CS200098B1 - Process for preparing polymeres of isobutylene and copolymers isobutylene with controlled structure - Google Patents

Description

The invention relates to a process for the preparation of isobutylene polymers and copolymers using tannic chloride as initiator.

Among the most interesting monomers polymerizing by the cationic mechanism is isobutylene (the original name prd monomer 2-methylpropene), whose polymers and especially copolymers with dienes are important industrial elastomers. On an industrial scale, high molecular weight isobutylene polymerization and copolymerization of isobutylene with dienes is catalysed with aluminum chloride or magnesium fluoride at low temperatures of about -100 ° C.

In general, the polymerization of isobutylene, which is a classic representative of a monomer that polymerizes solely by the cationic mechanism, is known not to polymerize in a sufficiently dry environment in the presence of lewis acids. Polymerization can be retrieved only after the addition of a small quantity of water or other coinitiators (Evans AG Polynyi M. <Chem.Soo J., 252, 1947 PH $ Plesch: The ^{u u} ationic hemistry of Polymerization, Pergamon Press, London 1963 $ ^ Ennedi JPT Polymer Shemistry of Synthetio Elastomers, Part 1, Znterscienoe Publishers, ^and York 1968).

^ odle MS. U.S. Pat. Nos. 150787 and 150798 can be carried out by photochemical initiation of isobutylene polymerization and isobutylene copolymerization under the dry conditions. The pollutants are induced by light and the catalysing activity is highest for tannic chloride.

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Photoinitiated polymerizations yield polymerization products having a molecular weight considerably higher than polymerization products that have been prepared under the same conditions but classical cationic polymerization. This allows the preparation of significant isobutylene-isoprene copolymers called. Butyl rubber, at temperatures ^υ -4 to -35 ° C.

The use of photoinitiated polymerization in industry, especially for the industrial production of butyl rubber, would require a new design of the polymerization reactor. Because industry has already made and tested polymerization reactors was an effort (cf.

191 607) to conduct the polymerization so that it can be carried out on an existing industrial plant.

For this purpose, the activation of the VCl4-monomer complex outside the actual polymerization reactor has been carried out, but this method of activation has the disadvantage that during activation the self-active component which initiates polymerization is precipitated and agglomerated, especially when the VCl4 -diene monomer complex is activated. resulting in the highest VCl consumption.

A disadvantage of classical cationic polymerization is the need to perform polymerization at very low temperatures, especially when preparing isobutylene-isoprene copolymers (about -100 ° C).

R photoinitiated polymerization is a disadvantage of designing and introducing a continuous photopolymerization reactor because photoinitiated polymerizations cannot be performed on existing industrial equipment. The disadvantage of activating the VCl-monomer complex outside the actual reactor is the considerably higher catalyst consumption, which adversely affects the economy of the process.

It has now been found that the polymerization of isobutylene and the copolymerization of isobutylene with dienes under conditions where polymerization is carried out in a polar environment such as methyl chloride or ethyl chloride, even without visible light, the polymerization proceeds after a certain induction period. In the non-polar environment, the polymerization of isobutylene alone is not effected without light, but after the addition of diene, vinilomatic and cyclo-olene monomers the polymerization again occurs after a certain induction period. copolymer used. The molecular weights of copolymers and isobutylene polymer prepared by VCl4 in the dark are considerably higher than the molecular weights of polymers prepared under the same conditions but by classical cationic polymerization. This allows the preparation of high molecular weight isobutylene-diene copolymers at temperatures as low as -40 to -35 ° C, similar to photoinitiated polymerizations.

SUMMARY OF THE INVENTION The present invention provides a process for the polymerization of isobutylene and controlled-structure isobutylene copolymers by catalytic polymerization, characterized in that the polymerization is carried out in the dark in the presence of VCl2 which spontaneously initiates polymerization when carried out in a polar environment in a non-polar environment, it initiates polymerization in the presence of another comonomer, which is a conjugated member, a vinylaromatic monomer, or an ocycloalkene. The polymerization is carried out at temperatures of 8 ° to 4.10 ° C, preferably at temperatures of -20 to -50 ° C. Non-polar media are aliphatic saturated and unsaturated hydrocarbons having 2 to 8 carbon atoms and aromatic hydrocarbons having 6 to 8 carbon atoms. The molar ratio of isobutylene to comonomers ranges from 3.10 ³ to 0.1.

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The conjugated members are selected from the group consisting of 1,3 butadiene, isoprene, 2,3-dimethylbutadiene 1,3 and chloroprene. Vinilaromatic monomers are selected from the group consisting of styrene, alpha-methylstyrene, o, m, p, -methylstyrene. Of the cycloalkene, cyclopentene is preferably used.

Under the conditions of the present invention, polymerization with vanadium chloride inside the reactor takes place in the dark, allowing the use of a conventional type reactor.

The polymerization of isobutylene initiated by vanadium (II) chloride in a non-polar environment and in the presence of the above-mentioned comonomers is characterized by an induction period which depends on the type of comonomers used. For conjugated diene comonomers, the induction period is shortened under the same polymerization conditions as follows:

butadiene isoprene 2,3-dimethylbutadiene 1,3

It can be seen from the above dependence that the induction period is the longest when using butadiene and the least when using 2,3-dimethylbutadiene 1,3 as comonomers.

In the presence of aromatic comonomers, the induction period is the longest with styrene and gradually decreases in this series:

styrene divinylbenzene alpha-methylstyrene, o, m, p-methylstyrene

The actual polymerization of isobutylene in the presence of VCl 2 in a dry environment is dependent on the solvent in which it is carried out. ^x odrobným research it was found that in a polar solvent like e.g. methylene chloride or ethyl chloride polymerization is carried out in the dark and in the absence of the comonomers as described in Example 10 and 11.

In a non-polar environment (block or hydrocarbon solvent polymerization), isobutylene polymerization in the dark does not take place and is initiated after a short induction period by the addition of comonomers that affect the properties of the polymerization product as shown in the following scheme.

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In the dark copolymerization of isobutylene with isoprene or butadiene in the dark, the nature of the co-solvent affects the properties of the final product similar to that of the polymerization of isobutylene. In a non-polar environment, eg in olives or a heptane solution, practically insoluble sponge-like products (temperature below -20 ° C) are formed, as opposed to copolymerization carried out in a polar environment such as methyl chloride or ethyl chloride to form soluble copolymers. In the polar VCl2 environment, the same copolymer can be prepared with physicochemical and processing properties as the commercial isobutylene-isoprene copolymer under the designation Polysar 400 and Polysar 301, but at temperatures as low as -40 to -35 ° C. The effect of the environment on, for example, copolymerization of i-butylene with isoprene in the presence of VCl 2 is shown in the following scheme.

According to the present invention, it is naturally possible to prepare i-butylene-diene copolymers in a non-polar environment using another comonomer which shortens the induction period. For example, the copolymerization of isobutylene with isoprene VCl2 according to Example 2 starts after an induction period of 18 minutes, but when this copolymerization is carried out, for example, in the presence of 2,3-dimethylbutadiene 1,3 or alpha-methylstyrene, the induction period is substantially shortens.

The induction period in the copolymerization of isobutylene with dienes is considerably longer when polymerization is carried out in a non-polar environment compared to the induction period in a polymerization carried out in a polar environment (approximately 10%).

By varying the polarity of the environment (eg a mixture of heptane and methyl chloride), it is possible to change not only the induction period of polymerization but also the properties of the obtained copolymer. As a result, copolymers or terpolymers which are completely or insoluble in aliphatic and aromatic solvents can be prepared for selected copolymerizations (eg isobutylene-isoprene, isobutylene-butadiene, isobutylene-isoprene-styrene). By using a suitable comonomer and changing the polarity of the environment, copolymers of isobutylene can be used to obtain completely insoluble products but with different sieve densities, or suitable sieve densities, which swell well in an aliphatic or aromatic solvent and can also be processed well on rolls and vulcanized. Even low sieve density copolymers do not appear to have a cold flow compared to conventional commercial copolymers.

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In copolymerization of isobutylene with eg isoprene in a non-polar hydrocarbon medium, the copolymer is excreted in the form of a swollen gel during polymerization, with the result that the viscosity of the medium does not increase too much. ^The process proceeds similarly to the preparation of a soluble copolymer of isobutylene with isoprene in methyl chloride where the copolymer is also eliminated from the methyl chloride solution. ⁱⁿ technical practice, this so-called slurry process is considered to be advantageous as it allows good mixing of the reaction mixture and leading the polymerization to high conversions.

In the following, the invention is illustrated in more detail by means of several examples of a particular embodiment. In all of the examples below, the polymerizations were carried out in a glass-plate reactor with a stainless steel anchor stirrer. The stirrer speed ranged from 200 to 300 rpm. The polymerizations were carried out under dry conditions under an oxygen-free argon atmosphere, the isomeric isobutylene was dried in a glass pressure vial by standing over sodium wire for 7 days, the isoprene was dried with aluminum oxide and distilled from sodium under argon before use, butadiene was dried in glass pressure ampoule over molecular sieves Sweat 3 for 7 days, 2,3-dimethylbutadiene 1,3 dried over calcium hydride similar to styrene, alpha-methylstyrene, cyclopentene, divinylbenzene chloroprene α, mp-methylstyrenes. The argon was dried by passing through a molecular sieve column to shake 3 and deoxygenated on the catalyst deoxygenation. Vanadium chloride was added to the reaction mixture in the form of a heptane solution, which was kept under strictly dry conditions in a glass blackened vial with a three-way stopcock at -18 ° C. Reptan was purified by shaking with sulfuric acid and phosphorus pentoxide, distilled and rectified for several hours under argon, dried with KOH β then dried over sodium wire for 7 days. The methyl chloride was purified by passing through a column of concentrated sulfuric acid, dried

CaCl 3 and stored in a cylinder and Molecular Sieve 3 sieve for 7 days. Methyl chloride was also dried with Potasit 3 molecular sieves.

The molecular weights of the obtained polymerization products were determined by the viscosimetric method (heptau used as solvent) using Plory's ratio = 3.6 * 10 &lt; -1 &gt;

The double bond determination was performed by the ozonometric or iodometric method.

Example 1

Isobutylene polymerization was performed in the presence of isoprene in a non-polar medium without a co-solvent in the dark in the presence of vanadium chloride catalyst at -10 ° C. The monomer mixture was composed of 36 g of isobutene and 0.55 g of isoprene consumption 1,1.10 _{"rao-i with} vanadium tetrachloride. After an induction period of 25 minutes with continuous stirring, polymerization started, which was terminated by the addition of alcohol at a conversion of 52%. After drying the mixture under reduced pressure, a polymerization product having a viscosity molecular weight of 50,560 and an unsaturation of 1.5% was isolated. the copolymer was soluble in heptane, benzene and carbon tetrachloride.

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Example 2

Isobutylene polymerization was carried out in the presence of isoprene in a nonpolar co-solvent-free dark environment in the presence of vanadium chloride catalyst at -20, -30 and -40 ° C as in Example 1. After an induction period of about 18 minutes, polymerization proceeded. which excreted the polymer from the reaction medium over the entire temperature range. The polymerases were stopped after 10 minutes by addition of alcohol at a conversion ranging from 35 to 45%. Within this temperature range, a sponge-like copolymer was obtained which was insoluble in organic solvents such as heptane, benzene and carbon tetrachloride. The resulting copolymers were processed very well on a calender and after a short time the physical properties changed so that the copolymers had already become soluble in the abovementioned solvents. The copolymer prepared at -40 ° C was subjected to a vulcanization with sulfur at 143 ° C. for 20 minutes. The copolymer cured well and its strength was 17.8 MP a2.

EXAMPLE 3 Isobutylene polymerization in the presence of isoprene in a non-polar solvent without co-solvent in the dark in the presence of vanadium chloride catalyst at -60 and -78 ° C as in Example 1. After an induction period of about 10 minutes reaction environment. Of polymerization was stopped after the addition of alcohol at a conversion which ranged from 44-58% within the temperature range copolymer was obtained, which was insoluble in organic solvents as in Example 2. The ⁱ '• Similarly as in Example 2, after processing the calenders with the copolymers became soluble in the solvents mentioned, and rapid vulcanization with sulfur also took place.

Example 4

Isobutylene polymerization was performed in the presence of a heptane co-solvent. A mixture of 25 g of isobutylene, 0.8 g of isoprene and 35 g of heptane was stirred at -40 ° C a consumption VCljj 1,5.10 ^-4 mole. After 60 minutes of the induction period, polymerization began to occur, during which the polymerization product fell out of solution. After 80 minutes, the reaction was quenched by addition of alcohol at a conversion of 52%. The polymerization product of the same nature as in Example 2 was insoluble in heptane, benzene and carbon tetrachloride.

Example 5

Isobutylene polymerization in the presence of isoprene in methyl chloride co-solvent was performed. A mixture of 26 g of isobutylene, 0.8 g of isoprene and 24 g of methyl chloride was stirred at -40 ° C with a consumption of VCl of .105.10 ^{- 4} mol. After a very short induction period (1 minute), the polymerization was carried out to precipitate the polymerization product from the reaction mixture. After 45 minutes, the reaction was quenched by the addition of alcohol and a 38% conversion was achieved. ^The polymerization product was completely soluble in heptane, benzene, carbon tetrachloride and the viscosimetric molecular weight was 350,000 at an unsaturation of 1.6%.

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Example 6 The polymerization of iaobutylene in the presence of ioprene was carried out as in Example 5, but the polymerization was carried out at -60 ° C in methylene chloride. This was induced by a short induction period of 30 and polymerization was carried out, which led to a conversion of 55%, in which a completely soluble polymerization product with a viscosimetric molecular weight of 950,000 and an unsaturation of 1.5% was obtained.

Example 7.

Isobutylene polymerization was carried out in the presence of 2,3-dimethylbutylene 1,3 and in the absence of co-solvent at -35 ° C in the dark. A mixture of 53 g of isobutylene and 0.8 g

2,3 dimethylbutadiene-1,3 was stirred with vanadium chloride, which was consumed

1.8.10 ^-4 mol. After an induction period of 15 minutes, polymerization started and was stopped after 10 minutes by the addition of alcohol at a conversion of 30%. A polymerization product was obtained which was completely soluble in benzene heptane and CCl2. The viscosimeter had a molecular weight of 250,000 and an unsaturation of 1.1%.

Example 8

The polymerization of iaobutylene was carried out in the presence of 2,3 dimethylbutydiene 1.3 as in Example 7, but at -40 ° C with a feed of 53 g of isobutylene and 1.8 g of 2,3-dimethylbutadiene-1,3. At a conversion of 25%, a polymerization product having a viscosimetric molecular weight of 300,000 and an unsaturation of 2.2% was obtained. The copolymer was completely soluble in organic solvents such as heptane, benzene and CCl2.

Example 9

Isobutylene polymerization was carried out in the presence of butadiene and in the absence of co-solvent at -40 ° C. A mixture of 44 g of isobutylene and 5 g of butadiene was stirred with vanadium chloride, the consumption of which was 1.8.10 ^-4 mol. After an induction period of 45 minutes, polymerization started, which was stopped after 20 minutes by addition of alcohol at a conversion of 46%. The viscosimetric molecular weight of the soluble portion of the polymerization product was 457,400 with an unsaturation of 1.1%. The copolymer contained 20% insoluble fractions.

Example 10 A mixture of isobutylene with vanadium chloride was stirred at -25 ° C in the dark. 26 g of isobutylene with a consumption of 1.1.10 ^-4 mol of VCl2 were used for the experiment. The mixture was stirred in a variety of media, in a block (i.e., in the absence of a co-solvent), and in the presence of a solvent such as heptane, methyl chloride and ethyl chloride. Block polymerization did not take place for 60 minutes and no polymerization of isobutylene in a 50% heptane solution for 120 minutes. in contrast, 50% methyl chloride solution and 50% ethyl chloride solution started polymerization after a short induction period of about 2 minutes. After 15 minutes of polymerization, 95% and 80% conversion (for methyl chloride-ethyl chloride solution) was observed after addition of alcohol to the reaction mixture. The viscosimetric molecular weight of the polyisobutyleau for the given conversions ranged from 260,000 to 300,000.

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Example 11

The polymerization of iaobutylene with vanadium chloride in the dark was performed under the same conditions as in Example 10, but at -78 ° C. The polymerization in the block and in the heptane solution did not take place, but started in the methyl chloride / ethyl chloride solution after a short induction period of 10-20 s. At a conversion of 70-80%, polyiaobutylan with a viscosimetric molecular weight of about 5.10 &lt;

Example 12 ^f

The mixture was stirred between the iobutylene and vanadium chloride in the dark in the absence of a co-solvent at temperatures of -25, -40 and -78 ° C. 35 ia butylene was used for the experiment with a consumption of 1.5 x 10 ** mol VClCl. Polymerization was observed for 60 minutes at the temperatures observed. After this time, 1 wt. % of isoprene per monomer mixture and after 10 minutes polymerization was detected and stopped after an additional 8 minutes by the addition of alcohol. The polymerization achieved was in the range of 40 to 70% for the stated temperature range. In all cases, a sponge-like product was obtained which was insoluble in organic solvents as in Example 2.

Example 13

It was stirred with ammonium butylene and vanadium chloride in a 50% solution of heptane in the dark at -25, -40 and -78 ° C. 25 g of heptane were used in the experiment with a consumption of 2.10 &lt; -1 &gt; No polymerization was detected for 120 minutes. ^x at this time 2 wt. % of isoprene on the monomer monomer, and after 25 minutes polymerization was observed, which was terminated after 20 minutes by the addition of alcohol. For temperatures of -25 ° C, -40 ° C and -78 ° C, these conversions 1 30%, 41% and 58% were obtained. In all cases, a polymerization product was obtained which was insoluble in the organic solvents as in Example 2.

Example 14

The experiment was carried out in a non-polar heptane solution at the same temperatures as in Example 13, but divinylbenzene and butadiene were used instead of isoprene. The mixture was stirred containing 25 g of i-butylene, 25 g of heptane and 0.5 g of divinylbenzene with a consumption of 2.10 &lt; -1 &gt; mol of VCl2. Similarly, a mixture of 25 g of iaobutylene, 25 g of heptane and 5 g of butadiene was stirred, consuming 2.10 * 4 mol of VCl2. After an induction period of 15 minutes (when using divinylbenzene) and 40 minutes (when using butadiene), polymerization began in which the polymer precipitated with progressive conversion from the reaction medium over the observed temperature range of -25, -40 and -78 ° C. The polymerizations were terminated at about 55% conversion to give an insoluble polymerization product.

Example 15

The polymerization of iaobutylene in the presence of chloroprene without co-solvent in the dark in the presence of vanadium chloride was carried out at -25, -40 and -78 ° C. The monomeric ama was composed of 18 g of iaobutylene, 18 g of chloroprene with a consumption of 1.5 * 10 moles of VCl ^. After an induction period of 5 to 10 minutes, polymerization started and was stopped by addition

200 008 alcohol at a conversion in the range of 4 ^V to 50%. A soluble copolymer was obtained which contained in the range 5.5 to 6.1% chlorine with an unsaturation of 4.5 to 5.2%.

Example 16

Isobutylene polymerization was performed in the presence of chloroprene without co-solvent in the dark in the presence of VCl 2 at -50 ° C. The monomer mixture contained 25 g of isobutylene and 3.8 g of chloroprene with a consumption of 1.8 * 10 &lt; -1 &gt; mol of Cl2. After an induction period of 8 minutes, polymerization started, which was terminated by the addition of alcohol at a conversion of 38%. A soluble copolymer was obtained which had an unsaturation of 1.2% at a chlorine content of 0.8%. The viscosimetry molecular weight was 450,000.

Example 17

Isobutylene polymerization in the presence of butadiene and chloroprene was carried out in the dark at -40 ° C. The monomer mixture contained 30 g of isobutylene, 3 g of butadiene and 3 g of chloroprene with a consumption of 1.8 * 10 moles of VCl2. After an induction period of 8 to 10 minutes, polymerization began, which was terminated by the addition of alcohol at a conversion of 48%. A soluble polymerization product having a viscosimetric molecular weight of 360,000 was obtained, whose unsaturation was 1.3% at 0.5% chlorine.

Example 18

Isobutylene polymerization was carried out in the presence of cyclopentene at -40 ° C. A mixture of 50 g of isobutylene, 1 g of cyclopentene with VCl ^ was consumed, the consumption of which was 1.5 * 10 &quot;

After an induction period of 12 minutes, polymerization started, which was terminated after 15 minutes by addition of alcohol at a conversion of 36%. The viscosimetric molecular weight of the polymer product was 312,000 at an unsaturation of 0.25%.

Example 19

Isobutylene polymerization was performed in the presence of divinylbenzene in the dark at -10, -50 and -78 ° C. A mixture of 50 g of isobutylene containing 0.1 g, 1.0 g and 3.0 g of divinylbenzene with a consumption of 1.5 * 10 &lt; -1 &gt; mol VCl2 was stirred. induction period, which was in the range of 6 to 12 minutes, began polymerization, which was completed at a conversion of 30 to 55%. An insoluble copolymer was obtained, only at -10 ° C and a lowest divinylbenzene concentration of 0.1 g in the mixture, a partially soluble polymerization product was obtained.

Example 20

Isobutylene polymerization was carried out in the presence of alpha-methyl-styrene at -40 ° C in the dark. A mixture of 45 g of isobutylene containing 0.03 g, 0.25 g and 2.5 g of alphamethyl] styrene with a consumption of 1.5 * 10 &lt; -1 &gt; mol VCl2 was stirred. During a very short induction period of 1 to 4 minutes, polymerization started, which was stopped within 10 to 15 minutes by the addition of alcohol at a conversion of 20 to 25%. Viskozimetrioké molecular weight was dependent on the content of alphamethylstyrene in admixture ^ highest content (2.5 g) had a value of 100. 8 RRO content 0.25 g had a value of 78,000 and containing 0.03 g had a value of 210 000 ^e In all cases, a polymerization product soluble in organic solvents such as heptane, benzene and carbon tetrachloride was obtained.

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Example 21

Polybutylene was polymerized in the presence of styrene in the dark at -30 ° C. Stirred monomer mixture contained 46 g lsobutylenu, 2.4 g of styrene consumption 1.8 ^-4 mol VC1 _fourth After an induction period of 40 minutes, polymerization began, which was stopped by the addition of alcohol after 18 minutes at a conversion of 25%. The polymerization product was soluble in organic solvents such as heptane, benzene and carbon tetrachloride. The viscosimetric molecular weight of the polymer was 130,000.

Example 22

Polybutylene was polymerized in the presence of styrene in the dark in a toluene solution at -40 ° C. The stirred mixture contained 30 g of lsobutylene, 1.5 g of styrene and 30 g of toluene with a consumption of 1.8.10 ^-4 mol of VCl2. After an induction period of 60 minutes, polymerization started, which was stopped by the addition of alcohol at a conversion of 38%. The viscosimetric molecular weight of the polymerization product was 93,000.

Example 23

Polybutylene was polymerized in the presence of o, m, p-methylstyrene in the dark in a toluene solution at -40 ° C. The stirred mixture contained 50 g of lsobutylene, 10 g of toluene and 0.2 g of o-methylstyrene or 0.2 g of m-methylstyrene or 0.2 g of p-methylstyrene with a consumption of 2.10 &lt; ⁴ &gt; polymerization began, which was terminated by the addition of alcohol at conversions ranging from 20 to 25%. A soluble polymerization product having a viscosimetric molecular weight ranging from 60,000 to 85,000 was obtained.

Claims (6)

SUBJECT OF THE INVENTION Process for the production of lsobutylene polymers and controlled structure lsobutylene copolymers by catalytic polymerization, characterized in that the polymerization is carried out in the dark in the presence of vanadium chloride in a polar medium and / or in a non-polar medium in the presence of another comonomer, cycloalkene, preferably ocyclopentene, at a temperature of 80 to -10 ° C, preferably -20 to -50 ° C, 2. The method of claim 1 wherein the conjugated members are selected from the group consisting of 1,3-butadiene, isoprene, 2,3-dimethylbutadiene-1,3 chloroprene. 3. The process of claim 1 wherein the vinylaromatic monomers are selected from the group consisting of styrene, alpha-methylstyrene, o, m, p-methylstyrene. 4. A process according to any one of claims 1 to 4 wherein the molar ratio of lsobutylene to comonomer is in the range of from about 3 to about 0.1. 5. A process according to any one of claims 1 to 6 wherein the polar medium is an organic solvent selected from the group consisting of methyl chloride, ethyl chloride, methylene chloride. 6. A process according to any one of Claims 1 to 7 wherein the non-polar environment is a saturated and unsaturated aliphatic hydrocarbon having from 2 to 8 carbon atoms and the aromatic hydrocarbon having from 6 to 8 carbon atoms.