Abstract: A method for preparing resinous copolymers by sequential charge copolymerization of at least two charges, at least one being a conjugated diene and at least one being a monovinylarene; followed by a charge of a polyfunctional coupling agent; and the final charge being an essentially difunctional coupling agent. The copolymer made by this method and articles made from this copolymer are also provided.

Abstract: A method for preparing tapered block copolymers in a polymerization process by sequentially charging: (1) an initiator and monovinylaromatic monomers in the presence of a randomizer; (2) an initiator and a mixture of monovinylaromatic and conjugated diene monomers; (3) an initiator and a mixture of monovinylaromatic and conjugated diene monomers; and (4) a coupling agent to produce a polymodal tapered block copolymer. The copolymers are particularly useful for packaging applications which require good environmental stress crack resistance.

Abstract: A process for preparing continuously tapered polymers and copolymers having a continuous change in microstructure along the polymer backbone is disclosed. The process produces polymers and copolymers with multiple glass transition temperatures of very small energy absorption, i.e. no definable glass transition temperature. The polymers have a flexible chain end and they progressively become stiffer along the length of the chain.

Abstract: It is highly desirable for tire treads to exhibit good traction characteristics such as good wet skid resistance. However, it has traditionally been very difficult to improve the traction characteristics of a tire without sacrificing rolling resistance and tread wear. The high performance segmented elastomers of this invention offer a unique combination of desirable characteristics for utilization in making tire tread compositions. For instance, the rubbery polymers of this invention can be made into tire treads which exhibit outstanding traction characteristics while maintaining good rolling resistance and tread durability.

Abstract: A process for manufacturing block copolymers comprising anionically polymerizing a vinyl aromatic hydrocarbon mononer in solution in an aromatic hydrocarbon solvent capable of giving a homogeneous medium until attaining a homogeneous medium with a viscosity greater than 300 Pa.s at 20.degree. C. for a concentration of polymer in the aromatic hydrocarbon solvent between 60 and 90% by weight and then, after introduction of a conjugated diene, carrying out a copolymerization until a homogeneous medium is attained have a viscosity greater than 300 Pa.s at 90.degree. C. for a concentration of copolymer in the aromatic hydrocarbon solvent between 70 and 90% by weight, without the viscosity exceeding 3,000 Pa.s in either of the two polymerization steps.

Abstract: A viscous block copolymer of the formula(A--B--A).sub.n --Y.sub.r --(A.sub.q --B).sub.mwherein Y is a coupling agent or coupling monomers, andwherein A and B are polymer blocks which may be homopolymer blocks of conjugated diolefin monomers, copolymer blocks of conjugated diolefin monomer or copolymer blocks of conjugated diolefin monomers and monoalkenyl aromatic hydrocarbon monomers, andwherein the A blocks have a higher number of aliphatic double bonds between a tertiary carbon atom and either a primary or secondary carbon atom per unit of block mass than do the B blocks, andwherein the A blocks have a molecular weight from about 100 to about 3000 and the B blocks have a molecular weight from about 1000 to about 15,000, andwherein p and q are 0 or 1 and n>0, r is 0 or 1, m.gtoreq.0 and n+m ranges from 1 to 100.This block copolymer is preferably partially hydrogenated, epoxidized and crosslinked through at least some of the epoxy functionality to form an adhesive, coating or sealant composition.

Abstract: A method for preparing tapered block copolymers in a polymerization process by charging an initiator and monomers sequentially with one or more charges of first one of the monomers, then with a mixture of the two monomers, and then with one or more charges of the first monomer to produce a polymodal tapered block copolymer. Suitable monomers include conjugated dienes and monovinylaromatic compounds. The copolymers are particularly useful for applications requiring environmental stress crack resistance.

Abstract: A process for anionic polymerization of polymerizable monomers with an organo lithium initiator followed by polymerization termination characterized in that terminated reaction products are neutralized by contacting with sulfuric acid, phosphoric acid or a mixture thereof.

Abstract: A solid, cyclone-finishable polymer which does not exhibit cold flow and provides an unexpected balance of viscosity improving properties for oil compositions is produced by hydrogenating a copolymer comprising a homopolymer block of isoprene connected to a copolymer block of isoprene and a monoalkenyl aromatic hydrocarbon. The amount of the monoalkenyl aromatic hydrocarbon is sufficient to allow cyclone finishing although sufficiently distributed to provide oil compositions having good low temperature viscosity. Prior to hydrogenation, the copolymers have a number average molecular weight between 125,000 and 275,000, preferably 150,000 to 240,000, and a total monoalkenyl aromatic content between 10 and 2 percent by weight, preferably between 7 and 3 percent. The copolymer is hydrogenated to substantially saturate the isoprene and to reduce the size of monoalkenyl aromatic segments in the copolymer block.

Abstract: This application discloses linear methacrylic ABC triblock polymers in which the composition of each of the three blocks is different and wherein at least one of the blocks is hydrophobic and at least one of the blocks is hydrophilic.

Abstract: Polymers comprising anionically polymerized monomers such as butadiene or styrene and adjacent units of (1-methyl-1-alkyl)alkyl esters such as t-butylmethacrylate, as well as selectively hydrogenated derivatives thereof, are heated to at least 180.degree. C. to convert the adjacent ester units to stable anhydride rings.

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: The present invention relates to elastomeric copolymers and block copolymers, e.g., based upon styrene/isoprene, having a novel condensed phase structure wherein polymer branches occur along the polymer backbone, either at a predetermined location or at random locations. The polymers are made by a method which comprises the step of reacting, under polymerization conditions, hydrocarbyl lithium initiator, at least one anionically polymerizable compound, and an organometallic- substituted styrene condensing agent. The reactants may be added simultaneously to produce a copolymer with polymer branch segments randomly located along the polymer backbone or sequentially to produce a copolymer with branches located at the same predetermined location along the polymer backbone. The resultant polymers may be further reacted with a linking agent to form multi-arm copolymers.

Abstract: A pneumatic tire has a tread with a rubber composition produced by blending a rubber component with a styrene based thermoplastic elastomer. The rubber component is composed mainly of a diene based rubber, and the elastomer is so preliminarily internally crosslinked that tensile stress at a 100% elongation is increased to 10 to 1,000% of that of the styrene based thermoplastic elastomer not internally crosslinked. A pneumatic tire is also disclosed, having a tread portion with a rubber composition blended with a vinyl aromatic hydrocarbon thermoplastic elastomer in an amount of 5-80 parts by weight relative to 100 parts by weight of the rubber component.

Abstract: It is highly desirable for tire treads to exhibit good traction characteristics such as good wet skid resistance. However, it has traditionally been very difficult to improve the traction characteristics of a tire without sacrificing rolling resistance and tread wear. The high performance segmented elastomers of this invention offer a unique combination of desirable characteristics for utilization in making tire tread compositions. For instance, the rubbery polymers of this invention can be made into tire treads which exhibit outstanding traction characteristics while maintaining good rolling resistance and tread durability.

Abstract: Block copolymers useful in formulations of adhesives, coatings, and lubricating oils have a particular structure comprising blocks of a polymerized alkenyl aromatic compound such as styrene, an internal block of a polymerized conjugated alkadiene such as butadiene, as well as selectively hydrogenated derivatives thereof, and a polar block of a polymerized alkyl methacrylate such as t-butyl methacrylate.

Abstract: A new class of macromolecular monomers (hereinafter called "macromonomers") comprises the polymerized product of at least one of an ethenylarene and a conjugated diene monomer, the product having a terminal omega-alkenyl group of at least four carbon atoms. The novel macromonomer can be copolymerized with ethylene and alpha-olefin monomers to form graft copolymers having pendant side-chains. The graft copolymers are useful as coating and molding compositions. The macromonomers can be useful as coatings on chromatographic supports for analytical and preparative separation of chemical mixtures.

Abstract: A shape memory polymer resin, consisting essentially of a block copolymer having an A-B-A block structure in the polymer chain, and having a weight average molecular weight within the range of 10,000 to 1,000,000, wherein(a) block A is a polymer block comprising a homopolymer or a copolymer of a vinyl aromatic compound and/or a hydrogenated product thereof;(b) block B is a polymer block comprising a homopolymer or a copolymer of butadiene and/or a hydrogenated product thereof, the content of butadiene and/or the hydrogenated product thereof in block B being at least 80% by weight, and 80 to 91% of the linkages of the butadiene and/or the hydrogenated product thereof being 1,4-linkages;(c) at least 80% by weight of the conjugated diene in the block copolymer being hydrogenated; and(d) the block copolymer comprises 5 to 50% by weight of said block A; and a shape memory resin composition and a shape memorizing molded product thereof.

Abstract: A process for preparing modified diene polymer rubbers having an increased impact resilience and a reduced hardness at low temperatures and useful as rubber materials for automobile tires and other industries which comprises producing an alkali metal-containing conjugated diene polymer, and reacting the akali metal-containing polymer with an acrylamide modifier compound of the formula: ##STR1## wherein R.sup.1 is hydrogen atom or methyl group, R.sup.2 and R.sup.3 are independently an alkyl group and n is an integer said alkali metal-containing diene polymer being prepared by a living anionic polymerization using an alkali metal-based catalyst or by an addition reaction of a diene polymer having conjugated diene units and an alkali metal-based catalyst in a hydrocarbon solvent.

Abstract: There is disclosed a linear block copolymer comprising at least one triblock I-B-I, wherein I is a block of a polymerized conjugated diene of at least 5 carbon atoms, such as isoprene, and B is a block of a polymer of a conjugated diene, different from that of formula (1), of at least 4 carbon atoms, such as 1,3-butadiene. The B block is selectively hydrogenated, while each of the I blocks retains a sufficient amount of its original unsaturation to vulcanize the copolymer. There is also disclosed an alternative linear block copolymer containing at least one triblock of the first polymer block made from an aryl-substituted olefin, such as sytrene, and the conjugated diene used to polymerize the block I, the second middle polymer block of the diene used to polymerize the block B, and the third polymer block which is the same as the first polymer block.

Abstract: A process for anionic polymerization of polymerizable monomers with an organo lithium initiator followed by polymerization termination characterized in that terminated reaction products are neutralized by contacting with sulfuric acid, phosphoric acid or a mixture thereof.

Abstract: Novel diene/methacrylate ester block polymers, especially tertiary butyl methacrylate ester block polymers are uniquely prepared at near ambient temperatures and capable of being hydrolyzed and neutralized to yield the corresponding methacrylic acid and methacrylic acid salt (ionomer) derivatives. The compositions are usefully employed in the preparation of thermoplastic elastomers, adhesives and laminating films.

Abstract: Linear copolymers with four alternating blocks, represented by the following formula:B.sub.1 -T-A.sub.1 -B.sub.2 -A.sub.2where: A.sub.1 and A.sub.2 are polyvinylaromatic blocks, B.sub.1 and B.sub.2 are blocks consisting of ethylene-butene-1 or ethylene-propylene copolymers, and T is a statistical terpolymer segment formed from ethylene-propylene-vinylarene or ethylene-butene-1-vinylarene monomer units.The copolymers are characterized by a weight-average molecular weight of between 20,000 and 300,000 and a total content of vinylaromatic units of between 10 and 60% by weight. The ratio of the weight-average molecular weight of block A.sub.1 to that of block A.sub.2 is a number between 0.25 and 2.0, and the ratio of the weight-average molecular weight of block B.sub.1 to that of block B.sub.2 is a number between 0.05 and 0.5.

Abstract: A crystalline block copolymer containing at least a triblock or at least a radial structure and a process for producing the same, wherein at least one block comprising a vinyl aromatic compound having a glass transition temperature (Tg) of not lower than 50.degree. C., at least one block comprising a conjugated diene polymer having a 1,4-trans linkage content, a Tg not higher than 10.degree. C. and crystallinity at 25.degree. C. and in which the crystalline block copolymer optionally which contains the radial structure further comprises a coupling agent. The polymer or the composition containing the same can be utilized for fixing materials of affected portions for medical purposes, protector materials for various sports, films, laminates, toys, artificial flowers, heat-sensitive sensors, coupling devices, insulating materials, framework materials, etc.

Abstract: An unsaturated, elastomeric, asymmetrically coupled block copolymer of the formula:(A--B).sub.n --X--(B).sub.m,wherein block A is a block of polybutadiene having an 8 to 60% content of uniformly distributed vinyl groups and block B is a homopolymer of isoprene or a copolymer of at leat 10% isoprene units with 0 to 60% butadiene units and up to 45% styrene units and X is a radical of a coupling agent, and (m-n).gtoreq.0 while (m+n) ranges from 3 to 25.

Abstract: A process for preparing a grafted star polymer which comprises contacting a nitrogen-containing polymerizable organic polar compound with a star polymer (as hereinbefore defined) in the presence of a free radical polymerization initiator and characterized in that the reaction is carried out in a mineral oil solvent and, as coupling inhibitor, either a chain transfer agent, a pi-electron donor, or a comonomer, together with the modified, hydrogenated star polymers thus produced, and their use as luboil additives.

Abstract: A method for preparing tapered block copolymers in a polymerization process by charging an initiator and monomers sequentially with one or more charges of first one of the monomers, then with a mixture of the two monomers, and then with one or more charges of the second monomer alternating with one or more charges of the first monomer with subsequent coupling, to produce a polymodal tapered block copolymer. Suitable monomers include conjugated dienes and monovinylaromatic compounds. The copolymers are suitable for use in injection and blow molding equipment; the copolymers are particularly useful for shrink films, containers, tubes, fibers and other packaging applications.

Abstract: The present invention relates to elastomeric copolymers and block copolymers, e.g., based upon styrene/isoprene, having a novel condensed phase structure wherein polymer branches occur along the polymer backbone, either at a predetermined location or at random locations. The polymers are made by a method which comprises the step of reacting, under polymerization conditions, hydrocarbyl lithium initiator, at least one anionically polymerizable compound, and an organometallic-substituted styrene condensing agent. The reactants may be added simultaneously to produce a copolymer with polymer branch segments randomly located along the polymer backbone or sequentially to produce a copolymer with branches located at the same predetermined location along the polymer backbone. The resultant polymers may be further reacted with a linking agent to form multi-arm copolymers.

Abstract: A terminal-modified block copolymer having the remainder of an amino group or imido group-containing a terminal-treating agent bonded to the polymer terminal which is obtained by treating the active terminal of a block copolymer comprising conjugated dienes and vinylaromatic hydrocarbon compounds, which is obtained by using as the polymerization initiator at least one member selected from alkali metals or organoalkali metals and has a vinylaromatic hydrocarbon content of 5 to 95% by weight and a number average molecular weight of 5,000 to 1,000,000 with at least one terminal-treating agent selected from imide compounds, cyanamide compounds, aziridinyl compounds, amide compounds, or tertiary amino group-containing compounds other than the compounds.

Abstract: A new class of macromolecular monomers (hereinafter called "macromonomers") comprises the polymerized product of at least one of an ethenylarene and a conjugated diene monomer, the product having a terminal omega-alkenyl group of at least four carbon atomes. The novel macromonomer can be copolymerized with ethylene and alpha-olefin monomers to form graft copolymers having pendant side-chains. The graft copolymers are useful as coating and molding compositions. The macromonomers can be useful as coatings on chromatographic supports for analytical and preparative separation of chemical mixtures.

Abstract: A novel method is proposed for the preparation of a block copolymer of styrene and ethylene having a very narrow molecular weight distribution and controlled molar ratio of the styrene moiety to ethylene moiety in a high efficiency. The method comprises the steps of: (a) living-polymerizing styrene by using an organic lithium compound as a polymerization initiator; (b) admixing the polymerization mixture containing the living polymer of styrene with a tertiary diamine compound, such as N,N,N',N'-tetramethyl ethylene diamine; and (c) introducing ethylene monomer into the polymerization mixture to effect polymerization of ethylene on to the living polymer molecules of polystyrene.

Abstract: Statistical AB-block copolymers having improved properties, a process for their manufacture and their use. Tire treads made of the statistical AB block copolymers according to the invention are characterized by high skid resistance under wet conditions combined with persistently low abrasion, good dynamic properties and rapid vulcanization.

Abstract: An unsaturated, elastomeric ABC block copolymer comprised of the monomer units of 40 to 80% of 1,3-butadiene, 5 to 40% of isoprene and 2 to 30% of styrene, said copolymer comprising i) 40 to 75% of block A which contains styrene and butadiene units or isoprene and butadiene units with a content of distributed vinyl or isopropenyl groups of less than 15%, iia) up to 25% of a block B which contains styrene and butadiene units or isoprene and butadiene units with a vinyl or isopropenyl content of more than 70%, or iib) up to 25% of a block B' which contains styrene, isoprene and optionally butadiene units with a content of homogeneously distributed isopropenyl or vinyl groups of less than 15%, and iii) 20 to 55% of a block C which contains styrene and isoprene units and optionally butadiene units with an isopropenyl or vinyl content of more than 70%.

Abstract: A block copolymer composition is provided comprising:(1) 10-60% by weight of a block copolymer [(A--B).sub.11 ].sub.m --Y.sub.1(2) 20-90% by weight of a block copolymer [(A--B).sub.12 ].sub.n --Y.sub.2, and(3) 0-50% by weight of a block copolymer (A--B.sub.13,in which A represents a vinyl aromatic polymer block having a molecular weight of 10,000-30,000 wherein the vinyl aromatic compound is selected from the group consisting of styrene, alkyl substituted styrene and a vinyl naphtalene, B.sub.1 a conjugated diene polymer block having a molecular weight of 25,000-100,000, B.sub.2 a conjugated diene polymer block having a molecular weight at least 1.2 times as high as that of B.sub.1 wherein the conjugated diene compound of B.sub.1 and B.sub.2 is a conjugated diene having four to eight carbon atoms per molecule, Y.sub.1 and Y.sub.2 respectively represent a halogenated, tetravalent silicon compound and a halogenated, tetravalent stannic compound and 11=1-3, m=2-4, 12=1-6, n=2-4 and 13=1-6.

Abstract: A block copolymer composition comprising40-85% by weight of a block copolymer A.sub.1 -B.sub.1 from an aromatic vinyl compound and a conjugated diene, respectively, A.sub.1 being <20% by weight of (A.sub.1 +B.sub.1), A.sub.1 and B.sub.1 having a molecular weight >12,000 and >150,000, respectively, and15-60% by weight of a block copolymer A.sub.2 -B.sub.2 -A.sub.3 from an aromatic vinyl compound, a conjugated diene and aromatic vinyl compound, respectively, A.sub.2 +A.sub.3 being >20% by weight of A.sub.2 +B.sub.2 +A.sub.3, A.sub.2 and A.sub.3 having a molecular weight >12,000 and(molecular weight of B.sub.2).ltoreq.(molecular weight of B.sub.1)/1.5. an adhesive composition comprising100 parts by weight (pbw) of said block copolymer composition, 20-300 pbw of a tackifying resin, and0-200 pbw of a softener, anda process for the preparation of said adhesive composition by mixing the components in question.

Abstract: The present invention relates to a method of making elastomeric copolymers and block copolymers, e.g., based upon styrene/isoprene, having a novel condensed phase structure wherein polymer branches occur along the polymer backbone, either at a predetermined location or at random locations. The method comprises the step of reacting, under polymerization conditions, hydrocarbyl lithium initiator, at least one anionically polymerizable compound, and an organometallic- substituted styrene condensing agent. The reactants may be added simultaneously to produce a copolymer with polymer branch segments randomly located along the polymer backbone or sequentially to produce a copolymer with branches located at the same predetermined location along the polymer backbone. The resultant polymers may be further reacted with a linking agent to form multi-arm copolymers.

Abstract: Butadiene is polymerized alone or with a monomer such as styrene in a dispersion in propane, butane or its mixtures with minor amounts of other C.sub.4 -C.sub.6 alkanes, e.g., n-pentane and a dispersant which is preferably a styrene/hydrogenated isoprene block copolymer to achieve stable dispersions at higher solids and butadiene levels possible with similar alkane dispersants.

Abstract: An unsaturated elastomeric AB block copolymer, comprising:(i) 45-85 wt. % 1,3-butadiene,(ii) 5-40 wt. % isoprene, and(iii) up to 30 wt. % styrene,wherein said AB block copolymer comprising:40-80 wt. % of a block A, said block A comprising butadiene monomer units and having a content of uniformly distributed vinyl groups of 8-60 wt. %, and60-20 wt. % of a block B, said block B comprising 0-60 wt. % 1,3-butadiene, at least 10 wt. % isoprene and up to 45 wt. % styrene monomer units, wherein the butadiene and isoprene monomer units have a vinyl group content of 75-90 wt. %.

Abstract: Transparent linear resinous conjugated diene/monovinyl-substituted aromatic block copolymers of improved properties are prepared by forming a monovinyl-substituted aromatic homopolymer block referred to as S.sub.1, followed by forming a conjugated diene homopolymer block, referred to as B.sub.1 and linked to segments S.sub.1, followed by the formation of a conjugated diene/monovinyl-substituted aromatic random copolymer block, referred to as B/S and linked to segment B.sub.1, followed by the formation of a monovinyl-substituted aromatic homopolymer block, referred to as S.sub.2 and linked to segment B/S thereby forming the block copolymer S.sub.1 -B.sub.1 -B/S-S.sub.2 wherein the molecular weight of the S.sub.2 block is significantly greater than the molecular weight of the S.sub.1 block.

Abstract: An elasticized, dispersion-grade vinyl chloride resin powder is provided which not only imparts improved elasticity and reduced hysteresis losses to fluid plastisols made therewith, but also has excellent stability under adverse environmental conditions, insuring consistent performance in plastisols even after said powder has been in storage for several months. This resin powder has an average particle size between about 0.4 and about 4 microns and contains between about 0.5 and about 20% by weight of an elastomeric acrylic polymer having a T.sub.g below about -10.degree. C. which is present as discrete particles most of which are at least partly occluded by hard thermoplastic vinyl chloride polymer formed in situ, which vinyl chloride polymer represents substantially all of the remaining mass of said powder.Fluid plastisols prepared from said resin powder are also described as well as finished articles of improved resiliency and elasticity, which are made from said plastisols.

Abstract: Bimodal star-block copolymers are disclosed containing from 60 to 90% by weight of an aromatic vinyl monomer and from 40 to 10% by weight of a conjugated diene, said copolymers having the general formula:(S--S.sub.1 --B/S.sub.2 --B.sub.1).sub.m --X--(B.sub.1 --S.sub.2 /B--S.sub.1).sub.nwherein X is a polyfunctional radical, m and n are integers (being m.ltoreq.n) the sum of which is between 3 and 20 and equal to the functionality degree of the radical X, S and S.sub.1 are polymer blocks of an aromatic vinyl monomer, B.sub.1 is an elastomeric copolymer of conjugated dienic units, containing up to 20% of all the dienic units of the copolymer, and B/S.sub.2 and S.sub.2 /B are blocks of copolymers of aromatic vinyl monomer and conjugated diene of the random and/or tapered type.

Abstract: A rubber composition suitable for tire treads having well-balanced excellent steering stability in cornering, wet skid characteristic, ice skid characteristic and rolling characteristic, and an excellent processability, which comprises a rubber component containing a block copolymer consisting essentially of a block A and a block B, obtained by conducting polymerization of an aromatic vinyl compound and a conjugated diene compound in a hydrocarbon solvent in the presence of an organolithium initiator and modifying with a coupling agent, and satisfying the following conditions (A) to (E);(A) the block A having a content of an aromatic vinyl compound of 5 to 29% by weight and a content of 1,2-bonds in the conjugated diene component of 25 to 55% by weight,(B) the block B having a content of an aromatic vinyl compound of 35 to 60% by weight and a content of 1,2-bonds in the conjugated diene component of 20 to 70% by weight,(C) the content of the block A in the block copolymer being from 20 to 80% by weight,(D) th

Abstract: A continuous process as disclosed which produces a clear, high impact block copolymer having a vinyl aryl monomer content of at least 70 percent of the block copolymer. This continuous process involves the continuous preparation of a multiblock copolymer which comprises the alternate feeding of monomer streams to a reaction zone wherein a product stream is withdrawn from the polymerization system at the same rate as the total rate of the feed streams.

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: Block copolymers are prepared by providing an initial anionically polymerizable monomer portion; anionically polymerizing the initial monomer portion to provide polymer chains with living ends, and contacting the polymer chains with m-bis(phenyletheynl)benzene (PEB), a coupling agent, to bring about substantial coupling. In preferred embodiments the polymer chain living ends are capped with an .alpha.-alkylstyrene or a ring-alkyl substituted .alpha.-alkylstyrene, wherein the .alpha.-alkyl groups contain between about 1 to about 20 carbon atoms. and the ring-alkyl groups have at least 2 carbon atoms. The coupling agents employed with the capped polymer chain living ends include PEB, p-dibromoxylene, terephthaloyl chloride, 1,4-dibromobutene; and the multifunctional epoxides, multifunctional isocyanates, multifunctional aziridines, multifunctional aldehydes, multifunctional ketones, multifunctional anhydrides, multifunctional esters, and polyhalides.

Abstract: A linear copolymer constituted by four alternating blocks:B1-A1-B2-A2wherein:B1 and B2 are polydienic blocks, and preferably polybutadiene blocks, andA1 and A2 are polyvinylaromatic, and preferably polystyrene blocks;which polymer has a weight average molecular weight of from 30,000 to 250,000, and a global content of monomer dienic units of from 40 to 80% by weight, wherein the weight average molecular weight of B1 block is comprised within the range of from 0.1 to 0.5 times the weight average molecular weight of B2 block, and the weight average molecular weight of A1 block is comprised within the range of from 0.25 to 2.0 times the weight average molecular weight of A2 block, and which contains between B1 and A1 blocks a copolymeric moiety formed by randomly linked monomer dienic and vinylaromatic units; is endowed with a desired balance of mechanical characteristics, rheologic characterisatics and characteristics of thermooxidative resistance.The process to prepare such a block copolymer is disclosed.

Abstract: The present invention relates to elastomeric copolymers and block copolymers, e.g., based upon styrene/isoprene, having a novel condensed phase structure wherein polymer branches occur along the polymer backbone, either at a predetermined location or at random locations. The polymers are made by a method which comprises the step of reacting, under polymerization conditions, hydrocarbyl lithium initiator, at least one anionically polymerizable compound, and an organometallic- substituted styrene condensing agent. The reactants may be added simultaneously to proudce a copolymer with polymer branch segments randomly located along the polymer backbone or sequentially to produce a copolymer with branches located at the same predetermined location along the polymer backbone. The resultant polymers may be further reacted with a linking agent to form multi-arm copolymers.

Abstract: The present invention relates to a method of making elastomeric copolymers and block copolymers, e.g., based upon styrene/isoprene, having a novel condensed phase structure wherein polymer branches occur along the polymer backbone, either at a predetermined location or at random locations. The method comprises the step of reacting, under polymerization conditions, hydrocarbyl lithium initiator, at least one anionically polymerizable compound, and an organometallic- substituted styrene condensing agent. The reactants may be added simultaneously to produce a copolymer with polymer branch segments randomly located along the polymer backbone or sequentially to produce a copolymer with branches located at the same predetermined location along the polymer backbone. The resultant polymers may be further reacted with a linking agent to form multi-arm copolymers.

Abstract: A star-shaped polymer useful as a polymeric VI improver comprising at least one arm which is a block copolymer containing a conjugated diolefin block and a monoalkenyl aromatic hydrocarbon block and a plurality of arms which are either a homopolymer of a conjugated diolefin or a copolymer of tow or more conjugated diolefin or a copolymer of two or more conjugated diolefins. Oil compositions comprising star-shaped VI improvers of this type exhibit relatively low HTHSR viscosities, and hence, improved fuel efficiencies when used in automotive applications. Oil compositions comprising star-shaped VI improvers of this type also exhibit improved low temperature pumpability.

Abstract: A process for producing a thermoplastic elastomer comprising a block copolymer of the A-B-A' type, wherein A is a monovinyl aromatic hydrocarbon polymer block, B is a conjugated diolefin polymer block, and A' is either the same as A or a polymer block derived from a dialkenyl aromatic hydrocarbon or a dihalogenated hydrocarbon, which process comprises polymerizing a monovinyl aromatic hydrocarbon in a polymerization medium in the presence of an organomonolithium compound as a polymerization initiator, adding a conjugated diolefin to perform block copolymerization, and further adding a monovinyl aromatic hydrocarbon to perform polymerization or in the alternative, adding a dialkenyl aromatic hydrocarbon or a dihalogenated hydrocarbon to perform coupling, wherein the monomer components are used in such amounts that the weight ratio of (A+A') to B ranges from 10/90 to 65/35, and a chained aliphatic hydrocarbon solvent containing from 0.0001 to 0.