FIELD

The present disclosure relates to a process for the preparation of a pyridine -based halobutyl ionomer.

DEFINITIONS

As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.

Microstructure: The term “microstructure” refers to a very small scale structure of a material, and is defined as orientation of monomer units in the polymeric backbone. These polymeric microstructural identifications are visible by spectroscopic techniques such as NMR, FTIR and the like. The microstructure of a material (such as polymers, blends or composites) can strongly influence physical properties such as strength, toughness, hardness, high/low temperature behavior or wear resistance.

Endo-exo isomerism: The term “endo-exo isomerism” refers to a special type of stereoisomerism found in organic compounds with a substituent on a bridged ring system. The prefix endo is reserved for the isomer with the substituent located closest, or "syn", to the longest bridge. The prefix Exo is reserved for the isomer with the substituent located farthest, or "anti", to the longest bridge.

Mooney viscosity: The term “Mooney viscosity” refers to a measurement of viscosity of a rubber or compound, determined in a Mooney shearing disk viscometer. Mooney viscosity differentiates between different types and grades of polymers in order to ensure a high processing consistency.

Ionomer: The term “Ionomer” refers to a polymer that comprises repeating units of both electrically neutral repeating units and a fraction of ionized units (usually no more than 15 mole percent) covalently bonded to the polymer backbone as pendant group moieties. Alternatively, ionomers are polymers with bonded ionic species that are used under conditions where the salt groups are in a condensed state. BACKGROUND

Butyl rubber is a copolymer of isoprene and isobutylene rubber (HR). Bromobutyl rubber contains various functionality such as isoprene double bond and allylic bromide units. The isoprene and allylic bromide units are oriented in various ways and forms different microstructures. The isoprene functionality may be present as 1,4-(E & Z)-isomer and 1,2- isomer. Similarly, the allylic bromide units may also be present in different isomeric forms such as exo-isomer (exo-allylic bromide) and endo-isomer (endo-allylic bromide).

Butyl rubber (IIR) and bromobutyl rubber (BIIR) are an important class of industrial polymers which are broadly used in adhesives, automotive, pharmaceuticals and in various elastomeric applications. The exceptional air impermeability property of IIR and BIIR rubber makes them an efficient candidate for the inner liner that holds the air in the tire.

The properties of IIR and BIIR can be tuned by the incorporation of suitable functional moieties which will further widen their application. One way to incorporate functional moieties to polymers is through the introduction of functional monomers during the polymerization process. However, the incompatibility of cationic polymerization with most of the polar monomers makes it difficult for the direct synthesis of functional derivatives of butyl-based elastomer. Therefore, post-polymerization modification is an important way to functionalize the IIR and BIIR. An important way to modify BIIR is to convert BIIR to BIIR- ionomer via reaction with amines and phosphorous-based compounds. The introduction of ionic moiety into BIIR improves its polarity and results in good adhesion properties with a polar substrate. The ionic interaction between the ionic moieties in the ionomer acts as physical crosslinking points and improves the mechanical property of BIIR. The ionomers can be easily reprocessed since the crosslinks formed via ionic interaction are thermoreversible. The ionic cluster in the ionomer breaks at high temperature and again associates with the reduction of temperature. The association, dissociation and rearrangement of the ionic groups can induce self-healing property in the rubber.

The multifunctional benefit of the ionomer over IIR and BIIR motivates to design new classes of BIIR-based ionomers. The conventional BIIR-ionomers are based on various nucleophiles. A little change in the structure of the nucleophile has a great influence on the properties of the ionomer. Therefore, there is always a room to develop a new ionomer with desired properties. Therefore, the present disclosure provides a simple process for preparing pyridine-based halobutyl ionomer.

OBJECTS

Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:

It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.

An object of the present disclosure is to provide a process for the preparation of a pyridine- based halobutyl ionomer.

Another object of the present disclosure is to provide a process for the preparation of a pyridine-based halobutyl ionomer that converts exo-allylic halide unit to endo-halobutyl ionomer in 100%, without use of a catalyst.

Yet another object of the present disclosure is to provide a process for the preparation of a pyridine-based halobutyl ionomer that exhibits self-healing property.

Still another object of the present disclosure is to provide a process for the preparation of a pyridine-based halobutyl ionomer that has higher adhesion strength on wood and glass as compared to the commercial-grade butyl rubber ionomers.

Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY

The present disclosure relates to a process for the preparation of a pyridine -based halobutyl ionomer. The process comprises dissolving a halobutyl rubber in a fluid medium at a temperature in the range of 25 °C to 30°C to obtain a solution. The solution is heated at a first predetermined temperature to obtain a heated solution comprising the halobutyl rubber. A pyridine derivative is added to the heated solution, wherein the pyridine derivative is reacted with the halobutyl rubber at a second predetermined temperature for a predetermined time period to obtain the pyridine-based halobutyl ionomer. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The present disclosure will now be described with the help of the accompanying drawing, in which:

Figure 1 illustrates (i) NMR spectra of bromobutyl rubber (BIIR) and (ii) NMR spectra of pyridine-based bromobutyl ionomer;

Figure 2 illustrates NMR spectra of bromobutyl ionomer having hydroxyl functionality;

Figure 3 illustrates (i) NMR spectra of bromobutyl rubber (BIIR), (ii) NMR spectra of BIIR + trimethylamine (TEA) and (iii) NMR spectra of BIIR + triallylamine (TAA);

Figure 4 illustrates (a) pyridine-based halobutyl ionomer prepared in toluene and (b) and pyridine-based halobutyl ionomer prepared in xylene; and

Figure 5 illustrates the formation of an ionic cluster in the ionomer in accordance with the present disclosure.

DETAILED DESCRIPTION

Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.

Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.

Butyl rubber is a copolymer of isoprene and isobutylene rubber (HR). Bromobutyl rubber contain various functionality such as isoprene double bond and allylic bromide units. The isoprene and allylic bromide units are oriented in various ways and forms different microstructures. The isoprene functionality may be present as 1,4-(E & Z)-isomer and 1,2- isomer. Similarly, the allylic bromide units may also be present in different isomeric forms such as exo-isomer (exo-allylic bromide) and endo-isomer (endo-allylic bromide).

Butyl rubber (IIR) and bromobutyl rubber (BIIR) are an important class of industrial polymer which are broadly used in adhesives, automotive, pharmaceuticals and in various elastomeric applications. The post-polymerization modification is an important way to functionalize the IIR and BIIR. An important way to modify BIIR is to convert BIIR to BIIR-ionomer via reaction with amines and phosphorous-based compounds. The introduction of ionic moiety into BIIR improves its polarity and results in good adhesion property with polar substrate. The ionic interaction between the ionic moieties in ionomer acts as physical crosslinking points and improves the mechanical property of BIIR. The ionic cluster in the ionomer breaks at high temperature and again associates with the reduction of temperature. The association, dissociation and rearrangement of the ionic groups can induce self-healing property in the rubber.

The multifunctional benefit of the ionomer over IIR and BIIR motivates to design new classes of BIIR-based ionomers. The conventional BIIR-ionomer are based on imidazole and aliphatic amine-based nucleophiles. However, a little change in the structure of the nucleophile has a great influence on the properties of the ionomer.

The present disclosure provides a process for the preparation of a pyridine -based halobutyl ionomer. The process is described in detail herein below.

In a first step, a halobutyl rubber is dissolved in a fluid medium at a temperature in the range of 25 °C to 30 °C to obtain a solution. The halobutyl rubber used in accordance with the present disclosure is commercially available halobutyl rubber.

In the polymeric structure of the halobutyl rubber, endo-allylic halide unit and exo-allylic halide unit are defined based on attachment of halide into polymeric backbone. The allylic halide units in halobutyl rubber are oriented in different isomeric forms such as exo-isomer (exo-allylic halide) and endo-isomer (endo-allylic halide). In exo-isomer the double bond is present as pendant group and halide is attached to a secondary carbon atom. Whereas, in endo-isomer the double bond is present in the back-bone and halide is attached to a primary carbon atom. Under suitable reaction condition the exo-isomer gets converted to endo- isomer.

In accordance with the present disclosure, the pyridine-based halobutyl ionomer is endo- halobutyl ionomer.

The halobutyl rubber contains exo-allylic halide unit in an amount in the range of 70 mol% to 90 mol% and endo-allylic halide unit in an amount in the range of 10 mol% to 30 mol%. In an exemplary embodiment of the present application, the halobutyl rubber contains 85 mol% exo-allylic halide unit and 15 mol% endo-allylic halide unit.

In accordance with the present disclosure, the conversion of the exo-allylic halide unit of the halobutyl rubber to the endo-halobutyl ionomer is 100% without use of a catalyst.

In accordance with the present disclosure, the halobutyl rubber is selected from bromobutyl rubber and chlorobutyl rubber. In an exemplary embodiment of the present application, the halobutyl rubber is bromobutyl rubber.

The fluid medium is selected from toluene, benzene, xylene, hexane, cyclohexane and heptane. In an exemplary embodiment, the fluid medium is toluene. In accordance with the present disclosure, the amount of the fluid medium is in the range of 7.5 to 20 liters per kg of halobutyl rubber.

In a second step, the solution obtained in first step is heated at a first predetermined temperature to obtain a heated solution comprising the halobutyl rubber.

The first predetermined temperature is in the range of 90 °C to 120 °C. In an embodiment of the present application, the first predetermined temperature is in the range of 95 °C to 105 °C. In an exemplary embodiment of the present application, the first predetermined temperature is 100 °C.

In a third step, a pyridine derivative is added to the heated solution, wherein the pyridine derivative is reacted with the halobutyl rubber at a second predetermined temperature for a predetermined time period to obtain the pyridine-based halobutyl ionomer.

During the reaction, the exo-allylic bromide units are converted to endo-allylic bromide units which then reacts with the nucleophile to form ionomer.

In accordance with the present disclosure, the pyridine derivative is selected from dimethylamino pyridine, 2-methylpyridine, 3 -methylpyridine, 2, 3 -dimethylpyridine, 2,4- dimethylpyridine, 2, 5 -dimethylpyridine, 2,6-dimethylpyridine, 3,4-dimethylpyridine and 3,5- dimethylpyridine. In an exemplary embodiment of the present application, the pyridine derivative is dimethylamino pyridine.

The second predetermined temperature is in the range of 90 °C to 120 °C. In an embodiment of the present application, the second predetermined temperature is in the range of 95 °C to 105 °C. In an exemplary embodiment of the present application, the second predetermined temperature is 100 °C.

The predetermined time period is in the range of 2 hours to 10 hours. In an embodiment of the present application, the predetermined time period is in the range of 2.5 hours to 5 hours. In an exemplary embodiment of the present application, the predetermined time period is in the range of 2.5 hours.

In accordance with the present disclosure, the halobutyl ionomer is selected from bromobutyl ionomer and chlorobutyl ionomer. In an exemplary embodiment of the present application, the halobutyl ionomer is bromobutyl ionomer.

In accordance with the present disclosure, a molar equivalent of a halo group in said halobutyl rubber to said pyridine derivative is in the range of 1:0.5 to 1:2. In an exemplary embodiment of the present application, the molar equivalent of a halo group in said halobutyl rubber to said pyridine derivative is 1:2.

In an embodiment of the present application, a mass ratio of the halobutyl rubber to the pyridine derivative is in the range of 1:0.01 to 1:0.1. In an exemplary embodiment of the present application, the mass ratio of the halobutyl rubber to the pyridine derivative is 1:0.055.

In accordance with the present disclosure, a predetermined amount of nitrogen gas is passed through the solution for removing oxygen and moisture therefrom and attain a moisture-free and oxygen-free atmosphere.

In an exemplary embodiment of the present disclosure, the process for the preparation of pyridine-based bromobutyl ionomer comprises the step of dissolving bromobutyl rubber in toluene at 30 °C to obtain a solution. The solution is heated at 100 °C to obtain a heated solution comprising bromobutyl rubber. Dimethylamino pyridine is added to the heated solution, wherein dimethylamino pyridine is reacted with the bromobutyl rubber at 100 °C for 2.5 hours to obtain the pyridine -based bromobutyl ionomer.

In an exemplary embodiment of the present disclosure, the process for the preparation of pyridine-based halobutyl ionomer is represented as scheme 1.

Scheme 1

The reaction between the halobutyl rubber and pyridine-based nucleophile (pyridine derivative) is performed, wherein the exo-microstructure gets initially converted to endomicrostructure and then the endo-microstructure reacts with pyridine-based nucleophile to form the ionomer. The nitrogen lone pair on the pyridine-based nucleophile attacks the carbon atom of C-Br bond of endo-microstructure and becomes positively charged pyridinium ion. The replaced bromide ion stays as an associated anion with the positively charged pyridinium ion.

In accordance with the present disclosure, a Mooney viscosity of the pyridine -based halobutyl ionomer is in the range of 90 MU to 125 MU. In an exemplary embodiment of the present application, the Mooney viscosity of the pyridine -based halobutyl ionomer is 105 MU.

Higher Mooney viscosity in pyridinium ionomer indicates the presence of the ionic cluster in the backbone of the rubber which hinders the flow behavior of rubber in Mooney viscometer and hence, the money viscosity increases in ionomer.

The pyridine -based halobutyl ionomer is characterized by having the following properties: i. wood to wood adhesion lap shear strength in the range of 60 kgf to 70 kgf; and ii. tensile strength in the range of 16 Mpa to 20 Mpa.

The pyridine-based halobutyl ionomer prepared in accordance with the present disclosure, shows higher adhesion strength on wood and glass as compared to the commercial grade butyl rubber ionomer.

The process of the present disclosure provides the pyridine-based halobutyl ionomer that exhibits enhanced self-healing property and improved mechanical properties.

In accordance with an embodiment of the present disclosure, a film is prepared by using the pyridine-based halobutyl ionomer.

A process for preparing a film comprises forming a solution of pyridine-based halobutyl ionomer of the present disclosure followed by casting.

The solution is prepared by using a solvent selected from the group consisting of toluene, cyclohexane, heptane, Octane, decane, tetrahydrofuran (THF), Ethyl acetate, carbon tetrachloride (CCI4), chloroform (CHCI3).

The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.

The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.

Experimental details:

Experiment 1: Process for the preparation of the pyridine-based halobutyl ionomer in accordance with the present disclosure

Example 1: 3 kg of bromobutyl rubber (containing 85 mol% exo-allylic bromide unit and 15 mol% endo-allylic bromide unit) was dissolved in 30 liters of toluene at 30°C to obtain a solution. The solution was heated to 100°C to obtain a heated solution comprising bromobutyl rubber. 165 g of dimethylamino pyridine (DMAP) was added to the heated solution, wherein dimethylamino pyridine was reacted with the bromobutyl rubber at 100 °C for 2.5 hours to obtain the pyridine -based bromobutyl ionomer. The so obtained bromobutyl ionomer was coagulated and oven-dried and characterized by NMR.

The process for the preparation of the pyridine-based halobutyl ionomer in accordance with the present disclosure leads to the complete conversion of exo-allylic bromide unit of bromobutyl rubber to endo-bromobutyl ionomer. The conversion of exo-microstructure to endo-microstructure takes place via in-situ process during the preparation of pyridine-based bromobutyl ionomer.

The 100% conversion of exo-microstructure to endo-microstructure was evident from Figure 1 which illustrates (i) NMR spectra of bromobutyl rubber and (ii) NMR spectra of pyridine- based bromobutyl ionomer. In the NMR spectra of bromobutyl rubber (i), the peaks ‘d’ and ‘e’ indicates the presence of exo- allylic bromide units in the starting material (bromobutyl rubber), whereas the same peaks (‘d’ and ‘e’) were disappeared in the NMR spectra of the final product (pyridine-based halobutyl ionomer). The disappearance of peaks ‘d’ and ‘e’ and appearance of new peaks ‘h’ and ‘j ’ in the NMR spectra of the final product pyridine-based halobutyl ionomer, indicates the efficient conversion of exo-allylic bromide units into endo- bromobutyl ionomers. Comparative Example A: The same procedure as that of Example 1 was performed by using 2 g of bromobutyl rubber along with 0.12 g of 2-[2-(Dimethylamino)ethoxy] ethanol (DMAEE) instead of dimethylamino pyridine (DMAP) under identical experimental conditions to obtain the bromobutyl ionomer having hydroxyl functionality.

When DMAEE was used instead of DMAP as nucleophile, only 49 % of exo- microstructure was converted to endo microstructure and further to ionomer. This indicated that DMAEE as nucleophile is less efficient than that of dimethylamino pyridine (DAMP). The less efficient conversion of exo-microstructure to endo microstructure and ionomer was evident from Figure 2 which illustrates the NMR spectra of bromobutyl ionomer having hydroxyl functionality (final product). In the NMR spectra of bromobutyl ionomer having hydroxyl functionality, the peaks ‘d’ and ‘e’ indicates the presence of exo-allylic bromide units in the final product. This indicates the incomplete conversion of exo-microstructure to endo microstructure and further to ionomer.

Comparative Example B: The same procedure as that of Example 1 was performed by using 2 g of bromobutyl rubber along with 0.1823 g of triethylamine (TEA) instead of dimethylamino pyridine (DMAP) under identical experimental conditions.

Comparative Example C: The same procedure as that of Example 1 was performed by using 1 g of bromobutyl rubber along with 0.1234 g of triallylamine (TAA) instead of dimethylamino pyridine (DMAP) under identical experimental conditions.

When triethylamine (TEA) and triallylamine (TAA) were used instead of DMAP as nucleophile, no change in microstructure of bromobutyl rubber was observed after the reaction. This was evident from Figure 3 which illustrates (i) NMR spectra of bromobutyl rubber (BIIR), (ii) NMR spectra of BIIR + TEA and (iii) NMR spectra of BIIR + TAA. The peaks in the (ii) NMR spectra of BIIR + TEA and (iii) NMR spectra of BIIR + TAA are same as the peaks in the (i) NMR spectra of BIIR. This indicated that TEA and TAA as nucleophiles did not react with allylic bromide units of bromobutyl rubber.

Comparative Example D: The same procedure as that of Example 1 was carried out by using xylene as a fluid medium instead of toluene under identical experimental conditions. Comparative Example E: The same procedure as that of Example 1 was carried out by using hexane as a fluid medium instead of toluene under identical experimental conditions except the reaction temperature was 65 °C (due to low boiling point of hexane).

The conversion of exo-microstructure to endo microstructure and the ionomer made therefrom in xylene (85-95 %) was slightly lower than that in toluene (100%), whereas the conversion was very low in hexane (10-30%). The ionomer prepared in xylene was somewhat dark-colored than that prepared in toluene as illustrated in Figure 4 (a and b). In addition to dark coloration, another problem in xylene was the solubility of DMAP. DMAP is soluble in xylene at 55 °C and crystallizes out when cooled down to room temperature (RT). DMAP is not soluble in hexane even at 55 °C. So, to perform the reaction in hexane, DMAP was first dissolved in toluene (0.5-1.0 g per 2 ml) and then added to the bromobutyl rubber/hexane solution at 65 °C. In contrast, DMAP is soluble in toluene at 55 °C and does not crystallize out after cooling (RT).

The Mooney viscosity of the pyridine -based bromobutyl ionomer prepared in Example 1 is 105 MU.

Higher Mooney viscosity in pyridinium ionomer indicates the presence of the ionic cluster in the backbone of the rubber which hinders the flow behavior of rubber in Mooney viscometer and hence, the money viscosity increases in ionomer.

Experiment 2: Comparative studies of the pyridine-based bromobutyl ionomer of the present disclosure and commercial grade butyl rubber ionomer for adhesion properties, tensile strength and self-healing properties

I. Adhesion properties:

The adhesion properties were studied for the butyl rubber (IIR), bromobutyl rubber (BIIR), pyridine-based bromobutyl ionomer (hereinafter referred as pyridinium ionomer) and commercial-grade butyl rubber ionomer (hereinafter referred as phosphonium ionomer) and the comparative data is summarized in Table 1.

Table 1: Comparative data for Adhesion properties

From Table 1, it can be observed that both the ionomers (AIIR and PIIR) are showing higher adhesion strength on wood and glass substrates as compared to IIR and BIIR. However, the pyridinium ionomer of the present disclosure is showing highest adhesion on glass and wood substrates due to the presence of strong ionic cluster in the polymeric backbone which has very strong interaction with polar substrates.

II. Tensile strength:

The tensile strength was recorded for the butyl rubber (IIR), bromobutyl rubber (BIIR), pyridinium ionomer (AIIR) and commercial grade butyl rubber ionomer (PIIR) and the comparative data is summarized in Table 2. Table 2: Comparative data for Tensile strength

From Table 2, it can be observed that both the ionomers (AIIR and PIIR) are showing higher tensile strength as compared to IIR and BIIR. However, the pyridinium ionomer of the present disclosure is showing highest green strength, i.e. 15 times higher tensile strength as compared to IIR/BIIR and 3 times higher as compared to phosphonium ionomers) III. Self-healing studies: The self-healing behaviour was studied for the butyl rubber (IIR), bromobutyl rubber (BIIR), pyridinium ionomer (AIIR) and commercial grade butyl rubber ionomer (PIIR). The tensile strength and elongation at break was measured for fresh samples of IIR, BIIR, AIIR and PIIR. Then, samples were cut at joints and placed in oven at 110 °C for 2 hours for healing. These studies were repeated for 3 cycles and the comparative data recorded after each cycle is summarized in Tables 3a to 3d.

Table 3a: Comparative data before self-healing Table 3b: Comparative data after 1 ^st self-healing cycle

Table 3c: Comparative data after 2 ^nd self-healing cycle

Table 3d: Comparative data after 3 ^rd self-healing cycle

From Tables 3a to 3d, it can be observed that after first self-healing cycle, the pyridinium ionomer of the present disclosure, shows elongation at break similar to its original samples while in case of phosphonium ionomer, elongation at break is lower than its original samples (45% lower). In case of butyl and bromobutyl rubber, elongation at break reduced predominately (80% lower). In second self-healing cycle also, both pyridinium and phosphonium ionomers showed elongation at break similar to the first self-healing cycle. Tensile strength of pyridinium ionomer of the present disclosure was found to be higher as compared to butyl rubber, bromobutyl rubber and phosphonium ionomer and decreased after every self-healing cycle.

From the Experiments 1 to 2, it is evident that:

• use of toluene as a solvent leads to high conversion (-100%) of exo-allylic bromide units of the bromobutyl rubber to endo-bromobutyl ionomer as compared to the other solvents such as xylene (85-95 %) and hexane (10-30%);

• when 2-[2-(Dimethylamino)ethoxy] ethanol (DMAEE) was used as nucleophile, only 49% of exo-microstructure was converted to endo-microstructure and further to ionomer, indicating that DMAEE as nucleophile is less efficient than that of dimethylamino pyridine (DMAP);

• when triethylamine (TEA) and triallylamine (TAA) were used as nucleophile, no change in microstructure of bromobutyl rubber was observed after the reaction, indicating that TEA and TAA nucleophiles do not react with allylic bromide units of bromobutyl rubber;

• pyridine-based halobutyl ionomer of the present disclosure has higher adhesion strength on wood and glass as compared to the commercial grade butyl rubber ionomer; and

• pyridine-based halobutyl ionomer of the present disclosure exhibits enhanced self- healing property and improved mechanical properties.

TECHNICAL ADVANCEMENTS

The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a process for the preparation of the pyridine-based halobutyl ionomer that;

- is simple and economic;

- converts exo-allylic halide units of the halobutyl rubber to endo-halobutyl ionomer in 100%, without use of a catalyst; and

- provides the pyridine-based halobutyl ionomer that;

• exhibits enhanced self-healing property and improved mechanical properties; and

• has higher adhesion strength on wood and glass as compared to the commercial grade butyl rubber ionomer;

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention. The numerical values given for various physical parameters, dimensions, and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.

While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.