Abstract: Thermomechanical and thermo-oxidative stabilities in resin composites across the range of aerospace "engineering thermoplastic" resins are improved by forming four crosslinks at each addition polymerization site in the backbone of the resin using crosslinking functionalities of the general formula: ##STR1## wherein Z= ##STR2## .beta.=the residue an organic radical selected from the group consisting of: ##STR3## R.sub.R =a divalent organic radical; X=halogen;Me=methylT=allyl or methallyl.G=--CH.sub.2 --,--S--, --CO--, --SO--, --O--, --CHR.sub.3 --, or --C(R.sub.3).sub.2 --;i=1 or 2;R.sub.3 =hydrogen, lower alkyl, lower alkoxy, aryl, or aryloxy; and.theta.=--C.tbd.N, --O--C.tbd.N, --S--C.tbd.N, or --CR.sub.3 .dbd.C(R.sub.3).sub.

Abstract: The disclosure describes a process for preparing a polyamideimide resin having high molecular weight in a simple manner wherein major problems of the prior processes such as low heat resistance and low melt flowability are improved. The process comprises condensation of an aromatic tricarboxylic acid anhydride and an aromatic diamine in a polar solvent, subjecting the resulting diimidedicarboxylic acid to acyl halogenating agent treatment to give an intermediate having good reactivity at low temperature, and then subjecting the latter to direct polymerization by using diamine as a nucleophilic agent to give a polyamideimide resin having high molecular weight. The polyamideimide resin prepared by the present invention can be used as major heat resistant structural material in advanced industries and as paint, sheet, adhesives, sliding material, fiber and film having heat resistance.

Abstract: Methylenedianiline-free, PMR-type, curable compositions based on m-phenylenediamine or mixtures of m-phenylenediamine and p-phenylenediamine are described.

Abstract: Regiospecific polyamide-imides are cast to form membranes which exhibit superior gas separation properties when compared to polyamide-imide membranes formed from random copolymers. The regiospecific polyamide-imides are synthesized by reacting specific aromatic diimide dicarboxylic acids with select aromatic diamines.

Abstract: An improved polybenzimidazole wherein the total concentration of metals other than alkali metal and alkaline earth metals is 10 ppm or less. The resulting polybenzimidazole is industrially useable in parts or components of apparatus for the manufacture of semiconductors and display devices.

Abstract: Copolyetherimides are prepared by the reaction of an alkali metal salt of a dihydroxyaromatic compound with a bis(substituted phthalimide) and a third compound which may be a substituted aromatic ketone or sulfone or a macrocyclic polycarbonate or polyarylate oligomer. The reaction takes place the in presence of a solvent and a phase transfer catalyst having high thermal stability, such as a hexaalkylguanidinium halide. Random or block copolymers may be obtained, depending on the reaction conditions.

Abstract: Improved process for producing a polybenzimidazole compound in solution by dissolving a fully dried polybenzimidazole of the following general formula (1) or (2) in N,N-dimethylacetamide of a sufficiently reduced water content at an elevated temperature of 260.degree. C. or higher in an inert gas atmosphere and a solution of the polybenzimidazole compound produced by the process. The solution remains useful for an extended time without using metal salts or any other stabilizers: ##STR1## where R.sup.1, R.sup.2 and R.sup.5 are tetra-, di- and trivalent aromatic groups, respectively; R.sup.3, R.sup.4 and R.sup.6 are each independently a hydrogen atom, an alkyl group or an aryl group; n is an integer of 2 or more.

Abstract: In a method of synthesis of polybenzoxazole and polybenzothiazole precursors, a dicarboxylic acid or a dicarboxylaic acid ester is reacted with a bis-o-aminophenol or bis-o-aminothiophenol in a suitable solvent in the presence of an activating reagent having the following structure: ##STR1##

Abstract: A new diamine, 2,2'-dimethyl-4,4'-bis(4-aminophenoxy)-biphenyl was synthesized and used to prepare high performance engineering plastics by polycondensation. The new diamine as shown in the following formula has a noncoplanar 2,2'-disubstituted biphenylene and a flexible aryl units: ##STR1## The engineering plastics disclosed in the present invention includes polyamides, polyimides and poly(amide-imide)s.

Abstract: As a heteroaromatic compound made functional so as to be used in nonlinear optical materials, the present invention provides a heteroaromatic compound represented by the following Formula (1), (2), (3) or (4), a polymer obtained from any of these, a nonlinear optical element comprised of the polymer, an optical device having such an element, and a process for producing them. ##STR1## wherein Ar.sup.1, Ar.sup.2 and Ar.sup.3 each independently represent an aromatic group or an aromatic group having a substituent, R.sup.1, R.sup.2 and R.sup.3 each independently represent a hydrogen atom or a monovalent organic group, X represents a monovalent organic group, Y represents a hydrogen atom or a monovalent functional group, and n represents an integer of 2 to 10.

Abstract: The present invention provides injectable, bioabsorbable liquid copolymers suitable for use as a soft tissue repair or augmentation material in animals comprising a liquid polymer selected from the group consisting of liquid polymers of a plurality of at least two different first lactone repeating units and liquid polymers of a plurality of first lactone and second lactone repeating units; wherein the first lactone repeating units are selected from the group consisting of .epsilon.-caprolactone repeating units, trimethylene carbonate repeating units, ether lactone repeating units (which for the purpose of this invention shall mean 1,4-dioxepan-2-one and 1,5-dioxepan-2-one) and combinations thereof and the second lactone repeating units are selected from the group consisting of glycolide repeating units, lactide repeating units (which for the purpose of this invention are defined to be L-lactide, D-lactide, or D,L-lactide repeating units), p-dioxanone repeating units and combinations thereof.

Abstract: Disclosed is a process which comprises reacting a polyimide precursor with borane. Also disclosed is a thermal ink jet printhead containing a layer comprising the product of this reaction.

Abstract: Polyimide precursor solutions comprise an organic liquid and the reaction product of an aromatic dianhydride and an aromatic diaminobenzoxazole capped, on at least one terminal end, with a bifunctional chain extender. The bifunctional chain extender has one functional group reactive with the amine of the aromatic diaminobenzoxazole or the anhydride of the aromatic dianhydride and another functional group which does not form amic acid linkages, but which is capable of further reaction to increase the molecular weight of the polyimide precursor under conditions other than those used to react the aromatic diamine and aromatic dianhydride to form the polyimide precursor. These polyimide precursors can be converted into polyimidebenzoxazole polymers.

Abstract: The present invention provides a polyimide resin composition comprising:(a) a polyamide resin comprising a repeating unit represented by the general formula (1): ##STR1## wherein X represents a tetravalent organic group represented by the formula (2): ##STR2## Y represents a divalent organic group comprising a divalent siloxane residual group represented by the formula (3): ##STR3## wherein m is an integer of 60 to 120; and a divalent aromatic group represented by the formula (4): ##STR4## wherein R.sup.1 represents a hydrogen atom or a fluorine atom; and (B) cyclohexanone. From this composition, polyimide resin films can be obtained by heating at a lower temperature for a short time, and the films obtained show good adhesion under moisture-resistant conditions.

Abstract: Novel thermoset polyimide and composite materials comprising the thermoset polyimides and a fibrous reinforcement are prepared according to this invention. The thermoset polyimides are obtained by heat-treating a linear polyamic acid or a linear polyimide prepared by using 4,4'-bis(3-aminophenoxy)biphenyl and pyromellitic dianhydride as essential monomers or by adding 4,4'-diaminodiphenyl ether or 3,3',4,4'-biphenyltetracarboxylic dianhydride to the essential monomers and by end-capping the molecular chain end with an aromatic dicarboxylic anhydride having a carbon-carbon triple bond. The thermoset polyimides have essential excellent properties of thermoplastic polyimide and additionally has enhanced heat resistance and improved mechanical properties. The thermoset polyimide can be used to provide various kinds of composite materials for aircraft matrices, electric and electronic appliances and others.

Abstract: The invention provides novel thermoplastic polyimide featuring solid adhesive property under low temperature, low hygroscopic coefficient, and solid resistivity to radioactive rays. The invention also provides novel polyamide acid which is substantially precursor of the thermoplastic polyimide, and also provides novel thermally fusible laminated film for covering conductive wires, featuring solid adhesive property under low temperature, solid resistivity to radioactive rays, and distinct suitability for covering superconductive wires in particular.The novel thermoplastic polyimide is represented by general formula (1) corresponding to the chemical structure shown below; ##STR1## wherein, Ar.sub.1, Ar.sub.2, Ar.sub.4, and Ar.sub.6, respectively designate divalent organic radical, whereas Ar.sub.3 and Ar.sub.

Abstract: Disclosed are polymers and copolymers containing at least one repeating unit of the formula ##STR1## in which X is O or NH; R is a single bond or a hydrocarbon chain; R' is a hydrocarbon chain containing one or two carbon atoms, and P is the residue of an oligomer HX--P--XH whose solution viscosity determined in meta-cresol at 30.degree. C. at concentrations of 0.5 g/dl is lower than 0.50 dl/g.sup.-1. Also disclosed is a process for obtaining the polymers and copolymers.

Abstract: The present invention provide a novel polyimide which is soluble in organic solvents and excels in heat resistance, and to a process for producing the polyimide. The polyimide of the present invention comprises a repeating unit represented by the formula (1) and having a number average molecular weight of from 4,000 to 200,000. ##STR1## wherein X is --SO.sub.2 -- or --C(.dbd.O)--OCH.sub.2 CH.sub.2 O--C(.dbd.O)--, and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.

Abstract: The present invention is directed to an exciplex formed from a .pi.-conjugated polymer and an electron donor or acceptor component. The present invention also relates to assemblies comprising said exciplex, their use in optoelectrical devices and method of enhancing optoelectrical properties of .pi.-conjugated polymers by forming said exciplex.

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: 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: 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: Alcohol-soluble aromatic heterocyclic polymers and copolymers having repeating units of the formulae I or II: ##STR1## wherein Q is a benzobisazole of the formula: ##STR2## wherein X is --O-- or --S--; wherein x has a value of 0.0 to 1.00 and y has a value of 0.05 to 1.00, and R is selected from the group consisting of: ##STR3## and R' is selected from the group consisting of alkyl having 1 to 5 carbon atoms, alkaryl having 7 to 12 carbon atoms, aralkyl having 7 to 12 carbon atoms and substituted aromatic having 1 to 3 substituent groups. The alcohol-soluble polymers and copolymers may be used for fabricating organic/inorganic hybrid composites with metal alkoxides M(OZ).sub.v, wherein M is Si, Ti, Al or the like and Z is a lower alkyl group. These polymers and copolymers can also be used to coat materials or substrates which are susceptible to attack by highly corrosive acids.

Abstract: A polyimide comprises structural units represented by the following formula: ##STR1## wherein Ar is a group consisting of 10-90 mole % of a first specific structural sub-unit and 90-10 mole % of a second particular structural sub-unit. A process for the production of the polyimide and a thermosetting resin composition comprising the polyimide and a particular polymaleimide are also disclosed.

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: 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 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: Mixtures of salts of organic carboxylic acids and organic compounds of non-salt character, dissolved in a C.sub.1 -C.sub.4 alkanol, can be concentrated or separated with a semipermeable membrane made from a copolyamide or copolyimide-amide which contains (a) a first aromatic diamine radical and (b) a second aromatic diamine radical which carries --SO.sub.3 M groups, where M is H.sup..sym., a monovalent to polyvalent metal cation or an ammonium cation. Provided the first diamine radical contains C.sub.1 -C.sub.4 alkyl groups in the o-positions to the amino groups, the copolymers are radiation-sensitive and can be used for producing protective layers or relief images, development being carded out in an aqueous alkaline medium.

Abstract: Polyimide oligomers are described which comprise the intercondensation product of a monomer mixture comprising (A) at least one aromatic bis(ether anhydride), (B) at least one phenylindane diamine, and (C) at least one end-cap monomer selected from the group consisting of monoanhydrides, acyl halides and amines, wherein each end-cap monomer (C) contains at least one crosslinkable group in the molecule and wherein the phenylindane diamine component (B) is present in the mixture in a stoichiometric excess. The monomers react in a suitable solvent under an inert atmosphere to form polyimide oligomers having a number average molecular weight of from about 1,000 to about 15,000. The polyimide oligomers of the present invention are readily processed to form polyimide matrix resins with high temperature and oxidative stability.

Abstract: A structural panel for a vehicle or building contains a substrate and a layer of flame resistant polybenzazole polymer. If the substrate is heat resistant, the panel can serve as a fire barrier. If the substrate is not heat resistant, the polybenzazole layer can still serve to delay ignition and contain any volatile gases and molten polymer that forms when the panel is subjected to heat.

Abstract: Heat-stable polyimides and polyamideimides with modified benzhydrol structural elements and a process of preparing thereof; wherein the polyimides and polyamideimides are obtained by reacting 3,3'4,4'-benzhydroltetracarboxylic acid dimethyl ester a) with only a diamine and then cyclized to give polyimides or b) with a diamine and with trimellitic, phthalic-or isophthalic acid (or the anhydrides, acid chlorides, anhydride chlorides or esters) and is then cyclized to give polyamideimides.

Abstract: Polyimide resins useful at high temperatures are prepared from:(a) a dialkyl, trialkyl or tetraalkylester of biphenyltetracarboxylic acid;(b) phenylenediamine, preferably the phenylenediamine comprises a mixture of meta-and para-phenylenediamine; and(c) a divalent end cap compound that is capable of undergoing addition polymerization.

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: Low dielectric constant polyimides formed from an optionally fluorinated dianhydride and a fluorinated diamine are described. The fluorine containing constituents are sterically disposed so that the dipole moment of the constituents tend to cancel out. Since fluorine containing diamines are generally nonreactive, to achieve a polyimide of high enough molecular weight to be practically useful, a method of fabrication of a high molecular weight polymer from monomers of low reactivity is provided. The monomers, such as a diamine and dianhydride are provided in a solution within which a low molecular weight polyamic acid is formed. The solution is dried. The polyamic acid used is cured to a low molecular weight polyimide. The polyimide is redisolved, redryed and recured enough times to build up the molecular weight to a useful level. The method is applicable to fabricating other polymers of high molecular weight, such as polyamides, polyesters and polyurethanes.

Abstract: Mixtures of salts of organic carboxylic acids and organic compounds of non-salt character, dissolved in a C.sub.1 -C.sub.4 alkanol, can be concentrated or separated with a semipermeable membrane made from a copolyamide or copolyimide-amide which contains (a) a first aromatic diamine radical and (b) a second aromatic diamine radical which carries --SO.sub.3 M groups, where M is H.sup..sym., a monovalent to polyvalent metal cation or an ammonium cation. Provided the first diamine radical contains C.sub.1 -C.sub.4 alkyl groups in the o-positions to the amino groups, the copolymers are radiation-sensitive and can be used for producing protective layers or relief images, development being carried out in an aqueous alkaline medium.

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 process for forming a polymer (and the polymer formed thereby) for passivation, resist and bonding uses, for example, that is thermally stable at relatively high temperatures in excess of 400.degree. C., but is sensitive to electromagnetic radiation. The process includes forming a heteroatom ring polymer that includes a chain formed of a large number of closed aromatic rings such as polyimide groups. According to the present teaching, intervening moieties, (that is, chemical groupings) in the form of open ring precursors of the aromatic rings, such as polyamic acid groups are introduced between the successive closed aromatic rings, which destroy and/or delimit the colinear character and the coplanar character typical of the successive aromatic rings, thus rendering the aromatic rings sensitive to structural change by electromagnetic radiation exposure, and soluble in common organic solvents, but with the exposed HRP insoluble in resist developers.

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 chemical resistant copolymer useful in electronic applications, said copolymer is a polyimide containing a 3,3',4,4'-tetracarboxybiphenyl dianhydride (BPDA) moiety, at least one other dianhydride moiety, and at least one diamine.

Abstract: The diamine, 1,3-diamino-5-pentafluorosulfanylbenzene (DASP), was reacted with various dianhydrides to form polyimides containing an SF.sub.5 moiety. These polyimides exhibit high glass transition temperatures, high density, low solubility, and low dielectric properties. These polymers were used to prepare semi-permeable membranes, wire coatings, and films and are useful for electronic, space and piezoelectric applications.

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 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 gas separating asymmetric membrane such as a gas separating asymmetric hollow fiber comprises an aromatic polyimide comprising recurring units of the formulae (I) and (II): ##STR1## wherein A.sup.1 is a tetravalent unit having a diphenylhexafluoropropane structure, A.sup.2 is a tetravalent unit having a benzene structure, and A.sup.3 is a divalent aromatic unit which is a unit derived from a sulfur atom-containing diamine such as diaminodibenzothiophene, diaminodiphenylenesulfone, diaminothioxanthene-5,5-dioxide or diaminothioxanthone-5,5-dioxide. The aromatic polyimide contains the recurring unit of the formula (I) in an amount of 40 to 90 molar % and the recurring unit of the formula (II) in an amount of 10 to 40 molar %. Further, a process for the preparation of the gas separating asymmetric hollow fiber membrane is also disclosed.

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: Base-soluble release layer compositions for microlithographic processing, comprising nonamic acid functionalized polyamic acid/imide resins are disclosed. These materials permit concurrent lithographic development of photoresist and release layers. They also afford effective lift-off, by alkaline media, even after high imidization.

Abstract: A favorably processable polyimide which has recurring structural units represented by the formula (I): ##STR1## wherein R is a tetravalent radical having from 2 to 27 carbon atoms and is selected from the group consisting of an aliphatic radical, alicyclic radical, monoaromatic radical, condensed polyaromatic radical and noncondensed aromatic radical connected to each other with a direct bond or a bridge member, and is blocked at the polymer chain end with aromatic dicarboxylic anhydride represented by the formula (II): ##STR2## wherein X is a divalent radical selected from the group consisting of a monoaromatic radical having from 6 to 27 carbon atoms, condensed polyaromatic radical and noncondensed aromatic radical connected to each other with a direct bond or a bridge member.

Abstract: A process for preparing polyamides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15% by weight of additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

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.