Abstract: A free radical polymerization process for the preparation of a thermoplastic resin or resins includes heating a mixture of a multifunctional nitroxide compound and at least one polymerizable monomer compound to form a thermoplastic resin or resins; cooling the mixture; and optionally isolating and washing and drying the thermoplastic resin. A multifunctional nitroxide compound for use in the reaction is formed from a stable free radical agent and a compound having one or more halide functional groups. The free radical polymerization process may be used to prepare telechelic, branched and star polymers.

Abstract: Carboxyl-containing isobutene copolymers are obtainablea) by cationic polymerization of a mixture of from 1 to 99 mol % of isobutene and from 99 to 1 mol % of a 2-methylalk-1-ene at less than 20.degree. C. in the presence of a halogen-containing Lewis acid andb) subsequent grafting of the isobutene copolymer obtainable in this manner with an .alpha.,.beta.-ethylenically unsaturated carboxylic acid or carboxylic acid derivative at above 100.degree. C. and in the presence of a free radical initiator.Such carboxyl-containing isobutene copolymers are particularly suitable as adhesive raw materials or as sealing compounds.

Abstract: A polymer comprising at least one polymer chain is produced by polymerizing, in the presence of a radical generating source and an iodide compound, at least one monomer M.sub.1 having a radically polymerizable unsaturated bond between a carbon atom and an iodine atom constituting a carbon-iodine bond of the iodide compound to form at least one polymer chain between the carbon atom and the iodine atom, wherein the polymerization reaction is carried out in the presence of a monomer M.sub.2 which is different from the monomer M.sub.1 and has a larger addition reactivity with a carbon radical which is generated by cleavage of the carbon-iodine bond of the iodine compound than that of the monomer M.sub.1.

Abstract: Multiple sequential chemical reactions on a polymeric feedstock are carried out in an extruder with multiple reaction zones. Each reaction zone has means for introduction of reagents, for mixing of reagents with polymer and for removal of by/co-products or unreacted reagents.

Abstract: A process for preparing a rubber modified thermoplastic resin, in which a latex in aqueous emulsion is prepared in the presence of an ionic surfactant; a vinyl monomer insoluble or substantially insoluble in water is added, and the particles of the latex are transferred to the monomer to form an organic phase using a transfer agent of opposite charge to the surfactant; and a polymerization of the organic phase is performed.

Abstract: Disclosed is a free radical polymerization process for the preparation of a thermoplastic resin or resins comprising heating a mixture of a free radical initiator, a stable free radical agent, and at least one polymerizable monomer compound to form a thermoplastic resin or resins with a high monomer to polymer conversion; cooling said mixture; optionally isolating the thermoplastic resin or resins; and optionally washing and drying thermoplastic resin or resins.Related free radical processes are also disclosed for the preparation of mixtures and block copolymer thermoplastic resins. Resins prepared by the disclosed processes possesses a narrow polydispersity and a modality that is controlled by the selection of a free radical initiator and stable free radical agent addition step or steps.

Abstract: Resin compositions of improved dispersibility and mechanical properties are obtained by polymerizing a polymerizable compound (A), insitu in a melted thermoplastic resin (B), in the presence of a dispersant (C) reactive or compatible with at least one of the resin (B) and polymerizate of (A).Suitable dispersants include those represented by the general formula (1) or (2)R.sub.1 --L(X--M--X--L).sub.n X--M--R.sub.2 (1)R.sub.1 --L(X--M--X--L).sub.n --R.sub.2 (2)wherein R.sub.1 and R.sub.2 are groups, such as hydrocarbyl acyl, alkoxy, hydroxyl, mercapto, amino, epoxy, isocyanate, carboxylic, carboxylic anhydride, carboxylic halide and aldehyde groups; L and M are residues of a polymer having a number average molecular weight of about 500-about 3,000,000, the difference in solubility parameter between the residue L or M and the resin (B) or polymerizate of (A) being not more than 0.

Abstract: A process for preparing bifunctional living polymers which are able to forth bifunctional telechelic polymers or block copolymers with at least 3 blocks of conjugated dienes and/or vinylaromatics with molecular weights of from 1,500 to 500,000, by bifunctional initiators whose anionic centers are aliphatic carbon atoms which are substituted by lithium and an aliphatic hydrocarbon radical as well as by either 2 aryl radicals or by one aryl radical and one hydrogen radical, where one of the aryl radicals can also be part of the two anionic centers, in a first stage being reacted in the presence of not more than 2.5 moles of an aliphatic ether or a tertiary amine per mole of lithium and not less than 2 mol/l of a conjugated diene at from -40.degree. to +35.degree. C. with not less than two moles of diene, resulting in the formation of low molecular weight diene oligomers which in turn act as bifunctional initiators, and using the latter in a second reaction stage in a conventional manner at above 40.degree. C.

Abstract: A toner for developing electrostatic images contains a binder resin and a colorant or a magnetic material. The binder is prepared by polymerizing ethylenically unsaturated monomer(s) in the presence of less than 0.1% by weight of the monomer(s) of a radical polymerization initiator. The resulting polymer or copolymer is dissolved in a polymerizable monomer and solution or suspension polymerized with a radical polymerization initiator. The resulting binder resin is substantially free of fragments of radical polymerization initiator which tend to bond to molecular chain terminals.

Abstract: The present invention provides a novel dental composition and a method of making shaped dental articles therefrom via photoiniferter polymerization. The dental composition comprises acrylic photoiniferter block polymer, a monomer charge comprising free radically polymerizable acrylic monomer, and a filler and optionally includes pigments, sensitizers, medicaments, stabilizers, accelerators, etc. The dental composition is alternately exposed to a source of radiant energy and shaped in a desired manner in order to form a partially cured dental article. The partially cured dental article is then cured by a final exposure to the radiant energy source, providing a final cured article. The resultant reinforced acrylic copolymer system provides a shaped dental article which can be a denture base, a denture liner or a restorative.

Abstract: This invention concerns a "living" free radical polymerization process for preparing polymers having a narrow distribution of molecular weights.

Abstract: Disclosed are substantially non-crosslinked anhydride-modified, saturated ethylene polymers and a process for making them which comprises mixing together in the absence of solvent:(a) maleic anhydride;(b) a free radical initiator;(c) a saturated ethylene polymer; and(d) a polyamideat a temperature at which the saturated ethylene polymer and polyamide undergo deformation and are converted to a molten or fluid state.

Abstract: The invention concerns a process for the preparation of monodispersed polymer beads, wherein in a first stage a seed polymer is prepared in an organic solvent and in the presence of an R--X compound, separated and in a second stage an emulsion polymerization is carried out in an aqueous medium in the presence of the seed polymer. The polymer beads obtained in this manner have diameters in the range of 0.5 to 50 .mu.m, and may be used in the immobilization of proteins and cells, as carriers of catalysts and in peptide synthesis and in chromatography.

Abstract: There is provided a process for producing a styrenic graft copolymer which comprises coplymerizing a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond in the presence of a catalyst comprising as primary ingredient (A) a transition metal compound and (B) a contact product of an organoaluminum compound and a condensation agent or (C) a compound which produces an ionic complex by reacting with the above-mentioned transition metal compound and subsequently graft polymerizing an ethylenically unsaturated monomer onto the resultant styrenic copolymer.The above-described styrenic graft copolymer is greatly improved in terms of compatibility, adhesivity, coatability and wettability while preserving heat resistance and chemical resistance thereof, and thus effective as a variety of constructional materials and compatibilizing agents.

Abstract: A toner for developing electrostatic latent images with a good combination of fixability, anti-offset characteristic, anti-sticking characteristic and pulverizability is provided as a composition comprising a colorant or magnetic material and a binder resin. The binder resin has 0.1 to 60 wt. % of a chloroform-insoluble or a THF (tetrahydrofuran)insoluble and a THF-soluble, the THF-soluble providing a molecular weight distribution in the chromatogram of GPC (gel permeation chromatography) thereof such that there are a main peak in the molecular weight range of 1,000 to 25,000 and a sub-peak or shoulder in the molecular weight range of 2,000 to 150,000. The binder resin may suitably be obtained through two polymerization steps including a solution polymerization step and a suspension polymerization step.

Abstract: A process for producing monodispersed fine particles of a vinyl polymer is disclosed, which comprises polymerizing monomers containing at least one vinyl monomer selected from the group consisting of aromatic vinyl compounds, acrylic esters, and a methacrylic ester in the presence of (1) a surface active agent represented by formula (I) ##STR1## wherein R.sub.1 and R.sub.2, which may be the same or different, each represents a substituted or unsubstituted alkyl group having from 4 to 8 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted cyclohexyl group and M represents an alkali metal, (2) from 10.sup.-3 to 10.sup.-1 mol/l of a persulfate as a polymerization initiator, and (3) from 10.sup.-4 to 10.sup.-2 mol/l of a divalent metal sulfate as an electrolyte. Monodispersed vinyl polymer fine particles having a particle size of 1 .mu.m or greater with a very narrow size distribution are obtained.

Abstract: Elastomeric polymers comprising polymerized alpha-olefins or conjugated alkadienes are produced by cationic polymerization in the presence of titanium tetrachloride and an electron pair donor selected from pyridine or a non-hindered alkylpyridine. The polymers have very narrow, mono-modal molecular weight distributions such a achived by anionic polymerization. Polymerization of each monomer is terminated prior to broadening of the molecular weight distribution which significantly detracts from polymer properties.

Abstract: A method for preparing asymmetric radial polymers wherein the different polymeric arms are contacted sequentially with a nonpolymerizable coupling agent. Contacting of the final step in the process, which frequently but not necessarily always will be the second step in the process, will be carried out in the presence of a polar compound suitable for increasing the amount of vinyl content in a conjugated diolefin polymer during polymerization thereof. The method used narrows the relative arm distribution of the several asymmetric radial polymers produced and significantly increases the amount of total product having the desired ratio of polymeric arms and accomplishes this objective in relatively short reaction time.

Abstract: A crosslinked, unsaturated elastomeric polymer of a C.sub.4 to C.sub.7 isomonoolefin and a C.sub.4 to C.sub.14 conjugated multiolefin is produced by curing the corresponding uncrosslinked polymer having a low level of chemically bound halogen with a curing agent which reacts only with the halogen (e.g., zinc oxide) in combination with a bifunctional dienophile (e.g., a bismaleimide). The uncrosslinked elastomeric polymer is particularly suitable for use in the pharmaceutical industry, for example, for container closures. Shaped rubbery products comprising the crosslinked copolymer are also provided.

Abstract: An adhesive which contains a tackifying resin and a branched three-armed block copolymer composition comprised of polymeric blocks wherein the molecular weight is from about 180,000 to about 250,000, the polystyrene content is from about 17 to about 23% by weight of the block copolymer composition and the percentage of S-I arms which are load bearing is greater than about 85%.

Abstract: An AB-type block copolymer represented by formula (I): ##STR1## wherein R.sup.1 represents a hydrocarbon group having 1 to 10 carbon atoms; R.sup.2 represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; R.sup.3 represents a benzyl group, ##STR2## wherein R.sup.4 represents an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 18 carbon atoms; M represents a group represented by the formula (M.sup.2).sub.m --(M.sup.1).sub.n or (M.sup.1).sub.m --(M.sup.2).sub.n, each of m and n being a natural number of 20 to 5000; is prepared by a process of first polymerizing either a monomer for forming the M.sup.1 block or a monomer for forming the M.sup.2 block in the presence of a sulfur-containing compound having formula (XIII): ##STR3## wherein R.sup.1, R.sup.2 and R.sup.

Abstract: A process is provided for the production of a graft copolymer by means of emulsion polymerization. The graft base used is a sulfonate group-containing vinyl ester/ethylene latex which is stabilized exclusively by an anionic emulsifier (CMC.gtoreq.0.5% by weight in H.sub.2 O) and is grafted, preferably with vinyl chloride, without further addition of emulsifier or protective colloid. The graft copolymers according to the invention have good water resistance and very good thermoplastic processability. They are useful as impact modifiers and for the production of articles, such as, soft to semi-hard moldings.

Abstract: A thermoplastic elastomer comprising 55-90 parts by weight of a crosslinked acrylic rubber having a glass transition temperature of 0.degree. C. or lower and 45-10 parts by weight a copolymer of a methacrylate ester with a maleimide, which has a glass transition temperature of 110.degree. C. or higher. This thermoplastic elastomer may be produced by a first step of polymerizing an acrylic ester in the presence of a polyfunctional monomer with or without a chain transfer agent and a second step of adding a methacrylate ester and a maleimide to the resulting acrylic rubber to carry out copolymerization.

Abstract: An AB type-block copolymer of the formula: ##STR1## wherein R.sup.1 is a hydrocarbon group having 1 to 10 carbon atoms; R.sup.2 is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; R.sup.3 is a benzyl group, an alkyl group having 1 to 18 carbon atoms or ##STR2## wherein R.sup.4 is an alkyl group having 1 to 18 carbon atoms; M represents a fluorine-containing AB-type block copolymer having a fluorine-containing polymer chain and a polymer chain having affinity for a resin.

Abstract: A process for preparing a rubber modified thermoplastic resin, in which a latex in aqueous emulsion is prepared in the presence of a non-ionic surfactant; a vinyl monomer insoluble or substantially insoluble water is added, and the particles of the latex are transferred to the monomer to form an organic phase using a polymer or copolymer based on carboxylic acid units capable of forming an interpolymeric complex with the non-ionic surfactant; and a suspension or bulk polymerization of the organic phase is performed.

Abstract: This invention provides a novel catalyst composed of a complex of an organic ether and a Lewis acid, preferably boron trichloride that can add olefin monomers to increase the molecular weight of the complex from as low as 200 to in excess of 100,000 preferably 500 or 1000 to 10,000 and higher, with the complex being active viz., living, until the complex dies, viz., is decomposed or destroyed so that polymers in the liquid or easily liquefiable range of 300 to about 10,000 and preferably 500 or 1000 to 10,000 and higher can be made or those more difficult to be liquefied or unliquefiable, viz., those of over 10,000 up to 100,000 and having useful end groups such as the halogens and specifically chloride.

Abstract: Hybrid star polymers with acrylic arms and crosslinked polysiloxane cores can be made by a polycondensation of substituent alkoxysilyl groups contained in acrylic ester groups of acrylic block copolymers to form the cores.

Abstract: CF.sub.2 .dbd.CF.sub.2 and CF.sub.3 OCF.dbd.CF.sub.2 are subjected to copolymerization reaction in the presence of an organic compound containing at least one of iodine and bromine, and then CF.sub.2 .dbd.CF.sub.2 and CH.sub.2 .dbd.CF.sub.2 are supplied to the reaction system to continue the polymerization reaction.The thus obtained fluorine-containing block copolymer is of a low vinylidene fluoride content type and has a good solvent resistance.

Abstract: A process for preparing a rubber modified thermoplastic resin, in which a latex in aqueous emulsion is prepared in the presence of a non-ionic surfactant; a vinyl monomer insoluble or substantially insoluble water is added, and the particles of the latex are transferred to the monomer to form an organic phase using a polymer or copolymer based on carboxylic acid units capable of forming an interpolymeric complex with the non-ionic surfactant; and a suspension or bulk polymerization of the organic phase is performed.

Abstract: Process for adjusting the cis-trans-double bond configuration in polyalkenamers produced by ring-opening polymerization of cis,cis-1,5-cyclooctadiene or 2-norbornene wherein the polymerization is performed in the presence of isoprene and/or a cyclic olefin with a double-bond pair in the 1,3-position.

Abstract: Thermoplastic molding compositions are provided which comprise a polycarbonate resin alone or in combination with a saturated polyester resin and/or a poly(etherester) elastomer, a poly(etherimide ester) elastomer or a mixture thereof; a polyphenylene ether resin and a saturated polyester resin; a polyphenylene ether resin, a saturated polyester resin and a polycarbonate resin; or mixtures thereof modified with multi-stage polyorganosiloxane/polyvinyl-based graft polymers which exhibit markedly improved impact strength and weld line strength with no tendency to delaminate or to show mottled surfaces after molding.

Abstract: Thermoplastic resin compositions are blended with a novel silicone-based flame retardant which also imparts good impact resistance and low temperature ductility on the thermoplastic resins. Polyorganosiloxanes are grafted with vinyl-based polymers, such as bromostyrenes, capable of exhibiting flame retarding properties and then blended with normally flammable thermoplastic resins.

Abstract: A polymer prepared by subjecting to conditions of radical graft polymerization a copolymer of an .alpha.-olefin and an aliphatic nonconjugated diene and a monomer that is capable of radical polymerization with said copolymer is described. This polymer has high miscibility with a dissimilar resin and has a high practical value for use as a compatibilizing agent in blending two or more resins.

Abstract: This invention provides a novel catalyst composed of a complex of an organic ether and a Lewis acid, preferably boron trichloride that can add olefin monomers to increase the molecular weight of the complex from as low as 200 to in excess of 100,000 preferably 500 or 1000 to 10,000 and higher, with the complex being active viz., living, until the complex dies, viz., is decomposed or destroyed so that polymers in the liquid or easily liquefiable range of 300 to about 10,000 and preferably 500 or 1000 to 10,000 and higher can be made or those more difficult to be liquified or unliquefiable, viz., those of over 10,000 up to 100,000 and having useful end groups such as the halogens and specifically chloride.

Abstract: A process for preparing a rubber modified thermoplastic resin, in which a latex in aqueous emulsion is prepared in the presence of an ionic surfactant; a vinyl monomer insoluble or substantially insoluble in water is added, and the particles of the latex are transferred to the monomer to form an organic phase using a transfer agent of opposite charge to the surfactant; and a polymerization of the organic phase is performed.

Abstract: In block copolymers of the general formula A--B--A' which have a molecular weight of less than 300,000 and consist of from 18 to 40% by weight of a vinylaromatic hydrocarbon and from 60 to 82% by weight of one or more partially or completely hydrogenated hydrocarbons and in which A and A' are each a polymer block of a vinylaromatic hydrocarbon and B is a polymer block of a diene hydrocarbon, the weight ratio of the polymer blocks A to A' is less than or equal to 1:5 and greater than 1:10 and the mean molecular weight of polymer block A is from 2,000 to 20,000 and that of the polymer block A' is from 10,000 to 110,000 and the molecular weight of the B block is not less than 18,000.

Abstract: A process for the production of a product comprising ethylene/propylene copolymer incorporated into a matrix of propylene homopolymer or copolymer comprising the following steps:(a) contacting propylene or propylene and at least one alpha-olefin having 2 to 8 carbon atoms, and hydrogen, wherein the alpha-olefin is present in a ratio of about 0.01 to about 0.06 mole of alpha-olefin per mole of propylene and the hydrogen is present in a ratio of about 0.001 to about 0.

Abstract: Hybrid star polymers with functional acrylic arms made by group transfer polymerization and crosslinked cores made by condensation reactions with the functional groups on the arms.

Abstract: Hybrid star polymers with functional acrylic arms and crosslinked cores.

Abstract: Macromonomer prepared by contacting and reacting a polymer (oligomer) having at least three monomer repeat units and at least one silyl ether group, in the presence of an anion catalyst, with a terminally unsaturated acyl fluoride or sulfonyl fluoride.

Abstract: A linear alternating polymer of carbon monoxide and at least one ethylenically unsaturated hydrocarbon exhibits improved thermal stability as evidenced by reduced weight loss at elevated temperatures and enhanced crystallinity and crystallizability when produced with a catalyst composition formed from preformed palladium trifluoroacetate and a bidentate phosphine ligand.

Abstract: Ethylene propylene copolymer elastomers and ethylene propylene diene terpolymer elastomers are shown which, when cured, exhibit improved oil resistance and chemical aging properties at elevated temperatures and pressures. A previously polymerized liquid 1,2-polybutadiene is incorporated into the elastomer by chemical blending during the polymerization process. Such compositions are useful as electrical insulating materials for use under extreme environmental conditions, particularly in wire and cable constructions.

Abstract: "Living" polymers and their preparation from acrylic-type or maleimide monomers and organosilicon, -tin or -germanium initiators.

Abstract: The present invention provides a reactive acrylic oligomer obtained by the method of polymerizing at least one .alpha., .beta.-ethylenically unsaturated monomers having no oxirane ring and/or carboxyl groups, in an organic solvent and in the presence of azo initiator having carboxyl group and tertiary amine, and then reacting the same with a compound having .alpha., .beta.-ethylenically unsaturated bonding and oxirane ring. The invention further provides a grafted acrylic resinous composition obtained by the method of copolymerizing said reactive acrylic oligomer with at least one .alpha., .beta.-ethylenically unsaturated monomers which will constitute the backbone of the graft polymer, as well as the coating composition containing as resinous vehicle the abovesaid resinous composition and especially the resinous composition whose graft polymer is an amphoteric acrylic resin having backbone chain with acidic groups and branched chains with concentrated quantity of basic groups.

Abstract: In a process for producing a high impact polystyrene comprising the radical polymerization of styrene in the presence of a butadiene rubber, the improvement which comprises, the butadiene rubber being a highly branched polymer prepared by homopolymerizing 1,3-butadiene or copolymerizing 1,3-butadiene and styrene in the presence of an organolithium compound and a Lewis base compound, followed by further reacting the resulting polymer with a multifunctional halogen compound; in the butadiene rubber, the average content of 1,2-bonds being 18 to 32 mole % based on the total bonded butadiene, the content of bonded styrene being up to 10% by weight, and the content of branched polymer chains being at least 60% by weight; the butadiene rubber exhibiting a Mooney viscosity of 40 to 90 at 100.degree. C. and a solution viscosity in styrene of 60 to 90 cps at 25.degree. C.

Abstract: A polymerizable polymer is obtained by the anionic polymerization and termination by use of a vinyl monomer. It produces a graft copolymer by co-polymerization with another monomer. The process produces a new, polymerizable, optically active polymer and a graft copolymer thereof.

Abstract: A process for producing a propylene block copolymer by a three-step reaction in the presence of a stereoregular catalyst. At the first step, propylene is polymerized at a temperature of 55.degree. C. or more to form polypropylene having an intrinsic viscosity of from 0.5 to 3.5 in the prescribed amount. At the second step, propylene is polymerized at a temperature of from 30.degree. to 90.degree. C. to form polypropylene having an intrinsic viscosity of at least 4 in the prescribed amount. And at the third step, ethylene and propylene are copolymerized at a temperature of from 30.degree. to 90.degree. C. to form an ethylene-propylene copolymer having an intrinsic viscosity of at least three in the prescribed amount. The propylene block copolymer formed by the three steps is superior and well balanced in impact resistance and stiffness.

Abstract: A method for making impact resistant molding compositions wherein a hard phase having a glass transition temperature above 25.degree. C. and consisting principally of methyl methacrylate is polymerized at least partially in a first stage, following which the monomers of a rubbery phase whose polymers have a glass transition temperature below 25.degree. C. are added in a second stage and the polymerization is carried to completion, polymerization of the hard phase in the first stage being performed in a presence of an oil soluble free radical initiator and of an organosulfur chain transfer agent having at least two thiol groups in the molecule, and polymerization of the monomers of the rubbery phase in the second stage being carried out with graft crosslinkers in the presence of the previously formed hard phase.

Abstract: A MBS resin useful as a reinforcement for vinyl chloride polymers and capable of improving the impact resistance of the vinyl chloride polymers without impairing the transparency thereof, which is prepared by graft-polymerizing a monomer mixture comprising an aromatic vinyl compound and an alkyl methacrylate onto a butadiene copolymer comprising styrene and butadiene, the butadiene copolymer being present in the polymerization system in a higher proportion as compared with a conventional MBS resin and present in the form of an aqueous latex of particles having a structure such that a portion formed in the last stage of a polymerization for the preparation of the butadiene copolymer amounting to 20% by weight of the produced butadiene copolymer, has a very high butadiene content of 80 to 100% by weight and moreover has at least 5% by weight higher butadiene content than the average butadiene content of the produced butadiene copolymer.

Abstract: A process for the production of ethylene graft copolymers containing anhydride or carboxyl groups in homogeneous or heterogeneous phase in tert.-butanol or methylene chloride wherein (A) from 5 to 70% by weight of a monomer mixture of: (a) from 10 to 80% by weight of a vinyl ester of an aliphatic C.sub.1 -C.sub.18 -monocarboxylic acid; and (b) from 90 to 30% by weight of maleic acid anhydride and/or its C.sub.1 -C.sub.20 -alkyl semiesters; are radically polymerized in the presence of (B) from 95 to 30% by weight of an ethylene homopolymer or an ethylene/vinyl ester copolymer as the graft substrate.