HK1050539B - Halogenated terpolymers of isobutylene, diolefin monomer and styrenic monomer - Google Patents

Description

Halogenated terpolymers of isobutylene, diolefin monomers and styrenic monomers

In one aspect, the present invention relates to a halogenated butyl polymer. In another aspect, the present invention relates to a process for producing a butyl polymer.

Butyl polymers or rubbers are well known in the art, particularly for their use in tire production.

Furthermore, the use of halogenated butyl rubbers is also known, since these rubbers have particularly good adhesion behavior, flexural strength, service life and impermeability to air and water.

Despite this, there is still room for improvement. In particular, since manufacturers have agreed to ensure that tires continue to increase in size, it has been desirable to extend the useful life of tires. This places a need for improved properties in tire components, including rubber components (e.g., halogenated butyl rubber). This becomes particularly important in the field of tire retreading.

Accordingly, there is a continuing need in the art for halogenated butyl rubbers, in particular, having improved curing and/or aging properties.

It is an object of the present invention to provide a novel halogenated butyl polymer.

It is another object of the present invention to provide a novel process for producing halogenated butyl polymers.

It is a further object of the present invention to provide a novel vulcanizate derived from halogenated butyl polymers.

Accordingly, in one aspect the present invention provides a halogenated butyl polymer having improved curing and/or aging properties, the butyl polymer being derived from a butyl polymer containing C₄～C₈Monoolefin monomer, C₄～C₁₄A monomer mixture of a multiolefin monomer and a styrenic monomer.

In another aspect, the present invention provides a process for preparing a halogenated butyl polymer having improved curing and/or aging properties, the process comprising the steps of:

to contain C₄～C₈Monoolefin monomer, C₄～C₁₄Contacting a monomer mixture of a multiolefin monomer and a styrenic monomer with a catalyst system to prepare a terpolymer; and

halogenating the terpolymer to produce a halogenated butyl polymer.

In yet another aspect, the present invention provides a vulcanized rubber derived from a vulcanizable mixture comprising: derived from compounds containing C₄～C₈Monoolefin monomer, C₄～C₁₄A halogenated butyl polymer of a monomer mixture of a multiolefin monomer and a styrenic monomer; a filler; and a vulcanizing agent.

The present invention therefore relates to a butyl rubber polymer. The terms "butyl rubber", "butyl polymer" and "butyl rubber polymer" are used interchangeably throughout this specification, each of which is meant to be modified by the inclusion of C₄～C₈Monoolefin monomer, C₄～C₁₄A polymer prepared by reacting a monomer mixture of a multiolefin monomer and a styrenic monomer.

It has now been surprisingly and unexpectedly discovered that compounds derived by halogenation from compounds containing C₄～C₈Monoolefin monomer and C₄～C₁₄Halogenation of polymers derived from copolymers of monomer mixtures containing multiolefin monomers results in polymers containing C₄～C₈Monoolefin monomer, C₄～C₁₄Terpolymers of monomer mixtures of multiolefin monomers and styrenic monomers give polymers with improved properties. The improved properties include fast cure, higher maximum torque, higher delta torque, relatively stable modulus over time, improved hot air aging properties, and improved aged flex properties. It is believed that these improved properties result from direct interaction between the styrenic portion of the polymer backbone and the added crosslinking agent used to cure the halogenated butyl rubber.

Embodiments of the invention will be described with reference to the accompanying drawings, in which:

figures 1 and 2 are (raman infrared) r.i. and (ultraviolet) u.v. (256nm) trace traces (trace) of GPC chromatography of the terpolymers of the present invention;

FIG. 3 is a depiction of various bromine-containing structures;

FIG. 4 illustrates the curing behavior of typical polymers;

FIGS. 5 and 6 illustrate the curing behavior of the terpolymers of the present invention;

FIGS. 7 and 8 illustrate the hot air aging performance of the terpolymers of the present invention.

Thus, the terpolymers of the invention are obtained and the process of the invention involves a copolymer containing C₄～C₈Monoolefin monomer, C₄～C₁₄Use of a monomer mixture of a multiolefin monomer and a styrenic monomer.

Preferably, the monomer mixture contains about 80 to about 99 weight percent C₄～C₈Monoolefin monomer, from about 0.5 to about 5 weight percent C₄～C₁₄A multiolefin monomer, and from about 0.5 to about 15 weight percent of a styrenic monomer. More preferably, the monomer mixture contains about 85 to about 99 weight percent C₄～C₈Monoolefin monomer, from about 0.5 to about 5 weight percent C₄～C₁₄A multiolefin monomer, and from about 0.5 to about 10 weight percent of a styrenic monomer. Most preferably, the monomer mixture contains about 87 to about 94 weight percent C₄～C₈Monoolefin monomer, from about 1 to about 3 weight percent C₄～C₁₄Multiolefin monomers, and from about 5 to about 10 weight percent styrenic monomers.

Preferred is C₄～C₈The monoolefin monomer can be selected from the group consisting of isobutylene, 2-methylpropene-1, 3-methylbutene-1, 4-methylpentene-1, 2-methylpentene-1, 4-ethylbutene-1, 4-ethylpentene-1, and mixtures thereof. Most preferred C₄～C₈The monoolefin monomer comprises isobutylene.

Preferred is C₄～C₁₄The multiolefin monomer can be selected from isoprene, butadiene-1, 3, 2, 4-dimethylbutadiene-1, 3, 1, 3-Pentadiene (piperyline), 3-methylpentadiene-1, 3, hexadiene-2, 4, 2-neopentylbutadiene-1, 3, 2-methylhexadiene-1, 5, 2, 5-dimethylhexadiene-2, 4, 2-methylpentadiene-1, 4, 2-methylheptadiene-1, 6, cyclopentadiene, methylcyclopentadiene, cyclohexadiene, 1-vinylcyclohexadiene and mixtures thereof. Most preferred C₄～C₁₄Multiolefin monomers include isoprene.

Preferred styrenic monomers are selected from the group consisting of p-methylstyrene, styrene, α -methylstyrene, p-chlorostyrene, p-methoxystyrene, indene (including indene derivatives) and mixtures thereof. The most preferred styrenic monomer may be selected from styrene, p-methylstyrene and mixtures thereof.

As mentioned above, the butyl polymer is halogenated. Preferably, the butyl polymer is brominated or chlorinated. Preferably, the amount of halogen is from about 0.1 to about 8 weight percent, more preferably from about 0.5 to about 4 weight percent, and most preferably from about 1.5 to about 3.0 weight percent, based on the weight of the polymer.

Halogenated butyl polymers may be obtained by halogenating previously prepared butyl polymers derived from the above monomer mixtures. The manner of preparing the butyl polymer is generally employed and is within the knowledge of one of ordinary skill in the art. The process for preparing butyl polymer can therefore be carried out in the presence of conventional catalysts, such as aluminum trichloride, at the temperatures typically employed for preparing butyl polymers, for example, from about-100 ℃ to about +50 ℃, usually below-90 ℃. The butyl polymer may be prepared in the usual manner by solution or slurry polymerization processes. The polymerization is preferably carried out in suspension (slurry process). For more detailed information on the preparation of the butyl polymer, reference may be made, for example, to any of the following:

ullmann's Encyclopedia of Industrial Chemistry (fifth Edition, complete reviewed Edition, volume A23; editor: Elvers et al)

"Cationic Polymerization of Olefins: a Critical inventory "by Joseph P.Kennedy (John Wiley & Sons, Inc. * 1975); and

"Rubber Technology" (third edition) by Maurice Morton, Chapter10(Van nonstrand Reinhold Company * 1987).

The butyl polymer may then be halogenated in the usual manner. See, for example, USP 5886106. Thus, the halogenated butyl rubber may be prepared either by treating a finely divided butyl rubber with a halogenating agent such as chlorine or bromine, preferably bromine, or by intimately mixing a brominating agent such as N-bromosuccinimide with the butyl rubber prepared as described above in a mixing apparatus. Alternatively, halogenated butyl rubbers are prepared by treating a solution or dispersion of the previously prepared butyl rubber in a suitable organic solvent with the corresponding brominating agent. For more detailed information, see Ullmann's Encyclopedia of Industrial chemistry (fifth Edition, complete review Edition, volume A23; editor: Elvers et al) and/or "Rubber Technology" (third Edition) by MauriceMorton, Chapter10(Van Nostrand and Reinhold Company * 1987). The amount of halogenation during this process can be controlled such that the final terpolymer possesses the preferred amounts of halogen described above. The particular manner in which the halogen is attached to the polymer is not particularly limited and those skilled in the art will appreciate that means other than those described above can be used while still obtaining the benefits of the present invention.

The halogenated butyl rubber of the present invention can be used to produce vulcanized rubber products. For example, useful vulcanizates can be produced by mixing halogenated butyl rubbers with carbon black and/or other known components (additives) and crosslinking the mixture in the usual manner with customary curatives.

Embodiments of the present invention will be further illustrated with reference to the following examples, which should not be construed as limiting the scope of the invention. In the examples, "pbw" means parts by weight and "phr" means parts by weight per 100 parts by weight of rubber or polymer product.

Examples 1 to 7

In the examples, isobutene (IB, Matheson, 99%) and methyl chloride (MeCl, Matheson, 99%) were used in the form obtained. Isoprene (IP, Aldrich, 99.9%), p-methylstyrene (p-MeSt, Aldrich, 97%) and styrene (St, Aldrich, 99%) were treated with a t-butylcatechol inhibitor remover prior to use. Aluminum trichloride (Aldrich, 99.99%), stearic acid (NBS, technical grade) and zinc oxide (MidwestZinc co., technical grade) were used in the form obtained.

All polymerizations were in MBraun MB^TM150B-G-I drying oven.

About 1g AlCl₃And 100mL of MeCl to prepare a saturated catalyst solution. The solution was stirred at-30 ℃ for 30 minutes.

To a2 liter baffled glass reactor equipped with a stainless steel stirrer and thermocouple, IB, IP, p-MeSt and St were added at the concentrations listed in Table 1. The monomer-containing reactor was cooled to-95 ℃ before 10mL of the catalyst solution was added to the reactor. The polymerization is carried out until a maximum temperature is reached. The polymerization was terminated by adding 10mL of ethanol to the reactor. The polymer was recovered by dissolution in hexane and then coagulated with ethanol. The polymer was dried in a vacuum oven at 40 ℃ until a constant weight was reached.

It is clear that in example 1 no p-MeSt or St is used. This example therefore serves only for comparison and is not within the scope of the invention.

6 Waters Ultrastyragel columns (100, 500, 10) were used with GPC equipped with ultraviolet (U.V.) and Raman infrared (R.I.) detectors³，10⁴，10⁵And 10⁶Angstrom), the temperature was set at 35 ℃, and the molecular weight and molecular weight distribution were measured. The mobile phase was THF at a flow rate of 1 mL/min. The flow rate was measured using elemental sulfur as an internal standard. The instrument was calibrated with 14 narrow molecular weight distribution polystyrene standards. The average molecular weight was calculated using a universal calibration rule (Universal calibration rule), where K is_PSt＝1.12×10^-4dl/g，α_PSt＝0.725，K_PIB＝2.00×10^-4dl/g，α_PIB0.67. Calcium stearate, ESBO and EXO values were determined by FTIR. 500MHz is obtained in a conventional manner¹H NMR spectra obtained by analysis of the spectra in the usual manner, see for example (i) Chu et al, Macromolecules181423(1985), and (ii) Chu et al, Rubber chem.60,626(1987). Bromine content was measured by oxygen bottle combustion and Tg was measured by DSC. Hot air aging studies were performed according to ASTM-D573-81.

Figures 1 and 2 are r.i. and u.v. (256nm) trace traces of GPC chromatograms of p-MeSt terpolymer (example 4) and St terpolymer (example 7), respectively. Comparison of the r.i. and u.v. tracking traces provides information on the homogeneity of the polymer composition as a function of molecular weight. The r.i. signal is proportional to the total mass of the polymer chain. The u.v. signal is proportional to the number of aromatic monomer units entering the polymer chain, since the u.v. absorption at 256nm of IB and IP units is negligible compared to that of aromatic rings.

The r.i. and u.v. tracking traces of the p-MeSt terpolymer showed almost complete overlap. The u.v./r.i. ratio, which is proportional to the p-MeSt content of a given molecular weight fraction, is essentially constant over the entire molecular weight range. These results demonstrate that IB and p-MeSt are very similar in activity to isobutylene terminal propagating cations.

In contrast, St terpolymers show non-overlapping u.v. and r.i. tracking trajectories. The u.v./r.i. ratio, i.e. the styrene content of the polymer, increases with a factor of about 4 with decreasing molecular weight (increasing elution volume), which indicates that St acts as a chain transfer agent and is less active on IB-terminated propagating cations than IB.

The above analysis confirmed the formation of random copolymers.

The polymer product obtained from each batch was brominated in the following manner.

The polymer product was dissolved in hexane to produce a polymer cement (cement) to which 0.08phr octylated diphenylamine (O) was addedDPA) and 0.017phr of Irganox^TM1010. The cement was then solvent stripped and mill dried.

The resulting homogeneous rubber was again cut into small pieces and redissolved in hexane. The polymer cement thus obtained was then transferred to a 12 liter baffled reactor equipped with a mechanical stirrer and two syringe inlets. The cement container was rinsed with hexane and dichloromethane. Water was then added to the reactor and the mixture was stirred for several minutes.

Bromination of the polymer product is initiated by injecting an appropriate amount of bromine into the reactor. After 4 minutes of reaction, the reaction was terminated by injecting a caustic soda solution (6.4 wt% NaOH). The mixture was stirred for a further 10 minutes, after which time 0.25phr epoxidized soybean oil (ESBO), 0.02phr ODPA and 0.003phr Irganox were added to the mixture^TM1076. The brominated rubber mixture was then washed three times before adding ESBO (0.65phr) and calcium stearate (1.5phr) to the cement before stripping. The polymer is finally dried on a hot mill.

Bromine concentration, rubber concentration (solids), moisture content and reaction time were all kept constant. During bromination, 30 volume percent methylene chloride was used as a polar co-solvent to obtain improved control over the extent of the reaction, thereby obtaining the same concentration of brominated structures (about 1.0 mole%) in all of the brominated polymer products. The stabilizer and antioxidant content of the brominated terpolymer was kept constant. The calcium stearate content was set at 1.5phr and the ESBO content was set at 0.9 phr.

The composition of the brominated terpolymer as determined by 500MHz HNMR is reported in Table 2. The p-MeSt and St contents measured before and after bromination substantially agree with each other. According to the results, the amount of primary brominated structures in the terpolymer was smaller than in the control and decreased with increasing p-MeSt and St content. It is believed that this suggests that in addition to the 1, 4-IP match linkage, the aromatic ring also undergoes bromination. The presence of brominated aromatic rings was estimated from mass balance: the total bromine content of the sample minus the amount of bromine attached to the 1, 4-IP unit. The total bromine content of the samples was determined by oxygen bottle combustion. The amount of bromine attached to the 1, 4-IP unit was also calculated from the HNMR results. Specifically, the calculated results are given by the sum of the bromine-containing structures: exo substitution (Exo.) + rearranged Exo substitution + Endo.) + hydrobrominated, see figure 3 for an illustration of these different bromine-containing structures. The results are reported in table 3.

Referring to table 3, the two values for bromine content in example 2 are reasonably matched, indicating that bromination of the aromatic ring is negligible. Referring to examples 3 and 4, respectively, the deviation of the two values of bromine content indicates that the aromatic ring underwent bromination. In the case of styrene terpolymers (i.e., examples 5-7), the deviation between the two values is more pronounced. This is not surprising because the more accessible para position in the case of styrene is not blocked from a steric hindrance perspective, and the effect of the ortho-para orientation of the alkyl group (polymer backbone).

For each example, a vulcanizate was prepared by adding 1phr stearic acid and 5phr zinc oxide (i.e., no filler or oil used during vulcanization) to the brominated polymer on a mill set at 40 ℃. The curing behaviour was determined with an ODR Monsanto rheometer (3 degrees (radian), 166 ℃ C.). Full-size (6X 6 inches) and half-size (3X 3 inches) plaques were prepared from these formulations cured at 166 ℃ for 30 minutes.

FIGS. 4, 5 and 6 show the curing behavior of the polymers of example 1 (control), 2 (low p-MeSt content terpolymer) and 6 (medium St content terpolymer), respectively. Table 4 lists the cure times and torques obtained for all formulations.

According to the rheologic diagram, the rubber prepared in example 1 shows large grooves (trough) or a long induction period before the curing starts. Specifically, the copolymer product obtained in example 1 reached the Tc50 point (semi-vulcanized state) in about 13 minutes and the Tc90 point in about 20 minutes. On the other hand, the terpolymers produced in examples 2 (low p-MeSt content terpolymer) and 6 (medium St content terpolymer) have narrower torque curves and it is observed that they reach their Tc50 point in less than half of the time described above, although the terpolymers of examples 2 and 6 contain 10-35% less external substituted fraction than the copolymer of example 1. This indicates that the aromatic ring takes part in the curing reaction.

As the level of exo-substitution decreases, the Mh-Ml values of the terpolymers made in examples 2 (low p-MeSt content terpolymer) and 6 (medium St content terpolymer) decrease with increasing p-MeSt or St content. However, the resulting torque values were at least equal to or even higher than the control. The most significant comparison can be made by comparing the delta torque values for the copolymer of example 1 (exo-substitution 0.97 mol%) with those for the terpolymer of example 2 (exo-substitution 0.87 mol%, p-MeSt 2.69 mol%) and the terpolymer of example 6 (exo-substitution 0.85 mol%, St 1.81). By comparing the delta torque values, the effect of mooney viscosity can be explained. According to the results reported in table 4, both terpolymers gave higher delta torque values (14.0 dNm for example 2 and 12.4dNm for example 6) compared to example 1(10.8 dNm). This difference again indicates that the aromatic ring does participate in the crosslinking reaction.

The rubber was cured at 166 ℃ for 30 minutes in each example. The cured sheets were left at room temperature for 16 hours and then cut into tensile test pieces according to standard test methods (astm d 412-68). Each vulcanizate was subjected to hot air aging testing (ASTM D573-81) under two different conditions: at 120 ℃ for 168 hours and at 140 ℃ for 168 hours.

The hot air aging test results for the rubbers prepared in examples 1-3 and 5-7 are reported in Table 5. The 100% modulus is also illustrated in table 7. The unaged terpolymer exhibited a modulus about 15% greater than the control, which is consistent with the higher torque values measured. After 168 hours of hot air aging at 140 ℃, the 100% tensile modulus of the control sample decreased by about 50%. The terpolymer shows better ageing resistance: the 100% tensile modulus is reduced by only about 25%. FIG. 8 illustrates the 300% modulus at 140 ℃ before and after hot air aging for 168 hours. The 300% modulus at elongation of the copolymers in the examples is reduced by 36% after aging. In contrast, the 300% modulus of the terpolymer decreased by only about 2-5%.

Table 5 also lists the unaged stress strain results for St terpolymers, as well as the results of a limited hot air aging study with low St content terpolymers (example 5). Again, the modulus of the terpolymer was somewhat higher than that of the control. The result of hot air ageing at 140 ℃ for 168 hours is a 30% reduction in the 100% modulus and a 16% reduction in the 300% modulus of the St terpolymer, which shows a better resistance to ageing compared with the copolymer of example 1.

While the present invention has been described with reference to preferred and specific embodiments, it will, of course, be appreciated by those skilled in the art that various modifications may be made to the preferred embodiments without departing from the spirit and scope of the invention.

All publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.

TABLE 1

Examples	[p-MeSt]1(mol/L)	[St]1(mol/L)	Mw，×103	Mw/Mn	[IP](mol％)	[p-MeSt]2(mol％)	[St]2(mol％)
								1	-	-	474	4.3	1.37	-	-
2	0.055	-	440	2.9	1.26	2.63	-
								3	0.11	-	375	2.9	1.12	5.3	-
4	0.22	-	400	2.2	0.86	10.6	-
								5	-	0.055	580	4.2	1.24	-	0.83
6	-	0.11	540	4.6	1.15	-	1.71
								7	-	0.22	475	4.4	1.00	-	3.58

¹Concentration in the polymerization reactor

²Concentration in the Polymer product

Note: [ IB ] ≡ 1.95mol/L in the monomer charged to the polymerization reactor

[ IP ] ≡ 0.055mol/L of monomer fed to polymerization reactor

TABLE 2

Examples	1	2	3	4	5	6	7
								Before bromination
1，4-IP(mol％)	1.46	1.26	1.12	0.86	1.24	1.15	1
								p-MeSt(mol％)	-	2.63	5.3	10.6	-	-	-
St(mol％)	-	-	-	-	0.83	1.71	3.6
								After bromination
p-MeSt(mol％)	-	2.69	5.29	11.3	-	-	-
								St(mol％)	-	-	-	-	0.97	1.81	4.05
1，4-IP(mol％)	0.39	0.21	0.16	0	0.44	0.3	0.3
								External substitution (mol%)	0.97	0.87	0.79	0.63	0.71	0.85	0.7
Internal substitution (mol%)	0.05	0.04	0.04	0.03	0.04	0.05	0.03
								Internally substituted CDB (mol%)	0.03	0.02	0.02	0.02	0.02	0.03	0.03
General first order bromination Structure(mol％)	1.05	0.93	0.85	0.68	0.77	0.93	0.76

TABLE 3

Examples	pMeSt(mol％)	St(mol％)	Br content (mol%) by HNMR	Br content (mol%) measured by oxygen bottle combustion
					1	-	-	1.02	1.16
2	2.69	-	1.02	1.04
					3	5.29	-	0.95	1.13
4	11.26	-	0.84	1.33
					5	-	0.97	0.78	1.3
6	-	1.81	0.9	1.49
					7	-	4.05	0.73	1.54

TABLE 4

Examples	1	2	3	4	5	6	7
								External substitution (mol%)	0.97	0.87	0.79	0.63	0.71	0.85	0.7
pMeSt(mol％)	-	2.69	5.29	11.26	-	-	-
								St(mol％)	-	-	-	-	0.97	1.81	4.05
Scorch time 01(min.)	10.26	2.71	2.89	4.24	4.84	3.63	4.18
								Tc50(min.)	13.36	4.03	4.12	5.78	6.59	5.02	5.77
Tc90(min.)	21.31	6.74	10.25	20.91	9.69	10.75	9.71
								Mh(dNm)	18.57	22.48	18.79	17.98	18.35	18.81	20.69
Ml(dNm)	7.77	8.51	6.35	7	8.97	6.47	8.4
								Delta torque (dNM)	10.81	13.96	12.43	10.98	9.37	12.35	12.29

TABLE 5

Examples	1	2	3	5	6	7
							Not aged
Modulus @ 100% (MPa)	0.33	0.38	0.37	0.39	0.42	0.4
							Modulus @ 300% (MPa)	0.45	0.56	0.52	0.56	0.6	0.63
Ultimate tensile Strength (MPa)	3.5	2.1	2.7	4.1	4	3.4
							Ultimate elongation (%)	1055	910	1020	965	880	850
Hardness Shore A2(pts.)	23	26	28	25	24	25
							Aging at 120 deg.C in air for 168 hr
Modulus @ 100% (MPa)	0.36	0.41	0.4	-	-	-
							Modulus @ 300% (MPa)	0.67	0.75	0.72	-	-	-
Ultimate tensile Strength (MPa)	2.6	1.9	1.9	-	-	-
							Ultimate elongation (%)	670	570	595	-	-	-
Hardness Shore A2(pts.)	26	28	28	-	-	-

TABLE 5 (continuation)

Examples	1	2	3	5	6	7
							Aging at 140 deg.C in air for 168 hr
Modulus @ 100% (MPa)	0.17	0.3	0.29	0.27	-	-
							Modulus @ 300% (MPa)	0.29	0.53	0.51	0.47	-	-
Ultimate tensile Strength (MPa)	1.8	2.1	2.2	2.8	-	-
							Ultimate elongation (%)	805	670	725	850	-	-
Hardness Shore A2(pts)	23	27	26	21	-	-

Claims (6)

1. A process for the preparation of halogenated butyl polymers derived from C having improved hot air aging and curing properties₄～C₈Monoolefin monomer, C₄～C₁₄Multiolefin monomer, characterized in that at least one styrenic monomer is added to the above mixture of monoolefin monomer and multiolefin monomer and the catalyst system to prepare a butyl polymer, which is subsequently halogenated.

2. The method of claim 1, wherein C₄～C₈The monoolefin monomer may be selected from one or more of isobutylene, 2-methylpropene-1, 3-methylbutene-1, 4-methylpentene-1, 2-methylpentene-1, 4-ethylbutene-1 and 4-ethylpentene-1.

3. The method of claim 1, wherein C₄～C₁₄The multiolefin monomer is selected from one or more of isoprene, butadiene-1, 3, 2, 4-dimethylbutadiene-1, 3, 1, 3-pentadiene, 3-methylpentadiene-1, 3, hexadiene-2, 4, 2-neopentylbutadiene-1, 3, 2-methylhexadiene-1, 5, 2, 5-dimethylhexadiene-2, 4, 2-methylpentadiene-1, 4, 2-methylheptadiene-1, 6, cyclopentadiene, methylcyclopentadiene, cyclohexadiene and 1-vinylcyclohexadiene.

4. The process of claim 1 wherein the styrenic monomer is selected from the group consisting of one or more of p-methylstyrene, styrene, α -methylstyrene, p-chlorostyrene and p-methoxystyrene.

5. The process of claim 1, wherein the halogenated butyl polymer is a brominated butyl polymer.

6. The process of claim 1, wherein the final halogenated butyl polymer comprises 0.5 to 15 weight percent of repeating units derived from styrenic monomers.