Low molecular weight telechelic diene copolymers and their use in tire components

Abstract

A method for preparing a low-molecular weight telechelic copolymer, the method comprising (i) providing a dilithium initiator prepared by reacting a dialkenyl compound with an alkyl lithium compound; (ii) combining the dilithium initiator with monomer including conjugated diene monomer and vinyl aromatic monomer to form a polymerization mixture; (iii) allowing the conjugated diene monomer and the vinyl aromatic monomer to copolymerize and form a low molecular weight copolymer including first and second reactive ends; and (iv) reacting the first and second reactive ends of the low molecular weight copolymer with a functionalizing agent to thereby form the low molecular weight telechelic copolymer.

Description

Low MOLECULAR WEIGHT TELECHELIC DIENE COPOLYMERS AND THEIR USE IN TIRE COMPONENTSFIELD OF THE INVENTION

[0001] Embodiments of the present invention provide low molecular weight telechelic diene copolymers, as well as the use of these copolymers in the preparation of tire components.BACKGROUND OF THE INVENTION

[0002] Polydienes, such as poly(butadiene) and diene copolymers (e.g. polyfstyrene- co-butadiene)) are often made by employing anionic polymerization techniques whereby diene monomer, optionally together with copolymerizable monomer such as vinyl aromatic monomer, are polymerized using an anionic initiator. The use of anionic polymerization techniques leads to several advantages including the ability to control molecular weight, prepare relatively linear polymer chains, and functionalize the polymer chain through a chain termination reaction. Useful anionic initiators may include, for example, alkyl lithium compounds such as n-butyl lithium. Multi-functional initiators can be formed by reacting, for example, an alkyl lithium compound with a dialkenyl compound such as diisopropenylbenzene. Polymers prepared by using multi-functional initiators have multiple reactive chain ends, which provides the ability to functionalize both ends of a polymer chain to form a telechelic polymer.SUMMARY OF THE INVENTION

[0003] One or more embodiments of the present invention provide a method for preparing a low-molecular weight telechelic copolymer, the method comprising (i) providing a dilithium initiator prepared by reacting a dialkenyl compound with an alkyl lithium compound, (ii) combining the dilithium initiator with monomer including conjugated diene monomer and vinyl aromatic monomer to form a polymerization mixture, (iii) allowing the conjugated diene monomer and the vinyl aromatic monomer to copolymerize and form a low molecular weight copolymer including first and second reactive ends, and(iv) reacting the first and second reactive ends of the low molecular weight copolymer with a functionalizing agent to thereby form the low molecular weight telechelic copolymer.

[0004] Other embodiments of the present invention provide a vulcanizable composition comprising a low-molecular weight telechelic copolymer prepared by the method set forth above, silica, and a curative.

[0005] Still other embodiments of the present invention provide a method for forming a vulcanizable composition, the method comprising (i) providing low-molecular weight telechelic copolymer prepared by the method set forth above, (ii) providing silica, (hi) providing a curative, and (iv) mixing the low-molecular weight telechelic copolymer, silica, and curative to form the vulcanizable composition.

[0006] Yet other embodiments of the present invention provide vulcanizable compositions, tire components, and tires prepared therefrom, where the vulcanizable compositions include telechelic copolymers prepared by the methods set forth above.DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0007] Embodiments of the invention are based, at least in part, on the discovery of low molecular weight telechelic diene copolymers prepared by polymerizing monomer with a dilithium initiator. In one or more embodiments, the low molecular weight telechelic diene copolymers are characterized by a relatively high glass transition temperature due to their high vinyl and high styrene content. Also, the combination of being low molecular weight and telechelic offers advantages relative to the ability to provide a high degree of functionalization relative to the mass of the polymer. Also, the overall microstructure allows the polymers to be incorporated into a cured rubber network, which can advantageously contribute to the wet performance of vulcanizates when used as tire treads.PREPARATION OF TELECHELIC COPOLYMERS

[0008] In one or more embodiments, the low molecular weight telechelic diene copolymers, which maybe referred to as low molecular weight difunctional copolymers, low molecular weight difunctionalized polymers, low molecular weight functionalized polymers, or simply low molecular weight polymer or copolymer, are generally prepared by anionic polymerization techniques by using a dilithium initiator. The dilithium initiator is preparedby reacting an alkyl lithium compound with a dialkenyl compound. In one or more embodiments, the dilithium initiator is aged in an appropriate solvent in the presence of a Lewis base prior to its use in polymerization. Once the dilithium initiator is prepared and optionally aged, the dilithium initiator may optionally be introduced to seed monomer to thereby form a reactive difunctional oligomer. After formation of the dilithium initiator (or optional difunctional oligomer), the dilithium initiator or difunctional oligomer is introduced to a blend of diene monomer and vinyl aromatic monomer to copolymerize the monomer and produce a reactive diene copolymer (i.e. di-reactive diene copolymer). According to embodiments of the invention, copolymerization of the diene monomer and vinyl aromatic monomer optionally takes place in the presence of a polymerization modifier such as potassium alkoxide. The reactive diene copolymer may then be reacted with a functionalizing agent to form the low-molecular weight telechelic copolymer.INITIATOR PREPARATION AND AGING

[0009] As indicated above, the dilithium initiator, which may also be referred to as DiLi initiator, is prepared by combining a dialkenyl compound with an alkyl lithium compound within a solvent that forms a reaction mixture in which the reactants and product are at least partially soluble. In one or more embodiments, the DiLi initiator is then aged in an appropriate solvent in the presence of a Lewis base.

[0010] In one or more embodiments, the dialkenyl compound is a 1,3-dialkenylbenzene compound such as 1,3-diisopropenylbenzene. In one or more embodiments, the alkyl lithium compound is a butyl lithium compound such as n-butyl lithium, t-butyl lithium, and / or sec-butyl lithium. In particular embodiments, sec-butyl lithium is employed.

[0011] In one or more embodiments, the Lewis base may include any Lewis base that does not include an active hydrogen atom, where the presence of an active hydrogen atom is determined by the Zerewitinoff test. Exemplary Lewis bases include oxolanyl propanes such as 2,2-bis(2-oxolanyl) propane (also known as 2,2-ditetrahydrofurylpropane), meso-2,2- diterahydrofurylpropane, DL-2,2,-ditetrahdydrofurlypropane, tetramethylethylenediamine, and mixtures thereof, as well as trialkyl amines such as triethyl amine. In particular embodiments, aging takes place in the presence of oxolanyl propanes and the presence of amines is limited or, in certain embodiments, excluded since it has been observed that theuse of amines (e.g. triethyl amine) during the aging process can lead to reduced efficacy of vinyl modification during copolymerization.

[0012] In one or more embodiments, aging of the initiator takes place in the substantial absence (or complete absence) of an amine compound such as a trialkyl amine compound (e.g. triethyl amine). In one or more embodiments, the aging of the initiator takes place in the presence of less than, including an absence of, an amount of trialkyl amine, where the amount of trialkyl amine can be quantified based upon a molar ratio of trialkyl amine to moles of lithium introduced with the alkyl lithium during formation of the DiLi initiator, of less than 0.2:1, in other embodiments less than 0.1:1, and in other embodiments less than0.05:1.

[0013] The amount of alkyl lithium compound reacted with the dialkenyl compound may be quantified based upon the molar ratio of lithium to alkenyl groups; that is, equivalents of lithium associated with the alkyl lithium compound (i.e. mole of Li) relative to the equivalents of alkenyl groups within the dialkenyl compound (e.g. equivalents of isopropenyl groups within 1,3-diisopropenylbenzene. In one or more embodiments, the molar ratio of moles of Li associated with the alkyl lithium to equivalents of alkenyl groups associated with the dialkenyl compound may be from about 1.95:1 to about 2.05:1, in other embodiments from about 1.97:1 to about 2.03:1, and in other embodiments from about1.99:1 to about 2.01:1. Where sec-butyl lithium is reacted with 1,3-diisopropenylbenzene, 2.00 moles of sec-butyl lithium may be reacted with each mole of 1,3-diisopropenylbenzene.

[0014] The synthesis of the initiator takes place within a solvent in which the reactants and the product is at least partially soluble. Useful solvents include, but are not limited to, hydrocarbons with a low or relatively low boiling point such as aromatic hydrocarbons, aliphatic hydrocarbons, and cycloaliphatic hydrocarbons. Non-limiting examples of aromatic hydrocarbons include benzene, toluene, xylenes, ethylbenzene, diethylbenzene, and mesitylene. Non-limiting examples of aliphatic hydrocarbons include n-pentane, n- hexane, n-heptane, n-octane, n-nonane, n-decane, isopentane, isohexanes, isopentanes, isooctanes, 2,2-dimethylbutane, petroleum ether, kerosene, and petroleum spirits. And, non-limiting examples of cycloaliphatic hydrocarbons include cyclopentane, cyclohexane,methylcyclopentane, and methylcyclohexane. Mixtures of the above hydrocarbons may also be used.

[0015] As indicated above, the dilithium initiator formed by the foregoing reaction may be aged within an appropriate solvent (e.g. within the reaction medium) in the presence of a Lewis base. In one or more embodiments, the Lewis base is present at the introduction of the reactants to the reaction mixture. In other embodiments, the Lewis base is introduced after synthesis of the dilithium initiator, and aging takes place after introduction of the Lewis base.

[0016] The amount of Lewis base introduced to the reaction mixture maybe quantified based upon the moles of Lewis base (e.g. 2,2-ditetrahydrofurylpropane) relative to the moles of lithium associated with the alkyl lithium compound (i.e. molar ratio of moles Lewis base to moles of lithium). In one or more embodiments, the molar ratio of moles of Lewis base introduced to the reaction medium to moles of lithium introduced with the alkyl lithium compound is from about 0.05:1 to about 1:1, in other embodiments from about 0.1:1 to about 0.6:1, and in other embodiments from about 0.2:1 to about 0.45:1.

[0017] In one or more embodiments, aging of the initiator takes place under an inert atmosphere at atmospheric conditions at a temperature of from about 0 to about 150 °C, in other embodiments from about 25 to about 100 °C, and in other embodiments from about35 to about 60 °C. In one or more embodiments, the initiator is aged for greater than 15 minutes, in other embodiments greater than 20 minutes, in other embodiments greater than 25 minutes, and in other embodiments greater than 30 minutes before introducing the initiator to the monomer to be polymerized. In one or more embodiments, the initiator is aged for from about 15 minutes to about 4 hours, in other embodiments from about 20 minutes to about 3 hours, and in other embodiments from about 30 minutes to about 2 hours before introducing the initiator to the monomer to be polymerized. The appropriate aging time is temperature dependent; that is, the time necessary to age the initiator decreases with increased temperature. Likewise, the maximum amount of aging decreases with temperature. It should also be appreciated that the temperature dependence of the aging process may allow for longer storage times at cold temperatures. For example, it is believed that the initiator (i.e. the combination of the dialkenyl compound and the alkyl lithium) canbe stored for periods of, for example, 24 hours or at temperatures below 0 °C (e.g. at temperatures as low as -35 °C).OLIGOMER FORMATION (SEEDING)

[0018] As indicated above, embodiments of the invention may optionally include first synthesizing oligomer by first polymerizing seed monomer to form reactive oligomer chains (i.e. reactive difunctional oligomers). This process (i.e. sub step) may also be referred to as seeding. As the skilled person will appreciate, this can be accomplished by first introducing seed monomer and the initiator described above, which results in the formation of a polymerization mixture in which the seed monomer is polymerized to thereby form a reactive macromolecule having two reactive polymer chains extending from the initiator residue. This reactive macromolecule may be referred to as a reactive difunctional oligomer. The seed monomer may include the polymerizable monomer described herein including, but not limited to, conjugated diene monomer (e.g. 1,3-butadiene) and / or vinyl aromatic monomer (e.g. styrene).

[0019] In one or more embodiments, the oligomer chains that are formed are relatively short chains that are formed by introducing a limited amount of seed monomer. The amount of seed monomer employed within the seeding step may be quantified based upon the equivalents of lithium associated with the initiator. In one or more embodiments, less than 100 moles, in other embodiments less than 75 moles, in other embodiments less than 50 moles, in other embodiments less than 30 moles, in other embodiments less than 15 moles, and in other embodiments less than 10 moles of seed monomer per equivalent of lithium associated with the initiator is polymerized in the seeding step. In one or more embodiments, the amount of seed monomer polymerized in the seeding step is from about 3 to about 100, in other embodiments from about 5 to about 50, and in other embodiments from about 10 to about to about 50 moles of seed monomer per equivalent of lithium associated with the initiator. Stated differently, the molar ratio of seed monomer to the DiLi initiator is less than 200:1, in other embodiments less than 150:1, in other embodiments less than 50:1, in other embodiments less than 30:1, in other embodiments less than 15:1, and in other embodiments less than 10:1. In one or more embodiments, the molar ratio of seed monomer to lithium atoms associated with the DiLi initiator is from about 3: 1 to about 100: 1,in other embodiments from about 5:1 to about 50:1, and in other embodiments from about 10:1 to about 50:1.

[0020] In one or more embodiments, seeding takes place in the presence of a potassium alkoxide. The potassium alkoxide can be introduced simultaneously or sequentially (before or after) with the introduction of the initiator and the seed monomer. In one or more embodiments, the amount of potassium alkoxide present during seeding (i.e. during synthesis of the oligomer) can be quantified as a molar ratio of the moles of potassium alkoxide to the moles of lithium associated with the initiator. In one or more embodiments, the molar ratio of potassium alkoxide to lithium (within the polymerization mixture during butadiene seeding) is greater than 0.01: 1, in other embodiments greater than 0.1:1, in other embodiments greater than 0.1:1, and in other embodiments greater than 0.75:1. In these or other embodiments, the molar ratio of potassium alkoxide to lithium (within the polymerization mixture) is less than 1:1, in other embodiments less than 0.5:1, in other embodiments less than 0.1:1, and in other embodiments less than 0.01:1. In these or other embodiments, the molar ratio of potassium alkoxide to lithium during butadiene seeding is from about 0.001:1 to about 1.1:1, in other embodiments from about 0.01:1 to about 0.5:1, and in other embodiments from about 0.1:1 to about 0.25:1.

[0021] In one or more embodiments, seeding takes place in the presence of a Lewis base. This Lewis base may include the Lewis base present during initiator formation and optional aging, or additional Lewis base may be introduced at the butadiene seeding sub step. In one or more embodiments, the amount of Lewis base present during seeding can be quantified as a molar ratio of the moles of Lewis base to the moles of lithium associated with the initiator. In one or more embodiments, the molar ratio of Lewis base to lithium (within the polymerization mixture) is less than 5:1, in other embodiments less than 1:1, in other embodiments less than 0.5:1, and in other embodiments less than 0.1:1. In these or other embodiments, the molar ratio of Lewis base to lithium during butadiene seeding is from about 5:1 to about 1:1, in other embodiments from about 0.5:1 about 0.1:1, and in other embodiments from about 0.01:1 to about 0.05:1.POLYMERIZATION REACTIONGENERAL TECHNIQUES

[0022] The dilithium initiator as prepared above, which may optionally be aged, or the oligomeric DiLi initiator where a seeding step is employed, is combined with monomer to be polymerized within an appropriate solvent to form a polymerization mixture in which the monomer and resulting polymer are at least partially soluble. In one or more embodiments, the DiLi initiator is also at least partially soluble within the polymerization mixture.

[0023] Generally speaking, the polymerization of monomer by the DiLi initiator proceeds by anionic polymerization techniques. The preparation of polymer by employing anionic polymerization techniques is generally known. The key mechanistic features of anionic polymerization have been described in books (e.g., Hsieh, H. L.; Quirk, R. P. Anionic Polymerization: Principles and Practical Applications; Marcel Dekker: New York, 1996) and review articles (e.g., Hadjichristidis, N.; Pitsikalis, M.; Pispas, S.; latrou, H.; Chem. Rev. 2001, 101(12), 3747-3792). The skilled person appreciates that anionic initiators may advantageously produce polymer having reactive chain ends (e.g., living polymers) that, prior to quenching, are capable of reacting with additional monomers for further chain growth or reacting with certain functionalizing agents to give functionalized polymers. The polymers having reactive polymer chain ends may simply be referred to as reactive polymers. As those skilled in the art appreciate, these reactive polymers include a reactive chain end, which is believed to be ionic, at which a reaction between a functionalizing agent and the reactive chain end of the polymer can take place, which thereby imparts a functionality or functional group to the polymer chain end, or which may couple multiple polymers together.

[0024] The polymerization mixture can be formed by introducing the various constituents in any order. For example, in one or more embodiments, the monomer and solvent can first be combined, and then the DiLi initiator can be introduced to the mixture.SOLVENT FOR POLYMERIZATION MIXTURE

[0025] In one or more embodiments, suitable solvents that can be used within the polymerization mixture include those organic compounds that will not undergo polymerization or incorporation into propagating polymer chains during the polymerizationof monomer in the presence of catalyst. In one or more embodiments, these organic species are liquid at ambient temperature and pressure. In one or more embodiments, these organic solvents are inert to the catalyst. Exemplary organic solvents include hydrocarbons with a low or relatively low boiling point such as aromatic hydrocarbons, aliphatic hydrocarbons, and cycloaliphatic hydrocarbons. Non-limiting examples of aromatic hydrocarbons include benzene, toluene, xylenes, ethylbenzene, diethylbenzene, and mesitylene. Non-limiting examples of aliphatic hydrocarbons include n-pentane, n-hexane, n-heptane, n-octane, n- nonane, n-decane, isopentane, isohexanes, isopentanes, isooctanes, 2,2-dimethylbutane, petroleum ether, kerosene, and petroleum spirits. And, non-limiting examples of cycloaliphatic hydrocarbons include cyclopentane, cyclohexane, methyl cyclopentane, and methylcyclohexane. Mixtures of the above hydrocarbons may also be used. The low-boiling hydrocarbon solvents are typically separated from the polymer upon completion of the polymerization. Other examples of organic solvents include high-boiling hydrocarbons of high molecular weights, such as paraffinic oil, aromatic oil, or other hydrocarbon oils that are commonly used to oil-extend polymers. Since these hydrocarbons are non-volatile, they typically do not require separation and remain incorporated in the polymer.MONOMER TO BE POLYMERIZED

[0026] As described above, DILI initiator (or the difunctional oligomer) is introduced with diene monomer and vinyl aromatic monomer to form the low-molecular weight copolymer of the invention. To distinguish this monomer from the butadiene monomer polymerized during the optional butadiene seeding step, reference may be made to monomer to be polymerized or bulk monomer. The skilled person will understand that since the DiLi initiator (or the difunctional oligomer) includes two reactive ends, the reactive ends will react with the diene and vinyl aromatic monomer and thereby add additional units to two growing polymer chains extending from the initiator core.

[0027] Examples of conjugated diene monomer, which may also be referred to as diene monomer, that is introduced with the reactive oligomer include 1,3-butadiene, isoprene,1.3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-l,3-butadiene, 2-ethyl-l,3-butadiene, 2-methyl- 1,3-pentadiene, 3-methyl-l,3-pentadiene, 4-methyl- 1,3-pentadiene, and2.4-hexadiene. Mixtures of two or more conjugated dienes may also be utilized incopolymerization. Examples of vinyl-substituted aromatic monomer, which may also be referred to as vinyl aromatic monomer, include styrene, p-methylstyrene, a-methylstyrene, and vinylnaphthalene.

[0028] The relative amounts of butadiene, vinyl aromatic monomer, and DiLi initiator introduced to form the low-molecular weight copolymer may depend on the interplay of various factors such as the type of initiator employed, the purity of the ingredients, the polymerization temperature, the polymerization rate and conversion desired, the molecular weight desired, and many other factors. In one or more embodiments, the relative amount of DiLi initiator and monomer (i.e. conjugated diene and vinyl aromatic) may be expressed as the mmols of DiLi initiator per weight of monomer (i.e. the combined weight of the diene and vinyl aromatic monomer) introduced to the polymerization mixture.

[0029] In one or more embodiments, the polymerization mixture includes greater than 0.10 mmol, or in other embodiments greater than 0.25 mmol, and in other embodiments greater than 0.50 mmol of the DiLi initiator per 100 grams of monomer within the polymerization mixture (i.e. monomer to be polymerized). In one or more embodiments, the polymerization mixture includes from about 0.10 to about 1.0 mmol, or in other embodiments from about 0.25 to about 0.75 mmol, or in other embodiments from about 0.45 to about 0.70 mmol of the DiLi initiator per 100 grams of monomer within the polymerization mixture (i.e. monomer to be polymerized).MODIFIER

[0030] The polymerization of the bulk monomer (which leads to formation of the low- molecular weight copolymer) may be conducted in the presence of a modifier, which may also be referred to as a polar coordinator or a vinyl modifier. This modifier may include the Lewis base present during initiator formation or during polybutadiene seeding, or it may include additional modifier introduced at the step of copolymerizing the bulk monomer.

[0031] As those skilled in the art appreciate, modifier compounds may serve multiple roles in the polymerization. For example, they can modify the vinyl content of the mer units deriving from dienes, and / or they can assist in randomizing comonomer throughout the polymer chain. Generally speaking, modifiers include those compounds having an oxygen or nitrogen heteroatom and a non-bonded pair of electrons. It can be convenient to referto modifiers by their function such as vinyl modifiers or randomizers. Some modifiers may serve both functions. Examples of modifiers include linear and cyclic oligomeric oxolanyl alkanes; dialkyl ethers of mono and oligo alkylene glycols (also known as glyme ethers); "crown" ethers; tertiary amines; linear THE oligomers; and the like. Linear and cyclic oligomeric oxolanyl alkanes are described in U.S. Patent Nos. 4,429,091 and 9,868,795, which are incorporated herein by reference. Specific examples of compounds useful as modifiers include 2,2-bis(2-oxolanyl)propane (also known aass 2,2- ditetrahydrofurylpropane), meso-2,2-diterahydrofurylpropane, DL-2,2,- ditetrahdydrofurlypropane, and mixtures thereof, 1,2-dimethoxyethane, N,N,N',N'- tetramethylethylenediamine (TMEDA), tetrahydrofuran (THE), 1,2-dipiperidylethane, dipiperidylmethane, hexamethylphosphoramide, A-A'-dimethylpiperazine, diazabicyclooctane, dimethyl ether, diethyl ether, tri-n-butylamine , and mixtures thereof. In one or more embodiments, the modifier is a non-amine vinyl modifier such as an oligomeric oxolanyl alkane. In one or more embodiments, the vinyl modifier is the same type of compound used as the Lewis Base during aging of the initiator as outlined above. For example, in one or more embodiments, an oligomeric oxolanyl alkane is employed for initiator formation and aging and an oligomeric oxolanyl alkane, either the same or separately introduced, is used as a modifier during copolymerization.

[0032] In these or other embodiments, a potassium alkoxide can be used as a modifier. It is believed that potassium alkoxides are useful to randomize the styrene distribution, and therefore reference may be made to randomizers. In one or more embodiments, a modifier other than a potassium alkoxide is employed. In other embodiments, potassium alkoxide is the only modifier present within the polymerization mixture. In other embodiments, copolymerization takes place in the presence of both potassium alkoxide and a modifier other than potassium alkoxide such as an oligomeric oxolanyl alkane. In one or more embodiments, the potassium alkoxide is defined by the formula R — 0 — K, where R is a monovalent organic group. For example, R may be a hydrocarbyl group such as, but not limited to, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, allyl, aralkyl, alkaryl, or alkynyl groups. In one or more embodiments, the cycloalkyl, cycloalkenyl, and aryl groups are non- heterocyclic groups. In one or more embodiments, the hydrocarbyl group may include fromabout 2 to about 20, or in other embodiments from about 4 to about 16 carbon atoms. In one or more embodiments, hydrocarbyl groups may include substituted hydrocarbyl groups, which refer to hydrocarbyl groups in which one or more hydrogen atoms have been replaced by a substituent such as a hydrocarbyl group. In one or more embodiments, these groups may include from one, or the appropriate minimum number of carbon atoms to form the group, to about 20 carbon atoms. In one or more embodiments, the substituents forming substituted hydrocarbyl groups are non-heterocyclic groups. In one or more embodiments, the hydrocarbyl groups may or may not contain heteroatoms. In one or more embodiments, the potassium alkoxide is at least partially soluble in the polymerization mixture, where at least partially soluble refers to a degree of solubility or more where the potassium alkoxide is not visible without magnification within the mixture. Exemplary potassium alkoxide compounds that are useful in the practice of this invention include potassium tert-amylate and potassium tert-butoxide.

[0033] In one or more embodiments, the amount of modifier (e.g. oligomeric oxolanyl alkanes) present during copolymerization of the bulk monomer can be quantified as a molar ratio of the moles of modifier to the moles of lithium associated with the oligomer (i.e. initiator). In one or more embodiments, the molar ratio of moles of modifier present during copolymerization to moles of lithium associated with the DiLi initiator is greater than 0.01:1, in other embodiments greater than 0.1:1, in other embodiments greater than 0.5:1, and in other embodiments greater than 0.9:1. In these or other embodiments, the molar ratio of moles of modifier present during copolymerization to moles of lithium associated with the DiLi initiator is less than 2: 1, in other embodiments less than 1: 1, in other embodiments less than 0.5:1, and in other embodiments less than 0.1:1. In one or more embodiments, the molar ratio of moles of modifier present during copolymerization to moles of lithium associated with the DiLi initiator is from about 0.1:1 to about 0.3:1, in other embodiments from about 0.25:1 about 0.5:1, and in other embodiments from about 0.4:1 to about 1:1.

[0034] As indicated above, this amount of modifier may be present because of the use of the modifier in the formation of the DiLi initiator, or it my introduced to the polymerization, for example added to the monomer in conjunction with the DiLi initiator. Where the modifier is added to the polymerization (i.e. added to the bulk monomer)separately from the DiLi initiator, which may take place contemporaneously or sequentially with the DiLi initiator, the amount introduced to the polymerization can be quantified as a molar ratio of the moles of modifier to the moles of lithium associated with the initiator. In one or more embodiments, the molar ratio of moles of modifier added to the polymerization to moles of lithium associated with the DiLi initiator is greater than 0.01:1, in other embodiments greater than 0.1:1, in other embodiments greater than 0.5:1, and in other embodiments greater than 0.9:1. In these or other embodiments, the molar ratio of moles of modifier added to the polymerization to moles of lithium associated with the DiLi initiator is less than 2:1, in other embodiments less than 1:1, in other embodiments less than 0.5:1, and in other embodiments less than 0.1:1. In one or more embodiments, the molar ratio of moles of modifier added to the polymerization to moles of lithium associated with the DiLi initiator is from about 0.1:1 to about 0.3:1, in other embodiments from about 0.25:1 about 0.5:1, and in other embodiments from about 0.4:1 to about 1:1. As noted above, the DiLi initiator and the modifier can be introduced to the polymerization system by various methods. In one or more embodiments, the anionic initiator and the modifier may be added separately to the monomer to be polymerized in either a stepwise or simultaneous manner. In one or more embodiments, practice of the invention is devoid of the addition of modifier to the polymerization mixture besides that which is associated with the DiLi initiator.POLYMERIZATION CONDITIONS AND TECHNIQUES

[0035] Copolymerization of conjugated diene monomer and vinyl aromatic monomer, in the presence of an effective amount of initiator, produces a reactive polymer. The introduction of the initiator, the conjugated diene monomer, the comonomer, and the solvent forms a polymerization mixture in which the reactive polymer is formed. Polymerization within a solvent produces a polymerization mixture in which the polymer product is dissolved or suspended in the solvent. This polymerization mixture may be referred to as a polymer cement.

[0036] In one or more embodiments, the polymerization may be conducted in any conventional polymerization vessel known in the art. For example, the polymerization can be conducted in a conventional stirred-tank reactor. In one or more embodiments, all of the ingredients used for the polymerization can be combined within a single vessel (e.g., aconventional stirred-tank reactor), and all steps of the polymerization process can be conducted within this vessel. In other embodiments, two or more of the ingredients can be pre-combined in one vessel and then transferred to another vessel where the polymerization of monomer (or at least a major portion thereof) may be conducted. Because various embodiments of the present invention include the use of multiple reactors or reaction zones, the vessel (e.g., tank reactor) in which the polymerization is conducted may be referred to as a first vessel or first reaction zone.

[0037] The polymerization can be carried out as a batch process, a continuous process, or a semi-continuous process. In the semi-continuous process, the monomer is intermittently charged as needed to replace that monomer already polymerized. In one or more embodiments, the heat of polymerization may be removed by external cooling by a thermally controlled reactor jacket, internal cooling by evaporation and condensation of the monomer through the use of a reflux condenser connected to the reactor, or a combination of the two methods. Also, conditions maybe controlled to conduct the polymerization under a pressure of from about 0.1 atmospheres to 50 atmospheres, in other embodiments from about 0.5 atmosphere to about 20 atmospheres, and in other embodiments from about 1 atmosphere to about 10 atmospheres. In one or more embodiments, the pressures at which the polymerization may be carried out include those that ensure that the majority of the monomer is in the liquid phase. In these or other embodiments, the polymerization mixture may be maintained under anaerobic conditions.

[0038] In one or more embodiments, the conditions under which the polymerization proceeds may be controlled to maintain the peak polymerization temperature of the polymerization mixture at greater than 30 °C, in other embodiments greater than 50 °C, and in other embodiments greater than 70 °C. In these or other embodiments, the conditions under which the polymerization proceeds may be controlled to maintain the peak polymerization temperature of the polymerization mixture at less than 120 °C, in other embodiments less than 110 °C, and in other embodiments less than 100 °C. In one or more embodiments, the conditions under which the polymerization proceeds may be controlled to maintain the temperature of the polymerization mixture within a range from about -10 °Cto about 200 °C, in other embodiments from about 0 °C to about 150 °C, and in other embodiments from about 20 °C to about 110 °C.PRE-FUNCTIONALIZATION POLYMER CHARACTERISTICS

[0039] Prior to functionalization, which is further described below, the low-molecular weight copolymers may be characterized by their molecular weight, which may include number average molecular weight (Mn), weight average molecular weight (Mw), and peak molecular weight (Mp). As those skilled in the art will appreciate, molecular weight can be determined, for example, by using gel permeation chromatography (GPC) together with an UV absorption, differential refractometer (DRI), refractive index (RI), infrared (IR) absorption detector and by employing appropriate calibration standards and THF as a solvent. For purposes of this specification, GPC measurements employ polystyrene standards and polystyrene Mark Houwink constants unless otherwise specified. For purposes of this specification, prior to functionalization, the polymer may be referred to as the base polymer, and the pre-functionalized characteristics of the polymer may be referred to as the characteristics of the base polymer.

[0040] In one or more embodiments, the pre-functionalized low-molecular weight copolymers have an Mp, which may also be referred to as the base Mp, of greater than 1 kg / mol, in other embodiments greater than 5 kg / mol, in other embodiments greater than 7 kg / mol, in other embodiments greater than 8 kg / mol, in other embodiments greater than 9 kg / mol, in other embodiments greater than 10 kg / mol, in other embodiments greater than 12 kg / mol, and in other embodiments greater than 20 kg / mol. In one or more embodiments, the pre-functionalized polymers have a base Mp of from about 1 to about 10 kg / mol, in other embodiments from about 5 to about 15 kg / mol, in other embodiments from about 5 to about 50 kg / mol, in other embodiments from about 7 to about 35 kg / mol, in other embodiments from about 8 to about 25 kg / mol, and in other embodiments from about 10 to about 50 kg / mol.

[0041] In one or more embodiments, the pre-functionalized low-molecular weight copolymers have an Mn, which may also be referred to as the base Mn, of greater than 1 kg / mol, in other embodiments greater than 5 kg / mol, in other embodiments greater than 7 kg / mol, in other embodiments greater than 8 kg / mol, in other embodiments greater than 9kg / mol, in other embodiments greater than 10 kg / mol, in other embodiments greater than 12 kg / mol, and in other embodiments greater than 20 kg / mol. In these or other embodiments, the pre-functionalized polymers have a base Mn of less than 50 kg / mol, in other embodiments less than 25 kg / mol, and in other embodiments less than 10 kg / mol. In one or more embodiments, the pre-functionalized polymers have a base Mn of from about 1 to about 10 kg / mol, in other embodiments from about 5 to about 15 kg / mol, in other embodiments from about 5 to about 50 kg / mol, in other embodiments from about 7 to about 35 kg / mol, in other embodiments from about 8 to about 25 kg / mol, and in other embodiments from about 10 to about 50 kg / mol.

[0042] In one or more embodiments, the pre-functionalized low-molecular weight copolymers have an Mw, which may also be referred to as the base Mw, of greater than 1 kg / mol, in other embodiments greater than 5 kg / mol, in other embodiments greater than 8 kg / mol, in other embodiments greater than 10 kg / mol, in other embodiments greater than 12 kg / mol, in other embodiments greater than 15 kg / mol, and in other embodiments greater than 20 kg / mol. In these or other embodiments, the pre-functionalized polymers have a base Mw of less than 50 kg / mol, in other embodiments less than 25 kg / mol, and in other embodiments less than 10 kg / mol. In one or more embodiments, the pre-functionalized polymers have a base Mw of from about 1 to about 10 kg / mol, in other embodiments from about 5 to about 15 kg / mol, in other embodiments from about 6 to about 60 kg / mol, in other embodiments from about 8 to about 42 kg / mol, in other embodiments from about 10 to about 30 kg / mol, and in other embodiments from about 10 to about 50 kg / mol.

[0043] In one or more embodiments, the pre-functionalized (i.e. base) low-molecular weight copolymers is monomodal. In these or other embodiments, the base polymer may be characterized by a polydispersity, which may also be referred to as a molecular weight distribution (Mw / Mn) of less than 3.0, in other embodiments less than 2.0, in other embodiments less than 1.5, and in other embodiments less than 1.1.

[0044] The pre-functionalized low-molecular weight copolymers produced according to aspects of the present invention may be characterized by vinyl content, which may be described as the number of unsaturations in the 1,2-microstructure relative to the total unsaturations within the polymer chain. As the skilled person will appreciate, vinyl contentcan be determined by NMR analysis at 400 MHz using CDCI3 as a solvent. In one or more embodiments, the pre-functionalized polymers include greater than 35%, in other embodiments greater than 40%, in other embodiments greater than 45%, in other embodiments greater than 50%, in other embodiments greater than 55%, and in other embodiments greater than 60% vinyl. In these or other embodiments, the prefunctionalized polymers include less than 85%, in other embodiments less than 80%, and in other embodiments less than 75%. In one or more embodiments, the pre-functionalized polymers include from about 35% to about 85%, in other embodiments from about 40% to about 80%, and in other embodiments from about 60% to about 75% vinyl.

[0045] The pre-functionalized low-molecular weight copolymers produced according to aspects of the present invention may be characterized by bound styrene content (i.e. the amount of styrene incorporated in the polymer chains), which refers to the weight percent vinyl aromatic monomer incorporated into polydiene copolymers. As the skilled person appreciates, bound styrene can be determined with reference to the relative weight of vinyl monomer included into the polymerization mixture relative to the diene monomer. Alternatively, bound styrene can be determined by NMR analysis at 400 MHz using CDCI3 as a solvent.

[0046] In one or more embodiments, the pre-functionalized polymers include greater than 5 wt %, in other embodiments greater than 15 wt %, in other embodiments greater than 25 wt %, in other embodiments greater than 35 wt %, in other embodiments greater than 40 wt %, in other embodiments greater than 45 wt %, in other embodiments greater than 50 wt %, in other embodiments greater than 55 wt % bound styrene. In these or other embodiments, the pre-functionalized polymers include less than 70 wt %, in other embodiments less than 65 wt %, in other embodiments less than 60 wt %, in other embodiments less than 50 wt %, and in other embodiments less than 40 wt % bound styrene. In one or more embodiments, the pre-functionalized polymers include from about5 to about 70 wt %, in other embodiments from about 15 to about 65 wt %, in other embodiments from about 35 to about 65 wt %, in other embodiments from about 45 to about 60 wt %, and in other embodiments from about 50 to about 60 wt % bound styrene.

[0047] In one or more embodiments, the bound styrene may be further characterized as micro-block styrene or chemical-block styrene. As the skilled person understands, microblock styrene represents styrene mer units that, while they maybe in blocks (i.e. small repeat units), the blocks are sufficiently small and randomly distributed such that the bound styrene does not phase separate from the diene segments of the copolymer. Chemical blocks, on the other hand, are larger, well-defined blocks of styrene mer units that phase separate from the diene segments of the copolymer. The skilled person also appreciates that several techniques can be employed to determine micro-block and chemical-block styrene. For example, differential scanning calorimetry (DSC) can be used to detect the presence of multiple Tg or a single Tg peak. NMR analysis can be used to determine the sequence distribution of the styrene mer units. For purposes of this specification, micro-block and chemical-block styrene are determined by NMR, and those blocks with 13 or more styrene mer units are deemed to be chemical-block styrene. For purposes of this specification, micro-block and chemical block styrene are determined by NMR, where micro-blocks include 2 to 12 styrene repeat mer units and chemical blocks include 13 or more styrene repeat mer units. Those skilled in the art appreciate that the remainder of the styrene units are single mer units randomly distributed throughout the polymer chain.

[0048] In one or more embodiments, the pre-functionalized polymers include greater than 30 wt %, in other embodiments greater than 40 wt %, and in other embodiments greater than 45 wt % micro-block styrene, based upon the total weight of the styrene mer units. In these or other embodiments, the pre-functionalized polymers include less than 60 wt %, in other embodiments less than 55 wt %, and in other embodiments less than 50 wt % micro-block styrene, based upon the total weight of the styrene mer units. In one or more embodiments, the pre-functionalized polymers include from about 30 to about 60 wt %, in other embodiments from about 40 to about 55 wt %, and in other embodiments from about45 to about 50 wt % micro-block styrene, based upon the total weight of the styrene mer units.

[0049] In one or more embodiments, the pre-functionalized polymers include greater than 7 wt %, in other embodiments greater than 10 wt %, and in other embodiments greater than 15 wt % chemical block styrene, based upon the total weight of the styrene mer units.In these or other embodiments, the pre-functionalized polymers include less than 30 wt %, in other embodiments less than 25 wt %, and in other embodiments less than 20 wt % chemical block styrene, based upon the total weight of the styrene mer units. In one or more embodiments, the pre-functionalized polymers include from about 7 to about 30 wt %, in other embodiments from about 10 to about 25 wt %, and in other embodiments from about15 to about 20 wt % chemical block styrene, based upon the total weight of the styrene mer units.

[0050] The pre-functionalized low-molecular weight copolymers produced according to aspects of the present invention may be characterized by a glass transition temperature (Tg), which is determined according to ASTM E1356-08 by using differential scanning calorimetry (DSC) techniques. In one or more embodiments, the Tg of the copolymers is greater than -85 °C, in other embodiments greater than -50 °C, in other embodiments greater than -20 °C, in other embodiments greater than -10 °C , in other embodiments greater than 0 °C, in other embodiments greater than 10 °C, in other embodiments greater than 15 °C, in other embodiments greater than 20 °C, and in other embodiments greater than 25 °C. In these or other embodiments, the Tg of the copolymers is less than 40, in other embodiments less than 25, and in other embodiments less than 0 °C. In one or more embodiments, the functionalized low-molecular weight copolymers have a Tg of from about -85 to about -50, in other embodiments from about -20 to about 0, and in other embodiments from about 0 to about 40 °C.POLYMER FUNCTIONALIZATION

[0051] The pre-functionalized low-molecular weight copolymers produced by the process of this invention (i.e. which proceeds by anionic polymerization techniques) includes first and second reactive ends (i.e. the growing ends) that are capable of being modified, which may also be referred to as functionalized, to provide functionalized polymers having a functional group at both ends of a linear polymer, which may be referred to as a telechelic polymer. That is, the reactive ends of the polymer are modified, which may also be referred to as functionalized, by introducing a functionalizing agent to the polymerization mixture. It is believed that the polymer chain ends react with the functionalizing agent (which may also be referred to as a modifying agent) to provide aresidue of the functionalizing agent at the end of the polymer chain. Accordingly, the reaction between the polymer and the functionalizing agents produces a polymer composition wherein both ends of a linear polymer include a terminal group deriving from the functionalizing agent. It should be appreciated that the reaction between the functionalizing agent and the reactive ends of the polymer can also result in polymer coupling of two or more polymer chains. In either event, the polymers bearing a chain-end functional group or polymers coupled with the residue of the functionalizing agent will both be referred to as modified or functionalized branched polymers unless otherwise designated. It should also be appreciated that the respective functionalizing agents that react with the respective reactive ends of the polymer may be of the same or different type of functionalizing agent; i.e. they may be of the same or different chemical species. The skilled person appreciates that two or more functionalizing agents of different chemical species may be introduced to the reactive polymer and that different chemical species may react at each of the respective ends of the polymer chain. Alternatively, the same chemical species may react at each end. The latter would be the result if one chemical species of functionalizing agent is introduced to the reactive polymer.FUNCTIONALIZING AGENTS

[0052] UUsseeffuull functionalizing agents iinncclluuddee tthhoossee functionalizing agents conventionally employed in the art. In one or more embodiments, the functionalizing agent imparts a terminal functionality that can be reactive or interactive with other polymer chains (propagating and / or non-propagating) or with other materials in a rubber compound such as particulate reinforcing fillers (e.g. carbon black or silica). As described above, enhanced interactivity between a polymer and particulate fillers in rubber compounds improves the mechanical and dynamic properties of resulting vulcanizates. For example, certain functionalizing agents can impart a terminal functionality that includes one or more heteroatoms. In one or more embodiments, the functionalizing agent may produce a functionalized polymer that can be used in rubber compositions from which vulcanizates can be provided, and these vulcanizates can possess high temperature (e.g., 50 °C) hysteresis losses that are less than those possessed by vulcanizates prepared from similar rubber compounds that do not include the functionalized polymers. Reductions in high temperaturehysteresis loss can be at least 5%, sometimes at least 10%, and occasionally at least 15%. In one or more embodiments, the functional group or groups (i.e. at each end of the polymer) are silica-interactive groups, which include those functional groups that when used in rubber compositions that include silica filler produce vulcanizates that exhibit less high temperature hysteresis loss than similar or comparable composition without the polymers bearing the silica-interactive groups.

[0053] Exemplary types of compounds that can be used to end-functionalize the reactive branched polymers of this invention include imines, amines, hydro carbyloxy silanes, amine-containing hydrocarbyloxy silanes, halogenated organics, trialkyl tin compounds, carbon dioxide, benzophenones, benzaldehydes, imidazolidones, pyrrolidinones, carbodiimides, ureas, isocyanates, and Schiff bases. It should also be appreciated that two or more different species of functionalizing agent can be employed in practicing the present invention.HYDROCARBYLOXY SILANE FUNCTIONALIZING AGENTS

[0054] In one or more embodiments, hydrocarbyloxy silane functionalizing agents may be defined by the formula:where R1is a halogen atom or a monovalent organic group, each R^ is a monovalent organic group, z is an integer from 1 to 4, and y is an integer from 0 to 2. In one embodiment, the halogen atom is chlorine.

[0055] In one or more embodiments, the monovalent organic groups include hydrocarbyl groups such as, but not limited to, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, allyl, aralkyl, alkaryl, or alkynyl groups. Hydrocarbyl groups also include substituted hydrocarbyl groups, which refer to hydrocarbyl groups in which one or more hydrogen atoms have been replaced by a substituent such as a hydrocarbyl group. In one or more embodiments, these groups may include from one, or the appropriate minimum number of carbon atoms to form the group, to about 20 carbon atoms. These groups may or may not contain heteroatoms. Suitable heteroatoms include, but not limited to, nitrogen, boron, oxygen, silicon, sulfur, tin, and phosphorus atoms. In one or more embodiments, thecycloalkyl, cycloalkenyl, and aryl groups are non-heterocyclic groups. In these or other embodiments, the substituents forming substituted hydrocarbyl groups are non- heterocyclic groups.

[0056] Suitable examples of siloxane terminating agents include tetraalkoxysilanes, alkylalkoxysilanes, arylalkoxysilanes, alkenylalkoxysilanes, and haloalkoxysilanes.

[0057] Examples of tetraalkoxysilane compounds include tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate, tetra(2- ethylhexyl) orthosilicate, tetraphenyl orthosilicate, and tetratoluyloxysilane.

[0058] Examples of alkylalkoxysilane compounds include methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, methyltri-n-butoxysilane, methyltriphenoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltri-n- propoxysilane, ethyltri-n-butoxysilane, ethyltriphenoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-propoxysilane, dimethyldi-n-butoxysilane, dimethyldiphenoxysilane, diethyldimethoxysilane, and diphenyldimethoxysilane.

[0059] Examples of arylalkoxysilane compounds include phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri-n-propoxysilane, phenyltri-n-butoxysilane, and phenyltriphenoxysilane.

[0060] Examples of alkenylalkoxysilane compounds include vinyltrimethoxysilane, vinyltri ethoxysilane, vinyltri-n-propoxysilane, vinyltri-n-butoxysilane, vinyltriphenoxysilane, allyltrimethoxysilane, octenyltrimethoxysilane, and di vinyl dimethoxysilane.

[0061] Examples of haloalkoxysilane compounds include trimethoxychlorosilane, triethoxychlorosilane, tri-n-propoxychlorosilane, tri-n-butoxychlorosilane, triphenoxy chlorosilane, dimethoxy dichlorosilane, diethoxydichlorosilane, di-n- propoxydichlorosilane, diphenoxydichlorosilane, methoxytri chlorosilane, ethoxytrichlorosilane, n-propoxytrichlorosilane, phenoxy trichlorosilane, trimethoxybromosilane, triethoxybromosilane, tri-n-propoxybromosilane, triphenoxybromosilane, dimethoxy dibromosilane, diethoxydibromosilane, di-n- propoxydibromosilane, diphenoxydibromosilane, methoxy tribromosilane, ethoxytribromosilane, n-propoxytribromosilane, phenoxytrib romosilane,trimethoxyiodosilane, triethoxyiodosilane, tri-n-propoxyiodosilane, triphenoxyiodosilane, dimeth oxydiiodosilane, di-n-propoxydiiodosilane, diphenoxydiiodosilane, methoxytriiodosilane, ethoxytriiodosilane, n-propoxytriiodosilane, and phenoxytriiodosilane.

[0062] Techniques for preparing functionalized polymers by using hydrocarbyloxy silane compounds are set forth in U.S. Patent Nos. 3,244,664; 6,008,295; 6,228,908; and 4,185,042, which are incorporated herein by reference.

[0063] In one or more embodiments, hydrocarbyloxy silane functionalizing agents is an imino-containing hydrocarbyloxy silane that may be defined by the formula:R3R5R2C N R4- Si R6OR7where R2, R3, and R7are monovalent organic groups, R4is a divalent organic group, and where R3and R6are each independently hydrocarbyloxy groups or hydrocarbyl groups.

[0064] In one or more embodiments, the divalent organic group is a hydrocarbylene groups such as, but not limited to, alkylene, cycloalkylene, alkenylene, cycloalkenylene, alkynylene, cycloalkynylene, or arylene groups. Hydrocarbylene groups include substituted hydrocarbylene groups, which refer to hydrocarbylene groups in which one or more hydrogen atoms have been replaced by a substituent such as a hydrocarbyl group. In one or more embodiments, these groups may include from one, or the appropriate minimum number of carbon atoms to form the group, to about 20 carbon atoms. These groups may or may not contain heteroatoms. Suitable heteroatoms include, but not limited to, nitrogen, boron, oxygen, silicon, sulfur, tin, and phosphorus atoms. In one or more embodiments, the cycloalkylene, cycloalkenylene, and arylene groups are non-heterocyclic groups. In these or other embodiments, the substituents forming substituted hydrocarbylene groups are non- heterocyclic groups.

[0065] Examples of these imino-containing hydrocarbyloxy silane compounds include triethoxy compounds such as, but are not limited to, N-(l,3-dimethylbutylidene)-3-(triethoxysilyl) -1-propaneamine, N-(l-methylethylidene)-3-(triethoxysilyl)-l- propaneamine, N-ethylidene-3-(triethoxysilyl)-l-propaneamine, N-(l-methylpropylidene)- 3-(triethoxysilyl)- 1-propaneamine, N-(4-N,N-dimethylaminobenzylidene)-3-(triethoxysilyl)- 1-propaneamine, and N-(cyclohexylidene)-3-(tri ethoxysilyl) -1-propaneamine. Other examples include trimethoxy compounds such as, but not limited to, N-(l,3- dimethylbutylidene)-3-(trimethoxysilyl)-l-propaneamine, N-(l-methylethylidene)-3- (trimethoxysilyl) -1-propaneamine, N-ethylidene-3-(trimethoxysilyl) -1-propaneamine, N-(l- methylpropylidene)-3-(trimethoxysilyl)- 1-propaneamine, N-(4-N,N- dimethylaminobenzylidene)-3-(trimethoxysilyl)-l-propaneamine, and N-(cyclohexylidene)- 3-(trimethoxysilyl)-l-propaneamine. Other examples include methyldiethoxy compounds such as, but not limited ttoo,, N-(l,3-dimethylbutylidene)-3-(methyldiethoxysilyl)-l- propaneamine, N-(l-methylethylidene)-3-(methyldiethoxysilyl) -1-propaneamine, N- ethylidene-3-(methyldiethoxysilyl) -1-propaneamine, N-(l-methylpropylidene)-3-(methyldiethoxysilyl)- 1-propaneamine, N-(4-N,N-dimethylaminobenzylidene)-3-(methyldiethoxysilyl)- 1-propaneamine, and N-(cyclohexylidene)-3-(methyl di ethoxysilyl) -1- propaneamine. Other examples include ethyldimethoxy compounds such as, but not limited to, N-(l,3-dimethylbutylidene)-3-(ethyldimethoxysilyl) -1-propaneamine, N-(l- methylethylidene)-3-(ethyldimethoxysilyl)-l-propaneamine, N-ethylidene-3-(ethyldimethoxysilyl)- 1-propaneamine, N-(l-methylpropylidene)-3-(ethyldim ethoxysilyl) -1- propaneamine, N-(4-N,N-dimethylaminobenzylidene)-3-(ethyldimethoxysilyl)-l- propaneamine, and N-(cyclohexylidene)-3-(ethyldimethoxysilyl) -1-propaneamine.

[0066] Techniques for preparing functionalized polymers by using imine-containing hydrocarbyloxy compounds are disclosed in U.S. Publication Nos. 2005 / 0009979; 2010 / 0113683; and 2011 / 0092633, which are incorporated herein by reference.

[0067] In one or more embodiments, hydrocarbyloxy silane functionalizing agents is a hydrocarbyloxy silane defined by the formula:R5A R4- Si R6OR7where R4is a divalent organic group, where R5and R6are each independently hydrocarbyloxy groups or hydrocarbyl groups, R5is a monovalent organic group, and A is selected from the group consisting of carboxylic ester, cyclic tertiary amine, non-cyclic tertiary amine, pyridine, silazane, and sulfide groups.

[0068] Examples of hydrocarbyloxy silane compounds including a carboxylic ester group include, but are not limited to, 3-methacryloyloxypropyltriethoxysilane, 3- methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, and 3-methacryloyloxypropyltriisopropoxysilane.

[0069] Examples of hydrocarbyloxy silane compounds including a cyclic tertiary amine group include, but are not limited to, 3-(l-hexamethyleneimino)propyltriethoxysilane, 3-(l- hexamethyleneiminojpropyltrimethoxysilane, (1-hexamethyleneimino) methyltri ethoxysilane, (1-hexamethyleneimino) methyltrimethoxysilane, 2-(l- hexamethyleneiminojethyltriethoxysilane, 3-(l-hexamethyleneimino) ethyltrimethoxysilane, 3-(l-pyrrolidinyl)propyltrimethoxysilane, 3-(l-pyrrolidinyl) propyltriethoxysilane, 3-(l- heptamethyleneiminojpropyltriethoxysilane, 3-(l- dodecamethyleneiminojpropyltriethoxysilane, 3-(l- hexamethyleneiminojpropyldiethoxyethylsilane, aanndd 3-[10-(triethoxysilyl)decyl]-4- oxazoline.

[0070] Examples of hydrocarbyloxy silane compounds including a non-cyclic tertiary amine group include, but are not limited to, 3-dimethylaminopropyltriethoxysilane, 3- dimethylaminopropyltrimethoxysilane, 3-di ethylaminopropyltrimethoxysilane, 3- diethylaminopropyltri ethoxysilane, 2-dimethylaminoethyltriethoxysilane, 2- dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyldiethoxymethylsilane, 3- di ethylaminopropyldiethoxymethylsilane, 3-dimethylaminopropyl dimethoxymethylsilane, 3- di ethylaminopropyldimethoxymethylsilane, and 3-dibutylaminopropyltriethoxysilane.

[0071] Examples of hydrocarbyloxy silane compounds including a pyridine group include, but are not limited to, 2-trimethoxysilylethylpyridine.

[0072] Examples of hydrocarbyloxy silane compounds including a silazane group include, but are not limited to, N,N-bis(trimethylsilyl)-aminopropylmethyldimethoxysilane,l-trimethylsilyl-2,2-dimethoxy-l-aza-2-silacyclopentane, N,N- bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N- bis(trimethylsilyl)aminopropyltrieth oxysilane, N,N- bisftrimethylsilyljaminopropylmethyldiethoxysilane, N,N- bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N- bisftrimethylsilyljaminoethyltriethoxysilane, N,N- bisftrimethylsilyljaminoethylmethyldimethoxysilane, and N,N- bis(trimethylsilyl)aminoethylmethyldiethoxysilane.

[0073] Still other specific examples of useful functionalizing agents include trialkyltin halides such as triisobutyltin chloride, as disclosed in U.S. Patent Nos. 4,519,431; 4,540,744; 4,603,722; 5,248,722; 5,349,024; 5,502,129; and 5,877,336, which are incorporated herein by reference. Examples of useful halogenated organic compounds include cyclic amino compounds such as hexamethyleneimine alkyl chloride, as disclosed in U.S. Patent Nos. 5,786,441; 5,916,976; and 5,552,473, which are incorporated herein by reference.Additional examples include cyclic sulfur-containing or oxygen containing azaheterocycles such as disclosed in WO 2004 / 020475; U.S. Publication No. 2006 / 0178467; and U.S. Patent No. 6,596,798, which are incorporated herein by reference. Other examples include boron- containing terminators such as disclosed in U.S. Patent No. 7,598,322, which is incorporated herein by reference. Still other examples include cyclic siloxanes such as hexamethylcyclotrisiloxane, including those disclosed in U.S. Patent No. 9,920,149, which is incorporated herein by reference. Yet other examples include polydimethylsiloxanes.AMOUNT OF FUNCTIONALIZATION AGENT USED

[0074] The amount of functionalizing agent employed in the practice of the present invention can be described with respect to the lithium or metal cation associated with the initiator. In one or more embodiments, the amount of functionalizing agent introduced to the polymerization mixture is greater than 0.70, in other embodiments greater than 0.75, in other embodiments greater than 0.80, in other embodiments greater than 0.85, and in other embodiments greater than 0.90 moles of functionalizing agent per mole of lithium in the initiator. In these or other embodiments, less than 0.99, in other embodiments less than0.97, and in other embodiments less than 0.95 moles of functionalizing agent per mole oflithium is introduced to the polymerization mixture. In one or more embodiments, from about 0.7 to about 1.0, in other embodiments from about 0.75 to about 0.99, and in other embodiments from about 0.80 to about 0.97 moles of functionalizing agent per mole of lithium is introduced to the polymerization mixture.FUNCTIONALIZATION REACTION

[0075] The reaction between the respective species of functionalizing agents and the low-molecular weight copolymers can take place by introduction the functionalizing agent sequentially or simultaneously to the reactive polymer.

[0076] In one or more embodiments, the reaction between the functionalizing agent and the reactive low-molecular weight copolymers may take place at a temperature from about 10 °C to about 150 °C, and in other embodiments from about 20 °C to about 100 °C.The time required for completing the reaction between the functionalizing agent and the reactive polymer depends on various factors such as the type and amount of the initiator used to prepare the reactive polymer, the type and amount of the functionalizing agent, as well as the temperature at which the functionalization reaction is conducted. In one or more embodiments, the reaction between the functionalizing agent and the reactive polymer can be conducted for about 10 to 60 minutes.

[0077] In one or more embodiments, the functionalizing agent is introduced to the polymer cement (i.e. polymerization mixture) while the low-molecular weight copolymers are dissolved or suspended within a solvent. As those skilled in the art appreciate, this solution may be referred to as a polymer cement, or more specifically as a reactive or living polymer cement. In one or more embodiments, the characteristics of the polymer cement, such as its concentration, will be the same or similar to the characteristics of the cement prior to functionalization. The composition including the functionalized polymer and solvent may be referred to as a polymerization mixture; in other words, a polymerization mixture including a functionalized polymer.

[0078] In one or more embodiments, modification of the low-molecular weight copolymers (i.e., introduction of the functionalizing agent to the polymer cement), takes place within the same vessel in which the polymerization was conducted. In other embodiments, modification of the polymer takes place outside of the reaction vessel in whichthe polymerization takes place. For example, the firstand second functionalizing agents can be introduced to the polymerization mixture (i.e. polymer cement) in a downstream vessel or a downstream transfer conduit.

[0079] According to one or more embodiments, as a result of the functionalization reaction, greater than 60 mol %, in other embodiments greater than 70 mol %, in other embodiments greater than 80 mol %, in other embodiments greater than 85 mol %, in other embodiments greater than 90 mol %, and in other embodiments greater than 95 mol % of the polymer chains within the low-molecular weight copolymers cement include a terminal functional group (i.e. the residue of a functionalizing agent). In one or more embodiments, from about 60 to about 100 mol %, in other embodiments from about 70 to about 99 mol %, in other embodiments from about 80 to about 98 mol %, and in other embodiments from about90 to about 97 mol % of the polymer chains within the polymer composition include the terminal functional group.

[0080] According to one or more embodiments, as a result of the functionalization reaction, greater than 80 mol %, in other embodiments greater than 90 mol %, in other embodiments greater than 95 mol %, and in other embodiments greater than 99 mol % of the polymer chains within the polymer cement include terminal functional groups at both ends of the low-molecular weight copolymers (i.e. are telechelic polymers).POST FUNCTIONALIZATIONPOLYMER STABILIZATION

[0081] In one or more embodiments, following modification, the modified low- molecular weight copolymers (i.e. the telechelic polymer may optionally be stabilized (i.e. post-functionalization stabilized). That is, the modified polymer may be stabilized by introducing a stabilizing agent to the polymerization mixture including the modified polymer. It is believed that the stabilizing agent reacts with certain terminal functional groups (e.g. a hydro carbyloxy substituent), and it is believed that this reaction may take place at the introduction of the two molecules or after aging of the composition.

[0082] In one or more embodiments, stabilizing agents known in the art may be used. For example, the stabilizing agents may include alkylalkoxy silanes as disclosed in U.S. Patent No. 6,255,404, which is incorporated herein by reference. Exemplary alkylalkoxy silanesinclude octyltriethoxy silane. In other embodiments, the stabilizing agent may include long- chain alcohols as disclosed in U.S. Patent No. 6,279,632, which is incorporated herein by reference. Exemplary long chain alcohols include sorbitan stearate or sorbitan monooleate. In still other embodiments, the polymers may be stabilized by treatment with an alkylalkoxy silane followed by treatment with a silane including a hydrolyzable group that forms an acidic species upon hydrolysis, such as methyltrichlorosilane, as disclosed in U.S. Patent No. 9,546,237, which is incorporated herein by reference.

[0083] In one or more embodiments of this invention, the use of aryl silanols (also known as hydroxy phenyl silanes) is advantageously used as a stabilizing agent. Useful aryl silanols are disclosed in U.S. Patent No. 9,255,167, which is incorporated herein by reference. Exemplary aryl silanols include, but are not limited to, triphenylsilanol, which is also referred to as hydroxytriphenylsilane, diphenylsilanediol, which is also referred to as dihydroxydiphenylsilane, and phenylsilanetriol, which is also referred to as trihydroxy(phenyl)silane.

[0084] In one or more embodiments, the functionalized polymers of this invention may be stabilized by treatment with an aryl silanol (e.g. aryl silane diol or aryl silane triol) contemporaneously or followed by treatment with a silane including a hydrolyzable group that forms an acidic species upon hydrolysis. Silanes including a hydrolyzable group that form an acidic species upon hydrolysis are disclosed in U.S. Patent No. 9,546,237, which is incorporated herein by reference. In particular embodiments, the functionalized polymers are treated with diphenyl silane diol and trimethyl silyl chloride.

[0085] In one or more embodiments, the stabilizing agent is added to the polymer cement after a sufficient time is provided to allow completion of the reaction between the reactive polymer and the functionalizing agent. In one or more embodiments, the stabilizing agent is introduced to the polymer cement after 30 minutes, in other embodiments after 15 minutes, and in other embodiments after 10 minutes from the time that the functionalizing agent is introduced to the polymer cement.

[0086] The amount of stabilizing agent (e.g. aryl silanol) employed in the practice of the present invention can be described with respect to the moles of lithium associated with the initiator. In one or more embodiments, greater than 0.5, in other embodiments greater than1, in other embodiments greater than 2, and in other embodiments greater than 3 moles of stabilizing agent per mole of lithium in the initiator is introduced to the polymerization mixture. In these or other embodiments, less than 8, in other embodiments less than 7, in other embodiments less than 6, in other embodiments less than 5, and in other embodiments less than 4.5 moles of stabilizing agent per mole of lithium is introduced to the polymerization mixture. In one or more embodiments, from about 1 to about 7, in other embodiments from about 2 to about 6, and in other embodiments from about 3 to about 5 moles of stabilizing agent per mole of lithium is introduced to the polymerization mixture.

[0087] In other embodiments, the amount of stabilizing agent (e.g. aryl silanol) employed in the practice of the present invention can be described as a molar ratio relative to the moles of functionalizing agent employed. In one or more embodiments, the ratio of the moles of stabilizing agent to the moles of functionalizing agent employed is from about 0.5:1 to about 8:1; in other embodiments from about 1:1 to about 7:1, in other embodiment from about 2:1 to about 6:1, and in other embodiments from about 3:1 to about 5:1. In these or other embodiments, the ratio of the moles of stabilizing agent to the moles of functionalizing agent employed is less than 7:1, in other embodiments less than 6:1, in other embodiments less than 5.5:1, in other embodiments less than 5:1, and in other embodiments less than 4.5:1.

[0088] Where two reagents are employed, such as where the polymer is treated with an aryl silanol (e.g. aryl silane diol or aryl silane triol) together with a silane including a hydrolysable group that forms an acidic species upon hydrolysis (e.g. hydrocarbyl silyl chloride such as trimethyl silyl chloride), the amount of the respective reagents employed may be the same or different. In one or more embodiments, the total amount of stabilizer employed (i.e. both compounds) is, when described as a molar ratio relative to the moles of functionalizing agent, from about 3:1 to about 10:1, in other embodiments from about 4:1 to about 8:1, and in other embodiments from about 5:1 to about 7:1. In these or other embodiments, the molar ratio of the aryl silanol to the silane including a hydrolysable group that forms an acidic species upon hydrolysis is from about 0.5:1 to about 4:1, in other embodiments from about 1:1 to about 3:1, and in other embodiments from about 1.5:1 to about 2.5:1.

[0089] In one or more embodiments, the stabilization of the polymer (i.e., introduction of the stabilizing agent) takes place within the same vessel in which the polymerization took place. In these embodiments, this will include the same vessel in which the modification took place. In other embodiments, stabilization of the polymer (i.e., introduction of the stabilizing agent) takes place outside of the vessel in which the polymerization took place. Likewise, in one or more embodiments, stabilization of the polymer takes place outside of the vessel in which the modification of the polymer took place. For example, in one or more embodiments, the stabilizing agent can be added to the polymerization mixture (i.e., polymer cement) in a vessel or transfer line that is downstream of the vessel in which the polymerization took place and that is downstream of the vessel in which the polymer modification took place. For purposes of this specification, relative to the polymerization vessel, the vessel or conduit in which the stabilizing agent is introduced may be referred to as a second vessel or second reaction zone. In other embodiments, the stabilizing agent may be introduced to the polymer while the polymer is suspended or dissolved within monomer.CONDENSATION ACCELERATOR

[0090] In one or more embodiments, after the introduction of the functionalizing agent to the reactive polymer, optionally after the addition of a quenching agent and / or antioxidant, optionally after or together with the stabilizing agent, and optionally after recovery or isolation of the functionalized polymer, a condensation accelerator can be added to the polymerization mixture. Useful condensation accelerators include tin and / or titanium carboxylates and tin and / or titanium alkoxides. One specific example is titanium 2- ethylhexyl oxide. Useful condensation catalysts and their use are disclosed in U.S. Publication No. 2005 / 0159554 (Patent No. US 7,683,151), which is incorporated herein by reference. In other embodiments, an organic acid can be used as a condensation accelerator. Useful types of organic acids include aliphatic, cycloaliphatic and aromatic monocarboxylic, dicarboxylic, tricarboxylic and tetracarboxylic acids. Specific examples of useful organic acids include, but are not limited to, acetic acid, propionic acid, butyric acid, hexanoic acid, 2-methylhexanoic acid, 2 -ethylhexanoic acid, cyclohexanoic acid and benzoic acid.

[0091] The amount of condensation accelerator employed in the practice of the present invention can be described with respect to the moles of lithium associated with the initiator. In one or more embodiments, the moles of condensation accelerator per mole of lithium is greater than 1.0, in other embodiments greater than 1.5, and in other embodiments greater than 1.8 moles of condensation accelerator per mole of lithium in the initiator. In these or other embodiments, less than 4.0, in other embodiments less than 3.3, and in other embodiments less than 3.0 moles of condensation accelerator per mole of lithium is introduced to the polymerization mixture. In one or more embodiments, from about 1.0 to about 4.0, in other embodiments from about 1.5 to about 3.3, and in other embodiments from about 1.8 to about 3.0 moles of condensation accelerator per mole of lithium is introduced to the polymerization mixture.ANTIOXIDANT

[0092] In one or more embodiments, after the introduction of the functionalizing agent to the reactive low-molecular weight copolymers, optionally after the addition of a quenching agent and / or antioxidant, optionally after or together with the stabilizing agent, and optionally after recovery or isolation of the functionalized polymer, an antioxidant can be added to the polymerization mixture. Exemplary antioxidants include 2,6-di-tert-butyl- 4-methylphenol.

[0093] In one or more embodiments, after formation of the low-molecular weight copolymers, a processing aid and other optional additives such as oil can be added to the polymer cement.OPTIONAL QUENCHING

[0094] In one or more embodiments, after the polymerization reaction, or after the reaction between the reactive low-molecular weight copolymers and the functionalizing agent has been accomplished or completed, a quenching agent can be added to the polymerization mixture in order to inactivate any residual reactive polymer chains and the catalyst or catalyst components. The quenching agent may include a protic compound, which includes, but is not limited to, an alcohol, a carboxylic acid, an inorganic acid, water, or a mixture thereof. The amount of quenching agent employed may be in the range of 0.5 to 10 moles of quenching agent per mole of lithium used to initiate the polymerization.POLYMER DESOLVENTIZATION

[0095] Following polymerization and / or polymer modification, optional stabilization, optional introduction of a condensation accelerator and / or introduction of an antioxidant, the low-molecular weight copolymers product can be separated from the solvent, which may be referred to as desolventization. In other words, as described above, the low-molecular weight copolymers are synthesized in an organic solvent, and during the step of desolventization, the organic solvent is separated from the resulting polymer.

[0096] In one or more embodiments, the low molecular weight polymer cements of this invention are combined with polymer cements that include higher molecular weight polymers, and the blend is desolventized. This technique offers several advantages including the ability to desolventize the low molecular polymer, which would otherwise be problematic, and the ability to disperse the low molecular weight polymer within higher molecular weight polymers.

[0097] In one or more embodiments, desolventization includes hot water and / or steam coagulation. For example, the polymerization mixture, which includes the blend of modified polymers, can be combined with a steam or hot water stream. The heat associated with the steam or hot water stream volatilizes the solvent and any unreacted monomer. The polymer product is then dispersed within an aqueous phase in, for example, the form of polymer crumb. The nature and size of the polymer crumb can generally be manipulated by the introduction of mechanical energy (e.g., in the form of mixers).

[0098] In one or more embodiments, the polymer crumb is temporarily stored as a crumb dispersion within the water until subsequent drying steps, which are described below. The crumb dispersion is generally a mixture of polymer particles or crumb and water. The polymer particles, which may also be referred to as coagulated polymer, are generally on the macroscale and have at least one dimension that is greater than one mm. This crumb dispersion may be contained within a tank, such as a conventional reactor tank such as a continuously stirred tank reactor.

[0099] In one or more embodiments, the polymer crumb can be further processed to remove residual solvent and dry the polymer (i.e., separate the polymer from the water). In practicing the present invention, the polymer can be dried by using conventional techniques,which may include one or more of filtering, pressing, and heating. Following desolventization and drying, the volatile content of the dried polymer can be below 2.0%, in other embodiments below 1.0%, and in other embodiments below 0.5% by weight of the polymer.

[0100] In other embodiments, the polymer product can be desolventized by employing devolatilizers, which are extruder-type devices that can operate in conjunction with heat and / or vacuum. In yet other embodiments, the polymerization mixture can be directly drum dried.

[0101] Regardless of the methods used to desolventize and dry the polymer, the finished polymer product may be referred to as a dried polymer. Using conventional techniques, the dried polymer can be molded or otherwise manipulated into a bale.CHARACTERISTIC OF LOW-MOLECULAR WEIGHT TELECHELIC COPOLYMERS

[0102] The functionalized low-molecular weight copolymers produced according to aspects of the present invention may be characterized by a glass transition temperature (Tg), which is determined according to ASTM E 1356-08 by using differential scanning calorimetry (DSC) techniques. In one or more embodiments, the Tg of the copolymers is greater than - 85 °C, in other embodiments greater than -50 °C, in other embodiments greater than -20 °C, in other embodiments greater than -10 °C , in other embodiments greater than 0 °C, in other embodiments greater than 10 °C, in other embodiments greater than 15 °C, in other embodiments greater than 20 °C, and in other embodiments greater than 25 °C. In these or other embodiments, the Tg of the copolymers is less than 40, in other embodiments less than 25, and in other embodiments less than 0 °C. In one or more embodiments, the functionalized low-molecular weight copolymers have a Tg of from about -85 to about -50, in other embodiments from about -20 to about 0, and in other embodiments from about 0 to about 40 °C.INDUSTRIAL APPLICABILITY

[0103] In one or more embodiments, the low-molecular weight telechelic copolymers of the invention may be used in formulating vulcanizable rubber composition that may, for example, be useful in the preparation of tire components. Rubber compounding techniques and the additives employed therein are generally disclosed in The Compounding and Vulcanization of Rubber, in Rubber Technology (2ndEd. 1973).

[0104] Generally speaking, these vulcanizable rubber compositions include a vulcanizable rubber component, reinforcing filler, and a curative or curative system. These compositions may also optionally include metal activators, resins, and processing oils, as well the various ingredients that may be conventionally included in these vulcanizable rubber compositions.

[0105] In one or more embodiments, the low-molecular weight telechelic copolymers of this invention may form part of the rubber component of the vulcanizable compositions. That is, the rubber component may include other vulcanizable rubbers, which may also be referred to as elastomeric polymers or simply elastomers.

[0106] The rubber compositions can be prepared by using the low-molecular weight telechelic copolymers of this invention together with other elastomers (i.e., polymers that can be vulcanized to form compositions possessing rubbery or elastomeric properties). Other elastomers that may be used include natural and synthetic rubbers. The synthetic rubbers typically derive from the polymerization of conjugated diene monomers, the copolymerization of conjugated diene monomers with other monomers such as vinyl- substituted aromatic monomers, or the copolymerization of ethylene with one or more a- olefins and optionally one or more diene monomers.

[0107] Exemplary synthetic rubbers, synthetic polyisoprene, polybutadiene, polyisobutylene-co-isoprene, neoprene, poly(ethylene-co-propylene), poly(styrene-co- butadiene), poly(styrene-co-isoprene), poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, and mixtures thereof. These elastomers can have a myriad of macromolecular structures including linear, branched, and star-shaped structures. Natural rubber is synthesized by and obtained from plant life. For example, natural rubber can be obtained from Hevea rubber trees, guayule shrub, gopher plant, mariola, rabbitbrush, milkweeds, goldenrods, pale Indian plantain, rubber vine, Russian dandelions, mountain mint, American germander, and tall bellflower.

[0108] Generally, the rubber compositions of this invention include from about 30 to about 65, in other embodiments from about 35 to about 60, and in other embodiments fromabout 40 to about 55 weight percent rubber (i.e. the rubber component), based on the total weight of the tire component, of rubber.

[0109] In one or more embodiments, the rubber component of the rubber compositions of this invention include from about 1 to about 50 wt %, in other embodiments from about10 to about 30 wt %, and in other embodiments from about 15 to about 20 wt % of the low- molecular weight telechelic copolymers produced by the techniques of this invention.

[0110] As indicated above, the rubber compositions may include fillers such as inorganic and organic fillers. Examples of organic fillers include carbon black and starch. Examples of inorganic fillers include silica, aluminum hydroxide, magnesium hydroxide, mica, talc (hydrated magnesium silicate), and clays (hydrated aluminum silicates). Carbon blacks and silicas are the most common fillers used in manufacturing tires. In certain embodiments, a mixture of different fillers may be advantageously employed.

[0111] The amount of total filler employed in the rubber compositions can be up to about 150 parts by weight per 100 parts by weight of rubber (phr), with about 5 to about 125 phr, or about 30 to about 110 phr, being typical. In certain embodiments the total filler content is greater than about 100 phr. In other embodiments, the total filler content is from about 50 to about 100 phr, and in in further embodiments from about 55 to about 95 phr.

[0112] In one or more embodiments, carbon blacks include furnace blacks, channel blacks, and lamp blacks. More specific examples of carbon blacks include super abrasion furnace blacks, intermediate super abrasion furnace blacks, high abrasion furnace blacks, fast extrusion furnace blacks, fine furnace blacks, semi-reinforcing furnace blacks, medium processing channel blacks, hard processing channel blacks, conducting channel blacks, and acetylene blacks.

[0113] In particular embodiments, the carbon blacks may have a surface area (EMSA) of at least 20 m2 / g and in other embodiments at least 35 m2 / g; surface area values can be determined by ASTM D-1765 using the cetyltrimethylammonium bromide (CTAB) technique. The carbon blacks may be in a pelletized form or an unpelletized flocculent form. The preferred form of carbon black may depend upon the type of mixing equipment used to mix the rubber compound.

[0114] In one or more embodiments, the amount of carbon black employed in the rubber compositions can be up to about 75 parts by weight per 100 parts by weight of rubber (phr), with about 5 to about 6 parts by weight phr, or about 10 to about 55 parts by weight phr, being used in exemplary embodiments.

[0115] In one or more embodiments, silicas may be characterized by their surface areas, which give a measure of their reinforcing character. The Brunauer, Emmet and Teller ("BET") method (described in J. Am. Chem. Soc., 1939, vol. 60, 2 p. 309-319) is a recognized method for determining the surface area. The BET surface area of silica is generally less than 450 m2 / g. Useful ranges of surface area include from about 32 to about 400 m2 / g, about 100 to about 250 m2 / g, and about 150 to about 220 m2 / g. In one or more embodiments, the silica may be characterized by a pH of from about 5 to about 7 or slightly over 7, or in other embodiments from about 5.5 to about 6.8.

[0116] In certain embodiments, the silica employed in the rubber composition is derived from rice husk ash only, and in other embodiments the rubber compositions do not include silica from non-rice husk ash derived processes.

[0117] Some commercially available silicas which may be used include Hi-Sil™ 215, Hi- Sil™ 233, and Hi-Sil™ 190 (PPG Industries, Inc.; Pittsburgh, P.A.). Other suppliers of commercially available silica include Grace Davison (Baltimore, M.D.), Degussa Corp. (Parsippany, N.J.), Rhodia Silica Systems (Cranbury, NJ.), and J.M. Huber Corp. (Edison, N.J.).

[0118] In one or more embodiments, the rubber compositions may include from about 1 to about 150, in other embodiments from about 5 to about 140, and in other embodiments from about 10 to about 130 parts by weight silica per 100 parts by weight rubber. In particular embodiments, the present invention includes rubber compositions with high silica loadings, such as loadings greater than 70, in other embodiments greater than 90, and in other embodiments greater than 110 parts by weight silica per 100 parts by weight rubber, with the useful upper end being limited by the high viscosity imparted by silica. When silica is used together with carbon black, the amount of the silica or carbon black can be as low as about 1 phr. In one or more embodiments, where carbon black and silica are employed in combination as a filler, the weight ratio of silica to total filler may be from about 5% toabout 99% of the total filler, or in other embodiments from about 10% to about 90% of the total filler, or in yet other embodiments from about 50% to about 85% of the total filler.

[0119] In one or more embodiments, where silica is employed as a filler (alone or in combination with other fillers), a coupling agent may be added to the rubber compositions during mixing in order to enhance the interaction of silica with the elastomers. Useful coupling agents are disclosed in U.S. Patent Nos. 3,842,111; 3,873,489; 3,978,103; 3,997,581; 4,002,594; 5,580,919; 5,583,245; 5,663,396; 5,674,932; 5,684,171;5,684,172; 5,696,197; 6,608,145; 6,667,362; 6,579,949; 6,590,017; 6,525,118;6,342,552; and 6,683,135; which are incorporated herein by reference.

[0120] In one or more embodiments, the amount of coupling agent may be from about2 to about 30 wt %, in other embodiments from about 4 to about 25 wt %, and in other embodiments from about 6 to about 20 wt % based on the weight of silica within the composition.

[0121] In one or more embodiments, where silica is employed as a filler (either alone or in combination with other fillers), a silica dispersing agent, which may include silica shielding agents, may be included in the rubber formulations. The use of one or more silica dispersing agents has been found to be particularly useful in practicing the present invention in view of the telechelic polymers and / or high silica loadings. In one or more embodiments, useful silica dispersing agents include alkyl alkoxysilanes, fatty acid esters of hydrogenated or non-hydrogenated Cg or C6sugars, polyoxyethylene derivatives of fatty acid esters of hydrogenated or non-hydrogenated Cg or C6sugars, and esters of polyols, including glycols and polyhydroxy compounds, and mixtures thereof. In particular embodiments, the silica dispersing agent is glycol monostearate. Useful silane dispersing agents are disclosed in U.S. Patent Nos. 6,608,145; 7,799,870; 7,897,661; 8,962,746; 9,758,639; 9,951,208; and U.S. Publication Nos. 2004 / 0152811, and 2005 / 0070672, which are incorporated herein by reference.

[0122] In other embodiments, useful silica dispersing agents include metal glycerolates such as zinc glycerolate, calcium glycerolate, and magnesium glycerolate. These compounds are described in greater detail in U.S. Patent Nos. 10,087,306 and11,220,595, and U.S. Publication No. 2021 / 0388188, which are incorporated herein by reference.

[0123] In one or more embodiments, the rubber compositions of the invention may include from about 0.1 to about 30 wt %, in other embodiments from about 1.0 to about 25 wt %, in other embodiments from about 3.0 to about 20 wt %, and in other embodiments from about 4.0 to about 10 wt% silica dispersing agent based on the weight of the silica within the composition. In one or more embodiments, the rubber compositions include greater than 3 wt %, in other embodiments greater than 5 wt %, and in other embodiments greater than 7 wt % dispersing agent based upon the weight of the silica. In these or other embodiments, the rubber compositions may include greater than 3 parts by weight, in other embodiments greater than 4 parts by weight, in other embodiments greater than 5 parts by weight, and in other embodiments greater than 6 parts by weight silica dispersing agent per 100 parts by weight rubber.

[0124] A multitude of rubber curing agents (also called vulcanizing agents) may be employed, including sulfur or peroxide-based curing systems. Curing agents are described in Kirk-Othmer, Encyclopedia of Chemical Technology, Vol. 20, pgs. 365-468, (3rdEd. 1982), particularly Vulcanization Agents and Auxiliary Materials, pgs. 390-402, and A.Y. Coran, Vulcanization, Encyclopedia of Polymer Science and Engineering, (2ndEd. 1989), which are incorporated herein by reference. Vulcanizing agents may be used alone or in combination.

[0125] Other ingredients that are typically employed in rubber compounding may also be added to the rubber compositions. These include accelerators, accelerator activators, oils, plasticizer, waxes, scorch inhibiting agents, processing aids, zinc oxide, tackifying resins, reinforcing resins, fatty acids such as stearic acid, peptizers, and antidegradants such as antioxidants and antiozonants. In particular embodiments, the oils that are employed include those conventionally used as extender oils, which are described above. Generally, the rubber compositions of this invention can include from about 1 to about 70 parts by weight, or in other embodiments from about 5 to about 50 parts weight total oil per 100 parts by weight rubber.

[0126] All ingredients of the rubber compositions can be mixed with standard mixing equipment such as, but not limited to, Banbury mixers, Brabender mixers, intermesh mixers including tandem intermesh mixers, extruders, kneaders, and two-roll mills. In one or more embodiments, the ingredients are mixed in two or more stages. In the first stage (often referred to as the masterbatch mixing stage), a so-called masterbatch, which typically includes the rubber component and filler, is prepared. To prevent premature vulcanization (also known as scorch), the masterbatch may exclude vulcanizing agents. The masterbatch maybe mixed ata starting temperature of from about 25 °C to about 125 °C with a discharge temperature of about 135 °C to about 180 °°CC.. Once the masterbatch is prepared, the vulcanizing agents may be introduced and mixed into the masterbatch in a final mixing stage, which is typically conducted at relatively low temperatures so as to reduce the chances of premature vulcanization. Optionally, additional mixing stages, sometimes called remills, can be employed between the masterbatch mixing stage and the final mixing stage. One or more remill stages are often employed where the rubber composition includes silica as the filler. Various ingredients including the polymers of this invention can be added during these remills.

[0127] The mixing procedures and conditions particularly applicable to silica-filled tire formulations are described in U.S. Patent Nos. 5,227,425; 5,719,207; and 5,717,022, as well as European Patent No. 890,606, all of which are incorporated herein by reference. In one embodiment, the initial masterbatch is prepared by including the polymer and silica in the substantial absence of coupling agents and shielding agents.

[0128] The rubber compositions prepared from the polymers of this invention are particularly useful for forming tire components such as treads, subtreads, sidewalls, body ply skims, bead filler, and the like. In one or more embodiments, these tread or sidewall formulations may include from about 10% to about 100% by weight, in other embodiments from about 35% to about 90% by weight, and in other embodiments from about 50% to about 80% by weight of the polymer of this invention based on the total weight of the rubber within the formulation.

[0129] Where the rubber compositions are employed in the manufacture of tires, these compositions can be processed into tire components according to ordinary tiremanufacturing techniques including standard rubber shaping, molding and curing techniques. Typically, vulcanization is effected by heating the vulcanizable composition in a mold; e.g., it may be heated to about 140 °C to about 180 °C. Cured or crosslinked rubber compositions maybe referred to as vulcanizates, which generally contain three-dimensional polymeric networks that are thermoset. The other ingredients, such as fillers and processing aids, may be evenly dispersed throughout the crosslinked network. Pneumatic tires can be made as discussed in U.S. Patent Nos. 5,866,171; 5,876,527; 5,931,211; and 5,971,046, which are incorporated herein by reference.EXAMPLES

[0130] In order to demonstrate the practice of the present invention, the following examples have been prepared and tested. The examples should not, however, be viewed as limiting the scope of the invention. The claims will serve to define the invention.INITIATOR PREPARATION DILI-TEA

[0131] 0.97 ml of diisopropenylbenzene (DB, neat, 1.0 eq.) and 7.61 ml of sec-butyl lithium (s-BuLi, 1.43 M in cyclohexane, 2.0 eq.) were charged to a 187 ml air and water free glass bottle sealed with a rubber septum and a perforated metal cap. The contents were shaken. After combining DB and s-BuLi, 0.79 mb of triethylamine (NEtg, neat, 1.0 eq.) was charged to the bottle. The bottle was again shaken and then agitated in a 50 °C water bath for 30 minutes. The resulting initiator (which may be referred to as DiLi-TEA initiator) was either quickly used or stored cold (max. 5 °C) prior to use.INITIATOR PREPARATION DILI-THFP

[0132] 0.97 ml of diisopropenylbenzene (DB, neat, 1.0 eq.) and 7.61 mt of sec-butyl lithium (s-BuLi, 1.43 M in cyclohexane, 2.0 eq.) were charged to a 187 mt air and water free glass bottle sealed with a rubber septum and a perforated metal cap, shaking to combine. After combining DB and s-BuLi, 2.13 ml of 2,2-di-(2-tetrahydrofuryl)propane (THFP, 1.6 M in hexanes, 0.3 eq.) was charged to the bottle. The bottle was again shaken and then agitated in a 50 °C water bath for 30 minutes. The resulting initiator (which may be referred to as DiLi-THFP initiator) was either quickly used or stored cold (max. 5 °C) prior to use.POLYMER SYNTHESIS - DILI-TEA WITH MODIFIERS (SAMPLES 1-8)

[0133] To each of a plurality of reactors positioned inside of a nitrogen filled glovebox was charged hexanes, 4.27 g of butadiene (21.1 wt % butadiene in hexanes), 2.72 g of styrene(33.1 wt % styrene in hexanes), and the polymerization modifiers (i.e. THFP and potassium t-amylate (KT A). The total amount of hexanes within each reactor was 5.02 g. The amount of the modifiers added within each sample is set forth in Tables 1 and 2. In particular, the samples within Table 1 included varying amounts of THFP, and the samples within Table 2 included varying amounts of KT A. After addition of the modifier, stirring was initiated and then 0.2565 mmol of the DiLi-TEA initiator prepared above was injected, and heating was set to 63 °C. The polymerization reaction was quenched after 2 hours of reaction time by injection of a solution of octanol in hexanes (10% v / v, 1 mb). Polymer characteristics are provided in Tables 1 and 2. The values provided in the Tables for each sample are an average of two data points from separate samples.Table 1Samples 1 2 3 4ModifierKT A (mmol) 0.2508 0.2508 0.2508 0.2508THFP(mmol) 0.0257 0.0616 0.1283 0.2565Polymer CharacteristicsTotal Mn(g / mol) 12,874 13,750 12,840 13,570Total Mw, (g / mol) 26,540 27,250 25,970 26,330Total Mw / Mn2.06 1.98 2.02 1 .95% Styrene 60.5 63.4 66.2 64.9Micro-block Styrene (based upon 100% Styrene) 31.1 31.6 32.1 31.9Chemical-block Styrene (based upon 100% Styrene) 12.0 12.7 13.2 12.9% 1 ,2-Butadiene(based upon 100% Butadiene) 51.4 53.0 54.2 54.8% 1 ,4-Butadiene(based upon 100% Butadiene) 48.6 47.0 45.8 45.2Table 2Samples 5 6 7 8ModifierKT A (mmol) 0.2508 0.5016 1.2539 2.5078THFP (mmol) 0.0616 0.0616 0.0616 0.0616Polymer CharacteristicsTotal Mn(g / mol) 15,120 14,415 10,525 8,850Total Mw, (g / mol) 29,265 27,490 28,500 33,750Total Mw / Mn1.93 1.91 2.71 3.83% Styrene 66.4 64.0 64.8 69.0Micro-block Styrene (based upon 100% Styrene) 27.5 30.0 28.4 26.3Chemical-block Styrene (based upon 100% Styrene) 10.7 11.1 9.5 9.7% 1 ,2-Butadiene(based upon 100% Butadiene) 51.0 49.7 50.1 53.0% 1 ,4-Butadiene(based upon 100% Butadiene) 49.0 50.3 49.9 47.0POLYMER SYNTHESIS - DILI-TEA WITHOUT MODIFIERS (SAMPLES 9A & 9B)

[0134] To a 750 mL air and water free glass bottle sealed with a rubber septum and a perforated metal cap was charged with 135.8 g of hexanes. The bottle was vented, and115.52 g of butadiene (21.1 wt % in hexanes) was charged into the bottle. Finally, 8.33 mL of the DiLi-TEA initiator solution prepared above was added to the bottle, and the bottle was placed in a 50 °C water bath for 1 hour. The bottle was removed from the water bath and quenched via the addition of 3 mL of 1PA / BHT (1 mg / mL). Polymer characteristics are provided in Table 3, which were run in duplicate and labeled Samples 9A and 9B.POLYMER SYNTHESIS - DILI-THFP WITHOUT MODIFIERS (SAMPLES 10A & 10B)

[0135] To a 750 mL air and water free glass bottle sealed with a rubber septum and a perforated metal cap was charged with 135.8 g of hexanes. The bottle was vented, and115.52 g of butadiene (21.1 wt % in hexanes) was charged into the bottle. Finally, 8.33 mL of the DiLi-THFP initiator solution prepared as above was added to the bottle, and the bottle was placed in a 50 °C water bath for 1 hour. The bottle was removed from the water bathand quenched via the addition of 3 mb of IPA / BHT (1 mg / mb). Polymer characteristics are provided in Table 3, which were run in duplicate and labeled Samples 10A and 10B.Table 3Samples 9A 9B 10A 10BInitiator DiLi-TEA DiLi-TEA DiLi-THFP DiLi-THFPPolymer CharacteristicsPeak 1 Mn, (g / mol) 19,020 19,025 13,490 13,165Peak 1 Mw, (g / mol) 19,750 19,730 18,850 18,000Peak 1 Mw / Mn1.04 1.04 1.40 1.38Peak 1 Area % 37.1 36.9 100 100Peak 2 Mn, (g / mol) 4,185 4,120Peak 2 Mw, (g / mol) 5,235 5,140Peak 2 Mw / Mn1.25 1.25Peak 2 Area % 62.9 63.1Total Mn(g / mol) 5,890 5,800Total Mw, (g / mol) 10,615 10,525Total Mw / Mn1.80 1.82% Styrene 56.5 56.7 46.3 47.9Micro-block Styrene (based upon 100% Styrene) 28.8 27.0 19.8 19.1Chemical-block Styrene 5.7 4.1 n 100% Styrene) 12. 13.2 (based upo 8% 1 ,2-Butadiene(based upon 100% Butadiene) 67.0 63.0 6.9 9.0% 1 ,4-Butadiene(based upon 100% Butadiene) 33.0 37.0 93.1 91.0POLYMER SYNTHESIS WITH DILI-THFP WITH MODIFIERS AND FUNCTIONALIZATION (SAMPLES 11A-11D)

[0136] To a 750 mb air and water free glass bottle sealed with a rubber septum and a perforated metal cap was charged with 133.75 g of hexanes. The bottle was vented, and113.74 g of butadiene (21.1 wt % in hexanes) was charged into the bottle. 3.00 mb of 2,2-di-(2-tetrahydrofuryl)propane (THFP)(1.6 M in hexanes, 1.0 eq) and 0.267 mb of potassium tert-amylate (KTA)(0.9 M in hexanes, 0.05 eq) were added to the bottle. Finally, 9.057 mb ofthe DiLi-THFP initiator solution prepared as above was added to the bottle, and the bottle was placed in a 50 °C water bath for 30 minutes. After 30 minutes, the bottles were removed from the water bath and / V,A / -Bis (trimethylsilyl) aminopropylmethyldiethoxysilane (neat,0.7 eq.) was injected, and the bottles were placed back in the 50 °C water bath for an additional 30 minutes. The bottles were removed from the water bath and quenched via the addition of 3 mb of 1PA / BHT (1 mg / mL).). Polymer characteristics are provided in Table 4, which were run four times and labeled Samples 11A through 11B.Table 4Samples 11A 11B 11C 11DPolymer CharacteristicsPeak 1 Mn, (g / mol) 61 ,500 59,150 58,220 55,690Peak 1 Mw, (g / mol) 88,260 85,040 82,840 77,105Peak 1 Mw / Mn1.44 1.44 1.42 1.17Peak 1 Area % 73.8 73.4 73 70.5Peak 2 Mn, (g / mol) 15,340 15,070 14,825 14,770Peak 2 Mw, (g / mol) 18,080 17,610 17,365 17,310Peak 2 Mw / Mn1.18 1.17 1.17 1.17Peak 2 Area % 26.2 26.6 27 29.5Total Mn(g / mol) 34,410 33,260 32,540 30,620Total Mw, (g / mol) 69,900 67,100 65,180 59,440Total Mw / Mn2.031 2.017 2.003 1 .941% Styrene 57.8 63.1 58.5 57.2Micro-block Styrene (based upon 100% Styrene) 31 .2 38.8 30.1 29.6Chemical-block Styrene (based upon 100% Styrene) 10.0 17.9 10.6 10.2% 1 ,2-Butadiene(based upon 100% Butadiene) 68.8 75.2 68.2 67.5% 1 ,4-Butadiene(based upon 100% Butadiene) 31 .2 24.8 31.8 32.5POLYMER ANALYSIS

[0137] The chemical properties of the polymers were analyzed by NMR and GPC. The number average (Mn), weight average (Mw) molecular weights, and polydispersity (PDI) were determined by gel permeation chromatography (GPC) using a Tosoh Ecosec HLC-8320 GPC system and Tosoh TSKgel GMHxl-BS columns with THF as a solvent. The system was calibrated using polystyrene (PS) standards and referenced to PS standards. The vinyl content and the styrene content (micro-block and chemical-block) of the polymer was determined by 400 MHz NMR using CDCI3 as the solvent.

[0138] Various modifications and alterations that do not depart from the scope and spirit of this invention will become apparent to those skilled in the art. This invention is not to be duly limited to the illustrative embodiments set forth herein.

Claims

CLAIMSWhat is claimed is:

1. A method for preparing a low-molecular weight telechelic copolymer, the method comprising:(i) providing a dilithium initiator prepared by reacting a dialkenyl compound with an alkyl lithium compound;(ii) combining the dilithium initiator with monomer including conjugated diene monomer and vinyl aromatic monomer to form a polymerization mixture;(hi) allowing the conjugated diene monomer and the vinyl aromatic monomer to copolymerize and form a low molecular weight copolymer including firstand second reactive ends, and(iv) reacting the first and second reactive ends of the low molecular weight copolymer with a functionalizing agent to thereby form the low molecular weight telechelic copolymer.

2. The method of claim 1, where the dialkenyl compound is diisopropenyl benzene.

3. The method of any of the preceding claims, where the alkyl lithium is selected from n-butyl lithium, t-butyl lithium, and sec-butyl lithium.

4. The method of any of the preceding claims, where said dilithium initiator is prepared by aging the dilithium initiator under inert atmosphere at a temperature of from about 0 to about 150 °C for greater than 15 minutes.

5. The method of any of the preceding claims, where the molar ratio of moles of Li associated with the alkyl lithium to equivalents of alkenyl groups associated with the dialkenyl compound is from about 1.95:1 to about 2.05:1.

6. The method of any of the preceding claims, where said dilithium initiator is prepared by aging the initiator in the presence of a Lewis base.

7. The method of any of the preceding claims, where the Lewis base is selected from the group consisting of 2,2-bis(2-oxolanyl)propane (also known aass 2,2- ditetrahydrofurylpropane), meso-2,2-diterahydrofurylpropane, DL-2, 2,- ditetrahdydrofurlypropane, tetramethylethylenediamine, and mixtures thereof.

8. The method of any of the preceding claims, where the Lewis base is devoid of an amine.

9. The method of any of the preceding claims, where the polymerization mixture includes a polymerization modifier.

10. The method of any of the preceding claims, where the modifier includes potassium alkoxide.

11. The method of any of the preceding claims, where the modifier includes 2,2-bis(2- oxolanyl) propane (also known as 2,2-ditetrahydrofurylpropane), meso-2,2- diterahydrofurylpropane, DL-2, 2, -ditetrah dydrofurlypropane, tetramethylethylenediamine, and mixtures thereof.

12. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by at least one of an Mp of from about 1.0 to about 600 an Mn of from about 0.5 to about 750, and an Mw of from about 0.1 to about 1,000 kg / mol.

13. The method of any of the preceding claims, where the polymer having first and second reactive ends is monomodal and has a molecular weight distribution of less than 2.0.

14. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by a vinyl content of greater than 35%.

15. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by a vinyl content of greater than 55%.

16. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by a bound styrene content of greater than 40 wt %.

17. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by a vinyl content of greater than 50%.

18. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by a micro-block styrene content of greater than 30 wt %, based on the total weight of styrene mer units.

19. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by a micro-block styrene content of greater than 40 wt %, based on the total weight of styrene mer units.

20. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by a chemical-block styrene content of less than 30 wt %, based on the total weight of styrene mer units.

21. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by a chemical-block styrene content of less than 25 wt %, based on the total weight of styrene mer units.

22. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by a Tg of greater than -20 °C.

23. The method of any of the preceding claims, where the polymer having first and second reactive ends is characterized by a Tg of greater than -0 °C.

24. The method of any of the preceding claims, where the first and second functionalizing agents are hydrocarbyloxy silanes.

25. The method of any of the preceding claims, where the functionalizing agent includes first and second functionalizing agents that are different types of functionalizing agents.

26. The method of any of the preceding claims, where at least one of the first and second functionalizing agents are defined by the formulaR3R5R2C N R4- Si R6OR7where R2, R3, and R7are monovalent organic groups, R4is a divalent organic group, and where R5and R6are each independently hydrocarbyloxy groups or hydrocarbyl groups.

27. The method of any of the preceding claims, where one of R3and R6 is a hydrocarbyloxy group and the other of R5 and R6 is a hydrocarbyl group.

28. The method of any of the preceding claims, where at least one of the first and second functionalizing agent is selected from the group consisting of N-(l,3- dimethylbutylidene)-3-(triethoxysilyl)-l-propaneamine, N-(l-methylethylidene)-3- (triethoxysilyl)-l-propaneamine, N-ethylidene-3-(triethoxysilyl)-l-propaneamine, N-(l-methylpropylidene)-3-(triethoxysilyl)-l-propaneamine, N-(4-N,N- dimethylaminobenzylidene)-3-(triethoxysilyl)-l-propaneamine, and N- (cyclohexylidene)-3-(triethoxysilyl)-l-propaneamine.

29. The method of any of the preceding claims, where at least one of the first and second the functionalizing agent is selected from the group consisting of trimethoxy compounds such aass,, but nnoott limited to, N-(l,3-dimethylbutylidene)-3- (trimethoxysilyl)-l-propaneamine, N-(l-methylethylidene)-3-(trimethoxysilyl)-l- propaneamine, N-ethylidene-3-(trimethoxysilyl)-l-propaneamine, N-(l- methylpropylidene)-3-(trimethoxysilyl)-l-propaneamine, N-(4-N,N- dimethylaminobenzylidene)-3-(trimethoxysilyl)-l-propaneamine, and N- (cyclohexylidene)-3-(trimethoxysilyl)-l-propaneamine.

30. The method of any of the preceding claims, where at least one of the first and second the functionalizing agent is selected from the group consisting of methyldiethoxy compounds such aass,, but nnoott limited ttoo,, N-(l,3-dimethylbutylidene)-3- (methyldiethoxysilyl)-l-propaneamine, N-(l-methylethylidene)-3-(methyldiethoxysilyl)-l-propaneamine, N-ethylidene-3-(methyldiethoxysilyl)-l- propaneamine, N-(l-methylpropylidene)-3-(methyldiethoxysilyl)-l-propaneamine, N-(4-N,N-dimethylaminobenzylidene)-3-(methyldiethoxysilyl)-l-propan eamine, and N-(cyclohexylidene)-3-(methyldiethoxysilyl)-l-propaneamine.

31. The method of any of the preceding claims, where at least one of the first and second the functionalizing agent is selected from the group consisting of ethyldimethoxy compounds such aass,, but not limited to, N-(l,3-dimethylbutylidene)-3- (ethyldimethoxysilyl)-l-propaneamine, N-(l-methylethylidene)-3-(ethyldimethoxysilyl)-l-propaneamine, N-ethylidene-3-(ethyldimethoxysilyl)-l- propaneamine, N-(l-methylpropylidene)-3-(ethyldimethoxysilyl)-l-propaneamine, N-(4-N,N-dimethylaminobenzylidene)-3-(ethyldimethoxysilyl)-l-propaneamine, and N-(cyclohexylidene)-3-(ethyldimethoxysilyl)-l-propaneamine.

32. The method of any of the preceding claims, where at least one of the first and second the functionalizing agent is defined by the formulaR5A R4- Si R6OR7where R4is a divalent organic group, where and R6are each independently hydro carbyloxy groups or hydrocarbyl groups, R^ is a monovalent organic group, and A is selected from the group consisting of, carboxylic ester, cyclic tertiary amine, non- cyclic tertiary amine, pyridine, silazane, and sulfide groups.

33. The method of any of the preceding claims, where at least one of the first and second the functionalizing agent is selected from the group consisting of N,N- bis(trimethylsilyl) -aminopropylmethyl dimethoxysilane, l-trimethylsilyl-2,2- dimethoxy- l-aza-2-silacyclopentane, N,N- bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N- bis(trimethylsilyl)aminopropyltriethoxysilane, N,N- bis(trimethylsilyl)aminopropylmethyldiethoxysilane, N,N- bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N- bis(trimethylsilyl)aminoethyltriethoxysilane, N,N- bis(trimethylsilyl)aminoethylmethyldimethoxysilane, and N,N- bis(trimethylsilyl)aminoethylmethyldiethoxysilane.

34. The method of any of the preceding claims, where the conjugated diene monomer is 1,3-butadiene and the vinyl aromatic monomer is styrene.

35. The method of any of the preceding claims, where after said step of reacting the first and second reactive ends of the low molecular weight polymer further comprises introducing a stabilizing agent to the linear telechelic diene copolymer.

36. The method of any of the preceding claims, further comprising the step of isolating the low-molecular weight telechelic copolymer from the polymerization mixture.

37. A low-molecular weight telechelic copolymer formed by the method of any of the preceding claims.

38. A vulcanizable composition of matter including the low-molecular weight telechelic copolymer of any of the preceding claims.

39. A vulcanizate prepared by vulcanizing the vulcanizable composition of matter of any of the preceding claims.

40. A tire component prepared from the vulcanizable composition of any of the preceding claims.

41. A tire tread prepared from the vulcanizable composition of any of the preceding claims.

42. A vulcanizable composition comprising:(i) a low-molecular weight telechelic copolymer prepared by the method of claim 1;(ii) silica; and(iii) a curative.

43. The vulcanizable composition of any of the preceding claims, further comprising a silica coupling agent.

44. The vulcanizable composition of any of the preceding claims, further comprising a silica dispersing agent.

45. The vulcanizable composition of any of the preceding claims, where the silica dispersing agent is selected from the group consisting of alkyl alkoxysilanes, fatty acid esters of hydrogenated or non-hydrogenated C5 or Cg sugars, polyoxyethylene derivatives of fatty acid esters of hydrogenated or non-hydrogenated C5 or Cg sugars, and esters of polyols, and mixtures thereof.

46. The vulcanizable composition of any of the preceding claims, where the silica dispersing agent is glycol monostearate.

47. The vulcanizable composition of any of the preceding claims, where the silica dispersing agent is a metal glycerolate.

48. The vulcanizable composition of any of the preceding claims, where the metal glycerolate is zinc glycerolate.

49. The vulcanizable composition of any of the preceding claims, where the vulcanizable composition includes greater than 70 parts by weight silica per 100 parts by weight rubber.

50. The vulcanizable composition of any of the preceding claims, where the vulcanizable composition includes from about 2 to about 30 wt % silica coupling agent based upon the weight of the silica.

51. The vulcanizable composition of any of the preceding claims, where the vulcanizable composition includes from about 0.1 to about 30 wt % silica dispersing agent based upon the weight of the silica.

52. A vulcanizate prepared by vulcanizing the vulcanizable composition of matter of any of the preceding claims.

53. A tire component prepared from the vulcanizable composition of any of the preceding claims.

54. A tire tread prepared from the vulcanizable composition of any of the preceding claims.

55. A method for forming a vulcanizable composition, the method comprising:(i) providing low-molecular weight telechelic copolymer prepared by the method of claim 1;(ii) providing silica;(hi) providing a curative; and(iv) mixing the low-molecular weight telechelic copolymer, silica, and curative to form the vulcanizable composition.

56. The method of any of the preceding claims, further comprising providing a silica coupling agent; and further comprising mixing the branched polymer, silica, and silica coupling agent.

57. The method of any of the preceding claims, further comprising providing a silica dispersing agent; and further comprising mixing the branched polymer, silica, and silica dispersing agent.

58. The method of any of the preceding claims, further comprising providing a silica coupling agent and a silica dispersing agent; and further comprising mixing the linear telechelic diene copolymer, silica, and silica dispersing agent, and silica coupling agent.

59. The method of any of the preceding claims, where the silica dispersing agent is selected from the group consisting of alkyl alkoxysilanes, fatty acid esters of hydrogenated or non-hydrogenated Cg or C6sugars, polyoxyethylene derivatives offatty acid esters of hydrogenated or non-hydrogenated Cg or C6sugars, and esters of polyols, and mixtures thereof.

60. The method of any of the preceding claims, where the silica dispersing agent is glycol monostearate.

61. The method of any of the preceding claims, where the silica dispersing agent is a metal glycerolate.

62. The method of any of the preceding claims, where the metal glycerolate is zinc glycerolate.

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