WO2005028529A2

WO2005028529A2 - Block copolymers of alpha methylene lactone(am)s

Info

Publication number: WO2005028529A2
Application number: PCT/US2004/030314
Authority: WO
Inventors: Charles J. Brandenburg; Leo Ernest Manzer; Pallatheri Subramanian
Original assignee: E.I. Dupont De Nemours And Company
Priority date: 2003-09-16
Filing date: 2004-09-15
Publication date: 2005-03-31
Also published as: WO2005028529A3

Abstract

Elastomeric block copolymers comprising at least one block of alpha methylene lactone(am)s units and at least one block prepared from diene monomers are prepared by anionic polymerization. The block copolymers are used as impact modifiers, compatibilizers, and for the production of shaped articles, films, foams, sheets, fibers, and adhesives.

Description

TITLE BLOCK COPOLYMERS OF ALPHA METHYLENE LACTONE(AM)S

FIELD OF THE INVENTION

The present invention relates to a new composition of matter, which consists of block copolymers of alpha methylene lactone(am)s (alpha-MLs) and dienes. It also relates to a process for the preparation of block copolymers of alpha-MLs. It further relates to the application of alpha-MLs block copolymers in shaped articles, films, fibers, and adhesives. Some embodiments of this invention comprise materials that can be processed by thermoplastic methods, have elastomeric behavior, and have improved mechanical and thermal properties.

BACKGROUND

Block copolymers provide unique thermomechanical properties as a result of their phase morphology. Hsieh and Quirk, in Anionic Polymerization, Principles and Practical Applications, Marcel Dekker Publications, 1996 provide an excellent review of the synthesis and applications of block copolymers. Thermoplastic elastomers such as Styrene-Butadiene-Styrene (SBS), or Styrene-lsoprene-Styrene (SIS) triblock polymers, sold under the Kraton^® tradename, are the most common examples of block copolymers prepared by anionic polymerization. The microphase separation of the "hard" polystyrene block in a continuous rubbery diene phase provides a physical network of flexible chains. The triblock structure allows a single polymer molecule to associate with two separate polystyrene domains. This provides a reversibly crosslinked structure that imparts high tensile strength in the material. Diblock copolymers of styrene and diene monomers can also be prepared, but these cannot form highly crosslinked networks and thus have low tensile strength. These materials are typically vulcanized (crosslinked) to give the strength needed for molded articles(Hsieh and Quirk, p. 478). The block copolymers can also be hydrogenated to give a Styrene-ethylene- butylene-Styrene (SEBS) block copolymer. The microstructure of the hydrogenated polymer can be controlled by variation of the solvent during diene polymerization. A more detailed discussion of thermoplastic elastomers is found in "Thermoplastic Elastomers: A Comprehensive Review" Edited by N. Legge, G. Holden, H. Schroeder, Hanser Publishers, 1987. Although heterogeneous catalysts can also be used, hydrogenation is typically done with homogeneous catalysis, as shown in US Patents 3,670,054 and US 4,501 ,857 and in Macromolecules, 1996, 29, 7316.

The ultimate physical properties of the SBS or SIS polymers depend on the ability of the polystyrene to resist plastic deformation under stress. At temperatures near the polystyrene Tg (100°C), the strength of the copolymer is dramatically reduced. Accordingly, the upper service temperature of the SBS is limited to about 70°C. Hsieh and Quirk provide a summary of triblock copolymers utilizing vinylaromatic monomers other than styrene (p. 491) to try to increase the upper service temperature. The earlier work by Fetters (Macromolecules, 1969, 2, 453) showed that D-methylstyrene (Tg of about 165°C) could be used to increase the tensile strength of the rubber and give a higher temperature capability. A more recent example (Macromolecules, 1996, 29, 6090) used syndiotactic PMMA (Tg 120 130°C) as the high Tg phase. The authors mention the potential to form a stereocomplex with isotactic PMMA, which gives material with a melting point of 190°C. This clearly indicates the need for thermoplastic elastomers with higher end use temperatures. Other work by the same authors show that isobornyl methacrylate can be used as the high Tg phase to increase the end use temperature (Macromolecules, 1996, 29, 7316; Macromolecules, 1996, 29, 8362) However, there is still a need for lower cost monomers to form the high Tg block, alpha-methylene lactones are known to polymerize under radical, anionic, and group transfer polymerization (GTP) to give high Tg amorphous polymers. Depending on the degree of substitution around the lactone ring, the Tg can be 195°C or greater. Thus, alpha-methylene, lactones, specifically MeMBL (Tg of about 215°C), are excellent candidates for the preparation of elastomeric block copolymers with high temperature capability. Polymerization of MeMBL is described in US 2,624,723 and US 5,880,235 and Macromolecules, 1984, 17, 2913. Polymerization of alpha-methylene-gamma- butyrolactone is described in Macromolecules, 1987, 20, 1473 and Macromolecules, 1979, 12, 546. These papers provide an excellent review on the polymerization and utility of alpha-methylene-lactone polymers, however they do not teach the preparation of elastomeric block copolymers by anionic polymerization.

Block polymers can be prepared by sequential monomer addition, by chain coupling using a multifunctional reagent, or by using a difunctional initiator such as 1 ,3-diisopropenyl benzene. Examples of sequential monomer addition and chain coupling are described in US Patents 6,197,889, 5,932,663, and 6,489,262 and references therein. Examples of using a difunctional imitator are described in US Patents 4,034,021 , 5,554,696, 5,750,055, and 6,455,651 ,

Early work at DuPont by Foss, Sharkey et al (Macromolecules, 1977, 10, 287, Macromolecules, 1976, 9, 376, and US 4,034,021 ) showed that 1 ,3-diisopropenyl benzene is an effective difunctional initiator for diene polymerization. In their procedure, two equivalents of an alkyl lithium reagent, typically sec-butyl lithium, are added to 1,3-diisopropenyl benzene in the presence of triethyl amine. Triethyl amine is necessary to increase the rate of alkyl lithium addition and prevents formation of unreactive precipitate. This technique was used to prepare ABA block copolymers where the A block is polypivalolactone and the B block is polyisoprene. Later work (Macromolecules, 1996, 29, 2738 and US 5,750,055) showed that t-butyl lithium adds cleanly to diisopropenyl benzene in the presence of triethyl amine.

The property profile of these block copolymers is characterized by the content of polymerized diene monomers, ie. the length, arrangement and ratio of polydiene and alpha-MLs blocks in case of the present invention described below. The microstructure of the diene block is also extremely important. Moreover, the type of transition between different blocks plays an important role. The influence of crisp and tapered transitions (depending on whether the monomer change is abrupt or gradual) is explained by Hsieh and Quirk. SUMMARY OF THE INVENTION

The present invention relates to block copolymers of alpha-methylene lactone(am)s and dienes. A preferred alpha-ML is the gamma-methyl-alpha- methylene-gammabutyrolactone (MeMBL) based polymer block. These block copolymers can be processed by thermoplastic methods, can be solution cast, have elastomeric behavior, and have improved mechanical and thermal properties. A general formula of alpha-methylene lactone(am) monomer from which the blocks in the copolymer are derived is depicted in Formula 10 below:

(FORMULA 10)

wherein: n is O, 1 or 2; X is -O- or -NR⁹-; and R¹, R², R⁵, and R⁶ each of R³ and each of R⁴, are independently hydrogen, a functional group, hydrocarbyl or substituted hydrocarbyl, and R⁹ is independently hydrocarbyl or substituted hydrocarbyl.

The preferred MeMBL structure is depicted in Formula 20 below.

20) One embodiment of this invention comprises copolymers of the formula:

(MeMBL) _L - (diene) _M - (MeMBL) _N Formula 1

wherein L and N are between about 5 to 4000, and M is between about 25 TO 25,000. Preferred values for L and N are about 15 to 500, and for m about 100 to 5,000.

Another embodiment of this invention comprises copolymers of the formula:

(Styrene) ι_ - (diene) _M - (MeMBL) _N Formula 2:

In Formula 1 and Formula 2, the various L, M and N subscripts set out above are integers that represent the corresponding number of respective monomer units in the copolymer.

Triblock copolymers of Formula 1 are prepared as follows:

a) Preparation of a difunctional initiator by treating diisopropenyl benzene 1 with a lithium alkyl reagent, such as t-butyl lithium, to form dianion 2. This step is preferably done in the presence of triethyl amine. The amount of NEt₃ is typically from about 0.1 to about 1 mole equivalents based on the amount of alkyl lithium reagent.

b) Addition of a diene monomer, such as butadiene (R=H) or isoprene (R=Me), or mixtures thereof, to 2 to form a difunctional low Tg block 3. The microstructure of the diene block can be controlled by choice of polymerization solvent. For example, polyisoprene with high cis-1 ,4 content can be prepared in apolar solvents such as cyclohexane.

c) Capping the dianion 3 with diphenyl ethylene to give difunctional polymer 4. This reduces the reactivity of the anion and prevents side reactions upon addition of MeMBL monomer

d) Addition of a monomer mixture comprising at least 1 weight % of MeMBL monomer to dianion 4 to give a triblock polymer 5. The remaining 99% of the monomer mixture may consist of vinylaromatic monomers such as styrene, or methacrylate monomers such as methyl methacrylate. The amount of MeMBL in the monomer mixture depends on the desired Tg of the block and the required end-use temperature of the copolymer. The Tg of the hard block can be varied up to about 215°C by using only MeMBL monomer as the hard block. The polymerization can be run at about -60°C to about 50°C.

e) Quenching the polymerization with a proton source such as methanol. Alternatively, another electrophile may be added, such as CO2 or an alkyl halide, to produce an end-functionalized polymer f) optionally hydrogenating the polymer g) Isolating the polymer by precipitation/filtration or centrifugation or extrusion/devolatilization i) fabricating the polymer or polymer blend in to a film, sheet, foam, fiber, or molded article

Triblock copolymers of Formula 2 are prepared by:

a) Polymerization of styrene using an alkyl lithium reagent to form a living polystyrene-Li. The preferred alkyl lithium reagents are n-butyl lithium, sec-butyl lithium, or t-butyl lithium. b) Addition of a diene monomer, such as butadiene or isoprene, or mixtures thereof to the polymer of step a) to give a polystyrene-polydiene-Li diblock polymer. The microstructure of the diene block can be controlled by choice of polymerization solvent. c) Capping the product of step b) with diphenyl ethylene to give polystyrene- polydiene-diphenyl ethylene -Li diblock polymer d) Addition of a monomer mixture comprising at least 1 weight % of MeMBL monomer to the product of step c) to give a triblock polymer. The remaining 99% of the monomer mixture may consist of vinylaromatic monomers such as styrene, or methacrylate monomers such as methyl methacrylate. The amount of MeMBL in the monomer mixture depends on the desired Tg of the block and the required end-use temperature of the copolymer. The Tg of the hard block can be varied up to about 215°C by using only MeMBL monomer as the hard block. The polymerization can be run at about -60°C to about 50°C.

One embodiment of this invention is a block copolymer comprising alpha-MLs of Formula 10 and a diene selected from the group consisting of isoprene and butadiene, said copolymer being of the Formula 1 wherein L and N are about 5 to 4,000 and M is about 25 to 25,000, and wherein the molecular weights of the MeMBL segments are about 500 to 400,000 and the molecular weights of the polydiene segments are about 1300 to 1,700,000.

(MeMBL) L - (diene) - (MeMBL) _N Formula 1

Another embodiment of this invention is a block copolymer comprising MeMBL and a diene selected from the group consisting of isoprene and butadiene, said copolymer being of the Formula 1 wherein L and N are about 5 to 4,000 and M is about 25 to 25,000, and wherein the molecular weights of the MeMBL segments are about 500 to 400,000 and the molecular weights of the polydiene segments are about 1300 to 1 ,700,000. (MeMBL) L - (diene) _M - (MeMBL) _N Formula 1

A preferred embodiment is a copolymer according to Formula ! wherein L and N are 15 to 200 and m is 100 to 5,000. Another preferred copolymer according to Formula 1 is wherein the diene unit is isoprene. Another preferred copolymer is according to Formula 1 wherein the diene unit is butadiene. A preferred embodiment of this invention is an article of manufacture comprising the copolymer as described above. For example, such an article could be a fiber, film, a molded object, foam, or an adhesive.

Another preferred embodiment of this invention is a block copolymer comprising Styrene, MeMBL and a diene selected from the group consisting of isoprene and butadiene, said copolymer being of the Formula 2 wherein L and N are about 5 to 4,000 and m is about 25 to 25,000, and wherein the molecular weights of the MeMBL segments are about 500 to 400,000 and the molecular weights of the polydiene segments are about 1300 to 1 ,700,000. A preferred copolymer is wherein L and N are 15 to 200 and m is 100 to 5,000. 13. A further preferred copolymer is wherein the diene unit is isoprene or butadiene. A preferred embodiment of this invention is an article of manufacture comprising the copolymer. For example, such an article could be a fiber, film, a molded object, foam, or an adhesive.

(Styrene) ι_ - (diene) - (MeMBL) N Formula 2

This invention also embodies a process for hydrogenating the polymer of Formula 1 using a homogeneous catalyst. It also embodies a process for hydrogenating the polymer of Formula 1 using a heterogeneous catalyst.

This invention further embodies a process for hydrogenating the polymer of Formula 2 using a homogeneous catalyst. It further embodies a process for hydrogenating the polymer of Formula 2 using a heterogeneous catalyst. A preferred embodiment of this invention is an article of manufacture comprising the copolymer. For example, such an article could be a fiber, film, a molded object, foam, or an adhesive.

This invention further embodies a block copolymer obtained by hydrogenation of the polymer in Formula 1. It also embodies a block copolymer obtained by hydrogenation of the polymer in Formula 2. A preferred embodiment of this invention is an article of manufacture comprising the copolymer. For example, such an article could be a fiber, film, a molded object, foam, or an adhesive.

DETAILED DESCRIPTION OF THE INVENTION

The terms used in the present invention are defined below. A "hydrocarbyl group" is a univalent group containing only carbon and hydrogen. If not otherwise stated, it is preferred that hydrocarbyl groups (and alkyl groups) herein contain 1 to about 30 carbon atoms. By "substituted hydrocarbyl" herein is meant a hydrocarbyl group which contains one or more substituent groups which are inert under the process conditions to which the compound containing these groups is subjected. The substituent groups also do not substantially interfere with the process. If not otherwise stated, it is preferred that substituted hydrocarbyl groups herein contain 1 to about 30 carbon atoms. Included in the meaning of "substituted" are heteroaromatic rings. In substituted hydrocarbyl all of the hydrogens may be substituted, as in trifluoromethyl. By "functional group" herein is meant a group other than hydrocarbyl or substituted hydrocarbyl which is inert under the process conditions to which the compound or polymer containing the group is subjected. The functional groups also do not substantially interfere with any process described herein that the compound or polymer in which they are present may take part in. Examples of functional groups include halo (fluoro, chloro, bromo and iodo), ether such as -OR22 wherein R22 js hydrocarbyl or substituted hydrocarbyl. By "reactive functional group" is meant a functional group that may react with another functional group present in the process or composition. By "may react" is meant that the functional group may react with its counterpart reactive group, but it is not necessary that such reaction happen or that all of the reactive functional groups react with one another. Usually in the formation of the compositions described herein, some fraction of these reactive functional groups will react.

The novel products of this invention include copolymers comprising:

(MeMBL) _L - (diene) _M - (MeMBL) _N Formula 1

wherein L and N are between about 5 to 4000, and M is between about 25 TO 25,000. Preferred values for L and N are about 15 to 500, and for m about 100 to 5,000, and,

(Styrene) ι_ - (diene) M - (MeMBL) N Formula 2:

wherein L and N are between about 5 to 4000, and M is between about 25 TO 25,000. Preferred values for L and N are about 15 to 500, and for m about 100 to 5,000. In Formula 1 and Formula 2, the various L, M and N subscripts set out above are integers that represent the corresponding number of respective monomer units in the copolymer.

The present invention directly relates to an elastomeric block copolymer of Formula 1 and Formula 2 comprising at least one block having polymerized units of a MeMBL monomer and forming a hard phase and at least one elastomeric block having polymerized units of a diene and forming a soft phase. The glass transition temperature Tg of block MeMBL block being above 25°C and that of diene block being below 25°C.

Optionally present in the MeMBL block are other monomers polymerizable by anionic polymerization such as vinylaromatic monomers and methacrylates. The vinylaromatic monomer is preferably chosen from styrene, D-methylstyrene, vinyltoluene and 1 ,1-diphenylethylene. The methacrylate monomer is preferably chosen from methyl methacrylate, t-butyl methacrylate, or mixtures thereof.

Optionally present in the diene block are vinylaromatic monomers, such as the ones described above.

The preferred diene monomers for the diene block are butadiene and isoprene.

Novel block copolymers are very suitable for the production of elastomeric shaped articles by the conventional methods for processing thermoplastics, for example as film, foam, and sheet is thermoformed molding, injection molding or extruded profile. The MeMBL block is composed of, for example, 1-100% by weight of MeMBL and 1- 99% vinylaromatic monomers or methacrylates. Particularly preferably, the MeMBL block has a MeMBL content of at least 50%.

The diene block is composed of, for example, 0-100% by weight of isoprene and 0-100% by weight of butadiene.

The amount by weight of the diene phase in the polymer is of decisive importance for the mechanical properties. According to the invention, the amount by weight of the diene phase composed of diene and vinylaromatic sequences is 40-99, preferably 60-90, particularly preferably 65-80% by weight.

The MeMBL blocks formed from MeMBL monomer forms the hard phase in Formula 1 and Formula 2, the amount by weight accordingly accounts for 5-60, preferably 10-40, particularly preferably 20-35 % by weight.

The styrene blocks formed from styrene monomer forms the hard phase in Formula 2, the amount by weight accordingly accounts for 5-60, preferably 10-40, particularly preferably 20-35 % by weight.

The block polymers are prepared by anionic polymerization in a nonpolar solvent, initiation being effected by means of organometallic compounds. Compounds of the alkali metals, in particular of lithium, are preferred. Operable monolithio initiators are alkyllithiums and include methyllithium, ethyllithium, n- butyllithium, sec-butyllithium, octyllithium and dodecyllithium. The butyllithiums are preferred.

Suitable dilithio initiators include: (1 ) dilithio .alpha.- methylstyrene oligomer (Karoly, ACS Polymer Preprints, 10, No. 2, Sept.. 1969); (2) 1 ,3-bis(1-lithio-3- methylpentyl)benzene, made by addition of sec-butyllithium to m-divinylbenzene (Kamienski, Polymer Preprints, First Akron Summit Polymer Conference, Symposium on Anionic Polymerization, University of Akron, p.24, June 18-19, 1970), sold under the trademark DiLi-3.RTM., registered in the name of Lithium Corporation of America; (3) dilithio isoprene oligomers, (dilithio-isoprene oligomers in benzene- triethylamine solution), see Product Bulletin 191 , Lithium Corporation of America; (4) 1 ,4-dilithio-1 , 1 ,4,4- tetraphenylbutane prepared by reacting lithium with 1 ,1- diphenylethylene (Fetters and Morton, Macromolecules, 2, 453 (1969); and (5) 1 ,3- bis(1- lithio-1-methyl-2-alkyl)benzene ##STR6## wherein R is an alkyl, prepared by the addition of m-diisopropenylbenzene ##STR7## to an alkyllithium. When using this compound as the lithium initiator, its preparation should proceed in a solution of triethylamine and an aliphatic solvent, such as cyclohexane. Typical alkyl lithiums include n-butyl or s-butyl lithiums. Starting with the preferred s-butyllithium results in the desired 1 ,3-bis(1-lithio-1 ,3-dimethylpentyl)-benzene ##STR8## The steric hindrance induced by the 1 -methyl groups apparently precludes the addition of further m-diisopropenyl benzene molecules with the concommittant possibility of initiators with several rather than two lithium atoms. These preferred initiators with exactly two lithium atoms can then produce pure . alpha. ,.omega.-dilithiopolydienes free of undesired branch chains and permits the development of block copolymers with no side chains attached to the initiator molecules themselves.

Thus, in general, initiator types (2) and (5), especially the latter, represent the preferred initiators, Moreover, it is expected that other useful initiators would include compounds similar to the two preferred types (2) and (5) that can be described more generally as solutions of alpha-lithio substituted dialkylbenzenes and dialkylbenzene oligomers in hexane-triethylamine solution. The organometallic compound is added as a solution in a chemically inert hydrocarbon. The dose depends on the intended molecular weight of the polymer but is, as a rule, from 0.002 to 5 mol %, based on the monomers. Preferably used solvents are aliphatic hydrocarbons, such as cyclohexane and methylcyclohexane.

The polymerization temperature may be from -78°C to 130°C, preferably from -60°C to 50°C.

The amount by volume of the two phases can be measured by high-contrast electron microscopy or solid-state NMR spectroscopy. The amount of the MeMBL blocks can be determined by precipitation and weighing after osmium degradation of the polydiene fraction. The future phase ratio of a polymer can also be calculated from the amounts of monomers used if complete polymerization is permitted in each case.

The glass transition temperature Tg is influenced by the random incorporation of the vinylaromatic compounds in to the soft block of the block copolymer. A glass transition temperature from -75 to +25°C, preferably from -65 to +5°C, is typical.

Polymerization is carried out in several stages. For a triblock polymer structure of Formula 1 , the first stage is the preparation of the difunctional dilithium initiator. This is typically done by addition of an alkyl lithium reagent to a symmetrical divinyl aromatic compound, such as 1 ,3-diisopropenyl benzene in an apolar solvent such as cyclohexane. Additives such as triethylamine, anisole, ether, or THF can optionally be present. However, some oligomerization of the 1 ,3-diisopropenylbenze has been reported if no polymer additives are present (Macromolecules, 1996, 29, 273). The diene monomers are then charged to the reactor at a controlled rate and allowed to polymerize. In order to achieve a defined chain structure which can be calculated from the monomer and initiator dose, it is advisable to carry out the process up to a high conversion (more than 99%) before the second monomer addition. However, this is not absolutely essential. The polydiene chains are then capped with a reagent which makes the anion less nucleophilic. This is typically done with 1 ,1-diphenylethylene. This compound will react with the polydiene chain end, but will not undergo homopolymerization. The 1 ,1-diphenylethylene can be added neat or as a solution. A polar solvent such as THF is then added to the solution at about 0°C to promote dissociation of the lithium cations and allow for the polymerization of the more polar monomers. Optionally, lithium chloride may be added to the THF. This promotes the dissociation of the lithium at the polymer chain ends and allows for "living" polymerization of the MeMBL block. The MeMBL monomer is then added to the reaction mixture and allowed to polymerize. It can be added neat or as a solution in a solvent suitable for anionic polymerization, such as THF. The temperature of the MeMBL polymerization can be from about -60°C to about 50°C, preferably -30°C to 25°C, most preferably -10 °C to about 10°C.

Triblock copolymers of Formula 2 are prepared by sequential monomer addition. The first step is the polymerization of styrene using an alkyl lithium reagent to form a living polystyrene-Li. The preferred alkyl lithium reagents are n-butyl lithium, sec-butyl lithium, or t-butyl lithium. The second step is the addition of a diene monomer, such as butadiene or isoprene, or mixtures thereof to the living polystyrene. This gives a polystyrene-polydiene-Li diblock polymer. The microstructure of the diene block can be controlled by choice of polymerization solvent. The third step is capping the polystyrene-polydiene-Li with diphenyl ethylene to give polystyrene-polydiene-diphenyl ethylene -Li diblock polymer. The final block is done by addition of a monomer mixture comprising at least 1 weight % of MeMBL monomer to the polystyrene-polydiene-diphenyl ethylene -Li to give a triblock polymer. The remaining 99% of the monomer mixture may consist of vinylaromatic monomers such as styrene, or methacrylate monomers such as methyl methacrylate. The amount of MeMBL in the monomer mixture depends on the desired Tg of the block and the required end-use temperature of the copolymer. The Tg of the hard block can be varied up to about 215°C by using only MeMBL monomer as the hard block. The polymerization can be run at about -60°C to about 50°C.

The block polymers of Formula 1 or Formula 2 can also be hydrogenated to afford polymers with higher temperature capability. The hydrogenation catalyst can be heterogeneous or homogeneous. Heterogeneous catalysts are selected from the group consisting of Pd, Pt, Ir, and Rh metals on solid supports. The support is selected from the group consisting of AI2O3, SiO2, CaCO3, and carbon. Homogeneous catalysis, as shown in US Patents 3,670,054 and US 4,501 ,857 and in Macromolecules, 1996, 29, 7316 can also be used. These catalyst consist of the reaction products of triethyl aluminum and Nickel or Cobalt alkyl ester salts.

The reaction mass typically forms a viscous solution, which can be diluted with additional solvent if necessary. The reaction is typically quenched with an alcohol, such as isopropanol, methanol, or ethanol. The polymer can be stabilized with an oxidation inhibitor and a free radical acceptor. Some commercial additive products include trisnonylphenyl phosphite (TNPP), Irganox 1076, Irganox 1010, or Irganox 3052. Common lubricants, additives, fillers, and processing aids can be added if necessary.

The polymer can then be isolated in several ways. On a small scale, it can added to a 4x volume of methanol to precipitate the polymer. The material is then easily filtered and dried to give the triblock polymer. On a larger commercial scale, the polymer solution may be fed to a devolatilizing extruder to remove and recycle the solvent and isolate the polymer as a pellet. The granules can be protected from adhesion, as in the case of other rubber grades, with an antiblocking agent, such Acrawax®, Besquare® or Aerosil®.

The novel copolymers disclosed herein are useful for various purposes as will be evident to those skilled in the art. As articles of manufacture, uses include elastic fibers, extensible films, general purpose rubbers (tires), high impact strength plastics, injection molded articles, and the like.

EXAMPLES

The following Examples are meant to illustrate but not to limit the invention. In each of the Examples, the making of the corresponding butadiene-containing copolymer can be effected by substitution of equivalent amounts of butadiene for isoprene.

General: MeMBL, 1 ,3-diisopropenyl benzene, and diphenyl ethylene was distilled from NaH. Isoprene was filtered through basic alumina and stored over molecular sieves. Anhydrous THF, cyclohexane, NEt3, were obtained from aldrich and dried over molecular sieves. Molecular weight (GPC) was measured in CH₂CI₂ and results are reported versus polystyrene standards.

Example 1. Preparation of MeMBL-isoprene-MeMBL Triblock Copolymer A. Preparation of difunctional initiator: A one liter three neck flask equipped with a mechanical stirrer, condenser, thermometer, and an addition funnel was heated to 150°C and swept continuously with nitrogen for 30 minutes to remove moisture. The flask was allowed to cool and then charged with cyclohexane (100 mL), triethylamine (0.51 , 5 mmol), and a solution of t-butyl lithium in cyclohexane (5.96 mL of a 1.7 M solution, 10 mmol). To the clear, colorless solution was added 1 ,3-diisopropenylbenzene (0.8g, 5 mmol) dropwise via syringe. The solution gradually turned to a blue/green color and then to a dark red, clear solution over about 15 minutes. The solution was then heated to 50°C and held for 2 hours to give a clear, dark red solution free from any precipitate. An aliquot (1 mL) of the solution was drawn out and quenched with 0.5 mL methanol. GC-MS of the solution indicated the desired difunctional adduct at m/z 274, no 1 ,3-diisopropenyl benzene, and a trace of monofunctional adduct m/z 216. ¹H NMR (500 MHz, CDCI₃) D 0.8 (s, 18H), 1.1 (d, 6H), 1.3 (m, 2H), 1.6 (m, 2H), 2.7 (m, 2H), 6.8-7.1 (m, 4H). B. Polymerization of isoprene: A two liter three neck flask equipped with a mechanical stirrer, condenser, thermometer, and an addition funnel was heated to 150°C and swept continuously with nitrogen for 30 minutes to remove moisture. To the mixture was then added cyclohexane (475 mL), THF (9 mL) and initiator solution A (30 mL, 1.5 mmol initiator) via syringe to give a dark red clear solution. The solution was cooled to 0°C and isoprene (102g, 1.5 mol) was added over 15 minutes. The solution was allowed to warm to room temperature and gently heated to 40°C. The solution became a light yellow/orange color and gradually became much more viscous. When the temperature reached 50°C, cooling was applied to bring the temperature back to about 40°C. The viscous, light yellow solution was held at 40°C for 2 hours. O. Polymerization of MeMBL: The solution was cooled to 0°C and a solution of

THF (100mL) and 1 ,1-diphenylethylene (0.54g, 3 mmol) was added over 5 minutes.

The solution gradually turned from pale yellow/orange to a bright red solution. An additional amount of THF (940 mL) which, contained lithium chloride (0.64g, 0.015 mol) was added to give a bright red solution. The solution was cooled to about 0°C and then MeMBL monomer (84g, 0.75 mol) was added over about 5 minutes. The color of the polymerization changed immediately from a bright red to clear and colorless. The reaction was allowed to warm to room temperature to give a very viscous clear and colorless solution. The solution was diluted with 300 mL of reagent grade (wet) THF to give a clear solution. This was precipitated in to 4 L of methanol to give a white polymer. The non-tacky polymer was filtered and dried at 60°C in vacuo to give 158 g (187g theory, 84 % of theory) of the MeMBL-isoprene- MeMBL triblock polymer.

D. Characterization: Solubility: The ABA triblock copolymer is soluble in CH₂CI₂, CHCI₃, 1 ,2- dichloroethane, and slightly soluble in THF. It will swell in cyclohexane and toluene. Thermal properties: A film was compression molded at 270°C, 3 minutes, 10,000 psi. DMA analysis showed a Tg of 4°C for the isoprene mid-block and 217°C for the MeMBL end blocks. The polar solvent (THF) added during isoprene polymerization leads to a high vinyl (3,4-isoprene units) content and the high Tg. Molecular weight: GPC was done in CH₂CI₂. The peak molecular weight, Mp, was 152,000 (theory 124,000) versus polystyrene standards.

Tensile properties: a film was pressed at 270°C, 10,000 psi, 3 minutes to give a clear, colorless sheet. Microtensile bars were stamped from the sheet and tested on an Instron instrument. 12.7 cm/min. , 25°C

stress at break Mpa 11.0 stress at 10% strain Mpa 4.7 elongation at break (%) 133

Microscopy data: The compression molded film was stained with RuO4 and characterized by TEM. The MeMBL block was dispersed in to 100 nm round domains. Example 2. Preparation of MeMBL-isoprene-MeMBL Triblock Copolymer The procedure from example 1 was repeated with the exception that no THF was added during the isoprene polymerization. The non-tacky polymer was filtered and dried at 60°C in vacuo to give 174 g (187g theory, 93 % of theory) of the MeMBL- isoprene-MeMBL triblock polymer. Thermal properties: DSC analysis showed a Tg of -62°C for the isoprene mid- block and 217°C for the MeMBL end blocks.

Hydrogenation

A polymer prepared according to example 2 (E106604-9a) was dissolved in THF and hydrogenated at 150 °C for 2 hours, 700 psi H2. ¹H NMR of the polymer (500 MHz CDCI₃) showed that the majority of the double bonds had been hydrogenated.

example catalyst mole % isoprene hydrogenated

3 5% Rh/C Escat340 77

4 5% Rh/C JM1161 75

5 5% Rh/C Acros 80

6 5% Rh/AI2O3 78

7 5% Rh/SiO2 79

Claims

What is claimed is:

1. A block copolymer comprising alpha-methylene lactone(am) represented by Formula 10

(FORMULA 10)

wherein: n is 0, 1 or 2; X is -O- or -NR⁹-; and R¹, R², R⁵, and R⁶ each of R³ and each of R⁴, are independently hydrogen, a functional group, hydrocarbyl or substituted hydrocarbyl, and R⁹ is independently hydrocarbyl or substituted hydrocarbyl,

and a diene selected from the group consisting of isoprene and butadiene, said copolymer being of the Formula 1 wherein L and N are about 5 to 4,000 and M is about 25 to 25,000, and wherein the molecular weights of the MeMBL segments are about 500 to 400,000 and the molecular weights of the polydiene segments are about 1300 to 1 ,700,000.

(MeMBL) L - (diene) _M - (MeMBL) _N Formula 1

2. A block copolymer comprising MeMBL and a diene selected from the group consisting of isoprene and butadiene, said copolymer being of the Formula 1 wherein L and N are about 5 to 4,000 and M is about 25 to 25,000, and wherein the molecular weights of the MeMBL segments are about 500 to 400,000 and the molecular weights of the polydiene segments are about 1300 to 1 ,700,000.

(MeMBL) _L - (diene) _M - (MeMBL) _N Formula 1

3. A copolymer according to claim 1 wherein L and N are 15 to 200 and m is 100 to 5,000.

4. A copolymer according to claim 1 wherein the diene unit is isoprene.

5. A copolymer according to claim 1 wherein the diene unit is butadiene.

6. An exercised copolymer according to claim 1.

7. An article of manufacture comprising the copolymer of claim 1.

8. An article according to claim 6 in the form of a fiber.

9. An article according to claim 6 in the form of a film.

10. An article according to claim 6 in the form of a molded object.

11. An article according to claim 6 in the form of an adhesive.

12. A block copolymer comprising Styrene, MeMBL and a diene selected from the group consisting of isoprene and butadiene, said copolymer being of the Formula 2 wherein L and N are about 5 to 4,000 and m is about 25 to 25,000, and wherein the molecular weights of the MeMBL segments are about 500 to 400,000 and the molecular weights of the polydiene segments are about 1300 to 1 ,700,000. (Styrene) - (diene) _M - (MeMBL) _N Formula 2

13. A copolymer according to claim 12 wherein L and N are 15 to 200 and m is 100 to 5,000.

14. A copolymer according to claim 12 wherein the diene unit is isoprene.

15. A copolymer according to claim 12 wherein the diene unit is butadiene.

16. An exercised copolymer according to claim 12.

17. An article of manufacture comprising the copolymer of claim 12.

18. An article according to claim 16 in the form of a fiber.

19. An article according to claim 16 in the form of a film.

20. An article according to claim 16 in the form of a molded object.

21. An article according to claim 16 in the form of an adhesive.

22. A process for hydrogenating the polymer of Formula 1 using a homogeneous catalyst.

23. A process for hydrogenating the polymer of Formula 1 using a heterogeneous catalyst.

24. A process for hydrogenating the polymer of Formula 2 using a homogeneous catalyst.

25. A process for hydrogenating the polymer of Formula 2 using a heterogeneous catalyst.

26. A block copolymer obtained by hydrogenation of the polymer in Formula 1.

27. A block copolymer obtained by hydrogenation of the polymer in Formula 2.

28. An article of manufacture comprising the copolymer of claim 25.

29. An article of manufacture comprising the copolymer of claim 26.