Abstract: Polyethylene which comprises ethylene homopolymers and copolymers of ethylene with ?-olefins and has a molar mass distribution width Mw/Mn of from 6 to 100, a density of from 0.89 to 0.97 g/cm3, a weight average molar mass Mw of from 5000 g/mol to 700 000 g/mol and has from 0.01 to 20 branches/1000 carbon atoms and at least 0.5 vinyl groups/1000 carbon atoms, wherein the 5-50% by weight of the polyethylene having the lowest molar masses have a degree of branching of less than 10 branches/1000 carbon atoms and the 5-50% by weight of the polyethylene having the highest molar masses have a degree of branching of more than 2 branches/1000 carbon atoms, a process for its preparation, catalysts suitable for its preparation and also fibers, moldings, films or polymer blends in which this polyethylene is present.

Abstract: The invention relates to two-component or multicomponent compositions comprising at least the following ingredients: a) at least one (meth)acrylate; b) at least one compound of formula (I); c) at least one inorganic salt or a metal complex compound of at least one metal selected among the group encompassing the transition metals; and d) at least one peroxide or at least one perester or at least one hydroperoxide. A first component K1 contain at least ingredient c) while a second component K2 contains at least ingredient d). The inventive compositions are characterized in that oxygen inhibition is prevented or drastically reduced when the same are hardened. Said compositions are particularly suitable as adhesives, sealants, and coatings.

Abstract: Described are novel monomers bearing functionalities capable of initiating control free radical reactions, and a novel process using these initiating monomers in the co-polymerization of an olefin for the formation of well-controlled polyethylene graft polymers where the graft component is derived from controlled free radical polymerization reactions. The initiating monomers are produced by combining an amount of 5-norbornen-2-ol with a hydride or amine for a predetermined amount of time to form a mixture; and adding an amount of an alkyl or acyl halide to said mixture. Polymerization of an olefin with an initiating monomer is conducted in the presence of a metal compound, where the metal compound is comprised of a Group VIII transition metal complex.

Abstract: Provided are a photoreactive polymer that includes a multi-cyclicmulticyclic compound at as its main chain and a method of preparing the same. The photoreactive polymer exhibits excellent thermal stability since it includes a multi-cyclicmulticyclic compound having a high glass transition temperature at as its main chain. In addition, the photoreactive polymer has a relatively large vacancy so that a photoreactive group can move relatively freely in the main chain therein. As a result, a slow photoreaction rate, which is a disadvantage of a conventional polymer material used to form an alignment layer for a liquid crystal display device, can be overcome.

Abstract: A process is disclosed for the preparation of zinc alkyl chain growth products via a catalysed chain growth reaction of an alpha-olefin on a zinc alkyl, wherein the chain growth catalyst system employs a group 3-10 transition metal, or a group 3 main group metal, or a lanthanide or actinide complex, and optionally a suitable activator. The products can be further converted into alpha-olefins by olefin displacement of the grown alkyls as alpha-olefins from the zinc alkyl chain growth product, or into primary alcohols, by oxidation of the resulting zinc alkyl chain growth product to form alkoxide compounds, followed by hydrolysis of the alkoxides.

Abstract: A method of preparing a polymer having a tapered block copolymer structure. The method comprises polymerizing a first olefin monomer and a different second olefin monomer in the presence of a catalyst supporting living or quasi-living polymerization. In certain embodiments, the catalyst comprises two neutral metal complexes. In preferred embodiments, a tapered block copolymer structure is formed by adding one monomer in a single batch at the start of the polymerization reaction, and adding a second monomer throughout the course of the reaction. The present invention also provides polymers having one or more tapered block copolymer sections, and compositions based on these polymers.

Abstract: The present invention relates to a new hybrid catalyst system for the polymerization of olefins and to a polymerization process carried out in the presence of said catalyst. The new hybrid catalyst system comprises a tridendate iron compound and a zirconocene having a bridge of at least three carbon atoms connecting two indenyl ligands.

Abstract: The present invention discloses a metallocene catalyst system for producing polyolefins comprising: A. a hafnocene-based catalyst component suitable for producing the high molecular weight fraction of the polyolefin; B. one or more metallocene or post-metallocene components different from the component A and suitable for producing the low molecular weight fraction of the polyolefin; C. an activating agent having a low or no coordinating capability.

Abstract: A process for producing homopolymers or copolymers of conjugated dienes comprising contacting monomeric material comprising at least one conjugated diene with a catalyst system comprising two or more different transition metal compounds and optionally one or more activators. Preferred transition metal compounds are based on cobalt and chromium, especially complexes thereof having benzimidazole ligands.

Abstract: A hydrosilylation inhibitor comprising a reaction product of (1) a titanium compound having an alkoxy group in its ligand, and (2) an organosilicon compound having at least one hydrogen atom bonded to silicon atom per molecule is provided. This hydrosilylation inhibitor exhibits inhibitory activity for catalytic activity of a PGE (platinum group element)-bearing hydrosilylation catalyst in an oxygen atmosphere of up to 100 ppm and/or a moisture atmosphere of up to 100 ppm. By using the present invention, catalytic function of the hydrosilylation catalyst is reliably inhibited in the absence of oxygen and moisture while the same catalytic function is easily provided in the presence of the oxygen or the moisture.

Abstract: This invention relates to new transition metal complexes for use in olefin polymerization and oligomerization. The active complex is a pyridine amide having a metallocenyl substituent as part of the ligand structure. The invention also relates to novel precursors for the ligand systems of such complexes obtained from metallocenyl-substituted pyridine compounds through sequences involving addition-condensation or lithium-halogen exchange (with subsequent metathesis) reactions.

Abstract: An organic semiconducting copolymer according to example embodiments may be represented by Formula 1 below: An organic electronic device may include the above organic semiconducting copolymer. The organic semiconducting copolymer according to example embodiments may provide improved solubility, processability, and thin film properties. Consequently, the organic semiconducting copolymer may be used in a variety of electronic devices. A suitable electronic device may be an organic thin film transistor. When an active layer of an organic thin film transistor includes the organic semiconducting copolymer, higher charge mobility and lower breaking leakage current may be achieved.

Abstract: Process for the preparation of a double metal cyanide (DMC) catalyst comprising a) preparation of a DMC catalyst; b) dispersing the catalyst of step a) in a dispersion agent, yielding a catalyst dispersion; c) allowing sedimentation of part of the catalyst from the catalyst dispersion obtained in step b), yielding a sedimentated catalyst and a dispersed catalyst; d) separating the dispersed catalyst from the sedimentated catalyst.

Abstract: A process and catalyst for producing homopolymers or copolymers of conjugated dienes by polymerising the monomer with a catalyst system comprising (A) a first transition metal compound selected from Cr, Mo and W compounds, and a second transition metal compound selected from Fe Co and Ni compounds (B) a catalyst modifier (eg triphenyl phosphine) and optionally (C) one or more catalyst activators (eg MAO). The cis, trans and 1,2-vinyl microstructure of the produced diene polymer can be controlled.

Abstract: The present invention relates to a supported, treated catalyst system and its use in a process for polymerizing olefin(s). More particularly, it provides a supported, treated catalyst system produced by a process comprising the steps of: (a) forming a supported bimetallic catalyst system comprising a first catalyst component and a metallocene catalyst compound; and (b) contacting the supported bimetallic catalyst system of (a) with at least one methylalumoxane-activatable compound.

Abstract: A catalyst is disclosed for the polymerization and co-polymerization of olefins with functionalized monomers. The catalyst is formed from a combination of two neutral metal complexes, L(iPr2)M(CH2Ph)(PMe3)[L=N-(2,6-diisopropylphenyl)-2-(2,6-diisopropylphenylimino)propanamide] and M(COD)2(COD=cyclooctadiene). The catalyst displays a unique mode of action and performs at ambient conditions producing high molecular weight polyolefins and co-polymers with functional groups. The polymerized olefins include ethylene, ?-olefins and functionalized olefins.

Abstract: A multinuclear transition metal compound which has two or more catalytic active sites, and is useful in preparing the olefin polymer and copolymer, is disclosed. The multinuclear transition metal compound for olefin polymerization includes two or more metals, and at least one ligand having a cyclopentadienyl moiety, which connects the two or more metals. The preferable multinuclear transition metal catalyst for olefin polymerization includes the first transition metal, the first ? ligand having a cyclopentadienyl moiety, which is coordinated to the first transition metal, and the second transition metal to which the second ? ligand having a cyclopentadienyl moiety is coordinated, wherein the second transition metal is bonded to the first ?-ligand via a sigma (?) bond.

Abstract: There are provided (1) a process for producing a contact product, which comprises the step of contacting at least a phthalocyanine complex, a porphyrin complex, or their combination with a surfactant; (2) a catalyst component for addition polymerization, which comprises said contact product; (3) a process for producing a catalyst for addition polymerization, which comprises the step of contacting said catalyst component, a compound of a metal atom of Groups 3 to 12 or the lanthanide series, and an optional organoaluminum compound with one another; and (4) a process for producing an addition polymer, which comprises the step of polymerizing an addition polymerizable monomer in the presence of said catalyst.

Abstract: A catalytic composition, including a cationic metal-pair complex, is disclosed, along with a method for its preparation. A method for the polymerization of ethylenically unsaturated monomers using the catalytic composition, and the addition polymers produced thereby are also disclosed.

Abstract: A catalytic composition, including a cationic metal-pair complex, is disclosed, along with a method for its preparation. A method for the polymerization of ethylenically unsaturated monomers using the catalytic composition, and the addition polymers produced thereby are also disclosed.

Abstract: This invention is based upon the discovery that a catalyst system which is comprised of (a) palladium or a palladium compound and (b) a fluorinated alcohol is effective for polymerizing norbornene-functional monomers into polynorbornene-functional polymers. It has been further discovered that this catalyst system is more effective in polymerizing certain norbornene-functional monomers that are difficult to polymerize, such as norbornene ester monomers, than prior art catalyst systems. The activity of the catalyst systems of this invention can be further improved with respect to polymerizing some monomers by including a Lewis acid and/or a ligand, such as a phosphine or a carbene, in the system. In any case, the catalyst systems of this invention offer the advantage of being soluble in a wide variety of solvents, relatively inexpensive, and capable of polymerizing many norbornene-functional monomers that are difficult to polymerize with conventional catalyst systems.

Abstract: Olefin polymers having a comb-like structure with at least 0.3 long-chain branches per 1000 carbon atoms are disclosed. Some compositions have a melt strength of about 5 cN at 190° C., and when made into a film have a CD shrink of at least 20%. Some compositions described herein include a high molecular weight fraction and a low molecular weight fraction wherein the ratio of the molecular weight of the high molecular weight fraction to the molecular weight of the low molecular weight fraction is greater than about 1.3.

Abstract: Organometallic reversible addition-fragmentation chain transfer reagents (RAFT reagents), processes of free radical polymerization employing the same and polymers with low polydispersity index obtained thereby. The process includes polymerizing at least one monomer with at least one initiator and at least one organometallic RAFT reagent to obtain polymers having terminal organometallic functional groups with low polydispersity index. In addition, the terminal organometallic functional group may be removed by subjecting the obtained polymer to elimination to provide the corresponding organic polymers.

Abstract: A catalytic composition, including a cationic metal-pair complex, is disclosed, along with a method for its preparation. A method for the polymerization of ethylenically unsaturated monomers using the catalytic composition, and the addition polymers produced thereby are also disclosed.

Abstract: The present invention relates to a catalyst composition for polymerization of a conjugated diene, comprising: (A) a metallocene-type complex represented by a general formula (I): (C5R1R2R3R4R5)aMXb.Lc (where, M represents a rare earth metal; C5R1R2R3R4R5 represents a substituted cyclopentadienyl group; R1 to R5 represent the same or different hydrocarbon groups (except when R1=R2=R3=R4=R5=a methyl group); X represents a hydrogen atom, a halogen atom, an alkoxide group, a thiolate group, an amide group, or a hydrocarbon group having 1 to 20 carbon atoms; L represents a Lewis basic compound; “a” represents an integer of 1, 2, or 3; “b” represents an integer of 0, 1, or 2; and “c” represents an integer of 0, 1, or 2); and (B) an ionic compound composed of a non-coordinating anion and a cation, and/or an aluminoxane.

Abstract: A process for polymerizing olefins is disclosed. The process polymerizes an olefin in the presence of a dehydrogenation catalyst and an olefin polymerization catalyst. The dehydrogenation catalyst enables in-situ generation of alkenes from oligomers or solvent. The alkenes are then incorporated into the polyolefin. The polyolefin should have increased long-chain branching and lower density without the use of expensive comonomers.

Abstract: A catalyst composition and method for olefin polymerization are provided. In one aspect, the catalyst composition is represented by the formula ?a?b?gMXn wherein M is a metal; X is a halogenated aryloxy group; ? and ? are groups that each comprise at least one Group 14 to Group 16 atom; ? is a linking moiety that forms a chemical bond to each of ? and ?; and a, b, g, and n are each integers from 1 to 4.

Abstract: Novel compounds are provided that are useful as catalysts, particularly in the polymerization of addition polymerizable monomers such as olefinic or vinyl monomers. The compounds are multinuclear complexes of transition metals coordinated to at least one unsaturated nitrogenous ligand. Catalyst systems containing the novel compounds in combination with a catalyst activator are provided as well, as are methods of using the novel compounds in the preparation of polyolefins.

Abstract: The present invention relates to a multinuclear metallocene catalyst for olefin polymerization and a process for olefin polymerization using the same, in which the multinuclear metallocene catalyst for olefin polymerization comprises, as a main catalyst, a transition metal compound that contains at least two metal atoms in the groups III to X of the periodic table as central metals and a ligand having a cyclopentadienyl structure bridging between the two metal atoms, and, as a cocatalyst, an aluminoxane compound, an organoaluminum compound or a bulky compound reactive to the transition metal compound to impart a catalytic activity to the transition metal compound.

Abstract: A polymerization process comprises contacting one or more olefinic comonomers in the presence of at least a high molecular weight catalyst and at least a low molecular weight catalyst in a single reactor, and effectuating the polymerization of the olefinic comonomers in the reactor to obtain an olefin polymer. Preferably, both catalysts have the ability to incorporate a substantially similar amount of comonomers in the olefin polymer. The polymers produced by the process may have a relatively higher level of long chain branching while maintaining a relatively narrow molecular weight distribution, i.e., MWD less than about 6. These interpolymers may exhibit processability similar to or better than LDPE but have physical properties similar to metallocene catalyzed polymers.

Abstract: Blends of two or more polyethylenes are made by reacting ethylene with an oligomerization catalyst that forms ?-olefins, and two polymerization catalysts, one of which under the process conditions copolymerizes ethylene and ?-olefins, and the other of which under process conditions does not readily copolymerize ethylene and ?-olefins. The blends may have improved physical properties and/or processing characteristics.

Abstract: This invention relates to a process to polymerize olefin(s) comprising combining a solution, slurry or solid comprising one or more bulky ligand metallocene catalyst compounds, an optional support, and or one or more activator(s) with a solution comprising one or more phenoxide catalyst compounds, and thereafter, introducing one or more olefin(s) and the combination into a polymerization reactor. This invention also relates to a polymer of ethylene wherein the polymer has a density of 0.910 to 0.930 g/cc, a melt index of 0.3 to 2.0 dg/min, and a 15 to 35 ?m thick film of the polymer has a 45° gloss of 60 or more, a haze of 7% or less, and a dart impact of 600 g or more.

Abstract: Catalyst compositions and methods useful in polymerization processes utilizing at least two metal compounds are disclosed. At least one of the metal compounds is a Group 15 containing metal compound and the other metal compound is preferably a bulky ligand metallocene-type catalyst. The invention also discloses a new polyolefin, generally polyethylene, particularly a multimodal polymer and more specifically, a bimodal polymer, and its use in various end-use applications such as film, molding and pipe. The Group 15 containing metal compound is represented in one embodiment by the formulae: wherein M is a Group 4, 5, or 6 metal; each X is independently a leaving group; y is 0 or 1; n is the oxidation state of M; m is the formal change of the ligand comprising the YZL or YZL? groups; L is a Group 15 or 16 element; L? is a Group 15 or 16 element or Group 14 containing group; Y is a Group 15 element; Z is a Group 15 element; and the other groups are as defined herein.

Abstract: A process for transitioning between two catalysts is disclosed, comprising the steps of a) discontinuing the feed of the first catalyst into the polymerization reactor, and then b) introducing the second catalyst into the reactor, wherein one of the catalysts comprises a late transition metal catalyst and the other is a catalyst which is incompatible therewith. It is preferred that the late transition metal catalyst is a 2,6-diacetyl pyridine iron catalyst.

Abstract: A catalyst obtained by contacting a transition metal compound (A) of the general formula [1]: [LpXoCpjM(N2)nM′XmLl]X′k  [1], wherein M and M′ independently represent a transition metal of Group 3 to 10; X independently represents a hydrogen atom, halogen atom, a specific hydrocarbon group or the like; Cp is a cyclopentadienyl group; L represents a group which bonds to M or M′ by lone pair of electrons or a &pgr; electron; X′ represents a counter anion; k, l, m, o and p each independently represent an integer of 0 to 5; j represents an integer of 0 to 2; n+o+p+j≦6; n represents an integer of 1 to 3; and n+l+m≦6, with an organoaluminum, and an aluminoxane and/or boron compound, or with an aluminoxane and/or boron compound, and a process for producing an addition polymerization with the catalyst.

Abstract: A process for preparing propylene polymer comprising contacting, under polymerization conditions, propylene and optionally ethylene, with a catalyst system comprising a bridged metallocene and a suitable activating cocatalyst, said process being characteized by reducing the concentration of hydrogen formed during the polymerization reaction.

Abstract: A catalyst composition that is the combination of or the reaction product of ingredients comprising (a) an lanthanide compound, (b) an alkylating agent, (c) a nickel-containing compound, and optionally (d) a halogen-containing compound, with the proviso that the halogen-containing compound must be present where none of the lanthanide compound, the alkylating agent, and the nickel-containing compound contain a labile halogen atom.

Abstract: Compositions and processes of forming chemical bonds, such as carbon-carbon and carbon-heteroatom bonds are provided. The compositions include at least one &agr;-halo carbonyl compound, and one or more transmetallation reagents. The transmetallation reagents are formed by the addition of a metal or metal catalyst to a target compound. The target compound is the compound undergoing chemical bond formation. Bond formation can be carried out in both intermolecular reactions (i.e. between two or more target compounds), or intramolecular (within the same target compound) reactions.

Abstract: A coordination catalyst system comprising at least one metallocene or constrained geometry pre-catalyst transition metal compound, (e.g., rac-ethylene bis(indenyl)zirconium dichloride), at least one non-metallocene, non-constrained geometry, bidentate transition metal compound or tridentate transition metal compound (e.g., tridentate 2,6-diacetylpyridine-bis(2,4,6-trimethylanaline)FeCl2), at least one support-activator (e.g., spray dried silica/clay agglomerate), and optionally at least one organometallic compound (e.g., triisobutyl aluminum), in controlled amounts, and methods for preparing the same. The resulting dual transition metal catalyst system is suitable for addition polymerization of ethylenically and acetylenically unsaturated monomers into polymers; for example, polymers having a broad molecular weight distribution, Mw/Mn, and good polymer morphology.

Abstract: Modified polybutadiene having a high-cis and low-trans structure with a moderate 1,2-structure content and exhibiting improved characteristics such as cold flow properties, which is obtained by modifying starting polybutadiene having a Tcp/ML1+4 ratio (Tcp: 5% toluene solution viscosity at 25° C.ML1+4: Mooney viscosity at 100° C.) of 2.5 or more in the presence of a transition metal catalyst.

Abstract: Novel compounds are provided that are useful as catalysts, particularly in the polymerization of addition polymerizable monomers such as olefinic or vinyl monomers. The compounds are multinuclear complexes of transition metals coordinated to at least one unsaturated nitrogenous ligand. Catalyst systems containing the novel compounds in combination with a catalyst activator are provided as well, as are methods of using the novel compounds in the preparation of polyolefins.

Abstract: Mixed olefin polymerization catalysts, methods for preparing olefin polymers using the catalysts, and polymers obtained therefrom are disclosed. The mixed catalyst system comprises the combination of (a) a Group 8-10 transition metal complex of a bidentate or tridentate ligand comprising at least one nitrogen donor selected from Set 1, (b) either a Group 8-10 transition metal complex of a bidentate or tridentate ligand comprising at least one nitrogen donor selected from Set 1 or a bidentate ligand comprising a nitrogen-nitrogen donor selected from Set 2, or a Group 4 transition metal complex of a multidnentate ligand comprising at least 1 cyclopentadienyl or indenyl ring selected from Set 3 or a titanium or chromium Ziegler-Natta catalyst selected from Set 4, and optionally (c) a compound Y.

Abstract: A process for preparing 1,2-diimine compounds of the formula I where R1 and R2 are, independently of one another, alkyl, aryl or metallocenyl radicals, and R3, R4 are, independently of one another, H, alkyl or aryl radicals or R3 and R4 are joined so as to form, with inclusion of the two imine carbon atoms, a 5- to 8-membered ring which may be saturated or unsaturated and may be unsubstituted or substituted by any hydrocarbon radicals. The process involves reacting 1,2-dicarbonyl compounds with primary amines, which have been activated with trialkylaluminum compounds prior to the reaction with the 1,2-dicarbonyl compounds. 1,2-Diimine compounds of the formula I in which R1 and R2 are, independently of one another, metallocenyl radicals can be used to prepare metal complexes which can be used as catalysts in a process for the polymerization of unsaturated compounds.

Abstract: A semicrystalline propylene polymer composition with good suitability for producing biaxially oriented films and prepared by polymerizing propylene, ethylene and/or C4-C18-1-alkenes, where at least 50 mol % of the monomer units present arise from the polymerization of propylene. Also described is the use of the semicrystalline propylene polymer composition for producing films, fibers or moldings, the films, fibers and moldings made from these compositions, biaxially stretched films made from the semicrystalline propylene polymer compositions, and also a method for characterizing the semicrystalline propylene polymer compositions.

Abstract: Disclosed is a process of controlling the degree of branch of high 1,4-cis polybutadiene without any alternation in the 1,4-cis content and the polymerization yield, in which a dialkylzinc compound represented by the following formula I is added in a controlled amount as an agent for controlling the degree of branch of high 1,4-cis polybutadiene, thus guaranteeing the optimum processability and physical properties of polymer according to the use purpose. R1—Zn—R2  Formula I wherein R1 and R2 are same or different and include an alkyl group containing 1 to 5 carbon atoms.

Abstract: Polyolefins, especially branched polyethylenes, can be made by combining a catalyst that can oligomerize ethylene to one or more alpha-olefins and a polymerization catalyst which can copolymerize ethylene and &agr;-olefins, by first carrying out the process in, for example, a continuous stirred tank reactor or its equivalent, and then in a plug flow reactor or its equivalent. The process minimizes the occurrence of (unreacted) &agr;-olefins in the final polymer product.

Abstract: Olefin polymers are prepared in a plurality of polymerization stages, optionally in a plurality of polymerization reactors, in the presence of hydrogen and an olefin polymerization multisite catalyst, preferably a dualsite catalyst, having at least catalytic sites A and B, site A capable of yielding polymers of different molecular weights and differing MFR2 or MFR21 depending on the concentration of hydrogen in the polymerization reactor and site B capable of yielding polymers of certain molecular weight and MFR2 or MFR21 depending on the concentration of hydrogen in the polymerization reactor where the ratio between MFR2 or MFR21 of polymers produced by site B at two different selected hydrogen concentrations is less than ten and the ratio between MFR2 or MFR21 of polymers produced by site A at the same hydrogen concentrations is more than 50.

Abstract: A complex suitable for use as a catalyst in the polymerisation of olefins is disclosed, having the Formula (I) wherein M is a transition metal; X represents an atom or group covalently or ionically bonded to M; T is the oxidation state of M; b is the valency of the atom or group X; A1 to A3 are each independently N or P or CR, with the proviso that at least one but no more than two of them are independently CR; Y1 and Y2 are each independently CR′ or PR′R″; Z is oxygen or NR5, R5 and R7 and each R, each R′ and each R″ are independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl, substituted heterohydrocarbyl or SiR303 where each R30 is independently selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl and substituted heterohydrocarbyl; but excluding those complexes having the formulae (1) and (2) where in both cases R4 and R6 are Me, R5 and R7 are 2, 4, 6-trimethylphenyl, M is Fe, T is II, X is Cl a

Abstract: A method for preparing polybutadiene having controlled molecular weight and high 1,4-cis content over 95% in the presence of a diethylzinc compound as a cocatalyst (i.e., alkylating agent) and molecular-weight-controlling agent, in which the molecular weight of the polybutadiene is controlled by variating the added amount of the diethylzinc compound without deterioration of 1,4-cis content nor polymerization yield, thus guaranteeing the optimum processability and physical properties of polymer according to the use purpose.

Abstract: Blends of two or more polyethylenes are made by reacting ethylene with an oligomerization catalyst that forms &agr;-olefins, and two polymerization catalysts, one of which under the process conditions copolymerizes ethylene and &agr;-olefins, and the other of which under process conditions does not readily copolymerize ethylene and &agr;-olefins. The blends may have improved physical properties and/or processing characteristics.