Synthesis of isobutylene-co-p-methylstyrene-based elastomers with broad molecular weight distribution

Abstract

A method of making an isobutylene-co-p-methylstyrene composition is described herein. For example, one or more methods include treating an isobutylene-co-p-methylstyrene based elastomer with a peroxide initiator at a temperature of greater than or equal to 160 DEG C to chemically induce a thermal fracture along a copolymer backbone of the isobutylene-co-p-methylstyrene based elastomer, the peroxide treatment may result in a modified isobutylene-co-p-methylstyrene based elastomer having a ratio of Mw / Mn of greater than 2.5.

Description

Inventor: Sunny Jacob CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 405,927, filed on September 13, 2022, entitled "Synthesis of Isobutylene-Co-p-Methylstyrene-Based Elastomers with Broad Molecular Weight Distribution," the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] The present application relates to a method for controlling the molecular weight distribution of isobutylene-co-p-methylstyrene based elastomers, in particular a method for initiating chemical and thermal cracking of isobutylene-co-p-methylstyrene based elastomers by peroxide treatment to increase the proportion of low molecular weight species. Background Art

[0003] Molecular weight distribution (MWD=Mw / Mn), also known as polydispersity index, has a significant impact on the mechanical and physical bulk properties of the polymer and the resulting compounded product. For example, adjusting the balance of the MWD of an isobutylene-co-p-methylstyrene elastomer (e.g., controlling the high molecular weight fraction relative to the low molecular weight fraction) can affect various mechanical properties and / or processability factors of the polymer product. The high molecular weight fraction contributes to mechanical properties, such as: tensile break, elongation, impact strength, etc. The low molecular weight fraction contributes to processability factors, such as: low melt viscosity, plasticizer quality, etc. Therefore, the breadth of the MWD can affect the suitability of the isobutylene-co-p-methylstyrene elastomer for various applications, such as tire products (e.g., innerliners and / or airbag components) or pharmaceutical products (e.g., pharmaceutical closures). Summary of the invention SUMMARY OF THE INVENTION

[0004] In various non-limiting embodiments described herein, a method for preparing an isobutylene-co-p-methylstyrene composition is provided. The method may include treating an isobutylene-co-p-methylstyrene-based elastomer with a peroxide initiator at a temperature greater than or equal to about 160° C. to chemically induce thermal scission along the copolymer backbone of the isobutylene-co-p-methylstyrene-based elastomer. The treatment may produce a modified isobutylene-co-p-methylstyrene-based elastomer having a ratio of Mw / Mn greater than 2.5.

[0005] In one or more non-limiting embodiments described herein, another method for preparing an isobutylene-co-p-methylstyrene composition is provided. The method may include increasing the low molecular weight fraction of the isobutylene-co-p-methylstyrene-based elastomer by mixing the isobutylene-co-p-methylstyrene-based elastomer with a peroxide initiator at a temperature greater than or equal to about 160° C. The mixing produces a modified isobutylene-co-p-methylstyrene-based elastomer having a ratio of Mw / Mn greater than 2.5.

[0006] In one or more non-limiting embodiments described herein, an isobutylene-co-p-methylstyrene-based elastomer is provided. The isobutylene-co-p-methylstyrene-based elastomer may comprise 80 to 99.5 mol % of isobutylene, 0.5 to 20 mol % of p-methylstyrene, and have a substantially uniform composition distribution with a Mw / Mn ratio greater than 6.0.

[0007] In some embodiments, the isobutylene-co-p-methylstyrene based elastomer may be included in a cured article that is a tire inner liner, an inner tube, a wire coating, a medical rubber stopper, a hose, a film, an adhesive, or a sealant.

[0008] These and other features and properties of the disclosed method for controlling the MWD of the isobutylene-co-p-methylstyrene based elastomers of the present disclosure and its advantageous applications and / or uses will be apparent from the following detailed description. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present application relates to a method for controlling the MWD of an isobutylene-co-p-methylstyrene based elastomeric composition, and in particular to a method for broadening the MWD of an isobutylene-co-p-methylstyrene based elastomeric composition to a range of, for example, about 2.5 to 10 for various applications such as tires or pharmaceutical products.

[0010] For example, with respect to tire applications (e.g., tire innerliners), compound Mooney viscosity and compound Mooney relaxation are important for producing tires with good innerliner splicing properties and splicing strength after tire curing. A certain proportion of high molecular weight fractions and low molecular weight fractions are required to obtain a balance of mechanical strength and ease of processability with good splicing integrity. For example, a certain proportion of higher molecular weight is necessary for the required mechanical properties, while a certain proportion of low molecular weight fractions contributes to improved processability because the low molecular weight fractions can act as plasticizers. Therefore, it is important that commercial polymers have controlled wide MWD so that tire producers / converters / manufacturers can process products with faster cycle times, good surface appearance, splicing integrity, strength, etc. in the final product. Lower dispersity (narrower MWD) leads to processing difficulties and may result in weak splicing strength due to the slow relaxation of the compound. High Mooney viscosity can also contribute to narrow MWD, which may adversely affect the processability of elastomers based on isobutylene-co-p-methylstyrene.

[0011] The present disclosure provides a method for producing an isobutylene-co-p-methylstyrene-based elastomeric composition having a broad MWD. ​​The elastomeric composition described herein is particularly useful in applications where an isobutylene-co-p-methylstyrene elastomer or a brominated isobutylene-co-p-methylstyrene elastomer is used and it is desired to obtain high green strength while increasing the stress relaxation rate.

[0012] For example, various embodiments described herein provide one or more methods for broadening the MWD of an isobutylene-co-p-methylstyrene elastomer composition (e.g., isobutylene-co-p-methylstyrene elastomer and / or brominated isobutylene-co-p-methylstyrene elastomer) by changing the concentration of low molecular weight fractions via chemically induced thermal scission of the copolymer backbone with a peroxide initiator. In various embodiments, the isobutylene-co-p-methylstyrene based elastomer composition can undergo molecular weight modification before or after bromination. In addition, the MWD can be further controlled by blending the modified polymer with an unmodified polymer having a higher molecular weight and / or narrower MWD. ​​For example, modified and unmodified elastomers can be blended together in various proportions to achieve a desired MWD. Thus, according to one or more embodiments described herein, the MWD of an isobutylene-co-p-methylstyrene based elastomer can be modified by increasing the proportion of low molecular weight species (e.g., having a molecular weight of less than 100,000 Daltons (Da)) via peroxide treatment at elevated temperatures (e.g., about 160 to 190° C.) to induce chemical and / or thermal cracking of the copolymer backbone. definition

[0013] As used herein, the term "catalyst system" and grammatical variations thereof refer to and include any Lewis acid(s) or other metal complex(s) and optionally at least one initiator for catalyzing the polymerization of hydrocarbon monomers. Other additives, such as catalyst modifiers, may be included. The catalyst system is combined with a diluent for polymerization, collectively referred to as a "polymerization medium." As used herein, "polymerization system" and grammatical variations thereof refer to the use of a polymerization medium to produce a polymer.

[0014] As used herein, the term "diluent" and its grammatical variations refer to a diluent or a solvent, including mixtures thereof (eg, two or more separate diluents). The diluent can further be used to affect reactor mixing (using an overhead blender) since it acts as a diluent.

[0015] As used herein, the term "solvent" and grammatical variations thereof refer to a chemical agent that can dissolve the resulting polymer.

[0016] "Reactor" and its grammatical variants used herein refer to any container (one or more) in which a chemical reaction (e.g., polymerization) occurs. Examples of polymerization reactors include continuous flow stirred tank reactors utilizing continuous tank stirring, and a draft tube reactor (adraft tube type reactor). Various cooling jackets, pipelines, etc. can be used in combination with the reactor (and can be integrated) to control or otherwise maintain the reactor temperature during polymerization. Commercial reactors can generally be well-mixed containers with a volume greater than 400 to 500 liters, with a high circulation rate provided by a pump impeller (a pumpimpeller). Both polymerization and pumps can generate heat, and in order to keep the slurry cool, the reaction system can include a heat exchanger. In some reactors, the slurry can circulate through the pipeline of the heat exchanger. Cooling can be provided, for example, by boiling ethylene on the shell side. The slurry temperature can be set by boiling ethylene temperature, required heat flux, and total heat transfer resistance.

[0017] As used herein, the term "slurry" and grammatical variations thereof refer to an amount of diluent comprising polymer precipitated from the catalyst system and the diluent. The slurry concentration is the weight percent of partially or completely precipitated polymer, based on the total slurry.

[0018] As used herein, the term "quenching" and grammatical variations thereof refer to a process of rapidly heating a reactor effluent stream and mixing it with a quenching medium, wherein further polymerization is terminated.

[0019] As used herein, the term "polymer" and its grammatical variants refer to homopolymers, copolymers, interpolymers, terpolymers, etc. The term "copolymer" and its grammatical variants are intended to include polymers having two or more monomers. The term "interpolymer" and its grammatical variants refer to any polymer or oligomer having a number average molecular weight of 500 or more prepared by polymerization or oligomerization of at least two different monomers. As used herein, when a polymer is referred to as "comprising" a monomer, the monomer is present in the polymer in the polymerized form of the monomer or in the form of a derivative of the monomer. Similarly, when a catalyst component is described as comprising a neutral stable form of a component, it will be understood by those skilled in the art that the ionic form of the component is the form that reacts with the monomer to produce a polymer.

[0020] As used herein, the term "olefin" and its grammatical variants refer to hydrocarbons containing carbon-carbon double bonds. "Isoolefin" and its grammatical variants refer to any olefin monomer having two substitutions on the same carbon. The term "diolefin" and its grammatical variants refer to any olefin monomer having two double bonds.

[0021] As used herein, "elastomer" or "elastomeric composition" and grammatical variations thereof refer to any polymer or polymer composition that conforms to the definition of ASTM D1566-21A (November 2021). Elastomer is used interchangeably with the term "rubber(s)" herein.

[0022] "Mooney viscosity" and its grammatical variants used herein are the Mooney viscosity of a polymer or polymer composition. The polymer composition analyzed for the determination of Mooney viscosity should be substantially free of diluents and solvents. For example, the sample can be placed on a boiling water steam table in a hood to evaporate most of the diluent and unreacted monomers, and then dried overnight (12 hours, 90°C) in a vacuum oven according to laboratory analytical techniques before testing, or the test sample can be obtained from a devolatilized polymer (i.e., a polymer post-devolatilization in an industrial scale process). Unless otherwise stated, the Mooney viscosity is measured using a Mooney viscometer according to ASTM D1646-19A (November 2019), but the procedure is modified / described below. First, the sample polymer is pressed between two hot plates of a compression molding press before testing. The plate temperature is 125°C + / - 10°C instead of 50°C + / - 5°C recommended in ASTM D1646-17, because 50°C does not cause sufficient densification. Additionally, while ASTM D1646-17 allows for some options for die protection, if two options provide conflicting results, PET 36 microns should be used as die protection. Additionally, ASTM D1646-17 does not indicate sample weight in paragraph 8; therefore, to the extent that results may vary based on sample weight, the Mooney viscosity determined according to the D1646-17 Section 8 procedure using a sample weight of 21.5 + / - 2.7 grams (g) will govern. Finally, the remaining procedures prior to the test set forth in Section 8 of D1646-17 are 23 + / - 3°C in air for 30 minutes; the Mooney values ​​reported herein are determined after standing for 30 minutes at 24 + / - 3°C in air. The samples are placed on either side of the spindle according to the ASTM D1646-17 test method; the torque required to turn the viscometer spindle at 2 rpm is measured by the sensor that determines the Mooney viscosity. Results are reported as Mooney units (ML, 1+4@125°C or ML, 1+8@125°C), where MU is the Mooney viscosity number, L represents the large rotor (defined as ML in ASTM D1646-17), 1 is the warm-up time in minutes, 4 or 8 is the sample run time in minutes after the motor is started, and 125°C is the test temperature. Thus, a Mooney viscosity of 90 measured by the above method would be reported as a Mooney viscosity of 90MU(ML, 1+8@125°C) or 90MU(ML, 1+4@125°C). Alternatively, the Mooney viscosity may be reported as 90MU; in this case, unless otherwise stated, it should be assumed that the viscosity was determined using the (ML, 1+4@125°C) method just described. In some cases, a lower test temperature (e.g., 100°C) may be used, in which case the Mooney is reported as Mooney viscosity (ML, 1+8@100°C), or @T°C, where T is the test temperature.

[0023] The term "blending" or its grammatical variations refers to a mixture of two or more polymers. Blends can be produced, for example, by solution blending, melt mixing, shear mixing, combinations thereof, and the like.

[0024] Numerical ranges used herein include the values ​​recited in the range. For example, a numerical range of "1 wt % to 10 wt %" includes 1 wt % and 10 wt % within the recited range. Polymerization of elastomers based on isobutylene-co-p-methylstyrene

[0025] The term "isobutylene-co-p-methylstyrene-based elastomer" as used herein may refer to a polyolefin copolymer composition comprising a reaction product of isobutylene and p-methylstyrene. Copolymer may have a substantially uniform composition distribution. In various embodiments, the isobutylene-co-p-methylstyrene-based elastomer as described herein may have an average molecular weight (Mw) in the range of, for example, about 200,000Da to about 2,000,000Da (e.g., about 200,000Da to about 500,000Da, about 500,000Da to about 1,000,000Da, about 1,000,000Da to about 1,500,000Da or about 1,500,000Da to about 200,000Da), and an MWD (Mw / Mn) in the range of, for example, less than about 2.5. In one or more embodiments, the elastomer based on isobutylene-co-p-methylstyrene can include about 80 mol % to about 99.5 mol % of isobutylene and about 0.5 mol % to about 20 mol % of p-methylstyrene. In various embodiments, the elastomer based on isobutylene-co-p-methylstyrene can be substantially linear. In addition, p-methylstyrene can be halogenated. For example, p-methylstyrene can be characterized by Formula 1. wherein "X" is hydrogen, a halogen (e.g., bromine or chloride), or a combination of a halogen and another functional group which can be introduced by nucleophilic substitution of a benzylic halogen with other groups such as: carboxylic acid; carboxylates, esters, amides, and imides; hydroxyl, alkoxide; phenoxide; thiolate; thioether; xanthate; cyanide; nitrile; amino, and mixtures thereof. Covalent bonds to the isobutylene block of the copolymer backbone are indicated.

[0026] Elastomers based on isobutylene-co-p-methylstyrene can be synthesized via low temperature cationic polymerization processing using a Lewis acid catalyst system (e.g., using ethylaluminum dichloride or ethylaluminum tetrachloride). In one or more embodiments, methyl chloride can be used as a diluent for the reaction mixture at a temperature below, for example, 90° C.; wherein the methyl chloride acts as a solvent for the monomer catalyst and also acts as a non-solvent for the polymer product, thereby producing a slurry. Other suitable diluents include, but are not limited to: methylene chloride, vinyl chloride, and / or ethyl chloride. In addition, one or more stabilizers (e.g., gel-free polymers and / or gelling polymers) can be used with the slurry polymerization process to stabilize the slurry polymerization product to prevent agglomeration thereof.

[0027] In one or more embodiments, the diluent can serve as a solvent for both the monomer catalyst and the polymer product. For example, the diluent solution can include aliphatic hydrocarbons (e.g., hexane, pentane, heptane, etc.) and / or a mixture of aliphatic hydrocarbons and slurry-type diluents (e.g., methyl chloride and / or methylene dichloride). In addition, the diluent solution can be used together with a catalyst system such as hydrochloric acid and ethylaluminum dichloride or ethylaluminum tetrachloride. Those of ordinary skill in the art will recognize the various advantages of utilizing corresponding polymerization methods. For example, slurry polymerization methods can achieve a higher polymer concentration than solution polymerization.

[0028] In various embodiments, the slurry polymerization process can introduce one or more slurry stabilizers (e.g., butyl dispersion) generated during the polymerization into a diluent such as methyl chloride to prevent large-scale agglomeration of slurry particles. Thus, the slurry stabilizer is able to form a dispersed gel containing butyl particles in the reactor without depositing gel-containing fouled rubber on heat transfer surfaces. Through the use of a slurry stabilizer, modified rubber containing as much branching and / or gel as desired can be produced in a practical manner without interfering with the ability to wash the reactor to prepare it for reuse.

[0029] When copolymerizing, for example, isobutylene and p-methylstyrene using a slurry polymerization method; no olefinic unsaturation is introduced into the polymer backbone. Therefore, even at very high levels of p-methylstyrene introduction, gel generation can be avoided and / or suppressed. For example, crosslinkable reactive functional groups are not introduced into the copolymer before it is functionalized (e.g., halogenated in a post-polymerization step), and gel formation can be minimized. Therefore, slurry polymerization can enable high polymer concentrations to be handled at low viscosities and have good heat transfer. However, solution polymerization can achieve homogeneous polymerization and the ability to directly perform subsequent reactions on the resulting polymer solution. In addition, solution polymerization can produce isobutylene-co-p-methylstyrene-based elastomers in a desired solution state to allow post-polymerization chemical modification (e.g., MWD modification via peroxide treatment).

[0030] In one or more embodiments, the elastomer based on isobutylene-co-p-methylstyrene can be further subjected to a post-polymerization halogenation reaction (e.g., free radical bromination) to obtain a p-methylstyrene block characterized by Formula 1. Before halogenation, the copolymerization reaction can be quenched and residual monomers can be removed. The halogenation reaction described herein can be carried out on the copolymer in a solution or in a finely dispersed slurry. Suitable solvents for halogenation in solution include low-boiling hydrocarbons (e.g., C4 to C7) and halogenated hydrocarbons. The halogenation reaction can also be carried out in a suitable diluent using the copolymer as a fine slurry, and the diluent is a poor solvent for the copolymer.

[0031] In one or more embodiments, the isobutylene-co-p-methylstyrene copolymer may contain little to no backbone olefinic unsaturation contribution from p-methylstyrene, and the primary reactive halogenation site is the bound p-methylstyrene moiety. For example, the free radical halogenation (e.g., free radical bromination) of the bound p-methylstyrene moiety in the isobutylene-co-p-methylstyrene copolymer may be made highly specific by substitution on the p-methyl group. In addition, the isobutylene-co-p-methylstyrene copolymer in a hydrocarbon solvent (e.g., pentane, hexane, or heptane) may be selectively brominated using light, heat, or a selected radiation initiator as a promoter for free radical halogenation. For example, U.S. Pat. No. 5,162,445 (incorporated herein by reference in its entirety) discloses a halogenation reaction that may be performed to functionalize the isobutylene-co-p-methylstyrene-based elastomers described herein. In various embodiments, the halogenated isobutylene-co-p-methylstyrene-based elastomer may contain at least 0.25 wt % (e.g., from about 0.25 wt % to about 4 wt %) of halogen. Expressed in another way, the halogenated isobutylene-co-p-methylstyrene-based elastomer can contain from about 0.1 mol % to about 7.5 mol % of halogenated p-methylstyrene-derived units. For example, a suitable halogenated isobutylene-co-p-methylstyrene-based elastomer can include an Exxpro TM Elastomers are commercially available from ExxonMobil Product Solutions Company, Houston TX and are abbreviated as "BIMSM", for example: Exxpro TM 3035 (e.g., containing about 0.47 mol % benzyl bromide), 3433 (e.g., containing about 0.75 mol % benzyl bromide), 3563 (e.g., containing about 0.85 mol % benzyl bromide) and / or 3745 (e.g., containing about 1.2 mol % benzyl bromide). MWD modification based on peroxide treatment

[0032] When processing an elastomer based on isobutylene-co-p-methylstyrene, it is desirable to improve mechanical properties while maintaining or improving processability properties. These properties can be a function of molecular weight, and can include, for example: extrusion rate, die swelling, mixing time, filler dispersion, cold flow, green strength, tire cord puncture, build viscosity, adhesion, stress relaxation rate and / or various vulcanized rubber properties. However, various properties may have a conflicting relationship with the molecular weight of the elastomer. For example, as the molecular weight of the elastomer increases, the green strength value improves, while the stress relaxation rate decreases (for example, slows down). Green strength can characterize the ability of the elastomer to resist excessive flow and deformation during various treatments and / or processing operations. Stress relaxation rate can characterize the ability of the elastomer to relax after being subjected to stress; thereby enabling the elastomer to avoid shape changes. Therefore, because the elastomer based on isobutylene-co-p-methylstyrene becomes better able to resist flow and deformation in various processing operations, they also become easier to change shape or pull apart due to the unrelaxed stress. Furthermore, increasing molecular weight to increase green strength can make it more difficult to process the elastomer and disperse fillers and additives.

[0033] However, various embodiments described herein can achieve improved compromises between various conflicting properties desired in elastomer formation during processing, manufacturing, and / or end use in one or more applications. For example, improved mechanical properties (e.g., green strength) and processability (e.g., stress relaxation rate) of isobutylene-co-p-methylstyrene based elastomers can be achieved by broadening the MWD of the elastomer. For example, isobutylene-co-p-methylstyrene based elastomers can be produced at high molecular weight to improve mechanical properties, then one or more post-polymerization modifications can increase the low molecular weight fraction of the elastomer to improve processability (e.g., stress relaxation rate).

[0034] For example, the various synthetic methods described herein can produce isobutylene-co-p-methylstyrene-based elastomeric compositions that exhibit increased green strength values ​​and faster stress relaxation rates. Such compositions can be particularly useful in products such as: tire components (e.g., tire innerliners and / or tire curing bladders), inner tubes, wire and / or cable assemblies, hoses, films, automotive and / or mechanical items, sponge products, pharmaceuticals (e.g., medical rubber stoppers), adhesives, sealants, and / or the like.

[0035] In various embodiments, the isobutylene-co-p-methylstyrene based elastomer may be subjected to one or more post-polymerization peroxide treatments to modify the MWD. ​​The post-polymerization peroxide treatment may utilize chemical and thermal cracking of the copolymer backbone to increase the low molecular weight fraction of the copolymer composition. For example, the isobutylene-co-p-methylstyrene based elastomer may be treated with a peroxide initiator in a melt mixer at a temperature of, for example, about 150° C. to about 220° C. (e.g., about 160° C. to about 190° C.). Suitable peroxides may have a decomposition temperature greater than about 130° C. (e.g., greater than 140° C.) and / or be an organic peroxide having a 10 hour half-life temperature greater than about 110° C. Exemplary peroxides suitable for peroxide treatment include, but are not limited to: dicumyl peroxide; 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane; dicumyl peroxide; α,α-bis(tert-butylperoxy)diisopropylbenzene; 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; tert-butylcumyl peroxide; di-tert-butyl peroxide; 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne, and / or mixtures thereof; organic peroxides such as dialkyl peroxides, ketones; Peroxides, aralkyl peroxides, peroxide ethers, peroxide esters, such as di-tert-butyl peroxide, bis(tert-butylperoxyisopropyl)-benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)-hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)-hexene-(3), 1,1-bis(tert-butylperoxy)-3,3,5-trimethyl-cyclohexane, benzoyl peroxide, tert-butylcumyl peroxide, and tert-butyl perbenzoate; combinations thereof and / or the like. The amount of peroxide initiator can be, for example, about 0.2 to about 4.5 weight percent based on the amount of the isobutylene-co-p-methylstyrene-based elastomer. In various embodiments, the amount of peroxide initiator used in the MDW modification can increase as the halogen concentration in the isobutylene-co-p-methylstyrene-based elastomer increases. For example, the post-polymerization peroxide treatment can be performed before the halogenation reaction described herein or after the halogenation reaction (eg, before or after the bromination reaction).

[0036] In one or more embodiments, the peroxide treatment can produce a modified isobutylene-co-p-methylstyrene-based elastomer having a high proportion of low molecular weight species (compared to the isobutylene-co-p-methylstyrene-based elastomer before the peroxide treatment); thereby broadening the MWD of the copolymer. For example, the peroxide treatment can chemically induce thermal scission along the copolymer backbone of the isobutylene-co-p-methylstyrene-based elastomer to increase the proportion of low molecular weight species. The modified isobutylene-co-p-methylstyrene-based elastomer can have, for example, a Mw of about 10,000 Da to about 1,000,000 Da (e.g., about 25,000 Da to about 500,000 Da). In some examples, the modified isobutylene-co-p-methylstyrene-based elastomer can have a Mn of less than 150,000 Da, less than 100,000 Da, or less than 50,000 Da. The low molecular weight material can have a molecular weight of, for example, about 10,000 Da to about 200,000 Da (e.g., about 25,000 Da to about 100,000 Da). For example, peroxide treatment can increase the low molecular weight fraction to a range of about 20 Da to about 60 Da (e.g., about 20 Da to about 40 Da). Thus, the modified isobutylene-co-p-methylstyrene-based elastomer can have, for example, a MWD of about 2.5 to 10 (e.g., 6.1 to 10).

[0037] In various embodiments, the modified isobutylene-co-p-methylstyrene-based elastomer may further comprise one or more branched structural moieties resulting from one or more coupling reactions occurring as a result of the peroxide treatment. For example, the modified isobutylene-co-p-methylstyrene-based elastomers described herein may have a branched structure formed by the introduction (e.g., during the peroxide treatment) of crosslinking or cationically active comonomers and / or agents (referred to herein as "branching agents"). The introduction of branching (e.g., long chain branching) may result in further modification of the molecular weight of the polymer, and thus the amount of branching may be controlled to obtain a desired MWD (e.g., to obtain a desired MWD that may subsequently be broadened by one or more peroxide treatments described herein). For example, the MWD of a modified isobutylene-co-p-methylstyrene-based elastomer (not modified by one or more peroxide treatments) may further be a function of the linear fraction of the polymer relative to the branched fraction of the polymer.

[0038] Where branching agents are used to promote the crosslinking reaction, randomized long chain branching can occur to alter the overall MWD of an isobutylene-co-p-methylstyrene based elastomer. In contrast, soluble moieties containing multiple reactive sites can be used as branching agents to introduce controlled amounts of high molecular weight branched fractions into the distribution without altering the overall molecular weight distribution of the polymer. For example, a small amount of a very high molecular weight, highly branched material can be introduced into the distribution using a small amount of a very high functionality and reactive soluble moiety. Alternatively, a larger amount of a less reactive, less functional moiety can be used to introduce more but lower molecular weight branched fractions.

[0039] In various embodiments, the cationically reactive branching agent can be present during the polymerization process in an amount effective to produce the desired MWD change (e.g., it can subsequently serve as a high molecular weight component in one or more blended compositions). The amount of cationically reactive branching agent can vary depending on the amount and reactivity of the cationically active material, including variables such as the molecular weight and reactivity of the reagent (particularly the portion of the reagent containing the cationically active moiety). In addition, polymerization conditions can affect the effective concentration (e.g., batch vs. continuous, temperature, monomer conversion, etc.). In one or more embodiments, the amount of cationically reactive branching agent can be, for example, from about 0.3 to about 3.0 weight percent, based on monomer. Blended composition

[0040] In various embodiments, the modified isobutylene-co-p-methylstyrene-based elastomer (e.g., subjected to peroxide treatment) can be mixed with an unmodified isobutylene-co-p-methylstyrene elastomer (e.g., not subjected to peroxide treatment) to form a blend composition. For example, blending modified and unmodified elastomers can further control the MWD. ​​For example, the modified isobutylene-co-p-methylstyrene elastomer and the unmodified isobutylene-co-p-methylstyrene-based elastomer can have widely different and defined molecular weights; wherein the modified isobutylene-co-p-methylstyrene-based elastomer contributes low molecular weight species to the blend composition, and the unmodified isobutylene-co-p-methylstyrene-based elastomer contributes most of the high molecular weight species. By controlling the ratio of the modified isobutylene-co-p-methylstyrene-based elastomer to the unmodified isobutylene-co-p-methylstyrene-based elastomer, a customized MWD can be achieved. By broadening the MWD (e.g., compared to an unmodified isobutylene-co-p-methylstyrene elastomer-based composition alone), the blended composition can maintain or improve the mechanical properties of the polymer (e.g., green strength levels) while also improving the processability of the polymer (e.g., increasing stress relaxation rates).

[0041] In one or more embodiments, the effect of blending modified isobutylene-co-p-methylstyrene-based elastomers and unmodified isobutylene-co-p-methylstyrene-based elastomers can be achieved by utilizing polymer products from two or more reactors (e.g., operated in parallel or in series) or polymerization zones (e.g., polymerization zones of a single reactor) via a direct synthesis process. For example, each zone or reactor can produce a polymer having the desired molecular weight characteristics of the final product (e.g., a modified isobutylene-co-p-methylstyrene-based elastomer or an unmodified isobutylene-co-p-methylstyrene-based elastomer), wherein blending the polymer products together can achieve a target MWD and / or combine desired properties (e.g., mechanical and / or processability properties). For example, the blended compositions described herein can have an MWD of 2.5 to 10.0.

[0042] For example, the blending ratio of the unmodified isobutylene-co-p-methylstyrene-based elastomer to the modified isobutylene-co-p-methylstyrene-based elastomer may be, for example, about 0.1: 1 to about 1: 0.1. In various embodiments, the blend composition may have, for example, about 10 wt % to about 90 wt % of a low molecular weight fraction (e.g., characterizing the amount of substances with a molecular weight of less than 100,000 Da) and, for example, about 10 wt % to about 90 wt % of a high molecular weight fraction (e.g., characterizing the amount of substances with a molecular weight of greater than 100,000 Da).

[0043] The various embodiments and / or features described herein can be practiced in various orders. For example, peroxide treatment can be applied to an isobutylene-co-p-methylstyrene-based elastomer before or after halogenation. For example, a modified isobutylene-co-p-methylstyrene-based elastomer or a blended composition thereof can then be halogenated to achieve the various halogen composition properties described herein.

[0044] In a first example sequence, the synthesis methods of one or more embodiments described herein can be used to synthesize non-blended, non-halogenated isobutylene-co-p-methylstyrene-based elastomers having a MWD range of 2.5 to 10.0 (e.g., 6.1 to 10). For example, the synthesis can include treating the non-halogenated isobutylene-co-p-methylstyrene-based elastomer with a peroxide treatment (e.g., at 160° C. to 190° C.) to achieve the desired MWD.

[0045] In a second example sequence, the synthesis methods of one or more embodiments described herein can be used to synthesize a blended, non-halogenated isobutylene-co-p-methylstyrene-based elastomer composition having a MWD range of 2.5 to 10.0 (e.g., 6.1 to 10). For example, the synthesis can include: treating a non-halogenated isobutylene-co-p-methylstyrene-based elastomer with a peroxide treatment (e.g., at 160° C. to 190° C.) to obtain a modified non-halogenated isobutylene-co-p-methylstyrene-based elastomer; and blending the modified non-halogenated isobutylene-co-p-methylstyrene-based elastomer with an unmodified isobutylene-co-p-methylstyrene-based elastomer (e.g., having substantially the same composition as the previously treated non-halogenated isobutylene-co-p-methylstyrene-based elastomer) to obtain a blended composition having a desired MWD.

[0046] In a third example sequence, the synthesis method of one or more embodiments described herein can be used to synthesize a non-blended, halogenated isobutylene-co-p-methylstyrene-based elastomer having a MWD range of 2.5 to 10.0 (e.g., 6.1 to 10). For example, the synthesis can include: treating the non-halogenated isobutylene-co-p-methylstyrene-based elastomer with a peroxide treatment (e.g., at 160° C. to 190° C.) to obtain a modified non-halogenated isobutylene-co-p-methylstyrene-based elastomer; and subjecting the modified non-halogenated isobutylene-co-p-methylstyrene-based elastomer to a halogenation reaction to obtain a modified halogenated isobutylene-co-p-methylstyrene-based elastomer having a desired MWD.

[0047] In a fourth example sequence, the synthesis methods of another one or more embodiments described herein can be used to synthesize another non-blended, halogenated isobutylene-co-p-methylstyrene-based elastomer having a MWD range of 2.5 to 10.0 (e.g., 6.1 to 10). For example, the synthesis can include treating the halogenated isobutylene-co-p-methylstyrene-based elastomer with a peroxide treatment (e.g., at 160° C. to 190° C.) to achieve the desired MWD.

[0048] In a fifth example sequence, the synthesis method of one or more embodiments described herein can be used to synthesize a blended, halogenated isobutylene-co-p-methylstyrene-based elastomer composition having a MWD range of 2.5 to 10.0 (e.g., 6.1 to 10). For example, the synthesis can include: treating a non-halogenated isobutylene-co-p-methylstyrene-based elastomer with a peroxide treatment (e.g., at 160° C. to 190° C.) to obtain a modified non-halogenated isobutylene-co-p-methylstyrene-based elastomer; blending the modified non-halogenated isobutylene-co-p-methylstyrene-based elastomer with an unmodified isobutylene-co-p-methylstyrene-based elastomer (e.g., having substantially the same composition as the previously treated non-halogenated isobutylene-co-p-methylstyrene-based elastomer) to obtain a blended composition; and subjecting the blended composition to a halogenation reaction as described herein to obtain a blended, halogenated isobutylene-co-p-methylstyrene-based elastomer having a desired MWD.

[0049] In a sixth example sequence, the synthesis method of one or more embodiments described herein can be used to synthesize another blended, halogenated isobutylene-co-p-methylstyrene-based elastomer composition having a MWD range of 2.5 to 10.0 (e.g., 6.1 to 10). For example, the synthesis can include: treating a non-halogenated isobutylene-co-p-methylstyrene-based elastomer with a peroxide treatment (e.g., at 160° C. to 190° C.) to obtain a modified non-halogenated isobutylene-co-p-methylstyrene-based elastomer; subjecting the modified non-halogenated isobutylene-co-p-methylstyrene-based elastomer to a halogenation reaction; and blending the modified halogenated isobutylene-co-p-methylstyrene-based elastomer with an unmodified isobutylene-co-p-methylstyrene-based elastomer (e.g., halogenated or unhalogenated) to obtain a blended halogenated isobutylene-co-p-methylstyrene-based elastomer having a desired MWD.

[0050] In a seventh example sequence, the synthesis methods of one or more embodiments described herein can be used to synthesize another blended, halogenated isobutylene-co-p-methylstyrene-based elastomer composition having a MWD range of 2.5 to 10.0 (e.g., 6.1 to 10). For example, the synthesis can include treating the halogenated isobutylene-co-p-methylstyrene-based elastomer with a peroxide treatment (e.g., at 160° C. to 190° C.) to obtain a modified halogenated isobutylene-co-p-methylstyrene-based elastomer; and blending the modified halogenated isobutylene-co-p-methylstyrene-based elastomer with an unmodified isobutylene-co-p-methylstyrene-based elastomer (e.g., having substantially the same composition as the previously treated non-halogenated isobutylene-co-p-methylstyrene-based elastomer) to obtain a blended composition having a desired composition. Additional Implementations

[0051] Non-limiting example embodiments of the present disclosure include:

[0052] Embodiment A: A method for preparing an isobutylene-co-p-methylstyrene composition, the method comprising: treating an isobutylene-co-p-methylstyrene-based elastomer with a peroxide initiator at a temperature greater than or equal to 160°C to chemically induce thermal scission along the copolymer backbone of the isobutylene-co-p-methylstyrene-based elastomer, wherein the treatment produces a modified isobutylene-co-p-methylstyrene-based elastomer having an Mw / Mn ratio greater than 2.5.

[0053] Non-limiting example embodiment A may include one or more of the following elements.

[0054] Element 1A: wherein the treatment comprises the peroxide initiator in an amount of 0.2 to 4.5 weight percent, based on the isobutylene-co-p-methylstyrene-based elastomer.

[0055] Element 2A: wherein the temperature range is 160 to 190°C.

[0056] Element 3A: wherein the isobutylene-co-p-methylstyrene based elastomer comprises 80 to 99.5 mol % of isobutylene and 0.5 to 20 mol % of p-methylstyrene.

[0057] Element 4A: wherein the isobutylene-co-p-methylstyrene-based elastomer comprises 5 mol% of p-methylstyrene.

[0058] Element 5A: wherein the isobutylene-co-p-methylstyrene based elastomer has an average molecular weight (Mw), for example, of about 200,000 to about 2,000,000 Daltons.

[0059] Element 6A: wherein the isobutylene-co-p-methylstyrene based elastomer has a Mw / Mn ratio of less than 2.5.

[0060] Element 7A: wherein the isobutylene-co-p-methylstyrene based elastomer has a Mw / Mn ratio of less than 2.0.

[0061] Element 8A: Further comprising: blending the modified isobutylene-co-p-methylstyrene-based elastomer with a certain amount of isobutylene-co-p-methylstyrene-based elastomer to control the Mw / Mn ratio of the isobutylene-co-p-methylstyrene composition.

[0062] Element 9A: wherein the blending is performed at a blending ratio of the isobutylene-co-p-methylstyrene-based elastomer to the modified isobutylene-co-p-methylstyrene-based elastomer of 0.5:1.0 to 2.0:1.0.

[0063] Element 10A: wherein the blending ratio is 1:1.

[0064] Element 11A: wherein the isobutylene-co-p-methylstyrene composition has a Mw / Mn ratio that is at least twice the Mw / Mn ratio of the isobutylene-co-p-methylstyrene-based elastomer.

[0065] Element 12A: wherein the isobutylene-co-p-methylstyrene composition has a Mw / Mn ratio of 6.0 to 10.0.

[0066] Element 13A: wherein the isobutylene-co-p-methylstyrene based elastomer is halogenated prior to treatment with the peroxide initiator.

[0067] Element 14A: further comprising: halogenating the modified isobutylene-co-p-methylstyrene-based elastomer.

[0068] Element 15A: Further comprising: halogenating the modified isobutylene-co-p-methylstyrene-based elastomer prior to the blending.

[0069] Element 16A: Further comprising: halogenating the modified isobutylene-co-p-methylstyrene-based elastomer after the blending.

[0070] Each of elements 1A to 16A may be combined in any combination, but are not limited thereto.

[0071] Embodiment B: A method for preparing an isobutylene-co-p-methylstyrene-based elastomer, the method comprising: increasing the low molecular weight fraction of the isobutylene-co-p-methylstyrene-based elastomer by mixing the isobutylene-co-p-methylstyrene-based elastomer with a peroxide initiator at a temperature greater than or equal to 160°C, wherein the mixing produces a modified isobutylene-co-p-methylstyrene-based elastomer having a Mw / Mn ratio greater than 2.5.

[0072] Non-limiting example embodiment B may include one or more of the following elements.

[0073] Element 1B: wherein the isobutylene-co-p-methylstyrene-based elastomer is a non-halogenated elastomer, a halogenated elastomer, a branched elastomer, or a combination thereof.

[0074] Element 2B: wherein the isobutylene-co-p-methylstyrene-based elastomer comprises 80 to 99.5 mol % of isobutylene and 0.5 to 20 mol % of p-methylstyrene.

[0075] Element 3B: further comprising: blending the modified isobutylene-co-p-methylstyrene-based elastomer with a certain amount of isobutylene-co-p-methylstyrene-based elastomer to control the Mw / Mn ratio of the isobutylene-co-p-methylstyrene composition.

[0076] Element 4B: wherein the blending is performed at a blending ratio of the isobutylene-co-p-methylstyrene-based elastomer to the modified isobutylene-co-p-methylstyrene-based elastomer of 0.5:1.0 to 2.0:1.0.

[0077] Each of elements 1B to 4B may be combined in any combination, but are not limited thereto.

[0078] Embodiment C: An isobutylene-co-p-methylstyrene based elastomer comprising 80 to 99.5 mol% isobutylene and 0.5 to 20 mol% p-methylstyrene, having a substantially uniform composition distribution, and having a Mw / Mn ratio greater than 6.0.

[0079] Non-limiting example embodiment C may include one or more of the following elements.

[0080] Element 1C: wherein the p-methylstyrene is represented by the following formula: wherein X is hydrogen or halogen.

[0081] Element 2C: wherein X is bromine.

[0082] Element 3C: A cured article comprising the isobutylene-co-p-methylstyrene-based elastomer of embodiment C, wherein the cured article is a tire innerliner, an inner tube, a wire coating, a medical rubber stopper, a hose, a film, an adhesive, or a sealant.

[0083] Each of elements 1C to 3C may be combined in any combination, but are not limited thereto.

[0084] In order to facilitate a better understanding of the embodiments described herein, the following examples are provided.The following examples should not be construed in any way to limit, or define the scope of the present disclosure. Example

[0085] Various isobutylene-co-p-methylstyrene based elastomers are synthesized according to one or more embodiments described herein and analyzed using GPC and / or FTIR techniques to determine the associated MWD. ​​One of ordinary skill in the art will recognize that reactors typically used for butyl rubber polymerization are generally suitable for the various polymerization and / or MWD modification reactions described herein. Gel Permeation Chromatography (GPC) Molecular Weight

[0086] GPC is an analytical procedure used to separate molecules by size differences. The procedure applied to polymers results in a concentration distribution of molecular weights. Most commonly, the concentration is determined using the differential refractive index (DRI), and the concentration versus time elution curve is correlated to the molecular weight using a calibration curve based on a "known" standard. Direct determination of molecular weight can be performed using low angle laser light scattering (LALLS) photometry in conjunction with DRI.

[0087] Molecular weight averages can be calculated based on data obtained from GPC tests. Molecular weight averages include: number average (Mn), weight average (Mw), and Z average (Mz). These averages are also called the various moments of the distribution. Higher molecular weight substances have a greater impact on the Z average and weight average, while lower molecular weight substances have a greater impact on the number of moments. The width of the overall distribution and its parts can be characterized by reference to various ratios, such as Mw / Mn and Mz / Mw; the higher the ratio, the wider the molecular weight distribution.

[0088] Molecular weight (weight average molecular weight (Mw) and number average molecular weight (Mn)) and molecular weight distribution (MWD = Mw / Mn), which is sometimes also referred to as the polydispersity index (PDI) of the polymer, are measured by GPC. Molecular weight is determined by a Tosoh BioScience HLC-8320 GPC equipped with an internal DRI detector, an internal UV absorbance detector UV-8320 (254 nm absorbance detector), a Wyatt Technology miniDawn TREOS light scattering detector with three angles (45°, 90° and 135°) and a Wyatt Technology ViscoStar-II viscometer detector, a series of three PolymerLabs PLgel Mixed-B with a peak Mw; range of 580-10,000,000. The column is calibrated using Polymer Labs EasiVial polystyrene standards (high, medium and low) standards. About 20 mg of polymer was dissolved in 10 mL of tetrahydrofuran ("THF"), stabilized with butylated hydroxytoluene ("BHT") and toluene as mobile markers, the solution was filtered by using a 0.45 μm Acrodisc filter (membrane type PTFE), and 150 μL of sample was injected by automatic syringe. Test conditions: Sample solvent: tetrahydrofuran containing 250-400 ppm of butylated hydroxytoluene; sample concentration: 2.0 mg / mL; sample dissolution temperature: room temperature (~23°C); sample dissolution time: minimum 3 hours on the dissolution wheel; GPC pump oven and column oven temperature: 40°C; flow rate: 1 mL / min; mobile phase solvent: THF (same as sample solvent); sample injection size: 150 μL; sample elution time: 65 minutes. Data analysis was performed using Astra 6.1 GPC software from Wyatt Technology. Universal calibration curve methodology data are mainly used to report results. In order to understand the molecular weight of the elastomer in detail, an online light scattering measurement was performed using a laser light scattering ("LLS") detector connected online with the column and other detectors. The dn / dc value of 0.113 mL / g for butyl rubber was used to calculate the absolute molecular weight. The samples for light scattering were carefully prepared to avoid the presence of particulate matter. Data analysis was performed using Astra 6.1 GPC software from Wyatt Technology.

[0089] The functional groups, the percentage of p-methylstyrene and brominated p-methylstyrene (BrpMS) incorporated in the elastomers, and the quantification of other components or additives present were determined using a PerkinElmer Frontier FTIR spectrometer with a triglycine sulfate (TGS) detector and sample shuttle. TM10.6.0 software control. The infrared spectra of the elastomers were obtained using compression molded film specimens with a thickness of 0.060 cm using an automatic Carver hydraulic press. -1 FTIR spectra were collected with 16 scans at a resolution of 6525–400 cm -1 Target all FTIR spectra to the common region 4400-4250 cm -1 Normalized and at 4980-2040cm -1 The basic absorbance is measured at 1894 cm -1 p-methylstyrene concentration was quantified using the aromatic broad band centered at 615 cm -1 The C-Br band centered at quantifies the brominated p-methylstyrene units. The spectral regions corresponding to the structures or components of interest are correlated with their concentrations determined according to Beer's law and multi-point calibration to cover the range of p-methylstyrene and brominated p-methylstyrene concentrations, the calibration set being prepared from standard samples with known concentrations obtained by NMR. A model was developed to automatically calculate the mole % of p-methylstyrene and the mole % of brominated p-methylstyrene after collecting the spectra. Example 1

[0090] In a first embodiment group, the modified by peroxide treatment described herein is available from Exxon TM Commercially available non-halogenated isobutylene-co-p-methylstyrene based elastomer XP-50, wherein the As a peroxide initiator. Table 1 shown below shows the composition of three examples of isobutylene-co-p-methylstyrene-based elastomers (e.g., elastomers 1-3). In order to obtain the compositions characterized in Table 1, XP-50 was mixed with different amounts of Mix in a 280 gram mixing bowl at about 100° C. The temperature is then raised to 190° C. and the batch is mixed for a further 5 minutes. Table 1 - Example elastomer composition

[0091] Additionally, Table 2 provides molecular weight and MWD data for example isobutylene-co-p-methylstyrene based elastomers (e.g., Elastomers 1-3) as determined using a light scattering detector. Additionally, Table 3 provides molecular weight and MWD data for example isobutylene-co-p-methylstyrene based elastomers (e.g., Elastomers 1-3) as determined using universal calibration with online viscometer data. Table 2 - Light Scattering Detectors *The elastomer is brominated after MWD modification. Table 3 - General Calibration *The elastomer is brominated after MWD modification.

[0092] In addition, the brominated example elastomers (e.g., Elastomer 1-Br, Elastomer 2-Br, and Elastomer 3-Br) were blended with non-halogenated isobutylene-co-p-methylstyrene-based elastomers (referred to herein as "Comparative Elastomer A") at various blend ratios (Comparative Elastomer A to brominated example elastomers). Table 4 depicts the molecular weight and MWD data of the elastomers as determined by a light scattering detector. Table 5 depicts the molecular weight and MWD data of the elastomers as determined using a universal calibration with online viscometer data. For comparison, Tables 4-5 further include the molecular weight and MWD of the unmodified Comparative Elastomer A isobutylene-co-p-methylstyrene-based elastomer (which is a brominated embodiment of XP-50). Table 4 - Light Scattering Detectors *Blend ratio = Comparative Elastomer A versus Example Elastomer. Table 5 - General Calibration *Blend ratio = Comparative Elastomer A versus Example Elastomer.

[0093] Table 6 provided below includes FTIR data for brominated MWD modified example elastomers (e.g., Elastomer 1-Br, Elastomer 2-Br, Elastomer 3-Br). In particular, Table 6 depicts the mole % of the brominated and non-brominated para-methylstyrene ("PMS") components of the example elastomers. Table 6 - FTIR data Example 2

[0094] In a second embodiment group, the peroxide treatment described herein will be available from Exxon TM Commercially available brominated isobutylene-co-p-methylstyrene based elastomer Exxpro TM 3035 and Exxpro TM 3745 (e.g., bromination of an isobutylene-co-p-methylstyrene-based elastomer prior to MWD modification by peroxide treatment), wherein the As a peroxide initiator. Table 7 shown below shows the composition of six examples of isobutylene-co-p-methylstyrene-based elastomers (e.g., elastomers 4-9). In order to obtain the compositions characterized in Table 7, Exxpro TM 3035 or Exxpro TM 3745 with different amounts Mix in a 280 gram mixing bowl at about 100° C. The temperature is then raised to 190° C. and the batch is mixed for a further 5 minutes. Table 7 - Example Elastomer Composition

[0095] Additionally, Table 8 provides molecular weight and MWD data for example isobutylene-co-p-methylstyrene based elastomers (e.g., elastomers 4-9) as determined using a light scattering detector. Additionally, Table 9 provides molecular weight and MWD data for example isobutylene-co-p-methylstyrene based elastomers (e.g., elastomers 4-9) as determined using universal calibration with online viscometer data. Table 8 - Light Scattering Detectors Table 9 - General Calibration

[0096] In addition, Table 10 includes Exxpro TM FTIR data for 3035 and Elastomer 4. In particular, Table 10 depicts the mole % of the brominated and non-brominated para-methylstyrene ("PMS") components of the elastomers. Table 10 - FTIR data Example 3

[0097] In a third embodiment group, the peroxide treatment described herein will be available from Exxon TM Commercially available brominated isobutylene-co-p-methylstyrene based elastomer Exxpro TM 3035 is modified, wherein the or 101 as a peroxide initiator. Table 11 shown below shows the composition of six examples of isobutylene-co-p-methylstyrene-based elastomers (e.g., elastomers 10-15). In order to obtain the compositions characterized in Table 11, Exxpro TM 3035 with different amounts or 101 were mixed in a 280 gram mixing bowl at about 100° C. The temperature was then raised to 190° C. and the batch was mixed for a further 5 minutes. Table 11 - Example Elastomer Composition

[0098] Additionally, Table 12 provides molecular weight and MWD data for Example Elastomers 12-15 as determined using a light scattering detector. Additionally, Table 13 provides molecular weight and MWD data for Example Elastomers 12-15 as determined using universal calibration with online viscometer data. Table 12 - Light Scattering Detectors Table 13 - General Calibration

[0099] Additionally, Table 14 includes FTIR data for Elastomers 10- 15. In particular, Table 14 depicts the mole % of the brominated and non-brominated para-methylstyrene ("PMS") components of the elastomers. Table 14 - FTIR data

[0100] Optimizing the amount of peroxide used to treat isobutylene-co-p-methylstyrene based elastomers can affect the amount of brominated p-methylstyrene, as demonstrated by elastomers 10-15. For example, elastomers 10-15 exhibit high amounts of brominated p-methylstyrene, which can promote further crosslinking in various industrial applications.

[0101] Table 15 provided below depicts the Exxpro TM Mooney viscosities of 3035 and elastomers 12-14, each containing 5 wt. % p-methylstyrene. Table 15 sample* Mooney viscosity** <![CDATA[Exxpro TM 3035]]> 46.6 Elastomer 12 32.2 Elastomer 13 31.9 Elastomer 14 24.6 *Each sample contains 5 wt% p-methylstyrene **ML, 1+8 at 125℃

[0102] In addition, elastomers 12-14 are combined with Exxpro TM 3035 blend, wherein Table 16 depicts the molecular weight and MWD data of the elastomer as determined by a light scattering detector. Table 16 - Light Scattering Detectors * 3035 compared to example elastomer.

[0103] Advantageously, the peroxide treatment described herein can modify the MWD of halogenated (e.g., brominated) isobutylene-co-p-methylstyrene based elastomers while forming a substantially soluble non-gel-like product (e.g., while avoiding gel formation). For example, the peroxide treatment conditions described herein can produce a modified halogenated (e.g., brominated) isobutylene-co-p-methylstyrene elastomer composition without a significant amount of gel formation.

[0104] Unless otherwise indicated, all numerical values ​​used in the specification and the appended claims to express quantities of ingredients, properties such as molecular weight, reaction conditions, etc., should be understood in all cases as being modified by the term "about". Therefore, unless otherwise indicated, the numerical parameters listed in the following specification and the appended claims are approximate values, which may vary depending on the desired properties sought to be obtained by the embodiments of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be interpreted in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0105] One or more illustrative examples of incorporating one or more inventive elements are presented herein. For the sake of clarity, all features of physical implementation are not described or shown in this application. It should be understood that in the development of the physical implementation scheme incorporating one or more elements of the present invention, many execution-specific decisions must be made to realize the developer's goal, such as complying with system-related, business-related, government-related and other constraints, which depend on implementation and change from time to time. Although the efforts of the developer may be time-consuming, for those of ordinary skill in the art, this effort remains a routine task, and benefits from the present disclosure. Although compositions and methods are described herein in terms of "comprising" various components or steps, the compositions and methods may also be "consisting essentially of" or "consisting of" the various components and steps. Therefore, the present invention is fully adapted to obtain the objects and advantages mentioned as well as those inherent therein. The particular examples and configurations disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent ways apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitation is intended to the details of construction or design shown herein, except as described in the claims below. Therefore, it is apparent that the particular illustrative examples disclosed above may be changed, combined or modified, and all such variations are considered to be within the scope and spirit of the present invention. The present invention illustratively disclosed herein may be appropriately practiced in the absence of any element not specifically disclosed herein and / or any optional element disclosed herein. Although compositions and methods are described in terms of "comprising", "containing" or "including" various components or steps, the compositions and methods may also be "consisting essentially of" or "consisting of" the various components and steps. All numbers and ranges disclosed above may vary by a certain amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is explicitly disclosed. In particular, each range of values ​​disclosed herein (in the form of "from about a to about b" or equivalently "from approximately a to b" or equivalently "from approximately ab") should be understood to list each number and range covered in the wider range of numerical values. In addition, the terms in the claims have their ordinary normal meaning unless otherwise clearly and clearly defined by the patentee. In addition, the indefinite article "a" or "an" used in the claims is defined herein to represent one or more of the elements it introduces.

Claims

1. A method for preparing an isobutylene-copolymer-p-methylstyrene composition, the method comprising: An isobutylene-co-p-methylstyrene-based elastomer is treated with a peroxide initiator at a temperature greater than or equal to 160°C to chemically induce thermal scission along the copolymer backbone of the isobutylene-co-p-methylstyrene-based elastomer, wherein the treatment produces a modified isobutylene-co-p-methylstyrene-based elastomer having an Mw / Mn ratio greater than 2.

5.

2. The method of claim 1, wherein said treatment comprises said peroxide initiator in an amount of 0.2 to 4.5 weight percent, based on said isobutylene-co-p-methylstyrene based elastomer.

3. The method of claim 2, wherein the temperature ranges from 160 to 190°C.

4. The method of claim 1, wherein the isobutylene-co-p-methylstyrene based elastomer comprises 80 to 99.5 mole % of isobutylene and 0.5 to 20 mole % of p-methylstyrene.

5. The method of claim 4, wherein the isobutylene-co-p-methylstyrene based elastomer comprises 5 mol% p-methylstyrene.

6. The method of claim 4, wherein the isobutylene-co-p-methylstyrene based elastomer has an average molecular weight (Mw), for example, from about 200,000 to about 2,000,000 Daltons.

7. The method of claim 1 wherein the isobutylene-co-p-methylstyrene based elastomer has a Mw / Mn ratio of less than 2.

5.

8. The method of claim 7, wherein the isobutylene-co-p-methylstyrene based elastomer has a Mw / Mn ratio of less than 2.

0.

9. The method of claim 1, further comprising: The modified isobutylene-co-p-methylstyrene-based elastomer is blended with a certain amount of isobutylene-co-p-methylstyrene-based elastomer to control the Mw / Mn ratio of the isobutylene-co-p-methylstyrene composition.

10. The method of claim 9, wherein the blending is performed at a blending ratio of the isobutylene-co-p-methylstyrene-based elastomer to the modified isobutylene-co-p-methylstyrene-based elastomer of 0.5:1.0 to 2.0:1.

0.

11. The method of claim 10, wherein the blending ratio is 1:

1.

12. The method of claim 9, wherein the Mw / Mn ratio of the isobutylene-co-p-methylstyrene composition is at least twice the Mw / Mn ratio of the isobutylene-co-p-methylstyrene based elastomer.

13. The method of claim 12, wherein the isobutylene-co-p-methylstyrene composition has a Mw / Mn ratio of 6.0 to 10.

0.

14. The method of claim 1 wherein said isobutylene-co-p-methylstyrene based elastomer is halogenated prior to treatment with said peroxide initiator.

15. The method of claim 1, further comprising: The modified isobutylene-co-p-methylstyrene-based elastomer is halogenated.

16. The method of claim 9, further comprising: Prior to said blending, said modified isobutylene-co-p-methylstyrene based elastomer is halogenated.

17. The method of claim 9, further comprising: After said blending, said modified isobutylene-co-p-methylstyrene based elastomer is halogenated.

18. A method for preparing an elastomer based on isobutylene-co-p-methylstyrene, the method comprising: The low molecular weight fraction of the isobutylene-co-p-methylstyrene based elastomer is increased by mixing the isobutylene-co-p-methylstyrene based elastomer with a peroxide initiator at a temperature greater than or equal to 160° C., wherein the mixing produces a modified isobutylene-co-p-methylstyrene based elastomer having a Mw / Mn ratio greater than 2.

5.

19. The method of claim 18, wherein the isobutylene-co-p-methylstyrene based elastomer is a non-halogenated elastomer, a halogenated elastomer, a branched elastomer, or a combination thereof.

20. The method of claim 19, wherein the isobutylene-co-p-methylstyrene based elastomer comprises 80 to 99.5 mole % of isobutylene and 0.5 to 20 mole % of p-methylstyrene.

21. The method of claim 20, further comprising: The modified isobutylene-co-p-methylstyrene-based elastomer is blended with a certain amount of isobutylene-co-p-methylstyrene-based elastomer to control the Mw / Mn ratio of the isobutylene-co-p-methylstyrene composition.

22. The method of claim 21, wherein the blending is performed at a blending ratio of the isobutylene-co-p-methylstyrene-based elastomer to the modified isobutylene-co-p-methylstyrene-based elastomer of 0.5:1.0 to 2.0:1.

0.

23. An isobutylene-co-p-methylstyrene based elastomer comprising 80 to 99.5 mol% of isobutylene and 0.5 to 20 mol% of p-methylstyrene, having a substantially uniform composition distribution, and having a Mw / Mn ratio greater than 6.

0.

24. The isobutylene-co-p-methylstyrene-based elastomer of claim 23, wherein the p-methylstyrene is represented by the formula: wherein X is hydrogen or halogen.

25. The isobutylene-co-p-methylstyrene based elastomer of claim 24, wherein X is bromine.

26. A cured article comprising the isobutylene-co-p-methylstyrene-based elastomer of claim 24, wherein the cured article is a tire innerliner, an inner tube, a wire coating, a medical rubber stopper, a hose, a film, an adhesive or a sealant.

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