Abstract: A process for production of polyimide powder, which comprises reacting an aromatic diamine with a partial ester of a biphenyltetracarboxylic dianhydride, which is a partial ester of a biphenyltetracarboxylic dianhydride with a primary alcohol of 1-5 carbon atoms of which at least 30 mole percent is a 2,3,3′,4′-biphenyltetracarboxylic acid component, in the presence of the primary alcohol, separating out and collecting the resulting solid polyimide precursor and heating for dehydrating ring closure, polyimide powder obtained thereby, molded bodies of the polyimide powder, and a process for production of the molded bodies.

Abstract: This invention provides crosslinkable-group-containing polyimides of various known thermoplastic polyimide backbone structures, which are provided with far better heat resistance, chemical resistance and mechanical properties than known polyimides of the structures without impairing excellent moldability or formability, superb sliding property, low water absorption property, outstanding electrical properties, high thermal oxidation stability and high radiation resistance, all of which are inherent to the structures.

Abstract: The present invention relates to a novel polyimide of the general formula (1) and a process for the preparation thereof.

Abstract: A method for the synthesis of high molecular weight poly(imide)s comprising coupling poly(imide) precursors having complementary functional groups and a weight average molecular weight of less than about 50,000 Daltons to form high molecular weight poly (imides)s having a weight average molecular weight greater than 50,000 Daltons.

Abstract: The present invention provides a polymer in which coumarin, a photo-reactive molecule, is grafted onto a polyimide for preparing liquid crystal alignment layer which has a superior alignment property and an excellent thermal stability in photo-alignment, a process for preparing the said grafted polymer, a process for preparing liquid crystal alignment layer by employing the said grafted polymer, and a liquid crystal alignment layer prepared by the process. The polymer of the invention is prepared by mixing a coumarin compound with a polyimide, dissolving the mixture in an organic solvent, adding a catalyst, and stirring under an environment of N2 gas. The polymer of the invention is superior in terms of the thermal stability, which makes possible its universal application for the development of a novel liquid crystal display(LCD).

Abstract: This invention provides cycloaliphatic polyimide having the following formula (I): wherein 1 and n are integers from 4 to 7; m is an integer from 0 to 2; p is an integer from 1 to 8; polycyclic aliphatic compound R reprents C1-8 cycloalkyl, cycloalkenyl, cycloalkynyl, norbornenyl, decalinyl, adamantanyl, or cubanyl. That cycloaliphatic polyimide can be a through transparent film, their thermal stability is over 430° C. and dielectric constant is about 2.7.

Abstract: A new method for the synthesis of poly(etherimide)s comprises transimidation of bis(imide) (IV) in the presence of a substituted phthalic anhydride or 4-substituted tetrahydrophthalic anhydride to yield dianhydride (V) which may then be reacted with a diamine to produce poly(etherimide)s. By-product substituted N-alkylphthalimide or 4-substituted N-alkyltetrahydrophthalic anhydride may be recycled or converted to 4-substituted N-alkylphthalimide for use in the formation bisimide (IV), obviating the need for a nitration step.

Abstract: Disclosed are a polyamic acid having repeating units represented by the formula (1): 1

Abstract: A polycarbodiimide represented by the formula (I): wherein R1 is an alkylene group having 2 to 10 carbon atoms, R2 is a divalent aromatic group, R3 is a monovalent aromatic group, k is 0 or an integer of 1 to 30, m is an integer of 2 to 100, and n is 0 or an integer of 1 to 30, a process for preparing the same and uses of the polycarbodiimide. The polycarbodiimide is favorably used in the form of films such as adhesive films for die bonding and adhesive films for underfilling, which can be used in semiconductor devices.

Abstract: Novel polyimide copolymer, which is a copolymer of isopropylidene-bis-(4-phenyleneoxy-4-phthalic acid)dianhydride and 6-amino-2-(p-aminophenyl)benzimidazole or a copolymer of two kinds of tetracarboxylic acid dianhydrides consisting of isopropylidene-bis-(4-phenyleneoxy-4-phthalic acid)dianhydride and 3,3′,4,4′-benxophenonetetracarboxylic acid dianhydride and 6-amino-2-(p-aminophenyl)benzimidazole, can form a metal laminate by direct lamination with metallic foils. The metal laminate can fully satisfy the peel strength.

Abstract: An electronically active film comprising a compound of the formula: 1

Abstract: A method of making a solution of a polyimide from a diamine monomer and a dianhydride monomer is disclosed. A solution or slurry of one of the monomers in a solvent that boils at a temperature between about 80° C. and about 160° C. is prepared. The solution or slurry is heated to a temperature between about 80° C. and about 160° C. and the other monomer is slowly added to the solution or slurry. Polyamic acid that is formed quickly imidizes to form the polyimide.

Abstract: A process for production of polyimide powder, which comprises reacting a biphenyltetracarboxlic dianhydride and an aromatic diamine in an amide-based solvent optionally containing a water-soluble ketone, in the presence of an imidazole at 1-100 equivalent percent based on the carboxylic acid content of the polyimide precursor, separating and collecting the produced polyimide precursor powder from a water-soluble ketone solvent containing 3-30 wt % of an amide-based solvent, and heating the polyimide precursor powder to an imidation rate of 90% or greater, as well as polyimide powder obtained thereby, molded bodies of the polyimide powder, and a process for production of the molded bodies.

Abstract: A process for production of polyimide powder, which comprises reacting an aromatic diamine with a partial ester of a biphenyltetracarboxylic dianhydride, which is a partial ester of a biphenyltetracarboxylic dianhydride with a primary alcohol of 1-5 carbon atoms of which at least 30 mole percent is a 2,3,3′,4′-biphenyltetracarboxylic acid component, in the presence of the primary alcohol, separating out and collecting the resulting solid polyimide precursor and heating for dehydrating ring closure, polyimide powder obtained thereby, molded bodies of the polyimide powder, and a process for production of the molded bodies.

Abstract: A primary object of the invention is to provide a production technology for functional polyamic acid microfine particles and functional polyimide microfine particles by which the particle shape, size and size distribution can be freely controlled. The invention is concerned with a process for synthesizing polyamic acid particles having functional groups at least on the surface from a tetracarboxylic anhydride and a diamine compound characterized by its comprising (a) a first step which comprises providing a tetracarboxylic anhydride and a diamine compound at least one of which has functional groups and preparing a first solution containing the tetracarboxylic anhydride and a second solution containing the diamine compound and (b) a second step which comprises mixing the first and second solutions under ultrasonic agitation to thereby precipitate polyamic acid microfine particles from the mixed solution.

Abstract: A process for the preparation of an oligomeric polyimide comprises: mixing a tetracarboxylic acid, a dianhydride, a partially hydrolysed dianhydride or a mixture thereof with a diamine in a reaction medium comprising greater than 80% by weight water, and heating mixture in said reaction medium at a temperature above 100° C. for a time sufficient to form said oligomeric polyimide.

Abstract: A polyimide for optical communications, which is expressed by the formula (1) where R1 and R2 are independently selected from the group consisting of CF3, CCl3, unsubstituted aromatic ring group and halogenerated aromatic ring group; R3 and R4 are independently selected from the group consisting of Cl, F, I, Br, CF3, CCl3, unsubstituted aromatic ring group and halogenated aromatic ring group; and n is an integer from 1 to 39. The polyimides have a superior heat resistance, and can avoid the increase in optical absorption loss due to a refractive index increase and deterioration of adhesive and coating properties due to weak surface tension of a polyimide film. In addition, use of the polyimides as a material for a core layer of optical waveguides can expand the selection range of material for the cladding layer of the optical waveguide.

Abstract: The present invention provides polyimides and co-polyimides that are organosoluble. The polyimides and co-polyimides are prepared from an aromatic diamine having ortho-linked phenylene and pendant tert-butyl group, i.e., 1,2-bis(4-aminophenoxy)-4-tert-butyl-benzene, or its mixture with other diamines, and a mixture of dianhydrides that containing at least one dianhydride selected from s-BPDA, DSDA, ODPA, 6FDA and other diether-dianhydrides.

Abstract: The present invention relates to a treating agent for liquid crystal alignment, which is an agent for liquid crystal alignment to be used for a method in which polarized ultraviolet rays or electron rays are irradiated on a polymer thin film formed on a substrate in a predetermined direction relative to the substrate plane, and said substrate is used for aligning liquid crystal without rubbing treatment, wherein said agent for liquid crystal alignment contains a polymer compound having photochemically reactive groups in the polymer main chain and a glass transition temperature of at least 200° C.

Abstract: The present invention provides a process for preparing an optical alignment layer for aligning liquid crystals and liquid crystal displays comprising exposing polyimide layers with polarized light. The invention further describes optical alignment layers, liquid crystal displays incorporating optical alignment layers and novel polymer compositions within the class of polyimide, polyamic acids and esters thereof.

Abstract: Disclosed is a solvent soluble polyimide and a method for making thereof, which characterizes by producing a solvent soluble polyimide with low electric conductivity through the polymerization of an anhydride and a diamine under the condition with or without catalyst.

Abstract: Polyether polymers such as polyetherimides are prepared by a two-step reaction. The first step is the reaction between an alkali metal salt of a dihydroxy-substituted aromatic hydrocarbon, such as bisphenol A disodium salt, and a substituted aromatic compound such as 1,3-bis[N-(4-chlorophthalimido)]benzene, the alkali metal salt being employed in an amount less than stoichiometric. The intermediate low molecular weight polymer thus produced then undergoes reaction with additional alkali metal salt. By this method, a polyether polymer of closely controlled molecular weight can be conveniently prepared.

Abstract: Addition-cured polyimides that contain the reaction product of an aromatic triamine or trianhydride analogue thereof, a reactive end group such as 5-norbornene-2, 3-dicarboxylic acid, ester derivatives of 5-norbornene-2,3-dicarboxylic acid, anhydride derivatives of 5-norbornene-2,3-dicarboxylic acid, or 4-phenylethynylphthalic anhydride, an aromatic diamine, and a dialkyl ester of an aromatic tetracarboxylic acid. The resultant starlike polyimides exhibit lower melt flow viscosity than its linear counterparts, providing for improved processability of the polyimide. Also disclosed are methods for the synthesis of these polyimides as well as composite structures formed using these polyimides.

Abstract: A method for preparing polyamic acid and polyimide, which is suitable for use in adhesives or adhesive tapes for electronic parts. The polymers have such three-dimensional molecular structures that a significant improvement can be brought about in solvent solubility, thermal resistance, mechanical properties, and adhesive properties onto various substrates. The polyamic acid is prepared by reacting at least one tetracarboxylic dianhydride, at least one aromatic diamine, at least one diamine with a siloxane structure, represented by the following general formula I, and at least one polyamino compound represented by the following general formula II or III. The polyamic acid is converted into polyimide through thermal or chemical imidization.

Abstract: An aromatic polycarbodiimide comprising a structure represented by the following formula (1) has excellent low moisture resistance, heat resistance and a low dielectric constant: wherein Q is one selected from the group consisting of —CH2—, m is 0 or 1, A is a divalent organic group having 4 or less carbon atoms, Ph is a phenyl group, X's are a hydrogen atom when Q is and the same or different halogen atoms when Q is —CH2—, and n is an integer of 2 to 300.

Abstract: A curable, high temperature, carbonaceous, cement paste composition comprising a catalyst; a carbon filler present in an amount of about 20 to about 60 wt. %; a polymerizable monomeric system present in an amount of about 7 to about 30 wt. % comprising a dialkyl ester of an aromatic tetracarboxylic acid, an aromatic diamine, and a monoalkyl ester of an acid selected from the group consisting of 5-norbornene-2,3-dicarboxylic acid and phthalic acid; and a furan solvent present in an amount of about 20 to about 60 wt. %. The most preferred embodiment comprising a monomeric system comprising a dimethyl ester of 3,3′,4,4′-benzophenonetetracarboxylic acid, 2,2′-bis (4-[4-aminophenoxyl]phenyl)propane and a monomethyl ester of 5-norbornene-2,3-dicarboxylic acid with furfuryl alcohol and a catalytic solution of about 50% ZnCl2, has a glass transition temperature of about 280° C. after curing by heating at about 2° C./minute to about 240° C. and holding for about 2 hours.

Abstract: The present invention provides a series of easily processable poly(ether-imide)s that are organic-soluble and can afford colorless films, their organic solutions and their manufacturing process. The poly(ether-imide) is prepared from a dianhydride and a diamine, wherein the dianhydride is a bis(ether anhydride) having tert-butyl group, i. e. 1,4-bis(3,4-dicarboxyphenoxy)-2-tert-butylbenzene dianhydride.

Abstract: The invention herein relates to a novel soluble polyimide resin comprising polyalicyclic structures and the process of preparation of the same, wherein aromatic tetracarboxylic dianhydride and novel aromatic diamine having an polyalicyclic group with various structures are used to yield a novel form of a polyimide resin, which has superior heat-resistance, solubility, and transparency.More specifically, the invention herein relates to a novel polyimide resin having excellent heat-resistance and solubility, which is prepared by means of reacting diamine monomers having a novel chemical structure with various types of aromatic carboxilic dianhydrides, in stead of aromatic diamine used for the preparation of the conventional polyimide resin. As a result, the polymers so obtained had the glass transition temperature of 260.degree. C..about.410.degree. C. and showed a increase in solubility in proportion to the increase in a number of the aromatic rings between two phenyl groups.

Abstract: Methods and devices for controlling the oxidation of a hydrocarbon to an acid by regulating the temperature hold-up time, and conversion in consecutive reaction zones. The temperature in the consecutive reaction zones progressively decreases, while the hold-up time increases. Preferably, the conversion also increases. One of the major advantages of the methods and devices of the present invention is that an outstanding balance between productivity and selectivity/yield of the desired acid may be achieved. In this respect high yields and selectivities may be obtained without sacrificing productivity.

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 series of easily processable poly(ether-imide)s that are organic-soluble and can afford colorless films, their organic solutions and their manufacturing process. The poly(ether-imide) is prepared from a dianhydride and a diamine, wherein the dianhydride is a bis(ether anhydride) having tert-butyl group, i.e. 1,4-bis(3,4-dicarboxyphenoxy)-2-tert-butylbenzene dianhydride. The present invention is also directed to synthesis of this special dianhydride.

Abstract: A class of rigid rod and latter polymers having light emitting capability is provided. Included in this class of polymers are those having novel repeating structural units. These rigid rod and ladder polymers are employed in light emitting diodes.

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: This invention relates to a poly (imide amic ester) random copolymer, a precursor thereof, and a process for preparing the same. Specifically this invention relates to a novel precursor of polyimide, poly(imide amic ester) which is chemically stable and has excellent workability in either liquid or solid state, a polyimide obtained therefrom and a process for preparing the same.

Abstract: An intimate polyimide blend, prepared by chemical conversion, containing from 25 to 50 weight % of a first polyimide derived from 90 to 100 mole % of 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 0 to 10 mole % of pyromellitic dianhydride and p-phenylenediamine and from 50 to 75 weight % of a second polyimide derived from pyromellitic dianhydride, from 20 to 50 mole % of p-phenylenediamine and from 50 to 80 mole % of 4,4'-diaminodiphenylether. The polyimide blend provides blister free films having high modulus and low thermal expansion coefficients for use in electronics applications.

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: A method for making polyesterimide varnishes by polycondensing and imidat a mixture of trimellitic anhydride, 4,4'-diamino-diphenyl methane, glycol, dimethyl terephthalate and glycerol or tris(hydroxyethyl) isocyanurate or optionally p,p'-dihydroxy-diphenyl-dimethyl methane, with a transesterification catalyst added, and subsequently dissolving the resulting polyesterimide resin in an organic solvent with a crosslinking catalyst added, characterized by the feature that 2-methyl-1,3-propanediol and/or 2-butyl-2-ethyl-1,3-propanediol is used as the glycol or as one of the glycols.

Abstract: The present invention relates to a process of producing a polyimide-type copolymer, to a thin layer forming agent, to a liquid crystal alignment layer and to processes of producing thin layer formation agents and liquid crystal alignment layers. More specifically, this invention relates to a polyamic acid block copolymer, a polyimide block copolymer, a polyimide-polyamic acid block copolymer, a thin layer forming agent comprised of a polyimide-type block copolymer, and a liquid crystal alignment layer comprised of a polyimide-type block copolymer and processes of their production.

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: This invention provides a poly(amic acid) solution which does not contain aprotic polar solvents such as DMF, NMP, DMAc, DMSO, as well as a polyimide film obtained therefrom having appropriate flexibility and a small coefficient of linear thermal expansion and a coated material in which the polyimide film is formed on a substrate.More particularly, it provides a poly(amic acid) solution which has an aromatic poly(amic acid) and a tertiary amine as the solute and a water soluble alcohol compound and/or a water soluble ether compound as the solvent and contains substantially no aprotic polar solvent, as well as a polyimide film obtained from the poly(amic acid) solution and a coated material obtained by forming the film on a substrate.

Abstract: The invention relates to a PMR type resin which comprises a mixture of:(a) nadic acid of Formula (Ia) or a derivative thereof ##STR1## (b) a diaminobisimide of Formula (Ib) ##STR2## (c) an aromatic tetracarboxylic acid of Formula (Ic) or a derivative thereof ##STR3## the components (a), (b) and (c) being present in the approximate molar proportions of 2:n:n-1 respectively.

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: An electrically conductive bonding film useful in bonding an IC or LSI with a lead frame. The film comprises (A) a polyimide resin obtained by reacting a tetracarboxylic dianhydride component, in which the content of a tetracarboxylic dianhydride represented by the following formula (I): ##STR1## wherein n stands for an integer of 2-20 amounts to at least 70 mole %, with a diamine; and (B) an electrically conductive filler. Optionally, the film may further comprises a thermosetting resin or an imide compound having at least two thermally-crosslinking imido groups per molecule.

Abstract: Polyamide esters which can be prepared from tetracarboxylic dianhydrides and can be converted into polyimides by alcohol cleavage with cyclization, characterized in that the radicals OR of the ester groups --COOR which are substituted during the polyimide formation are alkoxy radicals having 2 to 5 C atoms which are monosubstituted or polysubstituted by fluorine.Polyimides prepared therefrom are suitable as orientation layers in liquid-crystal display elements and in optical wave guides.

Abstract: Described is an electrically conductive bonding film useful in bonding an IC or LSI with a lead frame. The film comprises (A) a polyimide resin obtained by reacting a tetracarboxylic dianhydride component, in which the content of a tetracarboxylic dianhydride represented by the following formula (I): ##STR1## wherein n stands for an integer of 2-20 amounts to at least 70 mole %, with a diamine; (B) an electrically conductive filler, and a thermoset resin. Optionally, the film may further comprises a thermosetting resin or an imide compound having at least two thermally-crosslinking imido groups per molecule.

Abstract: A class of rigid rod and latter polymers having light emitting capability is provided. Included in this class of polymers are those having novel repeating structural units. These rigid rod and ladder polymers are employed in light emitting diodes.

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 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: 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.