MX2012011830A - Arborescent polymers having a core with a high glass transition temperature and process for making same. - Google Patents

Abstract

The present invention relates to arborescent polymers comprising isoolefins and styrenic monomers, as well as processes for making same. In particular, the invention relates to highly branched block copolymers comprising an arborescent core with a high glass-transition temperature (Tg) and branches attached to the core terminated in polymer endblock segments with a low Tg. The copolymers of the invention desirably exhibit thermoplastic elastomeric properties and, in one embodiment, are desirably suited to biomedical applications.

Description

ARBORESCENT POLYMERS THAT HAVE A NUCLEUS WITH A HIGH VITREA TRANSITION TEMPERATURE AND PROCESSES FOR MANUFACTURING THEM FIELD OF THE INVENTION The present invention relates to arborescent polymers and to a process for manufacturing them. In particular, the invention relates to highly branched block copolymers comprising an arborescent core with a high glass transition temperature (Tg) and branches fixed to the core terminated in final polymer block segments with a low Tg. The copolymers of the invention desirably exhibit thermoplastic elastomeric properties. The invention also relates to halogenated arborescent copolymers, cured arborescent copolymer, filled articles comprising the copolymers and to processes for the production of the copolymers.

BACKGROUND OF THE INVENTION The branched or highly branched block copolymers comprising an internal core of low Tg with branches terminated in high Tg final blocks are known in the literature. See, for example, US 6,747,098 issued to Puskas et al. It is known that these block copolymers have thermoplastic elastomeric properties. Due to the chemical bonds between the high Tg and low Tg segments, these block copolymers also desirably exhibit a lower tendency towards phase separation than seen in the combinations of high Tg and low Tg polymers. However, the high Tg branches of these polymers are typically terminated in styrene groups, which contain a benzene ring. In biomedical applications, such as in stents, these benzene-containing groups can lead to higher rates of rejection by the body and inflammation at the implant site. The potential leachate of remaining residual monomers from the polymerization process may also be responsible for a number of adverse effects in vivo, necessitating extensive purification of the final product. Therefore, it would be desirable to reduce or eliminate styrenic groups from the outside (branched portion) of the copolymer.

The above-described tree block copolymers described above contain a major part of their mass in the branched core and a minor part in the final block segments. It is currently believed that this arrangement is necessary to achieve the desired thermoplastic elastomeric properties.

The styrenic groups are saturated and do not retain double bonds that can react to perform the functional chemistry additionally. In certain applications, it would be desirable to functionalize the final blocks of the copolymer to achieve a desired balance of properties.

There remains a need in the art for improved arborescent block copolymers.

SUMMARY OF THE INVENTION The present invention relates to arborescent block copolymers and processes for manufacturing them. The block copolymers comprise a highly branched core of a high Tg material and branches terminated with final blocks of low Tg. Surprisingly, these copolymers have thermoplastic elastomeric properties, despite having a majority of their mass in the final blocks and / or having relatively large molecular weight end blocks.

By keeping the high Tg monomers inside the copolymer, the effects of inflammation and / or rejection can be reduced in vivo. Since the high Tg monomers are allowed to polymerize essentially until complete before the introduction of the low Tg monomers, and since the high Tg monomers are located within the core of the copolymer, there is very little of the high monomer. Tg that can be leached inside the body. The configuration of the high Tg core, therefore, reduces the potential toxicity of the materials in vivo and reduces the amount of washing of the final material required to remove the high Tg monomers.

Providing the high Tg monomers within the inner core also has the advantage of increasing the adhesion of the copolymers to substrates, particularly cell substrates. This can be useful in the formation of coatings for a variety of articles, for example, stents for use in medical procedures.

Providing the low Tg monomers in the final blocks of the copolymer provides the opportunity for both the monoisoolefin and diolefin monomers to be located on the outside of the copolymer. The diolefin monomers are particularly interesting insofar as they allow additional chemistry to be performed on the exterior of the copolymer, for example, functionalization, such as with maleic anhydride, halogenation or curing using a variety of curing systems. Therefore, it is possible to have a cured exterior and an uncured internal core. This may be advantageous in a number of applications and may allow the copolymers of the invention to be combined with other rubbers, such as butyl rubbers and optionally be cured together with them to form new compounds with useful properties.

According to one aspect of the invention there is provided a highly branched arborescent block copolymer comprising: an arborescent polymer core having more than one branching point, the arborescent polymer core having a higher vitreous transition temperature (Tg) of 40 ° C; and, branches attached to the arborescent polymer core terminated in final block segments of the polymer having a low Tg of less than 40 ° C.

According to another aspect of the invention, there is provided an arborescent polymer with terminal functionalization comprising the reaction product of at least one inimer and at least one monomer of para-methylstyrene, in which the arborescent polymer with terminal functionalization has been functionalized terminally with more than about 65 weight percent end blocks derived from a homopolymer or copolymer having a low glass transition temperature (Tg) of less than 40 ° C.

According to yet another aspect of the invention, a process for producing a highly branched arborescent copolymer is provided which comprising: copolymerizing a reaction mixture comprising at least one inimer and at least one para-methylstyrene monomer in an inert polar solvent in the presence of a Lewis acid halide co-initiator at a temperature of about -20 ° C to about -100 ° C to form a highly branched core; controlling the reaction mixture for a decrease in temperature, indicative of a substantial consumption of the para-methylstyrene monomer; adding an isoolefin monomer to the reaction mixture to form end blocks of the highly branched core, thereby producing the arborescent copolymer; and separating the arborescent copolymer from the polar solvent.

BRIEF DESCRIPTION OF THE DRAWINGS Having summarized the invention, preferred embodiments thereof will now be described with reference to the appended figures, in which: Figure 1 is a graph representing the trace of SEC for the polymers selected in accordance with the present invention; Figure 2 is a graph showing the thermoplastic properties of Peak to Peak Elongation for the polymers selected in accordance with the present invention; Figure 3 is a graph depicting cell viability as a function of the concentration of leaching rubber in a cell culture medium; and Figure 4 is a graph representing the cell growth of the material surface compared to a glass microscope slide as a control.

DETAILED DESCRIPTION OF THE INVENTION In the specification and claims the word polymer is used generically and encompasses regular polymers (ie, homopolymers) as well as copolymers, block copolymers, random block copolymers and terpolymers.

The present invention relates to arborescent polymers that have been terminally functionalized, such polymers having been formed from at least one inimer and at least one high Tg monomer, preferably a styrenic monomer, more preferably para-methylstyrene. An exemplary reaction scheme for producing polymers according to this embodiment is shown below in Scheme 1, where each F represents one or more functional end blocks according to the present invention.

In one embodiment, the end blocks F comprise a homopolymer formed from a low Tg monomer, preferably an isoolefin monomer, more preferably isobutene. In another embodiment, the end blocks F comprise a copolymer formed from an isoolefin monomer and a diene monomer, preferably a conjugated diene monomer such as isoprene.

Scheme 1 When the final blocks F comprise a copolymer formed from an isoolefin monomer and a diene monomer, it is possible to halogenate the end blocks to form a halogenated arborescent copolymer, which optionally can be cured or used as the basis of the additional functional chemistry. When a styrenic monomer is used to form the high Tg core, a halogenated polymer can also be formed by bromination of the methyl group attacto the styrenic ring, for example, using liquid bromine (Br2) with a free radical initiator. Halogenated polymers are particularly suitable for non-biomedical applications.

In the present invention, a polymer or copolymer having a low vitreous transition temperature (Tg) is defined as a polymer or copolymer having a glass transition temperature of less than about 40 ° C, or less than about 35 ° C, or less than about 30 ° C or even less than about 25 ° C. In another embodiment, a polymer or copolymer having a low vitreous transition temperature is defined as a polymer or copolymer having a vitreous transition temperature less than about room temperature (i.e., about 25 ° C). It should be noted that the ranges indicated above are intended to encompass any polymer and / or copolymer having a glass transition temperature that falls below one of the previously establisthresholds. A low Tg monomer is any monomer that can be homopolymerized or copolymerized to form a low Tg homopolymer or copolymer. Suitable low Tg monomers include isoolefins within a range of 4 to 16 carbon atoms, in particular isomonoolefins having 4-7 carbon atoms, such as isobutene, 2-methyl-1-butene, 3-methyl-1- butene, 2-methyl-2-butene, 4-methyl-1-pentene and mixtures thereof. A preferred low Tg isoolefin monomer comprises isobutene.

Conversely, a polymer or copolymer having a high vitreous transition temperature is defined as a polymer or copolymer having a glass transition temperature of more than about 40 ° C, or more than about 45 ° C, or more than about 50 ° C, or even more than about 100 ° C. It should be noted that the previously establisranges are intended to encompass any polymer and / or copolymer having a glass transition temperature that falls above one of the previously establisthresholds. A high Tg monomer is any monomer that can be homopolymerized or copolymerized to form a homopolymer or high Tg copolymer. High Tg monomers suitable in accordance with the present invention include styrenic monomers, particularly those with a reactivity ratio close to that of isobutene, for example, those having an alkyl group in the para position, such as, para-alkylstyrenes. A preferred high Tg styrenic monomer comprises para-methylstyrene.

The polymers according to the present invention comprise a majority of their molecular weight as low Tg final blocks. For example, the polymers according to the invention can preferably have at least 65% by weight of low Tg end blocks, more preferably at least 75% by weight of low Tg end blocks, even more preferably at least 80% by weight. weight of low Tg end blocks, more preferably still at least 85% by weight of low Tg end blocks, even more preferably at least 90% by weight of low Tg end blocks. In another embodiment, the polymers according to the invention can comprise 65 to 95% by weight of low Tg end blocks, 65 to 90% by weight of low Tg end blocks, or 75 to 80% by weight of end blocks. final blocks of low Tg.

In another embodiment, the present invention relates to terminally functionalized thermoplastic elastomeric arborescent polymers formed from at least one inimer and at least one high Tg monomer (eg, a styrenic monomer, such as para-methylstyrene), in that the terminally functionalized portions of such polymers are made from a low Tg monomer (e.g., an isoolefin monomer, such as isobutene). Preferably, the terminal functionalized portions form homopolymers or copolymers having, overall, a number average molecular weight of greater than about 50,000 g / mol, greater than about 75,000 g / mol, greater than about 100,000 g / mol, greater than about 150,000 g / mol, greater than about 200,000 g / mol, greater than about 250,000 g / mol, or greater than about 300,000 g / mol. It is surprising that these arborescent copolymers have thermoplastic properties, given the relatively high molecular weight of the low Tg final blocks.

Inimer: Initially, the self-condensing monomers combine the characteristics of a monomer and an initiator and the term "first" (IM) is used to describe such compounds. If a small amount of a suitable initial is copolymerized, for example, with isobutylene, arborescent polyisobutylenes can be synthesized. Formula (I) below details the nature of the instant compounds that may be used in conjunction with the present invention. In Formula (I) A represents the polymerizable portion of the first compound, while B represents the initiator portion of the first compound.

A B (") In Formula (I), each of R-i, R2, R3, R4, R5 and R6. in one embodiment, it is independently selected from hydrogen, straight or branched C1 to C10 alkyl, or C5 to C8 aryl. In another embodiment, R1, R2 and R3 are all hydrogen. In another embodiment, each of R4, R5 and R6 is independently selected from hydrogen, hydroxyl, bromine, chlorine, fluorine, iodine, ester (-0-C (0) -R7), peroxide (-OOR7) and -O- R7 (for example, -OCH3 or -OCH2 = CH3). With respect to R7, R7 is a linear or branched unsubstituted C1 to C20 alkyl, a straight or branched unsubstituted C1 to C10 alkyl, a linear or branched substituted C1 to C20 alkyl, a linear or branched substituted C1 to C10 alkyl, an aryl group having from 2 to about 20 carbon atoms, an aryl group having from 9 to 15 carbon atoms, a substituted aryl group having from 2 to about 20 carbon atoms, a substituted aryl group having from 9 to 15 carbon atoms; to 15 carbon atoms. In one embodiment, where one of R 4, R 5 and R 6 is a chlorine or fluorine, the remaining two of R 4, R 5 and R 6 are independently selected from a linear or branched unsubstituted C 1 to C 2 alkyl, a non-substituted linear C 1 to C 10 alkyl. or branched, a linear or branched substituted C2o alkyl or a linear or branched substituted Ci to C10 alkyl. In yet another embodiment, any two of R 4, R 5 and F 6 can together form an epoxide.

In one embodiment, portions A and B of the inimer compound (I) are linked together through a benzene ring. In one case, the A portion of the inimer compound (I) is located in the 1-position of the benzene ring while the B-portion is located in any of the 3 or 4 positions of the benzene ring. In another embodiment, the A and B portions of the inimer compound (I) are linked together through the bond shown below in Formula (II): where n is an integer in the range of 1 to about 12 or 1 to about 6 or even 1 to about 3. In another embodiment, n is equal to 1 or 2.

In another embodiment, for the polymerization of isobutylene B may be a tertiary ether, tertiary chloride, tertiary methoxy group or tertiary ester. The very high molecular weight arborescent PIBs can be synthesized using the process of the present invention with inmers such as 4- (2-hydroxy-isopropyl) styrene and 4- (2-methoxy-isopropyl) styrene.

Exemplary enymers for use in conjunction with the present invention include, but are not limited to, 4- (2-hydroxyisopropyl) styrene, 4- (2-methoxyisopropyl) styrene, 4- (1-methoxyisopropyl) styrene, 4- (2-chlorosopropyl) ) styrene, 4- (2-acetoxyisopropyl) styrene, 2,3,5,6-tertamethyl-4- (2-hidoxyisopropyl) styrene, 3- (2-methoxyisopropyl) styrene, 4- (epoxyisopropyl) styrene, 4.4 , 6-trimethyl-6-hydroxyl-1-heptene, 4,4,6-trimethyl-6-chloro-1-heptene, 4,4,6-trimethyl-6,7-epoxy-1-heptene, 4 , 4,6,6,8-pentamethyl-8-hydroxyl-1-nonene, 4,4,6,6,8-pentamethyl-8-chloro-1-nonene, 4,4,6) 6,8-pentamethyl -8,9-epoxy-1-N-ene, 3,3,5-trimethyl-5-hydroxyl-1-hexen, 3,3,5-trimethyl-5-chloro-1-hexen, 3,3,5-trimethyl -5-6-epoxy-1-hexen, 3,3,5,5, 7-pentamethyl-7-hydroxyl-1-octene, 3,3,5,5,7-pentamethyl-7-chloro-1-octene , or 3,3,5,5,7-pentamethyl-7,8-epoxy-1-octene. In one embodiment, the inimer of the present invention is selected from 4- (2-methoxyisopropyl) styrene or 4- (epoxyisopropyl) styrene.

In another embodiment, the inimer used in conjunction with the present invention has a formula according to one of those shown below: H2C = CH Ar X wherein X corresponds to a functional organic group of the series -CR12Y, where Y represents OR, Cl, Br, I, CN, N3 or SCN and R1 represents H and / or a Ci to C20 alkyl. and Ar represents CeH4 or CioH8.

It is desirable that the inimer be substantially pure to avoid potentially poisoning the reaction process. The inimer is preferably at least 90% pure. For the production of arborescent polymers according to the invention intended for biomedical applications, a higher level of purity may be preferred, for example, 95% or even 99%.

In one embodiment, 4- (2-methoxyisopropyl) styrene or 4- (epoxyisopropyl) styrene is used as the inimer and a styrenic monomer comprising para-methylstyrene is used as the high Tg monomer, as will be described in detail below, to produce the core of an arborescent polymer as shown in step A of Scheme 2.

Scheme 2 After the reaction temperature decreases, indicating that substantially all the para-methylstyrene has been consumed in the formation of the high Tg core, isobutene is added to the system as the low Tg isoolefin monomer and polymerized at the branching points of the inimer to produce an arborescent copolymer having low Tg final blocks, as shown in step B of Scheme 2.

Using the process of the present invention, the structure of the arborescent polymers can be varied within a wide range. This structural variation is illustrated by the branching index. For example, the branching index, the molecular weight and the physical properties of tree-like polymers according to the present invention can be controlled through the molar proportions of inimer and monomer added to the polymerization filler. For example, decreasing the concentration of inimero with respect to the concentration of high Tg monomer in the feed will result in higher chains with reduced branching grades and a lower branching index. Conversely, increasing the concentration of inimero with respect to the amount of high Tg leads to the formation of a polymer with a highly branched structure having shorter arm lengths with a higher branching index. Further alteration of the arborescent core can be achieved by the sequential addition of the primer and / or monomer throughout the polymerization process.

The polymers according to the present invention preferably have a molecular weight (Mw) in the range of from about 100,000 to about 700,000, more preferably from about 200,000 to about 500,000, still more preferably from about 300,000 to about 450,000. The polymers preferably have a branching index (IR) of 0.5 to 20, more preferably 0.9 to 10. The polymers preferably have a narrow molecular weight distribution characterized by a polydispersity index (Pm / Mn, or PDI). ) from 1 to 4.5, more preferably from 1.2 to 3.5, or from about 1.9 to about 3.2. The above properties can be present individually or in any combination with each other.

Various changes in the Theological properties of a polymer formed in accordance with the present invention are possible by changes in the architecture of the chain. The arborescent polymers formed in accordance with the present invention may have a reduced shear sensitivity due to the branched structure, and a reduced viscosity as compared to linear polymers of equivalent chain length. They are preferably biphasic, having a block structure, as indicated by the presence of two distinct vitreous transition temperatures (Tg). They preferably have thermoplastic properties, expressed in terms of improved reinforcement compared to conventional butyl rubber controls. The non-cured and uncured polymers according to the present invention preferably have a peak elongation in the range of 5 to 400%, more preferably 9 to 375%, even more preferably 250 to 375%. The polymers do not charged and uncured according to the present invention preferably have a peak tension of 0.25 to 2.5 MPa, more preferably 0.5 to 2.0 MPa, even more preferably 0.59 to 1.66 MPa. Any combination of the above physical properties can also be provided.

The above embodiments of polymers according to the present invention are particularly useful in biomedical applications. 250 mg samples of the polymers according to the invention preferably produce less than 100 ppm of any individual leachable compound when analyzed by GC-MS after 300 hours of extraction in 5 ml of deionized water at 40 ° C, more preferably less of 10 ppm, even more preferably less than 1 ppm. Cells, particularly mouse myoblast cells, incubated in the leachable solutions preferably have at least 80% cell viability when cultured for 48 hours at a temperature of at least 37 ° C, more preferably 40 ° C. The surfaces of the polymers according to the invention preferably support cell growth, particularly the growth of mammalian cells, for example, of mouse myoblast cells. The surfaces preferably support an increase in the number of cells of at least 50% when the solutions of growth medium are incubated with the polymers for at least 24 hours under conditions of body temperature of at least 37 ° C, preferably 40 ° C. . The cells preferably adhere to the surface of the polymer. The above polymers according to the invention, therefore, are preferably biocompatible and are not toxic to cell growth.

In one embodiment, the process according to the present invention is carried out in an inert organic solvent or in a mixture of solvents so that the copolymer with high Tg core and the final arborescent copolymer product remain in solution. At the same time, the solvent also provides a degree of polarity so that the polymerization process can proceed at a reasonable speed. Suitable solvents include individual solvents such as n-butyl chloride. In another embodiment, a mixture of a non-polar solvent and a polar solvent can be used. Suitable non-polar solvents include, but are not limited to, hexane, methylcyclohexane, and cyclohexene. Suitable polar solvents include, but are not limited to, ethyl chloride, methyl chloride, and methylene chloride. In one embodiment, the solvent mixture is a combination of methylcyclohexane and methyl chloride, or even hexane and methyl chloride. To achieve adequate solubility and polarity it has been found that the ratio of non-polar solvent to polar solvent in a base by weight should be from about 80:20 to about 40:60, from about 75:25 to about 45:55, about 70:30 to about 50:50, or even about 60:40. Again, here, as elsewhere in the specification and in the claims, the limits of an individual interval may be combined.

The temperature range within which the process is performed is from about -20 ° C to about -100 ° C, or about -30 ° C.

° C at about -90 ° C, or about -40 ° C to about -85 ° C, or even about -50 ° C to about -80 ° C. The process of the present invention, in one embodiment, is carried out using from about 1 to about 30 percent of a solution of para-methylstyrene (weight / weight basis), or even from about 5 to about 10 percent by weight of a para-methylstyrene solution.

A co-initiator (e.g., a Lewis acid halide) is used to produce the arborescent polymers of the present invention. Suitable Lewis acid halide co-initiators include, but are not limited to, BCI3, BF3, AICI3, SnCl4, TiCl4, SbF5, SeCI3, ZnCI2, FeCI3, VCI4, AIRnCI3-n, where R is an alkyl group and n is less than 3, such as diethyl aluminum chloride and ethyl aluminum dichloride, and mixtures thereof. In one embodiment, titanium tetrachloride (TiCl 4) is used as the co-initiator.

The branched block copolymers of the present invention can also be produced in a one-step process in which the high Tg monomer is copolymerized with the initiator monomer together with the co-initiator in a solution at a temperature of about -20 ° C. at about -100 ° C, or about -30 ° C to about -90 ° C, or about -40 ° C to about -85 ° C, or even about -50 ° C to about -80 ° C. An electron donor and a proton trap are introduced, followed by the addition of a precooled co-initiator solution in a non-polar solvent (e.g., hexane). The polymerization is allowed to continue until it is terminated by the addition of the nucleophile such as methanol.

In some embodiments, the production of arborescent polymers according to the present invention requires the use of additives such as electron pair donors to improve blocking efficiency and proton traps to minimize homopolymerization. Examples of suitable electron pair donors are those nucleophiles that have an electron donor number of at least 15 and not greater than 50 as tabulated by Viktor Gutmann in The Donor Acceptor Approach to Molecular Interactions, Plenum Press (1978) and include, but are not limited to, ethyl acetate, dimethylacetamide, dimethylformamide, and dimethyl sulfoxide. Suitable proton traps include, but are not limited to, 2,6-ditertiarybutylpyridine, 4-methyl-2,6-ditertiarybutylpyridine, and diisopropylethylamine.

In yet another embodiment, suitable for non-biomedical applications, the present invention relates to end-functionalized thermoplastic elastomeric arborescent polymers that are reinforced with one or more fillers, wherein one or more fillers preferentially interact with the terminal functionalization portions of such arborescent polymers. The charges may include mineral or non-mineral charges.

Exemplary mineral fillers include silica, silicates, clay (such as bentonite), gypsum, alumina, titanium dioxide, talc and the like, as well as mixtures thereof. More specific examples include: highly dispersible silicas, prepared for example, by the precipitation of silicate solutions or the flame hydrolysis of silicon halides, with specific surface areas of from 5 to 1000, preferably from 20 to 400 m2 / g ( BET specific surface area), and with primary particle sizes from 10 to 400 nm; the silicas can optionally also be present as mixed oxides with other metal oxides such as those of Al, Mg, Ca, Ba, Zn, Zr and Ti; synthetic silicates such as aluminum silicate and alkaline earth metal silicates; magnesium silicate or calcium silicate, BET specific surface areas of 20 to 400 m2 / g and primary particle diameters of 10 to 400 nm; natural silicates, such as kaolin and other silicas of natural origin; glass fibers and glass fiber products (meshes, exempt) or glass microspheres; metal oxides, such as zinc oxide, calcium oxide, magnesium oxide and aluminum oxide; metal carbonates such as magnesium carbonate, calcium carbonate and zinc carbonate; metal hydroxides for example, aluminum hydroxide and magnesium hydroxide; or combinations thereof. Fillers that are not exemplary minerals include carbon black, for example, carbon prepared by lamp black, oven black or gas black processes, which preferably has a BET specific surface area of 20 to 200 m2 / g, such as Black smoke SAF, ISAF, HAF, FEF or GPF. Other non-mineral fillers include rubber gels, especially those based on polybutadiene, butadiene / styrene copolymers, butadiene / acrylonitrile copolymers or polychloroprene rubbers.

In the case that one or more fillers are used in conjunction with the present invention, the filler may be attached, fixed, captured and / or trapped by the terminally functionalized portion of the arborescent polymers of the present invention rather than the core portion thereof.

In yet another embodiment, again suitable for non-biomedical applications, the present invention provides a rubber composition comprising at least one arborescent polymer, optionally halogenated, at least one filler and at least one vulcanizing agent. To provide a vulcanizable rubber compound, at least one vulcanizing agent or curing system has to be added. The present invention is not limited to any type of curing system. An exemplary curing system is a sulfur curing system, although a peroxide-based curing system can also be used. For sulfur-based curing systems, the amount of sulfur used in the curing process may be in the range of about 0.3 to about 2.0 phr (parts by weight per one hundred parts of rubber). An activator, for example, zinc oxide, can also be used. If present, the amount of activator ranges from about 0.5 parts to about 5 parts by weight.

Other ingredients, for example, stearic acid, oils (for example, Sunpar® from Sunoco), antioxidants or accelerators (for example, a sulfur compound such as dibenzothiazoldisulfide (for example, Vulkacit® DM / C from Bayer AG) can also be added to the compound before curing Curing (eg, sulfur-based curing) is carried out in a known manner, see, for example, Chapter 2 of The Compounding and Vulcanization of Rubber, in Rubber Technology, Third Edition, Chapman & Hall, 1995. This publication is hereby incorporated by reference for its contents related to curing systems.

The vulcanizable rubber compound according to the present invention may contain additional auxiliaries for rubbers, such as reaction accelerators, vulcanization accelerators, vulcanization acceleration aids, antioxidants, foaming agents, anti-aging agents, thermal stabilizers, light stabilizers. ozone stabilizers, processing aids, plasticizers, tackifiers, blowing agents, dyes, pigments, waxes, diluents, organic acids, inhibitors, metal oxides and activators such as triethanolamine, polyethylene glycol, hexanotriol, etc. Such compounds, additives and / or products are known in the rubber industry. Rubber adjuvants are used in conventional amounts, depending on the intended use. Conventional amounts are, for example, from about 0.1 to about 50 phr. In one embodiment, the vulcanizable compound comprising a solution combination additionally comprises in the range of 0.1 to about 20 phr of one or more organic fatty acids as an auxiliary product. In one embodiment, the unsaturated fatty acid has one, two or more carbon double bonds in the molecule that can include about 10% by weight or more of a conjugated diene acid having at least one carbon-carbon double bond conjugated to its molecule. In another embodiment, the fatty acids used in conjunction with the present invention have from about 8 to about 22 carbon atoms, or even from about 12 to about 18 carbon atoms. Suitable examples include, although without limitation, stearic acid, palmitic acid and oleic acid and their salts of calcium, zinc, potassium, magnesium and ammonium. Additionally, up to about 40 parts of the processing oil, or even from about 5 to about 20 parts of the processing oil, may be present per one hundred parts of the elastomer.

It may be advantageous to additionally add silanes, silica modifiers, which give improved physical properties to compounds containing silica or siliceous fillers. Compounds of this type possess a silyl ether functionality (for reaction with the surface of the silica) and a specific functional group for the rubber. Examples of these modifiers include, but are not limited to, bis (triethoxysilylpropyl) tetrasulfan, bis (triethoxy-silylpropyl) disulfane, or S-triethoxysilyl methyl ester of thiopropionic acid. The amount of silica modifying silane is in the range of from about 0.5 to about 15 parts per hundred parts of elastomer, or from about 1 to about 10, or even from about 2 to about 8 parts per hundred parts of elastomers. The silica modifying silane can be used alone or together with other substances that serve to modify the surface chemistry of the silica.

The ingredients of the final vulcanizable rubber compound comprising the rubber compound are often mixed together, suitably at an elevated temperature which may vary from about 25 ° C to about 200 ° C. Usually the mixing time does not exceed one hour and a time in the range of about 2 to about 30 minutes is usually adequate. The mixture is made properly in an internal mixer, such as a Banbury mixer or a Haake or Brabender miniature internal mixer. A mixer with a two-roll mill also provides a good dispersion of the additives within the elastomer. An extruder also provides good mixing and allows for shorter mixing times. It is possible to carry out the mixing in two or more stages, and the mixing can be carried out in different apparatuses, for example, a stage in an internal mixer and a stage in an extruder. For the combination and vulcanization see also: Encyclopedia of Polymer Science and Engineering, Volume 4, p. 66 et seq. (Compounding) and Volume 17, p. 666 et seq. (Vulcanization). This publication is hereby incorporated by reference for its contents regarding combination and vulcanization.

In yet another embodiment, in case the arborescent polymers of the present invention have terminal functionalization, the core portion (e.g., the styrenic portion) is not cured, while the terminally functionalized portion is cured. This allows, among other things, that such arborescent polymers to undergo peroxide cure without causing damage to the overall arborescent polymer structure.

Examples The following examples are descriptions of methods within the scope of the present invention, and of the use of certain compositions of the present invention as described in detail above. The following examples are within the scope and, serve to exemplify the compositions, formulations and processes discussed above, described more general. As such, the examples are not intended to limit the scope of the present invention in any way.

The polymers according to the invention are prepared as will be discussed in detail below. All polymerizations are carried out in a MBraun MB 150B-G-I dry box.

Chemical products 4- (2-methoxy-isopropyl) styrene (p-methoxy-methyl styrene, pMeOCumSt) is synthesized while isobutylene and methyl chloride are used without further purification from a suitable production unit. Isoprene (IP, 99.9% and available from Aldrich) is passed through a p-tert-butylcatechol inhibitor elimination column before use and p-methylstyrene (pMeSt, Aldrich) is distilled at reduced pressure from calcium hydride.

Test methods The molecular weight and molecular weight distributions of the polymers are determined by size exclusion chromatography (SEC). The system consists of a Waters 515 HPLC pump, a Waters 2487 Double Absorbency Detector, a Wyatt Optilab Dsp Interferometric Refractometer, a Wyatt DAWN EOS multi-angle light scattering detector, a Wyatt Viscostar viscometer, a Wyatt quasi-elastic light scattering instrument QELS, a 717plus automatic sampler and 6 Styragel® columns (HR1 / 2, HR1, HR3, HR4, HR5 and H6). The IR detector and the columns are thermostated at 35 ° C and the freshly distilled THF from CaH2 is used as the mobile phase at a flow rate of 1 ml / min. The results are analyzed using the ASTRA software (Wyatt Technology). The calculation Molecular weight is performed using a 100% mass recovery as well as a dn / dc value of 0.108 cm3 / g.

The 1 H NMR measurements were performed using a Bruker Avance 500 instrument and deuterated chloroform or THF as the solvent.

The Differential Scanning Calorimetry (DSC) analysis was performed using a differential scanning calorimeter from TA Instruments 2910. Samples of 5-15 mg were placed in aluminum sample containers for testing and analyzed for glass transition temperatures ( Tg) in a helium atmosphere between -140 ° C and 200 ° C with a heating rate of 30 ° C / min. The Tg presented were taken as the mean value between the temperatures at the beginning and at the end point.

The tensiometry measurements were obtained using an Alpha Technologies T2000 tensiometer. Test specimens with 2.5 mm and 4 mm widths were die cut from compression molded sheets. The samples were drawn at 100 ml / min to observe the tension-elongation relationship.

Example 1 (09TS23) The polymerization was carried out in a three-mouth, round-shaped glass reactor of 500 cm.sup.3. The reactor was equipped with a glass stirring rod (mounted with an increasing teflon impeller) and a thermocouple. To the reactor were added 0.105 cm3 of pMeOCumSt, 135 cm3 of methylcidiohexane (measured at room temperature), 90 cm3 of methyl chloride (measured at -80 ° C), 0.3 cm3 of di-tert-butylpyridine (measured at temperature environment), and 10 cm3 of p-methylstyrene (measured at room temperature). The Polymerization was initiated at -80 ° C by addition of a pre-cooled mixture of 1.2 cm3 of TiCl4 and 5 cm3 of methylcyanohexane (both measured at room temperature). After 20 minutes of polymerization, a decrease in temperature was observed and a mixture of 36 cm 3 of isobutylene (measured at -80 ° C), 15 cm 3 of methylcyanohexane (measured at room temperature), 10.5 cm 3 of chloride was added. of methyl (measured at -95 ° C) and 0.1 cm3 of di-tert-butylpyridine (measured at room temperature). The polymerization was terminated at 95 minutes by the addition of 10 cm 3 of methanol containing 1.65 grams of NaOH. After evaporation of the methyl chloride, methylcyanohexane was added to the polymer solution and the diluted solution was filtered through a sintered frit of medium porosity to remove the 2+, and precipitated directly in acetone. The polymer product was isolated and dried in a vacuum oven for 24 hours at 60 ° C. The dry weight of the polymer was 17.0 grams. The molecular weight, the PDI and the branching frequency of the polymer are shown in Table 1. The glass transition temperature is shown in Table 2.

Example 2 (09TS25) The polymerization was carried out in a three-mouth, round-shaped glass reactor of 500 cm.sup.3. The reactor was equipped with a glass stirring rod (mounted with an increasing teflon impeller) and a thermocouple. To the reactor was added a first amount of 0.055 cm3 of the pMeOCumSt, 135 cm3 of methylcidiohexane (measured at room temperature), 90 cm3 of methyl chloride (measured at -80 ° C), 0.3 cm3 of di-tert-c. butylpyridine (measured at room temperature), and 10 cm3 of p-methylstyrene (measured at temperature ambient). Polymerization was initiated at -80 ° C by addition of a pre-cooled mixture of 0.6 cm3 of TiCl4 and 2.5 cm3 of methylcyanohexane (both measured at room temperature). After 20 minutes of polymerization, a decrease in temperature was observed and a mixture of 36 cm 3 of isobutylene (measured at -80 ° C), 15 cm 3 of methylcyanohexane (measured at room temperature), 10.5 cm 3 of chloride was added. of methyl (measured at -95 ° C) and 0.1 cm3 of di-tert-butylpyridine (measured at room temperature). After 30 minutes, a second amount of 0.055 cm3 of the pMeOCumSt emomer was added, followed by 0.6 cm3 of TiCU and 2.5 cm3 of methylcyanohexane (previously cooled). The polymerization was terminated at 95 minutes by the addition of 10 cm 3 of methanol containing 1.65 grams of NaOH. After evaporation of the methyl chloride, methylcyanohexane was added to the polymer solution and the diluted solution was filtered through a sintered frit of medium porosity to remove the 2+, and precipitated directly in acetone. The polymer product was isolated and dried in a vacuum oven for 24 hours at 60 ° C. The dry weight of the polymer was 16.0 grams. The molecular weight, the PDI and the branching frequency of the polymer are shown in Table 1. The glass transition temperature is shown in Table 2. A trace of SEC for the polymer is shown in Figure 1.

Example 3 (09TS27) The polymerization was carried out in a three-mouth, round-shaped glass reactor of 500 cm.sup.3. The reactor was equipped with a glass stirring rod (mounted with an increasing Teflon impeller) and a thermocouple. To the reactor was added 0.21 cm3 of pMeOCumSt, 135 cm3 of methylcyanohexane (measured at room temperature), 90 cm3 of methyl chloride (measured at -80 ° C), 0.3 cm3 of di-tert-butylpyridine (measured at room temperature) and 10 cm3 of p-methylstyrene (measured at room temperature ). Polymerization was initiated at -80 ° C by addition of a previously cooled mixture of 2.4 cm3 of TiCl4 and 7.5 cm3 of methylcyanohexane (both measured at room temperature). After 30 minutes of polymerization, a decrease in temperature was observed and a mixture of 36 cm 3 of isobutylene (measured at -80 ° C), 15 cm 3 of methylcyanohexane (measured at room temperature), 10.5 cm 3 of chloride was added. of methyl (measured at -95 ° C) and 0.1 cm3 of di-tert-butylpyridine (measured at room temperature). The polymerization was terminated at 95 minutes by the addition of 10 cm3 of methanol containing 1.65 grams of NaOH. After evaporation of the methyl chloride, methylcyanohexane was added to the polymer solution and the diluted solution was filtered through a sintered frit of medium porosity to remove Ti02, and precipitated directly into acetone. The polymer product was isolated and dried in a vacuum oven for 24 hours at 60 ° C. The dry weight of the polymer was 18.0 grams. The molecular weight, the PDI and the branching frequency of the polymer are shown in Table 1. The glass transition temperature is shown in Table 2.

Example 4 (L029-2) The polymerization was carried out in a three-mouth, round-shaped glass reactor of 500 cm.sup.3. The reactor was equipped with a glass stirring rod (mounted with an increasing teflon impeller) and a thermocouple. To the reactor was added 0.100 cm3 of pMeOCumSt, 160 cm3 of methylcidiohexane (measured at room temperature), 70 cm3 of methyl chloride (measured at -80 ° C), 0.3 cm3 of di-tert-butylpyridine (measured at room temperature) and 10 cm3 of p-methylstyrene (measured at room temperature) ambient). Polymerization was initiated at -80 ° C by addition of a pre-cooled mixture of 1.5 cm3 of TiCU and 5 cm3 of methylcyanohexane (both measured at room temperature). After 20 minutes of polymerization, a decrease in temperature was observed and a mixture of 36 cm 3 of isobutylene (measured at -80 ° C), 15 cm 3 of methylcyanohexane (measured at room temperature) was added., 10.5 cm3 of methyl chloride (measured at -95 ° C) and 0.1 cm3 of di-tert-butylpyridine (measured at room temperature). The polymerization was determined at 85 minutes by addition of 10 cm3 of methanol containing 1.65 grams of NaOH. After evaporation of the methyl chloride, methylcyanohexane was added to the polymer solution and the diluted solution was filtered through a sintered frit of medium porosity to remove the 2+, and precipitated directly in acetone. The polymer product was isolated and dried in a vacuum oven for 24 hours at 60 ° C. The molecular weight, the PDI and the branching frequency of the polymer are shown in Table 1. The thermoplastic properties of the peak voltages versus the peak elongation are presented in Table 3 and are illustrated in Figure 2.

Example 5 (L038-1) The polymerization was carried out in a three-mouth, round-shaped glass reactor of 500 cm.sup.3. The reactor was equipped with a glass stirring rod (mounted with an increasing Teflon impeller) and a thermocouple. To the reactor was added 0.100 cm3 of pMeOCumSt, 160 cm3 of methylcidiohexane (measured at room temperature), 73 cm3 of methyl chloride (measured at -80 ° C) and 10 cm3 of p-methylstyrene (measured at room temperature). The polymerization was started at -80 ° C by the addition of a previously cooled mixture of 1.5 cm3 of TiCl4 and 5 cm3 of methylcyanohexane (both measured at room temperature). After 20 minutes of polymerization, a decrease in temperature was observed and a mixture of 72 cm 3 of isobutylene (measured at -80 ° C) and 90 cm 3 of methyl chloride (measured at -95 ° C) was added. The polymerization was determined at 85 minutes by the addition of 10 cm3 of methanol containing 1.65 grams of NaOH. After evaporation of the methyl chloride, methylcyanohexane was added to the polymer solution and the diluted solution was filtered through a sintered frit of medium porosity to remove the 2+, and precipitated directly in acetone. The polymer product was isolated and dried in a vacuum oven for 24 hours at 60 ° C. The molecular weight, the PDI and the branching frequency of the polymer are shown in Table 1. The thermoplastic properties of the peak voltage versus the peak elongation are presented in Table 3 and are illustrated in Figure 2.

Example 6 (L037-1) The polymerization was carried out in a three-mouth, round-shaped glass reactor of 500 cm.sup.3. The reactor was equipped with a glass stirring rod (mounted with an increasing teflon impeller) and a thermocouple. To the reactor was added 0.100 cm3 of pMeOCumSt, 160 cm3 of methylcidiohexane (measured at room temperature), 70 cm3 of methyl chloride (measured at -80 ° C) and 10 cm3 of p-methylstyrene (measured at room temperature).

Polymerization was initiated at -80 ° C by addition of a previously cooled mixture of 1.5 cm3 of TiCU and 5 cm3 of methylcyclohexane (both measured at room temperature). After 20 minutes of polymerization, a decrease in temperature was observed and a mixture of 54 cm 3 of isobutylene (measured at -80 ° C) and 90 cm 3 of methyl chloride (measured at -95 ° C) was added. The polymerization was terminated at 85 minutes by the addition of 10 cm 3 of methanol containing 1.65 grams of NaOH. After evaporation of the methyl chloride, methylcyclohexane was added to the polymer solution and the diluted solution was filtered through a sintered frit of medium porosity to remove the 2+, and precipitated directly in acetone. The polymer product was isolated and dried in a vacuum oven for 24 hours at 60 ° C. The molecular weight, the PDI and the branching frequency of the polymer are shown in Table 1. The thermoplastic properties of the peak voltage versus the peak elongation are presented in Table 3 and are illustrated in Figure 2.

Table 1: Molecular Weight (Pm), PDI and Branch Frequency for Polymers of the Invention The branching frequency (FR), or degree of branching, is a theoretical calculation using the measured Mn of the polymer and the theoretical Mn of the polymer assuming that the species of inimer acts only as an initiator and does not participate in the branching. For all examples 1-6 above, FR = [Mn / Mn (teo)] - 1. PDI = Pm / Mn; therefore, to convert from Pm to Mn, Pm is divided by POI.

All these arborescent polymers have acceptable molecular weight and PDI values within the expected range.

Table 2: Vitrea Transition Temperature for Polymers of the Invention The DSC analysis of Examples 1-3 showed that each material had two different vitreous transition temperatures, confirming a biphasic composition. The SEC trace of Figure 1 confirms that the polymer of Example 2 has two distinct peaks, which means that the polymer has a bimodal molecular weight distribution indicative of an arborescent structure. Additionally, by observing the relative amount of each peak, it can be seen that the final blocks have a high molecular weight.

Table 3: Thermoplastic Properties - Tension versus Elongation The characterization of the thermoplastic elastomer was carried out by tensiometry (resistance in green). Examples 4-6 were compared with commercial grade butyl rubber (RB402 ™, LANXESS Inc., Canada). Reinforcement of the native films was observed with respect to RB402 ™; the thermoplastic properties of the material are illustrated in Figure 2. The uncured native materials were tested without additives or fillers.

Example 7: Leachate Four samples of 250 mg of material according to the invention were placed in vials (4 drachms (7 grams)), to which 5 ml of deionized water or colorless buffer solutions (pH 5, 7.38 or 9) were added. The vials were placed in an incubator oven at 40 ° C for approximately 300 hours. The material was removed from the solution and 1 ml of hexane was used to extract the leachates from the material of the aqueous phase. Liquid-liquid extraction using hexane was made a total of three times over the aqueous phase, followed by which the hexane was dried using magnesium sulfate. The solution was analyzed by gas chromatography with mass spectrometry using an HP 6890 GC system and an HP5973 mass selector device equipped with an Agilent column with a stationary phase DB-624 (125-1334, 30 mx 0.535 mm x 3.00 μ ??). There was no evidence of any leached substance other than those already present in hexane.

Example 8: Toxicity for cells The toxicity of the materials of Examples 2 and 5 was evaluated for mouse myoblast cells C2C12. The materials of Examples 2 and 5 were surface sterilized with ethanol and UV, then incubated in cell growth medium at 40 ° C for 24 hours, followed by which the medium was passed through a sterilization filter to remove Any biological contaminant greater than 450 nm in size. The filtered media was dispensed into a 96-well plate, seeded with C2C12 mouse myoblast cells and mixed with fresh growth medium to obtain various dilution levels of the original incubated medium. The sown samples were incubated for a further 48 hours, after which they were aspirated to remove the medium, leaving the cells behind in the well. Each well was then filled with new medium and the MTT test reagent. After 4 hours of incubation, the medium was again aspirated for removal from the well and the remaining MMT crystals were solubilized with DMSO. The absorbance at 540 nm of the contents of each well was measured to determine the concentration of original cells that were present in the well. The cell viability was 80% or higher in all cases, showing that there was no apparent toxicity due to leaching from the material. The results for Example 5 are shown in Figure 3; Example 2 showed similar results.

Example 9: Adhesion and cell growth Cell proliferation assays were performed to determine the ability of the materials according to the invention to support cell growth on their surface. The assay measured the number of C2C12 mouse myoblast cells adhered to the surface of the material. 2.5 cm disks sterilized with ethanol and by UV material according to Example 2 were seeded with a solution of 500 μ? of culture medium containing C2C12 cells; Cell concentration was determined by hemocytometric count. The discs covered with cells were placed in a biocabin for 20 minutes and then an additional 3.5 ml of growth medium was added to the material. After 24 hours of incubation, the surface of each disk was gently rinsed with cell medium to remove the non-adhered cells. A trypsin wash was used to separate the cells from the surface of the material and then the extracted cells were counted under a microscope in a hemocytometer, followed by extrapolation of the concentration. The growth of the material was compared to growth on a glass microscope slide, which was used as a control. The results are presented in Table 4 and in Figure 4.

Table 4: Adhesion and Cell Growth on the Material Surface Cell growth was determined to be viable on the surface of Example 2. An increase in the cell population was measured in the material of Example 2 of 67%, while the control had a population increase of 143%. These experiments indicate that the material is likely to be biocompatible and non-toxic for cell growth.

Although not limiting, the compounds of the present invention are useful in a variety of technical fields. Such fields include, but are not limited to, biomedical applications (e.g., use in stents), applications in tires (e.g., use in internal coatings), food-related packaging applications, pharmaceutical seals and in various sealing applications.

Although the invention has been described in detail with particular reference to certain embodiments detailed herein, other embodiments may achieve the same results. The variations and modifications of the present invention will be obvious to those skilled in the art and the present invention seeks to cover all these modifications and equivalents in the appended claims.

Claims (32)

1 . A highly branched arborescent block copolymer, comprising: to. an arborescent polymer core having more than one branching point, the arborescent polymer core having a high vitreous transition temperature (Tg) greater than 40 ° C; Y b. branches fixed to the arborescent polymer core terminated in final block segments of the polymer having a low Tg of less than 40 ° C.

2. The copolymer of claim 1, wherein the copolymer exhibits thermoplastic elastomeric properties.

3. The copolymer of claim 1, wherein the copolymer comprises at least 65% by weight of final block segments.

4. The copolymer of claim 1, wherein the molecular weight (Mn) of the final blocks is at least 50,000 g / mol.

5. The copolymer of claim 1, wherein the arborescent core comprises styrenic monomers.

6. The copolymer of claim 5, wherein the styrenic monomers comprise para-methylstyrene.

7. The copolymer of claim 1, wherein the final block segments comprise isoolefin monomers.

8. The copolymer of claim 7, wherein the isoolefin monomers comprise isobutene.

9. The copolymer of claim 7, wherein the final block segments further comprise conjugated diene monomers.

10. The copolymer of claim 9, wherein the conjugated diene monomers comprise isoprene.

11. The copolymer of claim 1, wherein the core has a branching frequency of about 0.5 to about 30.

12. The copolymer of claim 1, wherein the core has a branching frequency of from about 0.9 to about 10.

13. The copolymer of claim 1, wherein 250 mg of the polymer leaches less than 100 ppm of any individual leachable compound when analyzed by GC-MS after 300 hours of extraction in 5 ml of deionized water at 40 ° C.

14. The copolymer of claim 1, wherein a surface of the polymer can support cell growth.

15. A coating for a medical device or a medical device made from the arborescent copolymer of claim 1.

16. An arborescent polymer with terminal functionalization comprising the reaction product of at least one inimer and at least one para-methylstyrene monomer, wherein the terminally functionalized arborescent polymer has been terminally functionalized with more than about 65 weight percent of end blocks derived from a homopolymer or copolymer having a low vitreous transition temperature (Tg) of less than 40 ° C.

17. The arborescent polymer with terminal functionalization of claim 16, wherein the molecular weight (Pm) of the final blocks is at least 50,000 g / mol.

18. The arborescent polymer with terminal functionalization of claim 16, wherein the at least one inimer compound has a formula as shown below:

A B (I) where A is where B is wherein each of R f R2, R3, R4, R5 and R6, is independently selected from hydrogen, straight or branched C1 to C-m alkyl, or C5 to C8 aryl, or where Ri, R2 and R3 are all hydrogen or where each of R4, R5 and R6 is independently selected from hydrogen, hydroxyl, bromine, chlorine, fluorine, iodine, ester (-0-C (O) -R7), peroxide (-OOR7) and -O-R7 where R7 is a linear or branched unsubstituted C1 to C2o alkyl, a linear or branched unsubstituted C1 to C10 alkyl, a linear or branched substituted C1 to C20 alkyl, a linear or branched substituted C1 to C10 alkyl, an aryl group having 2 or to about 20 carbon atoms, an aryl group that has from 9 to 15 carbon atoms, a substituted aryl group having from 2 to about 20 carbon atoms, or a substituted aryl group having from 9 to 15 carbon atoms, or wherein one of R, R5 and F6 is any of chlorine or fluorine and the remaining two of R4, R5 and R6 are independently selected from a linear or branched unsubstituted C1 to C2o alkyl, a C1 to C10 unsubstituted linear or branched alkyl, a linear or branched substituted C 1 to C 20 alkyl or a linear or branched substituted C 1 to C 10 alkyl or where any two of R4, R5 and R6 can together form an epoxide, and the remaining R group in this case is either of a hydrogen, a linear or branched unsubstituted Ci to C10 alkyl or a linear or branched substituted C1 to C10 alkyl. 19. The terminally functionalized arborescent polymer composition of claim 18, wherein portions A and B of the first compound (I) are joined together through a benzene ring.

20. The terminally functionalized arborescent polymer composition of claim 18, wherein portions A and B of the first compound (I) are joined together through the bond shown below in Formula (II): where n is an integer in the range of 1 to about 12.

21. The arborescent polymer composition with terminal functionalization of Claim 20, wherein n is an integer in the range of 1 to about 6.

22. The arborescent polymer composition with terminal functionalization of claim 20, wherein n is equal to 1 or 2.

23. The terminally functionalized arborescent polymer composition of claim 18, wherein the at least one isoolefin compound has a formula as shown below: where Rg is a Ci to C4 alkyl group such as methyl, ethyl or propyl.

24. The arborescent polymer with terminal functionalization of claim 17, wherein one or more terminally functional portions of the polymer are derived from one or more homopolymers of isobutene.

25. The arborescent polymer with terminal functionalization of claim 17, wherein one or more terminally functional portions of the polymer are derived from one or more copolymers of an isoolefin and a conjugated diene.

26. The arborescent polymer with terminal functionalization of claim 25, wherein the isoolefin comprises isobutene and the conjugated diene comprises isoprene.

27. The arborescent polymer with terminal functionalization of claim 17, wherein the inimer compound is selected from 4- (2- Hydroxyisopropyl) styrene, 4- (2-methoxysopropyl) styrene, 4- (1-methoxyisopropyl) styrene, 4- (2-chloro-isopropyl) styrene, 4- (2-acetoxypropyl) estrene, 2,3,5,6-tertamethyl-4- (2-hydoxyisopropyl) styrene, 3- (2-methoxyisopropyl) styrene, 4- (epoxyisopropyl) styrene, 4,4,6-trimethyl-6-hydroxyl -1-heptene, 4,4,6-trimethyl-6-chloro-1-heptene, 4,4,6-trimethyl-6,7-epoxy-1-heptene, 4,4,6,6, 8-pentamethyl -8-hydroxyl-1-nonene, 4,4,6,6,8-pentamethyl-8-chloro-1-nonene, 4,4,6,6,8-pentamethyl-8,9-epoxy- 1-N-ene, 3,3,5-trimethyl-5-hydroxyl-1-hexene, 3,3,5-trimethyl-5-chloro-1-hexene, 3,3,5-trimethyl-5-6-epoxy- 1-hexene, 3,3,5,5,7-pentamethyl-7-hydroxyl-1-octene, 3,3,5,5,7-pentamethyl-7-chloro-1-ketene, or 3,3,5 , 5, 7-pentamethyl-7,8-epoxy-1-ketene.

28. The arborescent polymer with terminal functionalization of claim 17, wherein the inimer compound is selected from 4- (2-methoxyisopropyl) styrene or 4- (epoxyisopropyl) styrene.

29. The arborescent polymer with terminal functionalization of claim 17, wherein the arborescent polymer with terminal functionalization additionally comprises at least one charge.

30. A process for producing a highly branched arborescent copolymer comprising: to. copolymerizing a reaction mixture comprising at least one inimer and at least one para-methylstyrene monomer in an inert polar solvent in the presence of a Lewis acid halide co-initiator at a temperature from about -20 ° C to about - 100 ° C to form a highly branched core; b. control the reaction mixture for a temperature decrease, indicative of a substantial consumption of the para-methylstyrene monomer; c. adding an isoolefin monomer to the reaction mixture to form terminal blocks in the highly branched core, thereby producing an arborescent copolymer; Y d. separating the arborescent copolymer from the polar solvent.

31. The process of claim 30, wherein the process further comprises purifying the arborescent copolymer after removal of the solvent at a level of purification suitable for introduction of the copolymer into the human body without exhibiting rejection symptoms.

32. The process of claim 30, wherein the process further comprises purifying the inimer at a level of at least 99% purity before copolymerizing it with the para-methylstyrene monomer.