. to imidate the same or its derivative (b) in a good solvent of the polyimide precursor and then depositing the resultant polyimide precursor (c) solution in a poor solvent of the polyimide precursor, 0.1 to 5% by weight of the poor solvent, and 35 to 69.

Abstract: A process for producing an aromatic polyamide film, which comprises the steps of: (a) forming a thin layer of an optically isotropic dope in which an aromatic polyamide is dissolved in a polar amide, (b) immersing the thin layer dope of aromatic polyamide in a polar solvent, other than said polar amide, kept at a temperature not higher than -20.degree. C. to prepare a film, and (c) drying the film. The aromatic polyamide film thus obtained is excellent in transparency. Said process requires neither a step of dissolving an aromatic polyamide in conc. sulfuric acid nor an acid-resistant equipment, and hence, is inexpensive.

Abstract: The invention relates to a polyamide-imide containing recurring units according to the formula ##STR1## where Y is an arylene group, andR and R' are alkylene groups, in which at least 50 mole % of R and/or R' is a butylene group.The polyamide-imides are semi-crystalline.They are suitable for injection moulding applications, structural moulded parts, films, coatings and fibres. They can preferably be used in fields of application where temperatures above 200.degree. C. occur.

Abstract: Unimolecular micelies, generally referred to as cascade polymers, are constructed via the addition of successive layers, or tiers, of designed monomers, or building blocks, that possess a predetermined, branched superstructure consisting of connected physical matter inherently defining an internal void volume or void area within the molecular framework. Each of the branches define a flexible arm from a central core atom and terminate with a hydrodynamic reactive group. A method is described for manipulating such cascade polymers.

Abstract: A class of soluble polymers having a rigid rod backbone, which when used to cast films, undergo a self-orientation process whereby the polymer backbone becomes more or less aligned parallel to the film surface. This in-plane orientation results in a film that displays negative birefringence. The degree of in-plane orientation and thus, the magnitude of the negative birefringence is controlled by varying the backbone linearity and rigidity of the class of polymers which includes polyesters, polyamides, poly(amide-imides) and poly(ester-imides) through selection of substituents in the polymer backbone chain. By increasing the polymer backbone linearity and rigidity, the degree of in-plane orientation and associated negative birefringence can be increased, and that conversely, by decreasing the polymer backbone linearity and rigidity, the negative birefringence can be decreased.

Abstract: A heat-resistant adhesive film, an adhesion structure obtained using the same, and an adhesion method using the same are disclosed, the film comprising a polyisoimide resin containing at least 40 mol % of an isoimide unit represented by formula (I): ##STR1## wherein R.sub.1 represents a tetravalent aromatic or aliphatic residue; R.sub.2 represents a divalent aromatic or aliphatic residue; and the arrow represents a bond replaceable on isomerization, in the molecule thereof. The isoimide unit of the polyisoimide resin is easily converted to an imide unit on heating, e.g., hot pressing with an adherend, to provide a cover-lay film or a single-sided or double-sided base for printed circuit boards having excellent adhesion, heat resistance, dimensional precision, and workability.

Abstract: A polyimide precursor having a molecular structure obtained by polymerizing (a) 0.97 to 1.03 molar equivalent of a diamine component containing 0.40 molar equivalent or more of aromatic diamine compound represented by the general formula (DA1), and (b) an acid anhydride component containing (1-n.sub.1 /2) molar equivalent of a tetracarboxylic dianhydride and n.sub.1 molar equivalent of at least one selected from the group consisting of maleic anhydride and maleic derivative anhydride, wherein n.sub.1 ranges from 0.02 to 0.40.

Abstract: Polyetheramidoamine hydrogels consisting of polyetheramidomaine and/or polyamidoamine prepolymers crosslinked by Michael's nuceophilic polyaddition with alpha-omega-diamino monomers or with alpha-omega-diamino monomers or oligomers; said hydrogels having a swelling degree in water higher than 500% and are useful as superabsorbent materials.

Abstract: Aromatic copolyamides, production thereof, formed structures and production thereofDescribed are aromatic copolyamides comprising the structural repeat units of the formulae I, II and III ##STR1## where Ar.sup.1, Ar.sup.2, Ar.sup.3 and Ar.sup.

Abstract: Controlled molecular weight phenylethynyl terminated imide oligomers (PETIs) have been prepared by the cyclodehydration of precursor phenylethynyl terminated amic acid oligomers. Amino terminated amic acid oligomers are prepared from the reaction of dianhydride(s) with an excess of diamine(s) and subsequently endcapped with phenylethynyl phthalic anhydride(s) (PEPA). The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide under nitrogen at room temperature. The amic acid oligomers are subsequently cyclodehydrated either thermally or chemically to the corresponding imide oligomers. Direct preparation of PETIs from the reaction of dianhydride(s) with an excess of diamine(s) and endcapped with phenylethynyl phthalic anhydride(s) has been performed in m-cresol. Phenylethynyl phthalic anhydrides are synthesized by the palladium catalyzed reaction of phenylacetylene with bromo substituted phthalic anhydrides in triethylamine.

Abstract: High-performance polymers having a rigid-rod backbone comprising a chain length of at least 25 organic monomer units joined together by covalent bonds wherein at least about 95% of the bonds are substantially parallel; and solubilizing organic groups attached to at least 1% of the monomer units. The polymers are prepared in a solvent system which is a solvent for both the monomer starting materials and the rigid-rod polymer product.

Abstract: Aromatic polyamide compositions with improved electrostatic properties, formed structures produced therefrom, and use and production thereof.Described are compositions comprising an aromatic polyamide which is soluble in organic solvents and from 0.01 to 30% by weight, based on the weight of the composition, of an organic or organometallic charge control agent.The compositions can be used for producing formed structures, in particular fibers; these fibers are preferably used for producing webs which can be used for producing dust filters.

Abstract: Novel poly(N-arylenebenzimidazole)s (PNABls) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl-N-arylenebenzimidazole) monomers are synthesized by reacting phenyl-4-hydroxybenzoate with bis(2-aminoanilino)arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyI-N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

Abstract: A polyamide precursor of a polybenzazole polymer is prepared by reacting an aromatic bis(alkenyl)ester with a ring forming, aromatic diamine. The precursor can be prepared in an organic solvent for the monomers to form a soluble polyamide precursor which can be subsequently cyclocondensed to form a PBX polymer. A polybenzoxazole precursor is prepared by the reaction of a bis(alkenyl)ester and a bis(ortho-hydroxyamine). A polybenzazole polymer is easily prepared by heating the polyamide, PBX precursor.

Abstract: A process for preparing polyamideimide resins having high molecular weights as described wherein major problems of prior art processes such as low heat resistance and low melt flowability are improved. Polyamideimide resins having an intrinsic viscosity of 0.4 to 1.50 dl/g as measured on a solution of dimethylacetamide as a solvent at a concentration of 0.5 g/dl at 30.degree. C., are prepared by reacting an aromatic tricarboxylic acid anhydride with an aromatic diamine in N-methyl pyrrolidone solvent in the presence of a first catalyst selected from a group consisting of thionyl chloride, p-toluenesulphonly chloride, sulfuryl chloride, cyanuric chloride and phosphorus trichloride at a temperature of 50.degree. C. to 130.degree. C. over a period of 1 to 5 hours and further reacting the resultant reaction mixture in the presence of a second catalyst which is a compound of the formula (RO).sub.

Abstract: Polysulfoneimide oligomers having crosslinking end cap moleties which provide improved solvent-resistance to cured composites are generally represented by backbones of the formula: ##STR1## wherein ##STR2## n=1 or 2; R and R' are divalent aromatic organic radicals having from 2-20 carbon atoms; ##STR3## E=allyl or methallyl; R=a trivalent C.sub.(6-13) aromatic organic radical;R.sub.1 =any of lower alkyl, lower alkoxy, aryl, or substituted aryl;R'=a divalent C.sub.(6-30) aromatic organic radical;j=0, 1, or 2; andG=--CH.sub.2 --, --O--, --S--, or --SO.sub.2 --The crosslinkable oligomers are made by reacting substituted phthalic anhydrides with hydroxyaryl amines and suitable crosslinking end cap reactants, or by self-condensation of phthalimide salts followed by capping the polymers.

Abstract: A copolymer consisting essentially of a repeating sequence represented by the formula ##STR1## where Ar.sub.1, Ar.sub.2, and Ar.sub.3, are each independently chosen from the group consisting of ##STR2## which are either unsubstituted or are substituted with one or more substituents chosen from the group consisting of alkyl groups having 1-6 carbon atoms, halogen (F, Cl or Br), and phenyl; Z, Y.sub.1 and Y.sub.2 are each independently O, NH, or S; n and m are positive integers; and X is a covalent bond, O, S, SO.sub.2, CO, C(C.sub.6 H.sub.5).sub.2, C(C.sub.6 H.sub.5)H, C(C.sub.6 H.sub.5)(CH.sub.3), C(CH.sub.3).sub.2, C(CH.sub.3)H, CH.sub.2, C(CF.sub.3).sub.2, or 3,3,5-trimethyl cyclohexyl. The polymers of this invention are derived from a minimum of three different monomers.

Abstract: A copolymer having repeating units of the formula: ##STR1## wherein R is selected from the group consisting of --H, --CH.sub.3, --N(CH.sub.3).sub.2 and --OH, x has a value of 0.01 to 0.99 and Q is ##STR2## wherein X is --S-- or --O--.

Abstract: This invention concerns positive-working photodefinable polyimide precursors which make use of chemical amplification based on photoacid catalyzed cleavage of acid labile-poly(amic acetal esters).

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: A crosslinkable polymer having repeating units of the formula: ##STR1## wherein Ar is selected from the group consisting of ##STR2## These polymers are useful in the preparation of molecular composites with rigid-rod polymers, including para-oriented benzobisazole polymers, such as benzobisthiazole, benzobisoxazole and benzobisimidazole polymers.

Abstract: A melt processable poly(ester-amide) which is capable of forming an anisotropic melt phase is provided. A poly(ester-amide) of the present invention may have recurring units of: (a) 4-hydroxybenzoyl moiety, (b) 6-oxy-2-naphthoyl moiety, (c) 4,4'-biphenol moiety, (d) terephthaloyl moiety, and (e) an aromatic moiety capable of forming an amide linkage in the proportions indicated. Preferably, the moiety capable of forming an amide linkage is derived from p-aminophenol, p-phenylenediamine, N-acetyl-p-aminophenol, etc. The resulting poly(ester-amide) is capable of undergoing melt-processing in the temperature range of from about 300.degree. to about 400.degree. C.

Abstract: This invention relates to a novel polyimide or polyimide copolymer having excellent heat resistance and greatly improved processability, and has a novel aromatic diamino compound used for the polyimide, a preparation process thereof, a polyimide-based resin composition comprising the polyimide or polyimide copolymer and a fibrous reinforcement, a process for preparing the resin composition, an injection molded article of the resin composition.The polyimide comprise a requisite structural unit having one or more recurring structural units of the formula: ##STR1## wherein L is an oxygen atom, carbonyl, isopropylidene or hexafluoroisopropylidene, and X is ##STR2## and Ar is a tetravalent radical having 6 to 27 carbon atoms and being selected from the group consisting of a monoaromatic radical, condensed polyaromatic radical and noncondensed polyaromatic radical having aromatic radicals connected to each other with a direct bond or a bridge member.

Abstract: Thermoplastically processable aromatic polyether amideThermoplastically processable aromatic polyether amide of the formula (I) ##STR1## in which the symbols Ar, Ar', Ar.sub.1, Ar.sub.2, R, R', Y, x, y and z have the following meanings:Ar is a divalent, substituted or unsubstituted, aromatic or heteroaromatic radical or a group--Ar*--Q--Ar*--in whichQ is a bond or an --O--, --C(CH.sub.3).sub.2, --CO--, --S--, --SO-- or --SO.sub.2 -- bridge and Ar* is an aromatic radical. The carbonyl groups of the Ar radical are on non-adjacent ring carbon atoms.A is up to three different radicals.Ar' has the meaning given for Ar or is an Ar--Z--Ar group.In this case, Z is a --C(CH.sub.3).sub.2 -- or --O--Ar*--O--bridge.Y is a --C(CH.sub.3).sub.2 --, --SO.sub.2 --, --S-- or a --C(CF.sub.3).sub.2 --bridge and has up to two different meanings in the same polymer.Ar.sub.1 and Ar.sub.2 are identical or different from one another and are each a substituted or unsubstituted para- or meta-arylene radical.

Abstract: Disclosed is a thermally-stable SnO.sub.2 -surfaced polyimide film wherein the electrical conductivity of the SnO.sub.2 surface is within the range of about 3.0.times.10.sup.-3 to about 1.times.10.sup.-2 ohms.sup.-1,. Also disclosed is a method of preparing this film from a solution containing a polyamic acid and SnCl.sub.4 (DMSO).sub.2.

Abstract: Disclosed are bis-meta-benzotrifluoride compounds having the general formula ##STR1## where each A is independently selected from the group consisting of NO.sub.2, NH.sub.2, and NH.sub.3.sup.+ Z.sup.-, Z.sup.- is an anion and B is selected from the group consisting of O, CO, S, SO, and SO.sub.2. The diamine compounds are useful as monomers in making polyimides, polyamide-imides, and polyamides.

Abstract: Alcohol-soluble aromatic heterocyclic copolymers having repeating units of the formula: ##STR1## wherein x has a value of 0.05 to 0.50 and y has a value of 1.0-x. These copolymers are useful in the preparation of organic/inorganic hybrid materials having transparency which comprise the sol-gel derived, hydrolytically condensed reaction product of a metal alkoxide of the formula M(OR).sub.w wherein R is a lower alkyl group, M is Si, Ti, Al or a mixture thereof, and w is the valence value of M, and the above copolymer.

Abstract: Polyimides comprising recurring units of the following general formula (1) ##STR1## wherein Ar.sub.1 represents a tetravalent aromatic group and each Ar.sub.2 represents a divalent aromatic group. Polyimide copolymers and preparations of the polyimides and the polyimide copolymers are also described.

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: Polyimide polymers of the following recurring structure and the corresponding polyamic acids are disclosed: ##STR1## wherein AR.sub.1 is ##STR2## where X is O, S, SO, SO.sub.2, CO, C(CF.sub.3).sub.2, C(CH.sub.3).sub.2, Si(CH.sub.3).sub.2, or a single bond, wherein AR.sub.2 may be pyromellitic dianhydride, a substituted pyromellitic dianhydride, naphthanoic dianhydride, or ##STR3## where Y is O, S, SO, SO.sub.2, CO, C(CF.sub.3).sub.2, C(CH.sub.3).sub.2, Si(CH.sub.3).sub.2 --O--AR--O--, or a single bond, where AR is an aromatic nucleus.

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: This invention relates to a novel thermoplastic and amorphous polyimide which is readily soluble in organic solvent, a novel aromatic diamino compound used for the polyimide, a preparation process thereof, a polyimide-based resin composition comprising the thermoplastic polyimide and a fibrous reinforcement, a process for preparing the resin composition, an injection molded article of the resin composition, a polyimide-based composite obtained by molding the above soluble and thermoplastic polyimide in combination with a fibrous reinforcement, and a fibrous reinforcement having a surface modified with the above polyimide.

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: Polyimides comprising recurring units of the following general formula (1) ##STR1## wherein R.sub.1 represents a tetravalent aromatic group. Polyimide copolymers and preparations of the polyimides and the polyimide copolymers are also described.

Abstract: Polyimide oligomers are described which comprise the condensation product of: at least one phenylindane diamine and at least one aromatic bis(ether anhydride). The polyimide oligomers of the invention are readily processed to form solution prepregable polyimide composites having high glass transition temperatures and high temperature and oxidative stability. More particularly, the present invention provides for crosslinkable polyimide oligomers prepared by reacting, in a suitable solvent under an inert atmosphere, a mixture of monomers comprising: (A) an aromatic diamine component comprising from about 25 to 100 mole % of at least one phenylindane diamine; (B) a dianhydride component comprising from about 25 to 100 mole % of at least one aromatic his(ether anhydride); and (C) at least one end-cap monomer selected from the group consisting of monoanhydrides, acyl halides and aromatic amines, wherein each end-cap monomer contains at least one crosslinkable functional group in the molecule.

Abstract: Copolyimides from 1,4-bis(4-aminophenoxy)-2-phenylbenzene and m- or p-phenylene diamine with biphenyl dianhydride exhibit a high Tg and reduced melt viscosity.

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: This invention relates to a novel fluorine-containing polyimide or polyimide copolymer being colorless and having transparency and very low dielectric characteristics, and has a novel aromatic diamino compound used for the polyimide, a preparation process thereof, a polyimide-based resin composition comprising the polyimide or polyimide copolymer and a fibrous reinforcement, a process for preparing the resin composition, an injection molded article of the resin composition.

Abstract: Copolyamic acid is obtained from tetracarboxylic acid dianhydride, diamine and a fluorinated diamine and/or fluorinated tetracarboxylic acid dianhydride; and optionally ester or amine salt derivative thereof to obtain radiation sensitive polymer; and low optical high thermally stable polyimide from curing the above polyamic acid and/or derivative thereof.

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: This invention provides (1) a granular material of a polyimide precursor, which has excellent solubility in solvents and excellent moldability and from which a polyimide molding having excellent mechanical properties can be produced, (2) a mixture of a granular material of a polyimide precursor with a solvent, in which the polyimide precursor shows excellent storage stability and (3) a process for the production of a granular material of a polyimide precursor, in which a solvent can be easily removed. Particularly provided are a polyimide precursor granular material having an intrinsic viscosity of 0.7 or higher and a polyimide precursor mixture which consists of a polyimide precursor granular polyimide having an intrinsic viscosity of 0.7 or higher and a solvent that does not exhibit a strong-mutual interaction with the polyimide precursor, as well as a process for the production of the polyimide precursor granular material.

Abstract: Aramids which after drawing have high tensile strengths and tensile moduli are made from units derived from selected 2,2'-disubstituted-4,4'-diaminobiphenyls, p-phenylenediamine, oxydianiline and terephthalic acid. Also disclosed is a process for drawing such aramids at least 1.5%, which results in the drawn aramid having significant crystallinity and higher tensile strength. The aramids are useful for ropes and composites.

Abstract: A nonlinear optical material composed of a polyimide obtained from a diamine and/or a diacid anhydride or dithioacid anhydride substituted by a portion having a nonlinear optical effect or of molecules having a benzocyclobutene structure substituted at the portions having an nonlinear linear optical effect.

Abstract: Two monomers containing meta-biphenylenedioxy moieties were prepared. One monomer, a diamine, is used to prepare polyimide, polyamide, and epoxy polymers. The other monomer, a dianhydride, was used to prepare polyimide polymers. These polymers are used to make films, coatings, and selective membranes.

Abstract: The present invention relates to a polymeric film in-line coated with polyamido-polyethyleneimine to render the film receptive to direct extrusion coating with other polymers or to ink adhesion and to a method of making the same. Additionally, the present invention relates to an oriented polymeric film which has been in-line coated with polyamido-polyethyleneimine so that it has anti-static properties for other packaging applications.

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 optical material, composed of a perfluorinated polyimide having a perfluorinated repeating unit represented by general formula (1) ##STR1## wherein R.sub.1 is a tetravalent perfluorinated organic group; and R.sub.2 is a divalent perfluorinated organic group.

Abstract: Soluble polyimides are formed from oxydiphthalic anhydride and 2,4-diaminotoluene. Optionally, up to 30 mole % of an alternate diamine and up to 50 mole % of an alternate dianhydride can be used with the oxydiphthalic anhydride and 2,4-diaminotoluene.

Abstract: Polyimides are made from the novel diamines 1,2-bis(3-aminophenyl)perfluorocyclobutane, 1,2-bis(3- or 4-aminophenyl)perfluorocyclobutene, -cyclopentene and -cyclohexene, by reaction with aromatic carboxylic anhydrides. The polyimides are useful for coatings and films.