WO2012113068A1

WO2012113068A1 - Emulsions of free-radical curable elastomers

Info

Publication number: WO2012113068A1
Application number: PCT/CA2012/000170
Authority: WO
Inventors: Scott J. Parent; Ralph A. Whitney
Original assignee: Queen's University At Kingston
Priority date: 2011-02-23
Filing date: 2012-02-23
Publication date: 2012-08-30

Abstract

Emulsions of free-radical curable elastomers that may be applied to substrates and cured under free-radical conditions, forming polymeric films. Certain such films are antimicrobial. Emulsions described herein comprise a continuous aqueous phase, a dispersed free-radical curable elastomer phase, and a surfactant. Such elastomers have an isobutylene-rich main chain and pendant groups bearing moieties that undergo cross-linking reactions under free-radical conditions.

Description

Emulsions of Free-radical Curable Elastomers

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 61/445,822 filed on February 23, 2011 , the contents of which are

incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to emulsions that provide cross-linked polymeric films and coatings via free-radical initiated curing techniques.

BACKGROUND OF THE INVENTION

Poly(isobutylene-co-isoprene), or IIR, is a synthetic elastomer commonly known as "butyl rubber" that has been prepared since the 1940's through random cationic

copolymerization of isobutylene with small amounts of isoprene (1-2 mole %). As a result of its molecular structure, IIR possesses superior gas impermeability, excellent thermal stability, good resistance to ozone oxidation, exceptional dampening characteristics, and extended fatigue resistance.

In most applications butyl rubber is cross-linked to generate thermoset articles with greatly improved modulus, creep resistance and tensile properties. When sulfur and metal containing byproducts are not desired in the cross-linked product, free-radical initiated cures are used. Many halogen-free elastomers are readily cured by currently available peroxide- initiated crosslinking techniques, but butyl rubber is not (Loan, L. D. Pure Appl. Chem. 1972, 30, 173-180; Loan, L.D. Rubber Chem. Technol. 1967, 40, 149-176). Instead, under the action of organic peroxides, it suffers molecular weight loss by macro-radical fragmentation that is greater than any molecular weight gain obtained through macro-radical combination (Loan, L.D. J. Polym. Sci. Part A: Polym. Chem. 1964, 2, 2127-2134; Thomas, D.K. Trans. Faraday Soc. 1961, 57, 511-517).

Emulsions composed of a dispersed phase of butyl rubber (IIR) particles (i.e., non- derivatized butyl rubber) in a continuous phase of water are commercially available, and provide an aqueous delivery system for depositing IIR films and coatings. These emulsions typically include one or more surfactants that serve as ionic/steric stabilizers, which hinder particle coalescence and improve emulsion stability against coagulation. However, there are several shortcomings of conventional butyl rubber emulsion technology.

• The surfactants needed to stabilize the IIR emulsion can compromise adhesion of the final polymer film to the intended substrate, particularly when the film is exposed to water during product use. • These surfactants are not polymer bound, and can be leached out of the final product into contacting fluids, resulting in their contamination.

• Butyl rubber provides poor adhesive strength relative to more polar elastomers.

• Butyl rubber cannot be crosslinked using standard free-radical curing techniques.

Relatively inefficient sulphur-based vulcanization technology is therefore needed, which presents contamination problems associated with residual curatives and requires relatively high cure temperatures that can complicate the film crosslinking process.

• Butyl rubber is not an anti-microbial material.

Therefore, there is a need for butyl rubber-derived emulsion technology that can provide films and coatings that provide superior adhesion to other surfaces, and can be cured by free-radical cross-linking methods.

SUMMARY OF THE INVENTION

An aspect of the invention provides an emulsion comprising an aqueous phase, a dispersed macromonomer phase, and a surfactant. In some embodiments of this aspect, the macromonomer comprises azolium ionomer. Certain embodiments of this aspect further comprise filler. Some embodiments of this aspect comprise free-radical initiator, cross-linking coagent, reinforcing filler, non-reinforcing filler, viscosity modifier, processing aid, antioxidant, ultraviolet radiation stabilizer, wax, oil, or a combination thereof. Some embodiments of this aspect comprise other additives. In some embodiments of this aspect, the surfactant comprises vinyl alkyl azolium halide salt, a salt of itaconate half ester, a copolymer comprising an isobutylene-rich polymer backbone with pendant polyether chains covalently bound through itaconate diester, or a combination thereof.

An aspect of the invention provides a method of making a macromonomer emulsion comprising, in any order: adding a surfactant to an aqueous liquid; and dispersing macromonomer in the aqueous liquid to form an emulsion. In some embodiments of this aspect the surfactant comprises at least one moiety that is suitable to participate in crosslinking reactions.

Another aspect of the invention provides a cross-linked polymeric film prepared by spreading the emulsion of the above aspect and exposing the spread emulsion to a free- radical initiator. In some embodiments of this aspect the film is antimicrobial. Some embodiments of this aspect further comprise filler, free-radical initiator, reinforcing filler, non- reinforcing filler, viscosity modifier, processing aid, antioxidant, ultraviolet radiation stabilizer, wax, oil, or a combination thereof. A method of making a cross-linked polymer film, comprising: spreading an emulsion comprising surfactant, dispersed macromonomer, and a continuous aqueous phase on a substrate; reacting the macromonomer with a free-radical initiator; and allowing cross-linking reactions to occur so that cross-linked polymeric film is obained. Certain embodiments of this aspect further comprise allowing time for the spread emulsion to dry prior to reacting the macromonomer with a free-radical initiator. In some embodiments of this aspect the free- radical initiator is: a chemical free-radical initiator, a photoinitiator, heat, heat in the presence of oxygen, thermo-mechanical initiating means, electron bombardment, irradiation, high- shear mixing, photolysis (photo-initiation), ultraviolet light, electron beam radiation, radiation bombardment, or a combination thereof. In certain embodiments of this aspect the chemical free-radical initiator comprises an organic peroxide, a hydroperoxide, bicumene, dicumyl peroxide, di-t-butyl peroxide, an azo-based initiator, homolysis of an organic peroxide, or a combination thereof.

Another aspect of the invention provides a kit comprising: an emulsion of macromonomer dispersed in an aqueous liquid in the presence of surfactant; optionally, a free-radical initiator; and instructions for use of the kit comprising directions to form a cross- linked polymeric film from the emulsion.

In some embodiments of this aspect, the instructions comprise printed material, text or symbols provided on an electronic-readable medium, directions to an internet web site, electronic mail, or a combination thereof.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present invention provide emulsions comprising isobutylene-rich elastomers that are capable of being cured using free-radical initiation methods (such elastomers are known herein as "macromonomers"). Such macromonomers may additionally provide a moiety that fulfills a function other than crosslinking; such moieties are known herein as "functional moieties". An example of a functional moiety is a moiety that binds silaceous fillers. Macromonomers bearing functional moieties are known herein as "functional macromonomers". Other aspects of the present invention provide methods of making emulsions of macromonomers, and methods of cross-linking macromonomer emulsions to form cured polymeric films using free-radical crosslinking techniques.

Definitions

As used herein, the term "azole" is a cyclic five-membered heteroaromatic compound having one nitrogen atom and at least one other non-carbon atom of either nitrogen, sulfur, or oxygen. Examples of azoles described herein include imidazoles, pyrazoles, oxazoles, thiazoles, and triazoles. As used herein, the term "azolium ionomer" refers to a polymer backbone and a plurality of azolium cations that are covalently-bound to the backbone in a pendant position, and a plurality of anionic counterions associated with the plurality of cations. The anions may be halo, or may be a variety of other moieties.

As used herein, the term "continuous phase" means the phase in a two or more phase mixture that is interconnected in a uninterrupted fashion. As used herein, the term "dispersed phase" means the phase in a two or more phase mixture which has separate and unconnected globules, droplets, particles or bubbles.

As used herein, the terms "curing", "vulcanizing", or "cross-linking" refer to the formation of covalent bonds that link one polymer chain to another, thereby altering the physical properties of the material.

As used herein the term "emulsion" means a suspension of small globules of one liquid in a second liquid with which the first liquid is not miscible. Some molecules act at the many interfaces throughout the emulsion as surface active agents (called surfactants or emulsifiers) and reduce energy needed to keep these liquids apart.

As used herein, the term "radical generating technique" means a method of creating free-radicals, including the use of chemical initiators, photo-initiation, radiation

bombardment, thermo-mechanical processes, oxidation reactions or other techniques known to those skilled in the art.

As used herein, the terms "free-radical curing" and "free-radical polymerizable" mean able to polymerize when initiated by a free-radical initiator. As used herein, the term "free- radical curing" means crosslinking or curing that is initiated by free-radical initiators, which include chemical initiators, photoinitiators or radiation bombardment. As used herein, the term "free-radical curing" means cross-linking that is initiated by a radical generating technique. As used herein, the term "radical generating technique" means a method of creating free-radicals, including the use of chemical initiators, photo-initiation, radiation bombardment, thermo-mechanical processes, oxidation reactions or other techniques known to those skilled in the art.

As used herein, the terms "functional group" and "FG" refers to a moiety including but not limited to aliphatic, aryl, phenyl, halogen, silane, alkoxysilane, phenolic, aryl alcohol, ether, thioether, aldehyde, ester, thioester, dithioester, carbonate, carbamate, amide, imide, nitrile, imine, enamine, olefin, vinyl, alkyne, phosphate, phosphonate, phosphonium, sulfate, sulfonate, sulfoxide, ammonium, imidazolium, pyridinium, thiazolium or mixtures thereof.

As used herein, the term "functionality" is a chemical moiety that performs a function following ionomer preparation. For example, a pendant group on an polymer that includes an -Si(OMe)₃ moiety can perform the function of binding to siliceous fillers. Alternately, a pendant group on a polymer that includes C=C unsaturation can perform the function of peroxide-initiated cross-linking. Non-limiting examples of functionalities include: silane, alkoxysilane, siloxane, alcohol, epoxide, ether, carbonyl, carboxylic acid, carboxylate, aldehyde, ester, anhydride, carbonate, tertiary amine, imine, amide, carbamate, urea, maleimide, nitrile, olefin, acrylate, methacrylate, itaconate, styrenic, borane, borate, thiol, thioether, sulfate, sulfonate, sulfonium, sulfite, thioester, dithioester, halogen, peroxide, hydroperoxide, phosphate, phosphonate, phosphine, phosphate, phosphonium, alkyl, and aryl.

"Halogenated polymer" as used herein includes polymers comprising non- electrophilic mers that do not react with the azoles described herein, and electrophilic halogen- comprising mers that do react with nitrogen nucleophiles. The non-electrophilic mer composition within a halogenated polymer is not particularly restricted, and may comprise any polymerized olefin monomer. As used herein, the term "olefin monomer" is has a broad meaning and encompasses a-olefin monomers, diolefin monomers and polymerizable monomers comprising at least one olefin. In some embodiments, halogenated polymer comprises BUR, CIIR, BIMS, chlorinated polyethylene, or a combination thereof. As used herein, the term "MR" means poly(isobutylene-co-isoprene) containing less than 4 mole% isoprene, which is a synthetic elastomer commonly known as butyl rubber. As used herein, the term "BUR" means brominated butyl rubber. As used herein, the term "CIIR" means chlorinated butyl rubber. As used herein, the term "BIMS" means brominated poly(isobutylene-co-methylstyrene).

As used herein, the term "macromonomer" means a polymer with pendant groups bearing moieties that are capable of polymerization under free-radical curing.

As used herein, the term "pendant group" means a moiety that is attached to a polymer backbone.

As used herein, the terms "polymer backbone", "main chain", and "PB" mean the main chain of a polymer to which pendant group is attached. As used is structures shown herein, a connection to "Polymer" or "PB" is not meant to be limiting, and may, for example, be a bond to polymer backbone.

As used herein, the term "substrate" means a material or object, it usually refers to an object or surface that is desired to be coated, and may include glass, mylar, plastic, mineral, metal, composite, wood, construction materials and ceramic surfaces.

Description

An aspect of the invention provides an emulsion comprising a continuous aqueous phase, a dispersed macromonomer phase, and a surfactant. A macromonomer is an elastomer that is capable of being cured using free-radical initiation methods. In certain embodiments of the invention the macromonomer is an azolium ionomer and has azolium pendant groups. Certain aspects of the invention provide an emulsion that further comprises fillers or other additives. In some embodiments, cured polymeric film or coating that results from reacting the emulsion with a free-radical initiator has advantageous characteristics. Such characteristics may include superior adhesion, antimicrobial properties, or a combination thereof. Such antimicrobial films and coatings have use in childcare facilities, hospitals, spas, health clubs, etc as they can be applied to exercise equipment, shower stalls, handheld devices, shared tools, toilets, etc. Aspects of the invention provide films and coatings with improved adhesion, UV resistance, antioxidant properties, etc. Such coatings have use as adhesive liners in tanks, and containers for housing and/or transporting liquids, for coating pipes, and for many surfaces where a free-radical curable isobutylene-rich elastomer can be applied by, for example, spraying, dipping, wiping, or immersing.

Macromonomer and Azolium lonomer Pendant Groups

In certain embodiments of the invention the macromonomer is an azolium ionomer with a general formula (1) shown below, comprising: a polymer backbone, a plurality of covalently-bound, pendant azolium cations, and a plurality of anions associated with azolium cations to form ion pairs:

© Θ

Polymer- Azolium X ^ where " Azolium* " represents a polymer-bound azolium cation, " X " represents an anion associated with the azolium cation, and "Polymer" is a macromolecule to which the azolium cation is covalently attached. Notably, there are a plurality of anionic counterions to balance the charge of the crosslinking cationic azolium moieties. As those with skill in the art of the invention will recognize, a macromonomer may have many pendant groups attached.

Accordingly, for clarity in the discussion herein, a singular pendant group may be described to represent a plurality of pendant cations and associated anions.

Azotes

As defined above, the term "azole" is a cyclic five-membered heteroaromatic compound having one nitrogen atom and at least one other non-carbon atom of either nitrogen, sulfur, or oxygen. In certain embodiments of the invention, azole is an imidazole, which is a compound of formula (1 ) shown below:

wherein R¹, R³ and R⁴ are independently hydrogen, silane, a substituted or unsubstituted Ci to about Ci₆ aliphatic group, a substituted or unsubstituted d to about C ₆ aryl group, or a combination thereof, and optionally bear a functionality;

R² is non-hydrogen, and is independently a substituted or unsubstituted Ci to about C₁₆ aliphatic group, a substituted or unsubstituted d to about C₁₆ aryl group, or a combination thereof, and optionally bears a functionality; and

optionally, R³ and R⁴, together with the C=C unit to which they are attached, form a cyclic structure.

In certain embodiments of compounds of formula (1 ), R² is a substituted or unsubstituted olefin.

Non-limiting examples of compounds of formula (1 ) include the following imidazoles: N-butyl imidazole, N-(trimethylsilyl)imidazole, N-decyl-2-methylimidazole, and N- hydroxyethyl imid ively:

Further non-limiting examples of compounds of formula (1) include: N-(3- trimethoxysilylpropyl) imidazole, N-vinylimidazole, 2-(imidazol-1-yl)ethyl 2-methyl-2- propenoate, and 1-butylbenzimidazole, whose structures are illustrated below, respectively:

In certain embodiments of the invention, the azole is a pyrazole of formula (2) shown below:

wherein R , R³ and R⁴ are independently hydrogen, silane, a substituted or unsubstituted Ci to about C₁₆ aliphatic group, a substituted or unsubstituted C-, to about C₁₆ aryl group, or a combination thereof, and optionally bear a functionality; and

R² is a substituted or unsubstituted to about C₁₆ aliphatic group, a substituted or unsubstituted d to about C₁₆ aryl group, or a combination thereof, optionally bearss a functionality; optionally any combination of R\ R², R³ and R⁴ together with the azole ring atoms to which they are bonded, to form a cyclic structure.

In certain embodiments of compounds of formula (2), R² is a substituted or unsubstituted olefin.

Non-limiting examples of compounds of formula (2) include: N-(3- trimethoxysilylpropyl) pyrazole and N-vinylpyrazole, whose structures are illustrated below, respectively:

In an embodiment of the invention, the azole is a compound of formula (3) shown below:

wherein X is a heteroatom that is non-nitrogen, e.g., sulphur, oxygen;

R\ R² and R³ are independently hydrogen, silane, a substituted or unsubstituted to about Ci₆ aliphatic group, a substituted or unsubstituted Ci to about C ₆ aryl group, or a combination thereof, and optionally bear a functionality (e.g., substituents may bear a functionality); and

optionally R² and R³, taken together with the azole ring atoms to which they are bonded, form a cyclic structure.

Non-limiting examples of azoles of formula (3) include: oxazole and benzothiazole, whose structures are illustrated below, respectively:

In certain embodiments of the invention, azole is a compound of formula (4), known as a triazole, with three nitrogen atoms at the 1 ,2,3- or 1 ,2,4- positions of the heteroaromatic ring, as illustrated below:

wherein R¹ is a substituted or unsubstituted Ci to about C16 aliphatic group, a substituted or unsubstituted Ci to about Ci₆ aryl group, or a combination thereof, and optionally bearss a functionality moiety (e.g., substituents may bear a functionality);

R² and R³ are independently hydrogen, silane, a substituted or unsubstituted Ci to about Ci6 aliphatic group, a substituted or unsubstituted Ci to about Ci₆ aryl group, or a combination thereof, and optionally bear a functionality moiety (e.g., substituents may bear a functionality);

optionally, any combination of R¹, R², and R³, taken together with the azole ring atoms to which they are bonded, form a cyclic moiety.

In certain embodiments of compounds of formula (4), R¹ is a substituted or unsubstituted olefin.

Non-limiting examples of triazoles of formula (4) include: l-vinyl-1 ,2,4-triazole, and 1-methyl-1 ,2,3-triazole, whose below, respectively:

Macromonomer and Polymer Backbone

The macromolecule to which the azolium cation is bound, depicted as " Polymer " in formula (1), is not particularly restricted. In a preferred embodiment, the macromolecule comprises a random distribution of isobutylene mers and isoprene mers. In another preferred embodiment, the macromolecule comprises a random distribution of isobutylene mers and para-methylstyrene mers.

In certain embodiments, the azolium cation in formula (1) bears a C=C group that is capable of radical oligomerization. A non-limiting example of this embodiment is a BIIR-

wherein a plurality of -CH=CH₂ moieties support free-radical curing. Another non-limiting example of an azolium ionomer that bears oligomerizable methacrylate groups comprises a BIMS-derived backbone and 1-(2-ethylmethacrylate)-3- benzyl-imidazolium bro

wherein a plurality of -0-CO-C e=CH₂ moieties support free-radical curing.

In another embodiment of the invention, the macromonomer comprises a polymer backbone and pendant group with the following structure

where PB is the polymer backbone described hereinabove, R¹, R², R³, R⁴ are independently hydrogen, substituted or unsubstituted C-i to about C₁₂ aliphatic group, substituted or unsubstituted aryl, or combinations thereof. The variable n can range from 1 to 5. In some embodiments n is 1 to 3. In still other embodiments, n is 1. X is oxygen, N-H, or N-R where R is a substituted or unsubstituted Ci to about C₁₂ aliphatic group, substituted or unsubstituted aryl, or combinations thereof. The functionality within the group FG, defined hereinabove, is not particularly restricted, and is in the purview of those skilled in the art. Specific examples of functionality within the group FG include aliphatic, aryl, phenyl, halogen, silane, alkoxysilane, phenolic, aryl alcohol, ether, thioether, aldhehyde, ester, thioester, dithioester, carbonate, carbamate, amide, imide, nitrile, imine, enamine, olefin, vinyl, alkyne, phosphate, phosphonate, phosphonium, sulfate, sulfonate, sulfoxide, ammonium, imidazolium, pyridinium, thiazolium, and mixtures thereof.

Surfactant

Surfactant is not particularly restricted and can be cationic, anionic or non-ionic. The amount of surfactant or emulsifier employed can vary from about 2 to 20 weight percent based on the weight of macromonomer present. Some embodiments use surfactant that bears at least one moiety that can react in crosslinking reactions so that the surfactant participates in cross-linking reactions and is bound in the cured product. Such surfactants will not leach from the product. In one embodiment of the invention, the surfactant is a vinyl alkyl azolium bromide salt, a non-limiting example of which is illustrated below:

In another embodiment, the surfactant is the salt of itaconate half ester, examples of which are illustrated below:

n another embodiment, the surfactant is a copolymer comprising an isobutylene-rich polymer backbone with pendant polyether chains that are bound covalently through

Fillers

Provision of filler such as carbon black, precipitated silica, talc, clay, glass fibres, polymeric fibres, crystalline organic compounds, finely divided minerals and finely divided inorganic materials can improve the physical properties of polymers. Typically, the amount of filler is between 10 wt% and 60 wt%. Preferably, filler content is between 20 and 45 wt%.

Suitable fillers for use in the present invention comprise particles of a mineral, such as, for example, silica, silicates, clay (such as bentonite), gypsum, alumina, titanium dioxide, talc and the like, as well as mixtures thereof. Further examples of suitable fillers include:

• highly dispersable silicas, prepared, e.g., by the precipitation of silicate solutions or the flame hydrolysis of silicon halides, with specific surface areas of 5 to 1000, preferably 20 to 400 m²/g (BET specific surface area), and with primary particle sizes of 10 to 400 nm; the silicas can optionally also be present as mixed oxides with other metal oxides such as Al, Mg, Ca, Ba, Zn, Zr, and Ti;

• synthetic silicates, such as aluminum silicate and alkaline earth metal silicate;

• magnesium silicate or calcium silicate, with 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 naturally occurring silica; • natural clays, such as montmorillonite, and their ion-exchanged derivatives such as tetraalkylammonium ion exchanged clays;

• glass fibers, glass fiber products (matting, extrudates), and 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, e.g., aluminum hydroxide and magnesium hydroxide, or

combinations thereof.

Mineral fillers, as described hereinabove, can also be used alone or in combination with known non-mineral fillers, such as:

• carbon blacks; suitable carbon blacks are preferably prepared by the lamp black, furnace black or gas black process and have BET specific surface areas of 20 to 200 m²/g, for example, SAF, ISAF, HAF, FEF, and GPF carbon blacks;

• nano-crystalline cellulose and its surface modified derivatives;

• rubber gels, preferably those based on polybutadiene, butadiene/styrene

copolymers, butadiene/acrylonitrile copolymers and polychloroprene.

Provision of nano-scale filler such as exfoliated clay platelets, sub-micron particles of carbon black, and sub-micron particles of siliceous fillers such as silica can improve the physical properties of polymers, in particular the impermeability, stiffness and abrasion resistance of the material. Typically, the amount of nano-scale filler is between 0.5 wt% and 30 wt%. Preferably, nano-scale filler content is from about 2 to about 10 wt%.

In certain embodiments of the invention, fillers, as described hereinabove, are included during the preparation processes of azolium ionomer, and are part of the emulsions so they form part of the cured polymeric film or coating. The method of dispersing filler into the uncured formulation is not particularly restricted, and selection of an appropriate mixing device is within the purview of one skilled in the art. Typically, the amount of filler added to the uncured formulation ranges from 2- 60 percent of the total mixture weight. More preferably, the filler content is between 4 and 35 wt%.

Other additives

In some embodiments, emulsions include other additives that improve physical properties, chemical properties, and cost. These other additives can include, but are not restricted to, free-radical initiators, cross-linking coagents, reinforcing fillers, non-reinforcing fillers, viscosity modifiers, processing aids, antioxidants, ultraviolet radiation stabilizers, waxes, oils, and the like. In certain embodiments of the invention, additives known to those skilled in the art of the invention are included in the azolium ionomer preparation process to improve material properties. For example, provision of antioxidants such as phenolics and amines can improve oxidative stability of the material. Although not wishing to be limited, the inventors suggest that typical antioxidant amounts are 10-1000 ppm. Anti-ozone and UV-stabilizing compounds can be added to improve weathering characteristics. The provision of process aids such as, e.g., tackifiers, waxes, oils, and soaps can improve the processing properties and cost of a polymer emulsion formulation.

Enhanced Adhesion Properties

In an embodiment, cured and uncured azolium ionomers (cured in films and uncured in emulsions) provide enhanced adhesion. Adhesion of a polymer to solid surfaces is an important physical property that leads to formation of composite materials. However, owing to their low surface energies, most polyolefins exhibit only moderate adhesion to glass, mylar, plastic, mineral, metal and ceramic surfaces and, as a result, have deficiencies when used in composite applications. Introduction of an ionic moiety to a polymer composition is expected to improve adhesive properties over its non-ionic parent material, owing to the strength of ion-dipole interactions between ionomers and solid surfaces.

Antimicrobial Properties

In yet another embodiment of the present invention, azolium ionomers (cured in films and uncured in emulsions) reduce a population of and/or prevent accumulation of organisms, including bacteria, algae, fungi, mollusks, and/or arthropods. Although not wishing to be bound by theory, the inventors suggest that the ion pairs may impart antimicrobial properties that are not observed in typical halogenated polymers.

Microorganisms against which a thermoset azolium ionomer is expected to be effective include, for example: Gram-negative bacteria - Salmonella, Shigella, Neisseria

gonorrhoeae, Neisseria meningitidis, Haemophilus influenzae, Escherichia coli, Klebsiella, Pseudomonas aeruginosa. Gram-positive bacteria - Bacillus, Listeria, Staphylococcus, Streptococcus, Enterococcus, Clostridium, Epulopiscium, Sarcina, Mycoplasma,

Spiroplasma, Ureaplasma, Lactobacillus, Corynebacterium, Propionibacterium, Gardnerella, Frankia, Streptomyces, Actinomyces, and Nocardia. Algae: Chlorophyta, Rhodophyta, Glaucophyta, Chlorarachniophytes, Euglenids, Heterokonts, Haptophyta, Cryptomonads, Dinoflagellates. Fungi: Alternaria, Aspergillus, Basidiomycetes, Botrytis, Candida albicans, Cephalosporium, Cheatomium, Cladosporium, Cuvalaria, Drechslera, Epicoccum, Fusarium, Geotrichum, Helminthosporium, Humicola, Monilia, Neuspoa, Nigrospora, Penicillium, Phoma, Pullularia, Rhizophus, Rhodotorula, Scopulariopsis, Stemphylium, Trichoderma, Unocladium and Verticillum. Method of macromonomer preparation

Macromonomers have been prepared with a variety of moieties that crosslink under free-radical conditions. Non-limiting examples of certain macromonomer embodiments include acrylate ester macromonomers, maleimido-ester macromonomer, IIR-g-dodecyl maleate, and IMS-g-aminosilane itaconate. Syntheses for these example macromonomers are included in the Working Examples.

An aspect of the invention provides macromonomers bearing azolium ionomers. Syntheses of certain azolium macromonomers are included in the Working Examples. Briefly, to prepare such macromonomers, halogenated polymers and at least one azole are mixed to form a mixture. Optionally, the mixture can comprise other additives (e.g., filler) as described herein. This preparation method can be conducted both in the absence or in the presence of solvent.

In the absence of solvent, mixing is performed using standard polymer processing equipment (e.g., internal mixer, a two-roll mill, an extruder, or the like). Nucleophilic substitution by azole of halide from the halogenated polymer proceeds irreversibly to give an ionomer comprising azolium halide ion pairs. The reaction rate is dependent on

temperature, and the process is generally carried out from about 60°C to about 180°C, more preferably from about 90°C to about 160°C.

Solvent-free azolium ionomer preparations can be carried out to obtain various conversion amounts converting azole and halogenated electrophile to azolium salts. The amount of conversion of azoles to azolium salts is preferably maximized, such that isolation of residual azole from the product is not required. If residual azole remains in the ionomer product, it may be left in the material or removed by heating, placing under vacuum, or heating and placing under vaccuum. Amount of conversion of halogenated electrophile to azolium salt may be selected based on the desired azolium ionomer composition. Where ion pair concentrations are to be maximized, desired halogenated electrophile conversion is 100%. However, if residual halogenated electrophile is desired within the azolium ionomer, this conversion can be reduced. Such residual may be desired, for example, if halogenated electrophile is needed in the azolium ionomer for other reactions such as vulcanization.

In the presence of solvent, halogenated polymers, one or more azoles, and optionally, other additives, are mixed in the presence of a solvent that is suitable for dissolving the halogenated polymer. The selection of such a solvent is not particularly restricted, and the choice thereof for use in this process is within the purview of a person skilled in the art. Non-limiting examples of suitable solvents include toluene, hexane, tetrahydrofuran, xylene and mixtures thereof. The rate of these solvent-borne reactions is dependent on temperature, and these processes are typically carried out from about 60°C to about 160°C. If the desired temperature is above the boiling point of the solvent, then the reaction is conducted at a pressure that is sufficient to maintain the polymer mixture in a liquid state using a suitably equipped pressure vessel. As described hereinabove for the solvent-free method, azole and halogenated electrophiie conversions can be independently controlled to provide a desired azolium ionomer product composition. Recovery of product from solution is possible by addition of ionomer product solution to a solvent that does not dissolve the product, thereby leading to precipitation of azolium ionomer from solution. Alternatively, ionomer product cement can be subjected to steam stripping to remove solvent, leaving a crumb that can be dried using conventional methods.

Method of Making a Macromonomer Emulsion

The method of making a macromonomer emulsion is not particularly restricted, and may be selected by one of skill in the art. A non-limiting example of a method of making a macromonomer emulsion comprises dissolving the macromonomer in a suitable nonaqueous solvent, and dispersing the resulting mixture in an aqueous surfactant solution. Non-aqueous solvent is then removed under reduced partial pressure and/or at elevated temperature.

Method of Making Cured Polymeric Film or Coatings from a Macromonomer Emulsion

An aspect of the invention provides a cross-linked film comprising surfactants, and optionally fillers and/or other additives described hereinabove, and a macromonomer that has been cured by exposure to a radical generating technique. The method of generating this film from a macromonomer emulsion is not particularly restricted, and may comprise spraying, brushing, or rolling the emulsion on a surface and allowing the resulting coating to dry by water evaporation. The resulting film is then exposed to a free-radical generating technique to cross-link the coating, yielding a thermoset product. When a radical initiator is included in the macromonomer emulsion, the radical generating technique may comprise activating the initiator by heat, light, radiation, or combinations thereof.

The contents of the following patent applications are hereby incorporated by reference in their entirety:

U.S. Patent Application No. 61/345,400 filed May 17, 2010;

U.S. Patent Application No. 61/345,396 filed May 17, 2010;

U.S. Patent Application No. 61/345,391 filed May 17, 2010;

U.S. Patent Application No. 61/421,532, filed December 9, 2010; and

U.S. Patent Application No. 61/421 ,489, filed December 9, 2010. WORKING EXAMPLES

Example 1. Preparation of Macromonomer Emulsion using a standard surfactant

A macromonomer (0.5 g) comprising a IIR backbone and 0.15 mmole/g of pendant vinyl imidazoiium groups was dissolved in a mixture of hexanes (4.5 g) and hexanoi (0.12g). The resulting mixture was dispersed in an aqueous solution of Brij 35 surfactant (0.05g) (available from Acros Organics, NJ, USA) in water (5 g) using a sonicating probe (model CV33 Vibra Cell by Sonics, Sonics & Materials, Inc., Newtown, CT, USA) to yield an emulsion. The resulting emulsion was stable for 24 hours.

Alternatively, 1-vinyl-3-n-decyl-imidazoiium bromide is used as surfactant in place of Brij 35 in the above example. 1-vinyl-3-n-decyl-imidazolium bromide is advantageous since it is involved in crosslinking reactions, so the cured product does not leach surfactant.

Example 2. Preparation of Macromonomer Emulsion using a crosslinkable surfactant

An ionomer (0.5 g) comprising a IIR backbone and 0.15 mmole/g of pendant butyl imidazoiium groups was dissolved in a mixture of hexanes (4.3 g) and hexanoi (0.23g). The resulting mixture was dispersed in an aqueous solution of 1-vinyl-3-n-decyl-imidazolium bromide (0.2 g) surfactant in water (5g) using a sonicating probe. The resulting emulsion was placed in a rotary evaporator (R110 by BOchi, Flawil, Switzerland) at room temperature and placed under reduced pressure for several hours to remove the organic solvent, yielding an emulsion.

1-vinyl-3-n-decyl-imidazolium bromide surfactant was a synthesized according to the procedure in Bottino, F.A. ef a/. "Polystyrene-Clay Nanocomposites Prepared with

Polymerizable Imidazoiium Surfactants", Macromol. Rapid Commun. 2003, 24, 1079- 084, with the exception that instead of drying under vacuum at 45 °C, it was dried under vacuum without heating.

Example 3. Preparation of a Cured Polymeric Film using a Macromonomer Emulsion

A macromonomer (1 g) comprising a IIR backbone bearing 0. 5 mmole/g of pendant butyl imidazoiium groups and dicumyl peroxide (0.005 g) free-radical initiator is dissolved in a mixture of hexanes (10 g) and hexanoi (0.5 g). The resulting mixture is dispersed in an aqueous solution of 1-vinyl-3-n-decyl-imidazolium bromide (0.1 g) surfactant in water (30g) using a sonicating probe. The resulting emulsion is placed in a rotary evaporator at room temperature and placed under reduced pressure (17 inches water, 0.6 bar) for two hours to remove the organic solvent. The resulting macromonomer emulsion is used to coat a glass slide, and the water is allowed to evaporate prior to heating the film to 140 °C for 30 min to activate the initiator. The resulting cured macromonomer film has substantially no extractable surfactant, provides excellent adhesion to the glass substrate, and exhibits antimicrobial activity.

Example 4. Solvent-free preparation of azolium ionomer, IIR-g-BulmBr

This example illustrates the synthesis of an azolium ionomer under solvent-free conditions. BUR (40 g, 6.0 mmol of allylic bromide) was mixed with 1-butylimidazole (0.816 g, 6.57 mmole) in a Haake Polylab R600 internal batch mixer equipped with Banbury blades and operating at 85 °C and 60 rpm. Samples taken at specified time intervals were analyzed by 1 H N R. Residual allylic bromide contents were quantified by 1 H NMR spectrum integration to an estimated accuracy of ± 5%: δ 5.01 (Exo-Br, =CHH 1 H, s); δ 4.11 (E-BrMe, =CH-CH₂-Br, 2H, s), δ 4.09 (Z-BrMe, =CH-CH₂-Br, 2H, s). Imidazolium bromide contents were quantified by integration of the following allylic resonances: δ 4.86 (E-IIR- ImidazoliumBr, s); δ 4.95 (Z-IIR-lmidazoliumBr, s).

Example 5. Solvent-borne preparation of an azolium ionomer from BUR and 1 -butyl imidazole

This example illustrates the synthesis of an azolium ionomer by reaction of BUR with 1-butylimidazole under solvent-borne conditions. A solution of BUR (10.0 g, 1.5 mmol) and 1-butylimidazole (1.12 g, 9.0 mmol) in toluene (104 mL) was maintained at 100 ± 2 °C for 6 hours under a nitrogen atmosphere. Aliquots (-0.5 mL) withdrawn at time intervals were added to excess acetone to isolate the polymeric reaction product, which was dried under vacuum and characterized by 1 H NMR spectroscopy as described in the previous example. Displacement of bromide from BUR by 1 -butyl imidazole proceeds to full conversion of allylic bromide to imidazolium bromide.

Example 6. Synthesis of an azolium ionomer derived from CIIR and N-butyl imidazole

This example illustrates the synthesis of an azolium ionomer by reaction of CIIR with N-butylimidazole under solvent-borne conditions. A 10 wt% xylene solution of chlorinated butyl rubber comprising 0.02 mmole of exomethylene allylic chloride per gram of polymer and 0.12 mmole of Cl-Me alllylic per gram of polymer was heated to 135°C with 6 molar equivalents of N-butylimidazole for 56 minutes. The reaction product was isolated by precipitation from acetone, dried under vacuum, and analyzed by ¹H-NMR, revealing an N- butylimidazolium chloride content of 0.03 mmole/g. Example 7. Synthesis of acrylate ester macromonomers

BUR was transformed into acrylate ester macromonomers (IIR-g-AA) as follows. BUR (2 g, as received or isomerized) was dissolved in toluene (8 g) along with BHT (0.02 g) and the required amounts of nudeophile/phase transfer catalyst (0.19 g Bu4NAcrylate or 0.063 g KAcrylate+0.013 g Bu4NBr) under a nitrogen atmosphere, and heated to 85°C using an oil bath. Samples withdrawn at intervals were precipitated from acetone and dried in vacuo at room temperature. IIR-g-AA materials for rheological testing were prepared on 15 g scale from as received BUR for 3 hours to ensure complete allylic bromide consumption. ¹H NMR (CDCI₃, δ ppm. ¹H-NMR integration for allylic bromides: δ 5.01 (Exo-Br, =CHH, 1 H, s); δ 4.11 (E-BrMe, =CH-CH₂-Br, 2H, s), δ 4.09 (Z-BrMe, =CH-CH₂-Br, 2H, s). H-NMR integration for acrylate esters: δ 5.27 (Exo-AAester, =CHH, 1 H, s); δ 4.68 (E-AAester, =CH-CH₂-OCO-, 2H, s), δ 4.61 (Z-AAester, =CH-CH₂-OCO-, 2H, s). ¹H-NMR integration for stearate esters: δ 4.51 (E-stearate, =CH-CH₂-OCO-, 2H, s), δ 4.56 (Z-stearate, =CH-CH₂-OCO-, 2H, s).

Example 8. Synthesis of Maleimido-ester macromonomer

Maleic anhydride (5 g,0.05 mol) and p-amino benzoic acid (6.9 g,0.05 mol) were dissolved in acetone (20 g) and the mixture was stirred for 30 min at room temperature. The resulting precipitate was separated by vacuum filtration and dried. This maleamic acid (11.9 g,0.05 mol) was mixed with acetic anhydride (20 g,0.2 mol) and sodium acetate (2 g, 0.025 mol) in a round bottom flask and heated to 85°C for 15 min. p-Maleimidobenzoic acid (MBA) was recovered by precipitating the contents in cold water purified twice by

dissolution/precipitation in THF/hexane.

BUR (55 g) was dissolved in THF to make a 10 wt% solution prior to the addition of TBAB (2.73 g, 8.25 mmol) and sealing the mixture in a 1 L autoclave. The autoclave was pressurized with nitrogen gas to 200 psi and heated to 85°C for 120 min to rearrange Exo-Br to more reactive Ε,Ζ-BrMe isomers. The autoclave was cooled to room temperature prior to the addition of maleimidobenzoic acid (5.37 g, 24 mmol), KOH (2.31 g, 41 mmol) and N- phenylmaleimide (5 g, 28 mmol). The autoclave was pressurized to 200 psi with nitrogen gas and heated to 75°C for 8 hr. The fully converted product, IIR-g-MBA, was recovered by precipitation from acetone and dried under vacuum.

Example 9. Synthesis and Curing of IIR-g-dodecyl maleate

Dodecanol (6.7 mmol, 1.24 g), maleic anhydride (8.04 mmol, 0.8 g), were dissolved in toluene (10 g) and heated to 80°C for 4 hr. Residual starting materials and solvent were removed by Kugelrohr distillation (T= 80°C, P=0.6 mmHg). The resulting acid-ester (0.93 g, 3.3 mmol) was treated with a 1 M solution of Bu4NOH in methanol (3.3 mL, 3.3 mmol Bu4NOH) to yield the desired Bu4Ncarboxylate salt, which was isolated by removing methanol under vacuum.

BUR (11 g) and Bu4NBr (0.53 g, 1.65 mmol) were dissolved in toluene (100 g) and heated to 85°C for 180 min. Bu4Ncarboxylate salt (1.73 g, 3.3 mmol) was added before heating the reaction mixture to 85°C for 60 min. The esterification product was isolated by precipitation from excess acetone, purified by dissolution/precipitation using

hexanes/acetone, and dried under vacuum, yielding IIR-g-dodecyl maleate.

Example 10 - Synthesis and Curing of IMS-g-aminosilane itaconate

3-Aminopropyl triethoxysilane (5.9 mmol, 1.32 g), itaconic anhydride (5.9 mmol, 0.67 g) were dissolved in toluene (10 g) and stirred at room temperature for 1hr. Residual starting materials and solvent were removed by Kugelrohr distillation (T= 50°C, P=0.6 mmHg). The resulting acid-ester (1.53 g, 4.6 mmol) was treated with a 1 M solution of Bu₄NOH in methanol (4.6 mL, 4.6 mmol Bu₄NOH) to yield the desired Bu₄Ncarboxylate salt, which was isolated by removing methanol under vacuum. BIMS (11 g) was dissolved in toluene (100 g). Bu₄Ncarboxylate salt (2.64 g, 4.6 mmol) was added before heating the reaction mixture to 85°C for 120 min under N₂ atmosphere. The esterification product was isolated by precipitation from excess acetone, purified by dissolution/precipitation using hexanes/acetone, and dried under vacuum, yielding IMS-g-amidosilyl itaconate.

It will be understood by those skilled in the art that this description is made with reference to certain embodiments and that it is possible to make other embodiments employing the principles of the invention which fall within its spirit and scope as defined by the claims.

Claims

We claim:

1. An emulsion comprising an aqueous phase, a dispersed macromonomer phase, and a surfactant.

2. The emulsion of claim 1 , wherein the macromonomer comprises azolium ionomer.

3. The emulsion of any one of claims 1 and 2, further comprising filler.

4. The emulsion of any one of claims 1 to 3, further comprising free-radical initiator, cross- linking coagent, reinforcing filler, non-reinforcing filler, viscosity modifier, processing aid, antioxidant, ultraviolet radiation stabilizer, wax, oil, or a combination thereof.

5. A method of making a macromonomer emulsion comprising, in any order:

adding a surfactant to an aqueous liquid; and

dispersing macromonomer in the aqueous liquid to form an emulsion.

6. The method of claim 5, wherein the surfactant bears at least one moiety that is suitable to participate in crosslinking reactions.

7. A cross-linked polymeric film prepared by spreading the emulsion of any one of claim 1-4 and exposing the spread emulsion to a free-radical initiator to form a crosslinked polymeric coating.

8. The film of claim 7, wherein the film is antimicrobial.

9. A method of making a cross-linked polymer film, comprising:

spreading an emulsion comprising surfactant, dispersed macromonomer, and a continuous aqueous phase on a substrate;

reacting the macromonomer with a free-radical initiator;

allowing cross-linking reactions to occur so that cross-linked polymeric film is obained.

10. The method of claim 9, further comprising allowing time for the spread emulsion to dry prior to reacting the macromonomer with a free-radical initiator.

11. The method of claim 9 or 10, wherein the free-radical initiator comprises: a chemical free-radical initiator, a photoinitiator, heat, heat in the presence of oxygen, thermo- mechanical initiating means, electron bombardment, irradiation, high-shear mixing, photolysis (photo-initiation), ultraviolet light, electron beam radiation, radiation bombardment, or a combination thereof.

12. The method of claim 11 , wherein the chemical free-radical initiator comprises an organic peroxide, a hydroperoxide, bicumene, dicumyl peroxide, di-f-butyl peroxide, an azo- based initiator, homolysis of an organic peroxide, or a combination thereof.

13. A kit comprising:

an emulsion of macromonomer dispersed in an aqueous liquid in the presence of surfactant;

optionally, a free-radical initiator; and

instructions for use of the kit comprising directions to form a cross-linked polymeric film from the emulsion.

14. The kit of claim 13, wherein the instructions comprise printed material, text or symbols provided on an electronic-readable medium, directions to an internet web site, electronic mail, or a combination thereof.

15. The emulsion of any one of claims 1 to 4, wherein the surfactant comprises vinyl alkyl azolium halide salt, a salt of itaconate half ester, a copolymer comprising an isobutylene-rich polymer backbone with pendant polyether chains covalently bound through itaconate diester, or a combination thereof.

16. The crosslinked polymeric film of claims 7 or 8, comprising filler, free-radical initiator, reinforcing filler, non-reinforcing filler, viscosity modifier, processing aid, antioxidant, ultraviolet radiation stabilizer, wax, oil, or a combination thereof.