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

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

Abstract: There are disclosed dibenzofuran amorphous polymer comprising a recurring unit represented by following formula (II) and having a molecular weight giving a reduced viscosity of at least 0.2 dl/g as measured in the form of a 0.5% (W/V) solution in N-methyl-pyrrolidone at 25.degree. C., a process for producing said amorphous polymer, a dibenzofuran copolymer comprising, in addition to a recurring unit represented by following formula (II), at least one type of recurring unit represented by following general formula (III) in a specific proportion and having a molecular weight giving a reduced viscosity of at least 0.2 dl/g as measured in the form of a 0.5% (W/V) solution in concentrated sulfuric acid at 25.degree. C., and a process for producing said copolymer. ##STR1## wherein A is --O--, --CO--, --S--, --SO.sub.2 --, a divalent alkylene group or a single bond and n is a number of 0, 1 or 2.

Abstract: An improved process for the preparation of poly(aryl ether) polymers by reacting, in the absence of dipolar aprotic solvents, an alkali metal double salt of a dihydric phenol with a dihalobenzenoid compound in the presence of a macro bicyclic compound having nitrogen bridgehead atoms linked together by three hydrocarbon bridging chains having in each of the hydrocarbon bridging chains at least one additional hetro atom selected from the group consisting of oxygen, nitrogen and sulfur atoms.The poly(aryl ether) polymer resins produced by the process have a low degree of coloration and excellent mechanical and electrical properties which allow them to be molded into a variety of articles.

Abstract: A polyarylsulphone is prepared by the polycondensation of a bisphenol with an aryl dichloride, at least one of which contains a sulphone group, in the presence of a base and introducing into the reaction mixture less than 5% mole, relative to the aryl dichloride, of 4,4'-difluorodiphenylsulphone. The bisphenol and aryldichloride can be of 4,4'-dihydroxydiphenylsulphone and 4,4'-dichlorodiphenylsulphone respectively. The difluoro compound is added when the polymerisation is essentially complete. The polymer product if of improved quality.

Abstract: An improved process for the preparation of poly(aryl ether) polymers by reacting, in the absence of dipolar aprotic solvents, an alkali metal double salt of a dihydric phenol with a dihalobenzenoid compound in the presence of an alkoxylated tertiary amine compound having a nitrogen atom linking together three organic chains comprising hydrocarbon groups and in each of the chains at least one oxygen atom.The poly(aryl ether) polymer resins produced by the process have a low degree of coloration and excellent mechanical and electrical properties which allow them to be molded into a variety of articles.

Abstract: An improved process for the preparation of poly(aryl ether) polymers by reacting, in the absence of dipolar aprotic solvents, an alkali metal double salt of a dihydric phenol with a dihalobenzenoid compound in the presence of a macrocyclic polyether compound having one ether ring in which oxygen atoms are separated one from the other by 2 to 3 carbon atoms, the ring having fused thereto from 0 to 4 monocyclic or polycyclic aromatic or saturated hydrocarbon nuclei. The nuclei are attached by vicinal carbon atoms thereof to adjoining ring oxygens in oxygen-carbon-carbon-oxygen arrangement.The poly(aryl ether) polymer resins produced by the process have a low degree of coloration and excellent mechanical and electrical properties which allow them to be molded into a variety of articles.

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

Abstract: Aromatic polyether polymers, illustrated by polyethersulfones, polyetherketones and polyetherimides, are prepared by a phase transfer catalyzed reaction between a salt of a dihydroxyaromatic compound and a substituted aromatic compound such as bis(4-hydroxyphenyl) sulfone, bis(4-hydroxyphenyl) ketone or 1,3-bis[N-(4-chlorophthalimido)]benzene or the corresponding derivative of toluene or diphenyl ether, or the analagous fluoro-, bromo- or nitro-substituted compounds. The phase transfer catalysts employed are those which are stable at temperatures in the range of about 125.degree.-250.degree. C. Particularly preferred phase transfer catalysts are the hexaalkylguanidinium and .alpha.,.omega.-bis(pentaalkylguanidinium)alkane salts and the corresponding heterocyclic salts.

Abstract: Soluble and/or meltable benzothiazole-containing polyaryl ethers with a glass transition temperature of above 150.degree. C. and a melting point of up to 450.degree. C. are composed essentially of repeat units of the formula I ##STR1## whose rings may be substituted by C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.

Abstract: Polybenzazole polymers may contain perfluorocyclobutane rings to provide a flexible moiety which is stable at high temperatures.

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

Abstract: Disclosed are melt-processable wholly aromatic polyesters prepared from terephthalic acid, 2,6-naphthalenedicarboxylic acid, and hydroquinone.

Abstract: The new aromatic polyethers containing ester groups, which are distinguished by high dimensional stability, may be used for the production of all kinds of moulded products as well as for the preparation of block copolymers of aromatic polyether segments and segments of other thermoplastic polymers.

Abstract: 9,9-Bis(3,5-diphenyl-4-hydroxyphenyl)fluorene a novel compound can be used to produce amorphous poly(arylene ethers) which have high glass transition temperatures and good thermo-oxidative stability and which are soluble in aromatic and chlorinated solvents; the novel fluorene derivative is produced by transalkylation of 9,9-bis(4-hydroxyphenyl)fluorene or 9,9-bis(4-methoxyphenyl)fluorene with 2,6-diphenylphenol.

Abstract: A process for preparing a halogenated polycarbonate wherein phenolic-terminated, halogenated carbonate oligomers are prepared in the presence of a coupling catalyst, and are then condensed by contact with a carbonate precursor.

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

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

Abstract: The invention relates to polyarylene ethers which contain, based on the total amount of structural elements present in the polyether resin, 5-100 mol % of a recurring structural element of the formula I ##STR1## and 0-95 mol % of a recurring structural element of the formula II ##STR2## in which X and X' independently of one another are --SO--, --SO.sub.2 -- or --CO--, one of the radicals R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is phenyl or phenyl which is substituted by one to three (C.sub.1 -C.sub.4)alkyl groups and the remaining radicals R.sub.1, R.sub.2, R.sub.3 and R.sub.4 independently of one another are hydrogen, (C.sub.1 -C.sub.4)alkyl, phenyl or phenyl which is substituted by one to three (C.sub.1 -C.sub.4)alkyl groups, and A is an aromatic radical, at least 25% of the bonds X and/or Y and/or the bridge members contained in A being --SO.sub.2 --.These industrial materials are distinguished by very good mechanical properties and good solubility.

Abstract: Dihydroxydiphenyl bicycloalkanes characterized in that they contain 9 to 13 ring C atoms in the bicycloaliphatic component are disclosed. The disclosed compounds were found to be suitable for the preparation of high molecular weight, thermoplastic polycarbonate resins having favorable properties.

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

Abstract: A process for preparation of a random copolycarbonate from an ortho-substituted dihydric phenol and a non-ortho-substituted dihydric phenol.

Abstract: A process for preparing halogenated polycarbonate wherein the total amount of base, the end pH of the aqueous phase, and the amount of coupling catalyst employed in the reaction are controlled to selected levels.

Abstract: The invention relates to a method of preparing aromatic polycarbonates by catalytic interface polymerization of at least one bivalent phenol and a carbonyl halide in the presence of a polycondensation catalyst, which method is characterized in that the conversion is carried out in a two-phase system with continuous dosing of the carbonyl halide, which two-phase system is based on water and an organic solvent, in which the quantity of organic solvent at the beginning of the polycondensation lies between 10% and 75% of the quantity of organic solvent which is required at the polymerization temperature for dissolving the quantity of polycarbonate which may be formed from the quantity of bivalent phenol which is present at the beginning of the polycondensation, in that after dosing at least 20% of the carbonyl halide a remaining quantity of organic solvent is added which is at least sufficient to keep the formed polycarbonate in solution.

Abstract: Polyether polymers are prepared from 4,4"-dihydroxy-m-terphenyls, especially the unsubstituted dihydroxyterphenyl, by reaction under alkaline conditions with bis(4-halophenyl) sulfones, 4,4'-dihalobenzophenones or gem-dihaloalkanes. Both homopolymers and copolymers with other dihydroxyaromatic compounds, particularly bisphenol A, may be prepared. They have glass transition temperatures higher than those of the corresponding bisphenol A-derived polymers.

Abstract: There are disclosed carbonate polymers having terminal arylcyclobutene moieties. Such carbonate polymers are prepared from one or more multi-hydric compounds and have an average degree of polymerization of at least about 2 based on multi-hydric compound. These polymers, including blends thereof, can be easily processed and shaped into various forms and structures according to the known techniques. During or subsequent to the processing, the polymers can be crosslinked, by exposure to heat or radiation, for example, to provide crosslinked polymer compositions. These compositions have a good combination of properties, including for example, processability into shaped articles having unexpectedly good combinations of toughness, solvent resistance, ignition resistance, modulus and resistance to thermal linear expansion.

Abstract: Aromatic polyether sulfones based on 5 to 90 mol-%, based on total bisphenols, of special dihydroxydiphenyl cycloalkanes and 10 to 95 mol-% based on the bisphenols of specific phthaleins, a process for their production and their use as molding compounds.

Abstract: Process for the preparation of an aromatic polyether in the presence of finely divided condensation auxiliaries.The process for the preparation of an aromatic polyether by condensation of the reactants in the presence of carbonates of metals of Group I of the Periodic Table, as condensation auxiliaries, employs the metal carbonates sodium carbonate or sodium bicarbonate or mixtures thereof in the form of very finely ground salts.The fine particle size distribution of the carbonate allows a significant shortening of the reaction times and permits polyethers having a defined degree of condensation to be reproducibly prepared.

Abstract: The arylene sulfide ketone copolymers according to the present invention have mainly recurring units which are represented by formulas (I) and (II), ##STR1## The arylene sulfide ketone copolymers have a high glass transition point and excellent moldability and can be produced with industrial advantage.

Abstract: Poly(1,2,4-triazoles)(PT) have been prepared by involving the aromatic nucleophilic displacement reaction of di(hydroxyphenyl)-1,2,4-triazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as sulfolane or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl)-1,2,4-triazole monomers are first synthesized by reacting bis(4-hydroxyphenyl) hydrazide with aniline hydrochloride at 250.degree. C. in the melt and also by reacting 1,3 or 1,4-bis-(4-hydroxyphenyl)phenylenedihydrazide with 2 moles of aniline hydrochloride in the melt. Purification of the di(hydroxyphenyl)-1,2,4-triazole monomers is accomplished by recrystallization.

Abstract: Branched aromatic sulfide sulfone polymer is produced by contacting at least one dihalo aromatic sulfone, at least one polymerizable sulfur source other than lithium sulfide, at least one alkali metal carbonate, at least one organic amide, at least one alkali metal carboxylate, at least one polyhalodiarylsulfone having more than two halogen substituents and water including water of hydration under polymerization conditions for a period of time sufficient to form an aromatic sulfide sulfone polymer. The polymer exhibits higher melt and solution viscosity than obtained in the same process except without the use in the reaction mixture of polyhalodiarylsulfone having more than two halogen substituents and is useful in the production of coatings, films, molded objects, and fibers.

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

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

Abstract: A first reaction mixture of at least one dihalo aromatic sulfone, at least one polyhydroxy aromatic compound, at least one organic amide and at least one alkali metal carbonate is contacted under polymerization conditions including a period of time at a temperature sufficient to form a reaction product, with the resulting product mixture being contacted with at least one polymerizable sulfur source, at least one organic amide, at least one alkali metal carboxylate, and water under polymerization conditions including a period of time at a temperature sufficient to form a branched aromatic sulfide sulfone polymer. The resulting polymers are useful in the production of coatings, films, molded objects, and fibers.

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

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

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

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

Abstract: A process for preparing a metal phenolate of the formula II:Cl--Ar.sub.1 COAr.sub.2 OM (II)wherein each of Ar.sub.1 and Ar.sub.2 which may be the same or different is a bivalent group of the formula: ##STR1## wherein each of R.sup.1 and R.sup.12 is a hydrogen atom, a halogen atom, an alkoxy group, a phenoxy group, an alkyl group, a cycloalkyl group, a phenyl group, an aralkyl group, an acyl group, a nitrile group, a nitro group or an acyloxy group, each of Y and Z is an oxygen atom or a ketone group, and each of n and m is an integer of from 0 to 4, and M is an alkali metal, which comprises reacting a phenol compound of the formula I:Cl--Ar.sub.1 COAr.sub.2 OH (I)wherein Ar.sub.1 and Ar.sub.2 are as defined above, with an alkali metal compound in the presence of water, and then removing water, characterized in that water is azeotropically distilled off together with an organic solvent capable of forming an azeotropic mixture with water.

Abstract: Flame-resistant thermoplastic branched polycarbonates of high molecular weight are prepared from:(1) a carbonate precursor;(2) at least one dihydroxyaromatic compound of formula: ##STR1## where: R is a single bond, or a substituted or non-substituted linear or branched C.sub.1 -C.sub.5 alkylene radical, or a group chosen from O, S, SO.sub.2 and CO;X and Y, which may be the same or different, are H or CH.sub.3 ;m and n, which may be the same or different, are whole numbers from 1 to 4;(3) at least one halogenated pyrimidine compound of formula: ##STR2## where: R.sub.2, R.sub.3, R.sub.4, which may be the same or different, are chlorine or bromine or hydrogen, on condition that at least one is chlorine or bromine;R.sub.1 is chlorine or bromine, or a radical of formula: ##STR3## where Z is NH or S or O; (4) at least one polyfunctional organic compound as branching agent, characterized by possessing at least three equal or different groups chosen from the groups OH, COOH, COCl and SO.sub.2 Cl.

Abstract: Novel aromatic polysulfoneetherketone polymers having recurring units of Formula: ##STR1## wherein Ar is phenylene, biphenylene or ##STR2## in which --Y-- represents ##STR3## The aromatic polysulfoneetherketone polymers of the invention have superior properties over the known polysulfone or polyetherketone series polymers in terms of heat resistance, chemical resistance and electric insulation as well as mechanical properties such as dimensional stability.

Abstract: Polymers comprising perfluoroalkyl groups, reproduction layers containing these polymers and use thereof for waterless offset printing. The novel perfluoroalkyl group-containing polymers comprise polymers or polycondensates and have, in each case as substituents on different carbon atoms of benzene rings, phenolic OH groups and perfluoroalkyl groups which are optionally attached through intermediate members. In particular, at least 10% of the polymer units carry perfluoroalkyl groups. These polymers are either formed by condensation of substituted phenols (e.g., 4-hydroxybenzoic acid-perfluoroalkyl ester) with an aldehyde, a ketone, or a reactive bismethylene compound or by reacting polymers containing phenolic OH groups (e.g., hydroxypolystyrene) or polycondensates containing reactive OH groups (e.g., phenol-formaldehyde resins) with a perfluoroalkyl group-containing compound (e.g., 2,2-dihydroperfluorodecanoic acid chloride).

Abstract: New aromatic polycarbonates contain, in their bisphenol moiety, at least in part bisphenols of the type 1,1-bishydroxyphenylhexafluorodichlorocyclopentane, 1,1-bishydroxyphenylheptafluoromonochlorocyclopentane or 1,1-bishydroxyphenyloctafluorocyclopentane.

Abstract: New and useful aromatic polyethers, which are high in glass transition temperatures, possess excellent mechanical properties, thermal resistance, solvent resistance, and generate fluorescence, are described. Also described are fluorescent resin compositions containing the aromatic polyethers. Processes for preparing the aromatic polyethers and the fluorescent resin compositions are also described.

Abstract: The present invention relates to a novel fluorine-containing diaminobenzene derivative having a perfluoroalkyl group and to a novel fluorine-containing polyimide which is produced from the said diaminobenzene as a starting material and to a novel polyimide having both a fluorine-containing group and/or a siloxane chain in the side chain thereof, the polyimide being produced from the said fluorine-containing diaminobenzene and fluorine-containing polyimide and to a liquid crystal-aligning agent with an elevated tilt angle, which contains a polyimide having a fluorine-containing group and a siloxane chain.

Abstract: Aromatic polyester copolymers are provided consisting essentially of dihydroxy-meta-terphenyl units, and bisphenol A units chemically combined with aromatic diacid units such as isophthaloyl units, terephthaloyl units and mixtures thereof. Polyesters have been found to have a high glass transition temperature and stability up to 475.degree. C.

Abstract: Partially fluorinated tetracarboxylic acid and the dianhydride thereof, a process for their preparation and their useA compound of the formula ##STR1## and the dianhydride thereof are prepared by air oxidation in the presence of a catalyst mixture composed of at least 2 heavy metal salts and also bromine in an acid organic medium. The compounds can be employed for the preparation of partially fluorinated polycondensates, such as polyimides, polycarboxamides, esters of polyamidecarboxylic acids, polyamides and imide-oligomers.

Abstract: A fluorinated poly(naphthyl ether) having a repeat unit of the formula ##STR1## wherein Y is (CF.sub.2).sub.m, ##STR2## m is an integer from 1 to 4, inclusive, and X is S, CO, SO.sub.2, O, P(C.sub.6 H.sub.5), or C(OH)H. Such polymers are useful as low dielectric constant, low moisture absorption insulators for multilayered integrated circuit articles, especially in their crosslinked form.

Abstract: Dihydroxy-meta-terphenyl polycarbonates are provided having improved solvent resistance. Alternating and random polycarbonate copolymers resulting from interfacial and single phase organic solvent polymerization techniques with coreactants such as bisphenol A also are provided.

Abstract: Polyetherimide oligomers having crosslinking end cap moieties which provide improved solvent-resistance to cured composites are generally represented by the formula: ##STR1## wherein X=--O-- or --S--; ##STR2## n=1 or 2; ##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.