Abstract: A resin composition comprises an EVOH (A) and a thermoplastic polymer (B) having at least one functional group selected from the group consisting of boronic acid group, borinic acid group and boron-containing groups convertible into boronic acid group or borinic acid group in the presence of water. The composition may further comprise a thermoplastic polymer (C) other than (A) or (B). The resin compositions thus obtained have good compatibility and give molded products having superior transparency and good mechanical properties.

Abstract: A resin composition for low expansion moldings which comprises (A) 20 to 80 parts by weight of a vinyl chloride resin having an average degree of polymerization of from 500 to 1700 and (B) correspondingly from 80 to 20 parts by weight of a copolymer made of 60 to 90 parts by weight a polymerizable monomer mixture consisting of 20 to 40 wt % of acrylonitrile, 20 to 60 wt % of .alpha.-methylstyrene and 20 to 40 wt % of styrene and, correspondingly, 40 to 10 parts by weight of a crosslinked acrylic rubber. The resin composition further comprises (C) 0.5 to 30 parts by weight of an acrylic resin having a reduced viscosity of not less than 3.0 dl/g when measured by use of a chloroform solution of the acrylic resin at a concentration of 0.1 g/100 ml, (D) 0.1 to 10 parts by weight of a thermally decomposable rosining agent, and (E) from 1 to 10 parts by weight of a stabilizer, each based on 100 parts by weight of a mixture of the components (A) and (B).

Abstract: Polyisoolefins are produced using the process according to the invention by polymerising isoolefins, optionally with conjugated or unconjugated dienes and/or cationically polymerisable, mono- or polyunsaturated compounds in solution, in suspension or in the gas phase at temperatures of -100.degree. C. to +200.degree. C. and pressures of 0.1 to 100 bar in the presence of an initiator system consisting of aluminium-cyclopentadienyl compounds and boron compounds.

Abstract: The present invention provides a method of anionic synthesis of stable macrocyclic polymers that are compounded to form vulcanizable elastomeric compounds exhibiting reduced hysteresis properties. Cyclic organometallic compounds containing divalent metal atoms of Groups IIA and IIB of the Periodic System are employed as initiators of anionic polymerization of conjugated diene, vinyl aromatic and/or triene monomers. Coupling of the living ends of the resulting macrocyclic polymers or copolymers with a coupling agent or a coupling agent that is also a functionalizing agent results in stable macrocyclic polymers with improved hysteresis properties.

Abstract: The invention is a practical process for anionically synthesizing commercially significant quantities of macrocyclic polymers from polar and/or non-polar monomers by using Group IIA and IIB metal cyclic organometallic initiators. Activation of the ring metal atom results in anionic polymerization of the monomers by addition into the initiator ring at the bonds between the atom and its two adjacent carbon atoms, the metal atom acting as a bridge between the two living ends of the propagating chain. Coupling of the cyclic polymer living ends by coupling agents produces macrocyclic polymers that are stable in air and moisture and that exhibit desirable properties, such as low viscosities at high molecular weights. Such macrocyclic polymers provide enhanced polymer processability during molding, extruding and the forming of films.

Abstract: Living random (meth)acrylic copolymers, facilely converted into random co(meth)acrylates and block copolymers thereof, comprise the anionic copolymerizates of at least one comonomer A with at least one comonomer B selected from among the (meth)acrylates and maleimides, at least one of the comonomers A and B comprising a (meth)acrylate, in the presence of (i) at least one alkali or alkaline earth metal, mono- or difunctional initiator and (ii) at least one ligand, for example a nonnitrogenous macrocyclic complexant, e.g., a crown ether, or an alkali metal alcoholate.

Abstract: The invention is a practical process for anionically synthesizing multiblock polymers containing a plurality of blocks formed from polar and/or non-polar monomers by using a cyclic organometallic compound initiator that comprises a divalent metal atom and an organic moiety contained in a ring, preferably a cycloorganomagnesium initiator. Activation of the ring metallic atom results in anionic polymerization of the monomers by addition into the initiator ring at the bonds between the metallic atom and its two adjacent carbon atoms, the metallic atom acting as a bridge between the two living ends of the propagating chain. The active chain ends can be coupled or terminated.

Abstract: A composition of the invention includes a polymer component which consists essentially of an asymmetric telechelic polymer having a boron-containing head group. These asymmetric telechelic polymers can also have halogen tail groups. The end group functionalities make these polymers extremely useful because, for example, the functionalities facilitate subsequent elaboration of the polymer. A method of forming the composition includes forming a reaction mixture which consists essentially of an olefin, a Lewis acid, and a base which will react with essentially all protic impurities in the reaction mixture, thereby preventing protic initiation during polymerization of the olefin. The reaction mixture is exposed to conditions which cause the olefin to react to form an initiator in situ which can cause polymerization of additional olefin to form a polymerized olefin consisting essentially of a telechelic polymer. In another embodiment, the initiator has the structure BX.sub.2 --[CH.sub.2 --C(CH.sub.3).sub.2 ].sub.

Abstract: The subject invention relates to an anionic polymerization technique for synthesizing rubbery polymers of conjugated diolefin monomers, such as rubbery copolymer of .alpha.-methylstyrene and 1,3-butadiene. These rubbery copolymers exhibit an excellent combination of properties for utilization in tire tread rubber compounds. They have high trans-isomer contents which leads to good treadwear characteristics and a broad molecular weight distribution which enhances processability.

Abstract: The subject invention relates to an anionic polymerization technique for synthesizing rubbery polymers of conjugated diolefin monomers, such as a rubbery copolymer of .alpha.-methylstyrene and 1,3-butadiene. These rubbery copolymers exhibit an excellent combination of properties for utilization in tire tread rubber compounds. They have high trans-isomer contents which leads to good treadwear characteristics and a broad molecular weight distribution which enhances processability.

Abstract: The present invention provides anionic polymerization initiators, comprising lithium amino magnesiate complexes, resulting in diene polymer and copolymer elastomers. The invention initiators have stable living ends at high polymerization temperatures and produce polymers containing a high level of tertiary amine functionality. Such polymers exhibit an increased efficiency in coupling termination reactions, and elastomers and products prepared from such polymers exhibit reduced hysteresis properties. Methods are also provided for preparing the initiators, the polymers and the elastomers.

Abstract: Transparent cycloolefin copolymers having a high tensile strength are obtained by polymerization of a polycyclic olefin, ethylene and, if desired, an acyclic olefin and/or a monocylcic olefin in the presence of a catalyst system which comprises a cocatalyst and an asymmetrical metallocene compound of the formula ##STR1## in which R.sup.16 is cyclopentadienyl and R.sup.17 is indenyl.

Abstract: Living random (meth)acrylic copolymers, facilely converted into random co(meth)acrylates and block copolymers thereof, comprise the anionic copolymerizates of at least one comonomer A with at least one comonomer B selected from among the (meth)acrylates and maleimides, at least one of the comonomers A and B comprising a (meth)acrylate, in the presence of (i) at least one alkali or alkaline earth metal, mono- or difunctional initiator and (ii) at least one ligand, for example a nonnitrogenous macrocyclic complexant, e.g., a crown ether, or an alkali metal alcoholate.

Abstract: It has been unexpectedly discovered that various compounds, such as alkyl tetrahydrofurfuryl ethers, can be used to modify anionic polymerizations of conjugated diene monomers. These modifiers can be used to polymerize isoprene monomer into high 3,4-polyisoprene at excellent polymerization rates. This is in contrast to the modifiers such as tetramethylethylene diamine which are typically used to modify such polymerizations. This invention more specifically discloses a process for the synthesis of 3,4-polyisoprene which comprises polymerizing isoprene monomer in an organic solvent in the presence of a catalyst system which is comprised of (a) a lithium initiator and (b) an alkyltetrahydrofurfuryl ether modifier, wherein the alkyl group in the alkyltetrahydrofurfuryl ether modifier contains from 6 to about 10 carbon atoms.

Abstract: Processes for the synthesis of several new carbene compounds of ruthenium and osmium are provided. These novel complexes function as stable, well-defined catalysts for the metathesis polymerization of cyclic olefins.

Abstract: It has been unexpectedly discovered that various compounds, such as alkyl tetrahydrofurfuryl ethers, can be used to modify anionic polymerizations of conjugated diene monomers. These modifiers can be used to polymerize isoprene monomer into high 3,4-polyisoprene at excellent polymerization rates. This is in contrast to the modifiers such as tetramethylethylene diamine which are typically used to modify such polymerizations. This invention more specifically discloses a process for the synthesis of 3,4-polyisoprene which comprises polymerizing isoprene monomer in an organic solvent in the presence of a catalyst system which is comprised of (a) a lithium initiator and (b) a modifier which is an alkyltetrahydrofurfuryl ether selected from the group consisting of ethyltetrahydrofurfuryl ether, propyltetrahydrofurfuryl ether, and butyltetrahydrofurfuryl ether.

Abstract: A (halomethyl arene)-modified elastomer is made by reacting a lithium terminated elastomer intermediate with the halogen atoms of a halomethyl vinyl arene compound. A road-contacting tread component for a pneumatic tire is fabricated from vulcanized elastomer made by vulcanizing an elastomer composition of a (halomethyl arene)-modified elastomer, a carbon black reinforcing agent, and a sulfur-based vulcanizing system. A process for making a (halomethyl arene)-modified elastomer includes polymerizing at least one diene monomer with a lithium-containing initiator, capping the lithium terminated elastomer by reaction with a halomethyl arene compound, and recovering the modified elastomer.

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

Abstract: It has been unexpectedly discovered that salts of tetrahydrofurfuryl alcohols, such as the lithium, potassium, and sodium salts of tetrahydrofuryl alcohols, can be used to modify anionic polymerizations of conjugated diene monomers. These modifiers can be used to polymerize isoprene monomer into polyisoprene having from 20% to 30% 1,2-microstructure at excellent polymerization rates. This invention more specifically discloses a catalyst system which is particularly useful in the anionic polymerization of conjugated diene monomers into polymers which is comprised of (a) a initiator which is selected from the group consisting of organolithium compounds, organosodium compounds, organopotassium compounds, organomagnesium compounds, and organobarium compounds, and (b) a modifier which is a metal salt of a tetrahydrofurfuryl alcohol.

Abstract: Adhesive component formulations containing (meth)acrylic acid esters, containing formamide groups, and optionally an initiator, which are used as an adhesive component for the treatment of collagen-containing materials.

Abstract: This system for priming the animic polymerization of (meth)acrylates includes at least one primer of the formula R--M (I) in which M represents a metal selected from alkaline and alkaline earth metals and R represents an alkyl radical with a straight or branched chain containing 2 to 6 atoms of carbon or an aryl radical or an arylalkyl radical. H is characterized in that it further contains at least one organic derivative of an alkaline metal, with the proviso that said organic derivative is neither an alcoholate nor a carboxyl acid ester substituted in position .alpha. by said metal. Applications in the anionic polymerization of (meth)acrylates.

Abstract: A method of preventing polymer scale deposition in a polymerization vessel in polymerization of a particular monomer having an ethylenic double bond having a high dissolving power against the conventional scale preventive coatings, wherein said polymerization is carried out in a polymerization vessel of which the inner wall has been previously coated with a first coating solution comprising:(A) a water-soluble anionic dye, and(B) at least one member selected from the group consisting of inorganic colloids and cationic dyes, to form a first coating, and the first coating thus formed has been then coated with a second coating solution comprising:(C) an alkaline earth metal compound, and at least one member selected from the group consisting of:(D) a water-soluble anionic dye and(E) an inorganic colloid, to form a second coating. The polymerization vessel having the double coating as prepared above is also disclosed. Polymer scale deposition can be effectively prevented.

Abstract: A Grignard reagent having the formula RMgX where R is a cycloalkyl or cycloalkenyl group and X is Cl, Br or I, is used as the catalyst activator for the metathesis polymerization of dicyclopentadiene and other polycyclic cycloolefins.

Abstract: Disclosed is a linear acrylonitrile polymer having a viscosity average molecular weight of at least 50,000, which has a stereoregularity such that the polymer satisfies requirements of I>0.4 and (I+3S)>0.95, wherein I represents the fraction of the isotactic triad and S represents the fraction of the syndiotactic triad. A shaped article is made from a composition comprised of the linear acrylonitrile polymer and a solvent or plasticizer which is selected from a protonic acid and an aqueous solution thereof, an aqueous inorganic salt solution, and a mixture of an organic solvent and an inorganic salt. The fiber made therefrom has an enhanced drawability.

Abstract: A process for preparing a blend of a norbornene polymer and a vinyl polymer, the process comprising (a) injecting into a mold a reaction mixture comprising from about 30 to about 70 weight percent, based on the total monomer weight, of at least one substituted or unsubstituted norbornene monomer, from about 70 to about 30 weight percent of at least one polymerizable monomer, a metathesis catalyst system comprising a transition metal catalyst and a cocatalyst, and a free radical initiator, and (b) subjecting the reaction mixture to temperature conditions to sequentially initiate polymerization of the norbornene monomer and the vinyl monomer.

Abstract: A metathesis catalyst activator composition consisting essentially of an alkoxyalkylaluminum halide and a tin compound in a molar ratio of about 0.15 to 2 moles of the alkoxyalkylaluminum halide per mole of tin compound.

Abstract: Liquid telechelic polymers are made from dienes and are produced via anionic polymerization. While having low molecular weight, for example less than 15,000, the telechelic polymers are generally gel-free, have high amounts of trans-1,4 structure, low vinyl unsaturation and low bulk viscosities. The liquid telechelic polymers are made utilizing a trimetallic initiator comprised of (1) an organopolylithium compound and (2) a complex of a trialiphatic substituted aluminum compound or derivative thereof and a barium salt of an organic alcohol.

Abstract: The invention relates to an improved process for the polymerization of polar compounds which have a C.dbd.C double bond in the .alpha.-position to a carbonyl, nitrile, sulfone, phosphone or nitro group, such as, for example, acrylic acid derivatives, .alpha.-nitroolefins, vinyl sulfone derivatives and vinyl phosphonic acid esters. The quasi-ionic polymerization is initiated by organometallic compounds of silicon, germanium and tin as initiators together with nucleophilic or electrophilic catalysts, and is carried out at temperatures in the range of from -100.degree. C. to +100.degree. C., in which the initiators are selected from silanes, germanes, stannanes, siloxanes, germoxanes or stannoxanes having at least one metal-bonded allyl or propargyl group, which may be substituted by hydrocarbon groups, per metal atom.

Abstract: Isobutylene homopolymers and copolymers are prepared using a catalyst system comprising a haloadamantane component and a Lewis acid. Branched polymers are prepared using polyhaloadamantanes, the branches being attached to the adamantane at the former location of the halide. The preferred catalyst systems are diethylaluminum chloride and bromoadamantane as well as polybromo, or polychloroadamantanes.

Abstract: The invention provides a novel polymeric compound having crosslinkability by irradiation with actinic rays, e.g. ultraviolet light, and useful as a polymeric base ingredient of a negative type photoresist composition with high sensitivity and resistance against dry etching. The polymer is obtained by the anionic living polymerization of a vinylsilyl group-containing styrene derivative of the formulaCH.sub.2 .dbd.CH--C.sub.6 H.sub.4 --CH.sub.2).sub.n SiR.sub.2 --CH.dbd.CH.sub.2,in which R is a monovalent hydrocarbon group, e.g. methyl and phenyl, and n is an integer of 0 to 3, in a specific solvent in the presence of a specific polymerization initiator so that the polymerization takes place only at the styrenic vinyl groups leaving the silicon-bonded vinyl groups unpolymerized. Quite unexpectedly, the polymer has a very uniform monodisperse distribution of the molecular weight.

Abstract: A cyclohexylmethyleneimine compound represented by the following general formula: ##STR1## wherein R is an alkyl group bonded to individual carbon atom of the cyclohexyl ring and n is an integer of 0 to 5, or a methyleneimine composition containing at least the cyclohexylmethyleneimine compound can be stabilized by an organic lithium compound represented by the following general formula:R'--Li,wherein R' is an alkyl, aryl or aralkyl group, and can be preserved stably for a long time.

Abstract: An optically active polymer is obtained by polymerizing a vinyl monomer in the presence of a catalyst which comprises an asymmetric ligand compound of the formula (I) or (II): ##STR1## in which R.sub.1 and R.sub.4 each are --O--R.sub.7, --S--R.sub.7, ##STR2## R.sub.2, R.sub.3, R.sub.5, R.sub.6, R.sub.7 and R.sub.8 each are an alkyl group having 1 to 10 carbon atoms; X is hydrogen, an alkyl group having 1 to 10 carbon atoms or a halogen; and n is a number of 1 to 4; and an anionic initiator to form a complex with said ligand compound.

Abstract: An isoprene-butadiene copolymer rubber having improved processing properties which comprises a microstructure of the butadiene portion having from 70% to 90% of trans-1,4 linkage and from 2% to 8% of vinyl linkage, an isoprene content of from 3 to 25 wt %, and a styrene content of from 0 to 30 wt %, said copolymer rubber having a Mooney Viscosity of from 30 to 150, and a molecular weight distribution, Mw/Mn of from 1.2 to 3.5, said rubber, in the unelongated state, not showing a melting point measured by the differential calorimeter analysis method. The copolymer rubber of the present invention can be used for tires, for example, a tread and a carcass or for other rubber uses.

Abstract: What are disclosed are a method for making halogen-free organomagnesium alkoxides of the formulaR.sup.1.sub.a R.sup.2.sub.b Mg(OR.sup.3).sub.c (OR.sup.4).sub.c,wherein R.sup.1 and R.sup.2 are phenyl or alkyl, R.sup.3 and R.sup.4 are alkyl, and wherein (a+b)=(c+d)=1, by reacting(R.sup.1.sub.a R.sup.2.sub.b).sub.2 Mgwith Mg [(OR.sup.3).sub.c (OR.sup.4).sub.d ].sub.2,halogen-free organomagnesium alkoxides made by this method, and stable solutions of such organomagnesium alkoxides in an inert hydrocarbon solvent.

Abstract: New compositions and a process for the preparation of conjugated diene polymers of broadened molecular weight distribution by reacting non-terminated lithium catalyzed conjugated diene polymers with linear organic compounds selected from the group of carbonates, thiocarbonates and sulfites. The resulting new compositions are suitable for use in making high impact plastics and for fabricating rubber goods.

Abstract: New compositions and a process for the preparation of conjugated diene polymers of broadened molecular weight distribution by reacting non-terminated lithium catalyzed conjugated diene polymers with cyclic organic compounds selected from the group of carbonates, thiocarbonates and sulfites. The resulting new compositions are suitable for use in making high impact plastics and for fabricating rubber goods.

Abstract: The process disclosed herein comprises the use of a catalyst system comprising a complex of R.sub.2 Mg.(ROK).sub.2 in the hydrocarbon solution polymerization of 1,3-butadiene. Preferably the solvent is hexane, but cyclohexane or other alkane or cycloalkane may be used. The ratio of ROK to R.sub.2 Mg is from 1.0/1 to 5/1 and the R.sub.2 Mg and ROK are added separately to the butadiene solution. This process produces a high trans 1,4-polybutadiene which is particularly suitable as a coating for metals such as the coating of steel for beverage cans.

Abstract: A process for the anionic polymerization or copolymerization of olefinic monomers, dienic monomers, vinyl monomers and heterocyclic monomers is described which comprises reacting at least one monomer which is an olefinic monomer, a vinyl monomer or an heterocyclic monomer with a catalyst capable of inducing anionic polymerization and an aprotic macroheterocyclic cryptant, said at least one monomer being the only medium for the reaction.The macroheterocyclic complexing agent has general formula ##STR1## in which: R.sub.1 is hydrogen, a hydrocarbon radical or alkoxycarbonyl, or the two R.sub.1 together can form a group of the general formula: ##STR2## in which A is a hydrocarbon radical,D is oxygen, sulfur, or a hydrocarbon radical, with the proviso that at leat two of the D groups are oxygen or sulfur and that if R.sub.1 is hydrogen, a hydrocarbon radical or alkoxycarbonyl, one of these two D groups is oxygen or sulfur and the other is oxygen, andn and p are integers from 1 to 3 and m is 2 or 3.

Abstract: The process and catalyst system disclosed herein comprises the polymerization of a conjugated diene such as 1,3-butadiene in hydrocarbon solution in the presence of a new catalyst composition comprising:(a) a dihydrocarbyl magnesium compound of 1-10 carbon atoms, preferably a dialkyl magnesium having 3-8 carbon atoms in each alkyl group, and(b) an alkali metal compound of the formula R(SM).sub.n, R'.sub.2 NM, R'NHM or RC.tbd.CM, wherein R is a hydrocarbyl radical of 1-10 carbon atoms, preferably alkyl, n is 1, 2 or 3, M is Li, Na or K, and R' is a hydrocarbyl radical of 1-10 carbon atoms or an acyl radical of 1-10 carbon atoms.This process is particularly advantageous in that the polymer product can be controlled to have only a relatively small amount of 1,2 structure in accordance with the polymerization temperature. For example, at 125.degree. C. with Li compounds, the product generally has a 1,2 content of 12.6% or less; at 50.degree. C., 10.6% or less; and at 25.degree. C., 7% or less.

Abstract: The process and catalyst system disclosed herein comprises the polymerization of a conjugated diene such as 1,3-butadiene in hydrocarbon solution in the presence of a new catalyst composition comprising:(a) a dihydrocarbyl magnesium compound of 1-10 carbon atoms, preferably a dialkyl magnesium having 3-8 carbon atoms in each alkyl group, and(b) an alkali metal compound of the formula R(SM).sub.n, R'.sub.2 NM, R'NHM or RC.tbd.CM, wherein R is a hydrocarbyl radical of 1-10 carbon atoms, preferably alkyl, n is 1, 2 or 3, M is Li, Na or K, and R' is a hydrocarbyl radical of 1-10 carbon atoms or an acyl radical of 1-10 carbon atoms.This process is particularly advantageous in that the polymer product can be controlled to have only a relatively small amount of 1,2 structure in accordance with the polymerization temperature. For example, at 125.degree. C. with Li compounds, the product generally has a 1,2 content of 12.6% or less; at 50.degree. C., 10.6% or less; and at 25.degree. C., 7% or less.

Abstract: Esters of acrylic acid and methacrylic acid may be polymerized with the aid of either free radical forming or ionically effective initiators. The stereospecificy of the polymers may be influenced by the selection of specific initiators; magnesium-organic compounds are suitable for the synthesis of isotactic polymers. Acrylic acid and methacrylic acid esters having a high degree of isotacticity and a narrow molecular weight distribution are obtained with the aid of substituted phenylmagnesium halides. They are suitable as gauge and as test substances.

Abstract: In the polymerization of an anionically polymerizable monomer using a polymerization system comprising a monomer and a polymerization solvent wherein an organometallic compound polymerization initiator, soluble in said polymerization system and having the formula:MeR.sub.xwherein Me is a metal selected from the group consisting of Groups I and II of the Periodic Table; R represents an alkyl or aryl group, or an aliphatic or aromatic hydrocarbon residue; and the integer x is 1 or 2; is added to said system, the improvement which comprises adding said organometallic compound as a solution comprising said organometallic compound dissolved in a high viscosity solvent having a viscosity higher than 1 cp at room temperature, and which dissolves slowly in said polymerization system.

Abstract: Polymerization initiators are produced by contacting elemental calcium metal with pyridine-type compounds.

Abstract: Compounds which contain azo or peroxide linkages as well as the radical of an ultraviolet light stabilizing group are described. These compounds function as polymerization initiators which cause an ultraviolet light stabilization group to be chemically bound to the polymer.

Abstract: A process for the preparation of an amorphous, vulcanizable, elastomeric copolymer by copolymerization of ethylene and at least one .alpha.-olefin having from 3 to 10 carbon atoms e.g. propylene and optionally in the presence of at least one non-conjugated diene, using as catalyst a transition metal composition which is the product of reacting a transition metal complex of the general formulaR.sub.m MX.sub.p (1)with a substantially inert matrix material having a hydroxylic surface which is free from adsorbed water, where M is a transition metal of Groups IVA to VIA of the Periodic Table of the Elements, R is a hydrocarbon group or substituted hydrocarbon group, X is a monovalent ligand and m and p are integers, m having a value from 2 to the highest valency of the metal M, and p having a value from 0 to 2 less than the valency of the metal M, the copolymerization being effected in a diluent comprising the .alpha.-olefin or mixture of .alpha.

Abstract: Polymerization initiators are produced by contacting elemental calcium metal with pyridine-type compounds.

Abstract: An alternating copolymer of an olefinic unsaturated compound and a conjugated vinyl compound is produced by contacting said monomers with at least one organoboron halide or/and a mixture of at least one organo-compound of metal from Groups IIb, IIIb and IVb of the Mendeleev Periodic Table and at least one halogeno-compound of metal from Groups IIIb and IVb of the Mendeleev Periodic Table. A typical catalyst is ethylboron dichloride or a combination of triethylaluminum and tin tetrachloride.

Abstract: Organometallic compounds of high carbanion yield are prepared by metallation with barium, strontium or calcium or mixture of the same of certain acidic organic compounds having a pKa value of between about 15 and 35 on the MSAD scale in the presence of aprotic polar solvents, e.g., barium reacted with xanthene in 1,2-dimethoxyethane to yield dixanthenyl barium. Such organometallic compounds formed by metal-hydrogen exchange reaction are useful in initiating anionic growth-type polymerization of monomers, e.g., alkylene oxides and vinyl compounds, to form homopolymers and copolymers. The persistence of polymer carbanions created by such catalysts makes possible the controlled preparation of a variety of polymers, including block copolymers.