ALKYL AMMONIUM IONOMERS

Abstract: Ionomers comprising higher alkyl ammonium or quater­ nary polyammonium salts of polyacids, particularly sulfonic acids, having anionic groups covalently bonded to carbon atoms comprising a backbone chain of a polymer, or to acyclic, alicyclic or aromatic radicals which are pendant to the backbone chain of the polymer, are novel compositions of matter. These ionomers vary in properties from water-soluble polyelectrolytes useful as thickening agents to thermoplastic elastomers which can be extruded, injection molded, vacuum formed, etc. at elevated temperatures. The elastomers are useful as speciality and general purpose rubbers.

Description: This invention relates to the preparation and use of novel ionic polymers comprising alkyl ammonium, ammonium and polyammonium salts of polymers having one or more anionic groups covalently bonded to a carbon atom comprising the polymer. Preferred anionic groups are sulfonate, carboxylate and phosphonate groups. The most preferred anionic group is a sulfonate group. This invention relates to ionic polymers. More par ticularly, this invention relates to ammonium salts of anionic polymers, i.e. polymers containing covalently bound nega- tively charged groups. Most particul2rly, this invention is concerned with novel compositions of matter comprising certain higher alkyl ammonium salts or quaternary polyammonium salts of polymers having incorporated therein one or more covalently bonded anionic radicals selected from sulfonate, carboxylate and phosphonate radicals. The particular ammonium salts of this inventicn may be schematically represented as: 1. [C-A]p+1 R3N+ +Q - R2N+ +pR herein C is one of a plurality of carbon atoms comprising a portion of the polymer backbone chain of carbon atoms or is in an acyclic alicyclic or aromatic radical which is pendant to the backbone chaIn and wherein the C is in a single polymer molecule; A is an anionic radical, preferably a sulfonate group, covalently bonded to one or more of the C carbon atoms; and wherein the R groups represent substituents of the nitrogen atom(s) which are each independently selected from hydrogen, C1 to C50 straight or branched chain acyclic, alicyclic, aryl, alkaryl and aralkyl radicals and substituted functional derivatives thereof, provided at least one of the R groups is a C12 to C50 straight or branched chain acyclic, alicyclic, aryl, alkaryl, aralkyl radical or a substituted functional derivative thereof, and wherein each Q is independently selected from C1 to C40 divalent straight or branched chain alkylene, cycloalkylene, arylene, dialkylene-arylene radicals, a substituted functional derivative theroef or-(CHY)n-Zm-(CHY)n wherein Z is the hetero atom, oxygen or sulfur, m is zero or one, Y is hydrogen, said C1 to C50 radical-or a substituted functional derivative of the radical and n is an integer of from 1 to 10, wherein p is from zero (for a monoammonium counterion) to about 10, more preferably zero to about 4, and most preferably zero or one, and wherein the ammonium counterion at least partially neutralizes saict anionic acid radicals0 Other sulfonated salts of the present invention are represented by the formula: : 2o [C - S03 pal R13N+*Q - R'2N]-pR' wherein C is one of a plurality of carbon atoms comprising a portion of the polymeric backbone chain of carbon atoms or is in an acyclic, alicyclic or aromatic radical which is pendant to the backbone chain and wherein the C is in a single polymer chain, the -SO3 groups are covalently bonded to one or more of the C carbon atoms in one or more of the polymeric backbone chains wherein each Q is independently selected from C1 to C40 divalent straight or branched chain alkylene, cycloalkylene, arylene, dialkylene-arylene radical a substituted functional derivative thereof or -(CHY) Z -(CHY)n, wherein Z is the hetero atom, oxygen or sulfur, m is zero or one, Y is hydrogen, said C1 to C50 radical or a substituted functional derivative of the radical and n is an integer of from 1 to 10, wherein p is from one (for a diammonium counterion) to about 10, more preferably one to about 4, and most preferably one, and wherein the R' groups are each indepandently selected from cl to Cl referably- C1 to C4, most preferably Cl straight or branched chain acyclic, alicyclic, aryl, alkaryl or aralkyl radicals and substituted functional derivatives thereof. For example, in formul (3) and (4) below, diammonium and triammonium salts of formula 2 (p equal to 1 and 2 in formula (2)) are schematically represented as: EMI3.1 where the symbols have the same meanings as in formula 2. Using sulfonated polymers as the most preferred example of the anionic polymers of this invention, the ionically cross-linked ionomers of this invention may be readily prepared from the sulfonate precursor, for example a free sulfonic acid, by direct neutralization, either in bulk or in solution with an alkyl ammonium hydroxide wherein the cation is selected from one of the specified classes, or by a primary, secondary or tertiary amine from one of the speci dried classes, or by a combination of these neutralizing agents. Another means of preparation is by double decomposition (metathesis) of a salt of the sulfonic acid with an alkyl ammonium salt of an acid which is weaker (i.e. has a lower/pKa) than the sulfonic acid, or by double decomposition in a multiphase fluid medium in which the salt of the displaced counter ion is selectively removed from the phase containing the polymer to a phase in which the ammonium ionomer is substantially insoluble. The properties and utility of the ionic salts of this invention vary over a wide range depending on the structure of the anionic polymer, the average molecular weight and molecular weight distribution, the degree of neutralization of the anionic groups in the polymer, the mole concentration of the alkyl ammonium salt groups in the polymer, and in particular, the type and variety of the substituents attached to the nitrogen. The ionic salts can range from water-soluble polyelectrolytes useful as adhesives and thickening agents to elastomers or hard resins which are thermoplastic at elevated temperatures permitting the products to be extruded, injection molded, vacuum formed and sheeted. A particularly useful form for an ionomer is a waterinsoluble elastomer which can be melt fabricated and then used without curing, and which can subsequently be reprocessed at elevated temperature since the ionomer does not contain permanent crosslinks. The preferred polymers.are as follows: I. Sulfonate Polymers Polymers having sulfonic acid groups covalently bonded to carbon atoms which comprise a portion of the polymer can be prepared by the sulfonation of a pre-formed hydrocarbon polymer by sulfonating or grafting reagents, or by the homopolymerization or interpolymerization of a monomer incorporating a sulfonic acid group or salt of a sulfonic acid. As used herein the term "interpolymer" denotes a polymer comprising more than one monomer, e.g. copolymer, terpolymors, etc. in which the arrangement of the monomer moieties may be random, alternating, block, graft, stereoregular and the like. Suit- able non-limiting examples are grouped as follows: A. Pre-Formed Polymers a. Homopolymers and interpolymers of one or more acyclic and alicyclic mono-olefins in which the polymers are essentially free of unsaturation (except for chain-end unsaturation) prepared with the aid of cationic, free-radical, alkali metal anidnic, or Ziegler-Natta catalysts. Non-limiting examples include homopolymers and interpolymers of C2 to C18 olefines such as ethylene, propylene, isobutene, butene-l, pentene-l, hexene- 1, 4-methylpentene - 1, cyclopentene, b icyc lo (2,2,1) 2-heptene, dodecene-l and octadecene-l. Commercially available polymers in this group are polyethylene, polypropylene, ethylene-propylene rubber (EPR) and polyisobutylene. b. Homopolymers and incerpolyners of one or more alkenyl aromatic hydrocarbon monomers and substituted derivatives thereof having the general formulae Ar-C(R)=CHR' and Ar-CHR-CH=CH2 wherein Ar is a monovalent sulfonatable aromatic radical and R and R' are independently selected from hydrogen and a methyl radical, Non-limiting examples of monomers which can be polymerized with the aid of a variety of cacalyst systems to yield polymers which are suitable for the practice of this invention include: styrene, oc-mechyl styrene, propenyl benzene, allyl benzene, vinyl toluene, vinyl naphthalene and vinyl echylbenzene. c. Interpolymers of one or more C4 to C10 conjugated diolefins with one or more C3 to C12 vinyl aromatic hydrocarbons. Non-limiting examples include: copolymers of 1,3-butadiene with styrene, e.g. SBR rubber and graft polymers of styrene on polybutadiene. d. Random interpolymers of one or more C8 to C12 vinyl aromatic hydrocarbons comprising about 40 to 60 weight. percent of the vinyl aromatic with one or more C4 to 010 Type III mono-olefins. Non-limiting examples include the PARAPOL S resins comprising interpolymers cf styrene and isobutylene. e. Random elastomeric interpolymers of one or more C4 to C10 conjugated diolefins with one or more C4 to 010 Type III mono-olefins. Non-limiting examples include the family of BUTYL rubbers comprising interpolymcrs of isobucylene with butadiene, isoprene, piperylene, 1,3-hexadiene, 2,3-dimethyl-1, 3-bucadiene and cyclopencadiene. f. Homopolymers and interpolymers of one or more C10 acyclic and alicyclic monoterpenes and C15 S esquiterpenes prepared with the aid of cacionic, Ziegler-Natta and freeradical (e.g. gamma radiation) catalysts. Non-limiting examples of suitable monomers include: /-pinene, dicyclopentadiene, vinyl cyclohexane, dipentane, myrcene, ocimene and ss-farnesene. g. Homopolymers and incerpolymers of one or more C4 to C10 conjugated diolefins. Non-limiting examples of suitable monomers include: 1,3-butadiene; isoprene; piperylene; 2,3-dimethyl buta-1,3-diene; and cyclopentadiene. Enchainment, using a variety of catalysts for the polymerization, e.g. alkali metal anionic and Ziegler-Natta catalysts includesl,4-cis-, 1,4-trans-, 1,2- and 3,4-types of addition and random mixtures thereof. Non-limiting ex samples of commercially available polymers include: natural rubber and synthetic cis-1,4-polybutadiene and cis-1,4polyisoprene. h. Random interpolymers of one or more Type I C2 to C18 mono-olefins and one or more C6 to C12 acyclic or alicyclic non-conjugated diolefins. Non-limiting examples of co=ercially available EPDM polymers include: terpolymers of ethylene, propylene and 1,4-hexadiene (NORDEL); terpolymers of ethylene, propylene and 5-ethylidene-2-norbornene (VISTALON) and ethylene, propylene and dicyclopentadiene (DRILOP). Olefin types are in accordance with the Schmidt and Boord Classification, J.A.C.S. 54, 751 (1932). B. Polymers From Monomers Incorporating Sulfon.c Acids While the range and variety of monomers which incorporate sulfonic acid groups or their salts is noc large at the present rome, the use of these monomers permit the preparation of a variety of homopolymers and interpoly- mers that cannot be easily prepared by direct sulfonation of pre-formed polymers. Non-limiting exampies of monomers incorporating sulfonic acids or their salts include: vinyl sulfonic acid; allyl sulfonic acid; methallyl sulfonic acid; 2-allyl oxyethane sulfonic acid; 2-hydroxy- 3-allyl oxy propane sulfonic acid and styrene sulfonic acid. Vinyl sulfonic acid readily forms a wacer-soluble homopolymer and interpolymers with acrylonitrile, acrylic acid amide, vinyl acetate,. acrylic acid escers and N-vinyl pyrrolidone, using a variety of catalyst systems. Styrene sulfonic acid readily polymerizes to yield a water-soluble polymer. The above monomers or their salts are preferably interpolymerized with hydrocarbons, to provide the polymeric sulfonic acids or their salts. The useof ammonium sulfonate monomers directly provide the novel cDmpositions of this invention. C. Sulfonation of Pre-Formed Polyners Processes for the sulfonation of hydrocarbon polymers which are: (a) essentially free of olefinic unsaturation except for chain-end unsaturation, or (b) possess a measurable degree of olefinic unsaturation which may be in the polymer backbone chain of carbon atoms or is in an acyclic alkenyl dr alkylidene radical or alicyclic radical which is pendant to the backbone chain of carbon atoms, or (c) possess aryl or arylene radicals which comprise the backbone chain of carbon atom or are pendant to the backbone chain of carbon atoms are old in the art. Polymers which are free of unsaturation but have a measure of chain branching such as polyethylene, polypropylene, polyisobutylene and EPR rubbers may be sulfonated in solution by means of S02 and 02 wich the aid of a free-radical iniiator (Sulfoxidation Reaction), or sulfochlorinated in solution by means or S02 and Cl2 with the aid of a free-radical initiator (Reed Reaction) followed by hydrolysis of the sulfonyl chloride to the free sulfonic acid or a salt of the sulfonic acid, or by means of ccmplexes or coordination compounds of SO3 with Lewis bases such as triethyl phosphate as disclosed in U.S. Patent 3,205,285 which is herein incorporated by reference. The same reagent has been disclosed in U.S. Patents 3,672,618 and 3,072,619 for the sulfonation of polystyrene and in U.S. Patent 3,432,480 for the sulfonation of cis-1,4-poly butadiene. The above three patents and U.S. Patent 3,642,728 which discloses a variety of complexing agents for the sulfonation of nonaromatic polymers such as BVTYL rubber. U.S. Patent 3,836,511 discloses the sulfonation of unsaturaced elastomers using acetyl sulfate. The sulfonations are carried out in solution in an inert hydrocarbon solvent such as hexane, heptane or isooctane, or chlorinated solvents such as ethylene dichloride or chlorobenzene at temperatures in the range of -40 C to 1000C depending on the reactivity of the sulfonation reagent employed. Sulfonated polymers suitable for che practice of this invention include those having sulfur contents as high as 29.7 wt. 7. in the case of a honopolymer of vinyl sulfonic acid or 217.2 wt. % in the case of a homopolymer of styrene sulfonic acid and as low as 0.1 wt. 7. in the c ase of a sulfonated polyisobutylene or polypropylene. Ionomers which are melt fabricated are most useful when they have a concentration of ionic groups which is between .1 and 8 mole percent (based on the monomer units of the polymer), more preferably .2 to 6, most preferably .4 to 3 since at concentrations below .1 mole percent che effect of the ionic groups on trite physical properties tends to be slight while above 8 mole percent the ionomer tends to become difficult to melt fabricate. Polymers containing sulfonate groups and in addition containing other anionic groups either on the same polymer molecule or on different polymer molecules are also included in this invention. II. Other Anionic Grouts For the higher alkyl monoammoniun salts specified in this invention carboxylate and phosphonate polymers are also useful. Of these two classes of polymers containing anionic groups, carboxylate conraining polymers are preferred. A wide variety of polymers having one or more carboxylic acid or phosphonic acid grcups covalently linked to carbon atoms comprising the polymer which are suitable for the preparacion of the specified alkyl ammonium ionomers of this invention have been described in the patent and general chemical literature. Some polymers containing carboxylate or phosphonate groups which are particularly useful for the preparation of ionically cross-linked elastomers have been reviewed in "Ionic Polymers", referenced above and by Brown ec. al.; Rubber Chem. & Technol., 28, 937 (1955); Boguslavskii; Soviet Rubber Techno,, 18, 4 (1959); and Brown; Rubber Chem. & Technol., 36, 931 (1963). Non-limiting examples of useful polymers include interpolymers of acrylic and methacrylic acids with olefins and conjugated diolefins. III. Ammonium Counterions The ammonium counterions of this invention were specified in the above identified formulae (1) and (2). In the case of che ammonium cat ions of formula (1) within the specifications of this formula, it is preferred chat the four substituents of the nitrogen atom be hydrogen or an R group having about 1 to about 30 carbon atoms, which is a straight or branched chain acyclic, alicyclic, aryl,alkaryl or aralkyl-group, and more preferably hydrogen or an R group having one to about 26 carbon atoms1 provided at least one substituent is an R group having 12 to 50 carbon atoms, preferably 16 to 30 carbon atoms, and most preferably 16 to 26 carbon atoms. In the case of the di- or polyammonium quaternary cations of formula (2), it is preferred chat the R' groups be alkyl groups containing from one to four carbon acoms, more preferably one or two carbon atoms and most preferably one carbon atom. The preparation of halide salcs and hydroxides of the ammonium cations specified in this invention is generall) know. in the prir art. A partial list of some ammonium compounds which are suitable as starting materials for preparing the compositions of this invention is given below. A. Some Ammonium Salts and Amines Having at Least One Substituent Containing a Cl2 to C50 Alkyl GrouD 1. Quaternary higher monoalkyl ammonium salts. Some examples are coco trimethyl ammonium chloride, docosyl trimethyl ammonium chloride, oleyl triwothyl ammonium chloride, stearyl triethyl ammonium brcmide, iecosyl diethyl methyl ammonium sulfate, tetradecyl dimethyl benzyl ammonium chloride, hydrogenated tallow di-2-hydroxyethyl methyl ammonium chloride and octadecenyl methyl imidazolinium chloride. Monoalkyl trimethyl ammonium salts are preferred. 2. Quaternary higher dialkyl ammonium salts. Some examples are didodecyl dinethyl ammonium chloride, hydrogenated ditallow ammonium chloride, dodecyl scearyl propyl ethyl ammonium sulfate and dicoco 2-hydroxyethyl methyl ammonium chloride. Dialkyl dimethyl ammonium salts are preferred. 3. Quaternary higher crialkyl ammonium salts. Some examples are triundecylmethyl ammonium bromide and tridodecyl benzyl ammonium iodide. Trialkyl methyl ammonium salts are preferred. 4. Quaternary higher tetraalkyl ammonium salts. An example is tetradodecyl ammonium iodize. 5. Tertiary highter alkyl amines. Some examples are coco dimethyl amine, tetracosyl dimethyl amine, didodecyl methyl amine, pentaechoxylated callow amine stearyl diethyl gamine, tredodecyl amine, and didodecyl benzyl amine. Tertiary higher alkyl amines containing cwo or one methyl group(s) are preferred. 6. Secondary higher alkyl amines. Some examples are didodecyl amine, decyl docosyl amine, hexadecyl methyl amine, docosyl propyl amine and t-octadecyl hydroexyethyl amine. Higher alkyl methyl amines are preferred. 7. Primary higher alkyl amines. Some examples are stearyl amine, dodecyloxypropyl amine, dodecylthiopropyl amine, and lauryl amine. 8. Higher alkyl diamines having primary, secondary and/or tertiary amino groups. Some examples are octadecyl ethylene diamine, dodecyl tetramethyl decamechylene diamine, tetradecyl xylene diamine and bis-dodecyl piperazine. 9. Higher alkyl triamines having priry, secondary and/or tertiary amino groups such as docosyl ethylene triamine, tris-hexadecyl methylamino cyclohexane. 10. Higher alkyl substituted polyamines such as derivative of polyethylene imine, nitrilo bis-propylamine, and polyvinyl pyridine. 11. Higher alkyl substituted quaternary polyammonium compounds such as decamethylene bis-dodecyldimethyl ammonium dichloride. B. Some Quaternary Polya=oiu:n Salts 1. Quaternary ammonium compounds. Some examples are decamethylene bis-trimethyl ammonium dichloride, xylene bis-triethy.l ammonium dichloride, butenylene bisdiethyl methyl ammonium dichloride, ethylene bis tribenzyl ammonium dibromide, and thio bis-propyl trimethyl ammonium dichloride. Hydrocarbylene bis-trimethyl ammonium compounds are preferred. 2. Quaternary triammonium compounds. Polymethyl dialkylene triammonium compounds are preferred. An example is octamechyl diethylene triamine. 3. Quaternary polyammonium compounds. Some examples are polymethyl polyethylene polyamine, polymechyl polybutenylene polyamine, methylated polyxylene polyamine and methylated polyvinyl pyrididine. Polymethylated polyalkylene amines are preferred. The products of the present invention were characterized by the general formulas (1) and (2) which were des- cribed above. Such polymers range in properties from watersoluble polyelectrolytes useful as thickening agents to thermoplastic elastomers which can be extruded, injection molded, vacuum formed, etc. at elevated temperacures. The elastomers are useful as speciality and general purpose r ubbers. Products which have a limited concentration of anionic groups covalently bonded to one or more of the carbon atoms comprising the polymer, when neutralized or partially neutralized with metal cacions are generally referred to as ionomers. The acidity of the unnautralized anionic polymer may vary over a wide range; useful acidities being in the range from 0.1 to 200 milliequivalents of hydrogen per 100 grams of the anionic polymer. Such ionomers, when neutralized or partially neutralized with the ammonium cat ions specified in this -- invention (rather than with metal cations) are a preferred embodiment of this invention. In particular, such ionomers when based on an elastomeric backbone have applications as t hermoplastic elastomers. The plasticized ionomers of the invention can be readily compounded in convencional elastomer or plastic compounding equipment wich additives which are fillers processing oils, thermoplastic polymers, plasticizers, and pigments and mixtures thereof. The following examples more fully illustrace the invenrioz1. EXA^N2LE 1 - PREPARATION OF QUATERNARY AMMONIUM HYDROXIDES Four quaternary ammonium halides were obtained from the sources cited below and converted to the hydroxide form by the procedure described below. Dioctadecyldimethyl ammonium chloride, and octadecyltrimethylammonium chloride were purchased from Lachat Chemical Company. Decamethylene bistrimethyl ammonium dibromide was purchased from City Chemical Co=pany. Triethyloctadecylammonium bromide was prepared via quaternization of criethyl amine by octadecyl bromide. In order to convert these halides to the hydroxide form, a percolacion column having a height to diameter ratio of approximately 15:1 was packed with Amberlyst A-29, a commercially available anionic macroreticular ion-exchange resin markeced as the chloride salt by Rohm and Haas Co., Philadelphia, PA. The resin was converted to the hydroxide form by slowly passing 6.5 Ded volumes of a 10 wt. % aqueous solution of reagent grade sodium hydroxide downward through the bed, followed by discilled water until the effluent had a pH of 7.0. The water in the column and in che resin was then displaced by percolating 15 volumes of anhydrous methanol downward through che column. Each of the above four quaternary ammonium halides was dissolved in 300 ml. of a solvent consisting of either anhydrous methanol or ethanol, or mixcures of these alcohols with either benzene or cyclohexane depending on che solubility characteristics of che particular halide. The various solution which ranged in concentration from about 0.5 to 20 grams of halide per 300 ml. of solvent were percolated through a freshly prepared column of che hydroxide form of the ion exchange resin. The receiver for the percolaced solution was blanketed with oxygen-free nicrogen When sealed and refrigerated until used. Just before use an aliquoc of each solution was titrated wich standard alkali in order to check the basicicy. In addition to che quaternary ammonium hydroxides which were prepared above, the following qua ternary ammonium reagents were purchased in their hydroxide form from Southwestern Analytical Chemicals Company of Austin, Texas. [N(CH3)4] [OH] [N(CH2CH3)4]+ [OH] EXAMPLE 2 - PREPARATION OF QUATERNARY AMMONIUM SALTS OF A SULFONATED EPDM An EPDM available on a commercial scale (VISTA;ON) from Exxon Chemical Co., New York, New York, which comprised 52 wt. 7. of ethylene, 43 wt. % of propylene and 5 wt. X of 5-ethylidene-2-norbornene and had a number average molecular weight of 35,000 and a Money viscosity ML &commat; 100 C (1 + 8 min.) of 42 was sulfonated using acecyl sulfate in accordance with the method disclosed in U.S. Patent 3,836,511. This free acid form of the sulfonated polymer was isolated from solution by steam stripping and dried on a warm two-roll mill. The product was stored ac a temperature of -80 C prior to use. On the afternoon before che day of neutralization the free acid sulfonated polymer was cut into pieces and placed in a mixed solvent consiscing of 95% toluene and 5% methanol by volume, to prepare a solution having a concentration of 20 grams per liter. The mixture was stirred at room temperature overnight during which the polymer dissolved except for some small pieces of gel. In the morning the solution was filtered, and on nitration of an aliquot was found to have an acidity of O.39 milliequivalents of hydrogen per 100 ml. The following qua ternary ammonium hydroxides which were described in Example 1, were used to neutralize aliquots of the free acid sulfonated EPDM solution. 1. [(C18H37)2N(CH3)2]+ [OH] 2. [(C2H5)3 N(C18H37)]+ [OH] 3. [(CH3)3N(CH2)10N(CH3)3]++ (2[OH] 4. [(C18H37)3 N(CH3)3]+ [OH] 5. [N(CH3)4) [OH] 6. [(CH2CH3)4]+ [OH] The aliquots of the sulfonated EPDM solution were overbased with each of che quaternary ammonium hydroxide samples by the addition of 1.2 equivalents of the quaternary ammonium hydroxide per equivalent of sulfonic acid. The solutions were stirred under nitrogen for about 10 minutes, checked for basicity and slightly acidified with 2.5% acetic acid in methanol. Approxi=ately G.25 equivalencs of the acetic acid were added per equivalent of acidity previously present in che solution. On neutralization some of che samples became cloudy. These cloudy solutions were clarified by che addition of toluene. The products were recovered by precipitation with about 10 volumes of methanol, followed by settling and decan tat ion of the supernatant liquid. Ln some cases where settling was incomplete, the solutions were centrifuged to consolidace the precipitate. Each of che recovered ionomers was overlaid wich sufficient methanol to cover the product; then 0.1% by weight (based on the weight of recovered product) of a phenolic antioxidant (antioxidant 2246) was added to each sample and after standing overnight the methanol was decanted and the products dried at room temperature in a vacuum oven for several days. While all of the sulfonate groups in the above and subsequent examples were completely neutralized, i.e. 100% neutralization, in certain inscances it is desirable to partially neutralize. the anionic groups present in the polymer, e.g. 5 to 957. wich the quaternary ammonium hydroxides and leave some free acidity or complece che neucralizarion with a different counterion. EXAMPLE 3 - PHYSICAL PROPERTIES OF A SULFONATED EPDM CONTAINING MONOVALENT QUATERNARY AMMONIUM COOUNTERIONS Test pads were molded from the ionomer materials prepared from Samples (1), (2), (4), (5) and (6) of Example 2. The test pads were compression molded at 160"C. using a preheat of 2 minutes and 3 minutes under pressure. Microtensile pads having a thickness of about 0.6 em. and test regions measuring 2.54 mm. in widrh and 12.7 mm. in length were cut from the pads. Tensile screngths of the samples were measured at 25 C. and 100"C. with an Instron TM cable model instrument, using a pulling speed of about 51 mm. per minute. In addition, the melt flow races of che polymers were determined at 1500C., using rhe standard capillary and instru- ment specified in ASTM 1238-70. The weight of the probe plus the added weight was 12.5 kilograms. Flow rates were measured electronically as probe displacement per minute and these results were converted to grams per 10 minutes using a conversion factor. The results are given in Table I. The first data column in Table I compares the melt flow rates at 150"C. of materials containing various monovalent quaternary ammonium counterions. It is apparent that the samples containing the long-chain counterions (Samples (1), (2) and (4)) have nrch higher melt flow and are softer than the short-chain counterions (Samples (5) and (6)). TABLE I PHYSICAL PROPERTIES OF A SULFONATD EPDM CONTAINING VARIOUS MONOVALENT QUATERNARY AMMONIUM COUNTERIONS Melt Flow Rate Tensile Strength Sample Structure of 150 C, 250 psi (psi) Number Counterion (g/10 min.) 25 C 100 C 1 (C18H37)2N+ (CH3)2 0.020 1700. 70. 2 (C2H5)3NT (C18R37) 0.030 1110. 60. 4 (C18H37)N+ (CH3)3 0.0085 - 5 N (CH3)4 0.0030 -- - 6 N+ (C2H5)4 0.0045 -- - Higher melt flow usually results in easier melt processing such as by extrustion or injection molding. Softer elastomers tend to be more appropriate for applications requiring high degrees of flexibility and low stiffness such as, for example, hot melt sealants for joints which exper ience movement over time, or for gloves or shoe parcs which require high flexibility or softness. The difference in material properties which is caused by substituting quaternary ammonium counterions con raining long-chain substituents for shorter chain sub stituents is more clearly illuscraved by direct comparison of the compositions in Table I. Sample (6), containing the tetraethylammonium counterion gives a low melt flow rate of 0.0045 grams per 10 minutes. In one of the ethyl substituents of Sample (6) is replaced by an occadecyl substituent, Sample (2) is obtained. So, it is seen that the substitution of the long chain for the short chain re- sults in an increase in melt flow by more than 6 times. Sample (5), which contains the short methyl substituents on the councerion has a very low melt flow rate of 0.0030 grams per 10 minutes. Replacing one of the methyl groups with an octadecyl group gives Sample "4"; it can be seen from Table I that Sample "4" has almost 3 times the melt flow rate of Sample "5". If a second methyl substituent of Sample "5" is replaced by an octadecyl group, then Sample "1" is obtained. Sample "1" which contains the dioctadecyl dimethyl a:nonium counterion has over six times the melt flow rate of the tetramethyl ammonium counterion. It is clear from these results that utilizing long-chain substituents instead of short chains in a quaternary ammonium counterion results in materials having better processing (higher melt flow rates), and which are weaker and softer. EXAMPLE 4 - PHYSICAL PROPERTIES OF A SULFONATED EPDM NEUTRALIZED WITH POLYVALENT QUATERNARY AMMONIUM COUNTERIONS A. A Divalent Quaternary Ammonium Counterion Sample 3 of Example 2 was neutralized with the diva lent cation 1(CH3)3 N(CH2)10 N(CH3)33 '*. Test pads of this material were compression molded at 160 C, and microtensile pads (as described in Example 3) were cut from the pads. Tensile strengchs were measured at 250C and 100 C using a pulling speed of 51 mm. per minute. Also, the melt flow rate was measured using che method described in Example 3. The results were as follows: Sample Number ..... "3" Structure of Counterion ........... (CH3)3N+(Ch2)10N+(CH3)3 Melt Flow Rate at 1500C, 230 psi .. 0.0035 g/10 minutes Tensile Strenght at 25 C ........... 1820. psi Tensile Strenght at 100 C........... 180. psi It is seen that this sample containing this divalent counterion has melt flow rate which is less than one-half of the lowest flow rate long-chain counterion sample of Table I. In fact, the melt flow race of this material is almost as low as the cecramechyl ammonium counterion sample (Sample "5" of Table I). In addition to its low melt flow rate and resultant high melt strength the diva lent sample "3" has a high tensile strength than the values listed for the long-chain counterion samples in Table I. In particular, Sample "3" has an excellent 100"C tensile strength. This sulfonated material neutralized with this diva lent ammonium counterion has a low melt flow rate and high tensile strength at elevated temperature even though its diva lent counterion contains a fairly long (ten carbon) chain. Higher tensile strengths are obviously desirable in many applications which subject an article to high stresses, such as hoses or flexible industrial belts. High melt strength can be desirable in some fabrication processes such as blow molding or blow forming of thin flexible sheets. B. A. Polyvalent Quaternary Ammonium Counterion Maznifloc 577C is a Polovalen: Quaternary ammonium chemical having the structure EMI18.1 it has 2 n relatively low degree of polymerization. It is manufactured by the American Cyanamid Company. This material was converted to the hydroxide using the procedures cf Example 1, and it was used to neucralize a free acid sulfonated EPDM similar to that prepared in Example 2. A solution of this free acid containing 20g of polymer per liter of solvent had an acidity of 0.C057 milliequivalents of hydrogen per 100 ml. The neutralization procedure was similar to that used in Example 2. The isolation of the neutralized solfonated polymer from the solution was as follows. The solution was steam-stripped co remove the solvencs and precipitate the ionomer as a crumb for about one-half hour ac which cime the polymer had lose any tendency toward cackiness. The solids were filtered and washed in a Waring blender successively with methanol, discilled water and methanol. About 0.3 wt. Z of a hindered phenol antioxidant (antioxidant 2246) was added to che polymer before each wash. The polymer crumb was air dried ac room cemperacure and further dried at room temperature under a vacuum. For comparison with this polyvalent quaternary ammonium councerion, tetrramethylammonium hydroxide was used for the polyvalent counterion. The neutralzation and isolacion procedures were similar to che ones used br che polyvalent counterion. Tensile measurements and melt flow measuremencs were made on the samples containing the polyvalent and tetramechyl ammonium counterions using the methods described in Example 3. It was found thac the sample containing the polyvalent quaternary ammonium counterion had a lower melt flow race, and higher censile strengths and modulii at both 25 C and 100 C as compared with the tetramethylammonium counterion. This demonstrates that a sulfonated polymer containing a polyvalenc ammonium counterion can result in lower melt flow (and higher melscFength), and higher tensile strength and modulus than monovalent quaternary ammonium counterions of similar structure EXAMPLE 5 - PREPARATION AND PHYSICAL PROPERIES OF A SULFONATED EPDM NEUTRALIZED WITH LONG CHAIN MONOVALENT AMINES An EPDM having a Mooney viscosity .'L &commat; lG0 C (1 + 8 min.) of about 20 was used as the starting material for making a lighcly sulfonated polymer. This EPDM con cained about 5 wt. % of 5-echylioene-2-norbornene and it concained about 50 wc. % of ethylene. It was sulfonatec using acetyl sulfate in accordance with the method d isclosed in U.S. Patent 3,836,511, to produce the free acid form of the polymer. This material was isolated by steam stripping and dried on a warm mill. This dried polymeric sulfonic acid was dissolved at a concencration of 30 gram per licer in a mixed solvent consisting of 93% toluene and 7 methanol by volume. By titration of an aliquot, che polymer was found co have an acidity of 25 milliequivalents of acid per 100g or polymer. The acid form of che lighcly sulfonated EPDM was divided into a number of portions, and different portions were neutralized in solution by the long chain amines listed below: 7. C20,22H41,45NH2 8. C20,22H41,45N(CH3)2 9. (C20,22H41,45)2 N(CH3) 1C. (C12H25)3N The double subscripcs in Samples 7, 8 and 9 indicace that these materials contain a major amount of boch C20R41 and C22H45 in the long-chain substituent(s). These amines also concain a minor amount of C18H37 in their long-chain substituent(s). These three samples were obtained from the Humko Sheffield Chemical Company; Sample 7 as Kemamine P-190-D, Sample 8 as Kemanine T-1902-D, and Sample 9 as Kemanine T-1901. Sample 10, tridodecylamine was obtained from the Eastman Chemical Company. Portions of the free acid sulfonated EPDM solution were slightly overbased with each of the above long-chain amines by the addition of 1.15 equivalents of che longchain amine per equivalent of sulfonic acid. The solutions were stirred ac room temperature for about 20 minutes. The neutralized polymers were recovered rrc= the solution by steam scripping and dried on a hoc tworool mill. Tensile pads were molded from che amine neu.ralized sulfonated EPDM's in che manner described in Example 3, and microtensile test dumbbells were cuc from the pads. Tensile strengths of the sulfonated EPDM's neutralized with the four long-chain amines were measured at room temperature on an Inscron TM table model apparatus at a pulling speed of 51 mtn. per minute. In addition, melt flow rate measurements were made using the procedure described in Example 3. The results are shown in Table II. TABLE II PHYSICAL PROPERTIES OF A SULFONATED EPDM NEUTRALIZED WITH VARIOUS LONG CHAIN AMINES Melt Flow Tensile Properties at Room Temperatur Sample Rate 150 C Strenght Elongation Initial Modul Number Neutralizing Agent 250 psi (g/10 min.) (psi) (%) (psi) 7 C20,22H41,45NH2 0.044 1600 600 340 8 C20,22H41,45N(CH3)2 0.7 975 840 300 9 (C20,22H41,45)2N(CH3) 1.9 735 795 275 10 (C12H25)3N 2.1 220 1480 175 By comparing Samples 7 and 8 of Table II ic is seen that substituting methyl groups for hydrogens (actached ro the nitrogen acom) greatly increases che melt flow rate and thereby improves processability. This change also results in a soft material (lower modulus) and tends to reduce strength. In comparing Samples 8 and 9 of Table II it is observed thac substituting a long chain in place of a short chain sub- stiruent further increases the melt flow rate, and further increases softness. The last sample 10, in Table II illustrates that the presence of additional long-chain substituents, C12 in chis case, can be more important in increasing melt flow increasing softness then simply having a large amount of hydrocarbon in a lesser number of long chains; e.g., Sample 10 with chree long chains but only 36 carbon atoms has greater melt flow and softness chan Sample 9 with over 40 carbon atoms. In order to determine the relative effects on physical properties of neutralizing an ionomer wich an amine containing a long-chain substituant of cwelve carbons or more as compared with an amine of corresponding structure out containing shorter substituents, a short-chain amine was utilized as a neutralizing agenc. Tripropylamine, N(C3H7)3, was obcained from Aldrich Chemical Company. It was used to neutralize a portion or che free acid sul fonated EPDM described earlier in this example and it was worked up in exactly the same manner as the materials neutralized wich the long-chain amines, and censile samples were prepared, and tensile and melt flow race measurements were made. The physical properties of the sulfonated EPDM neutralized with cripropylamine are presenced in Table III. For comparison, results for an amine of similar for: (chree hydrocarbon substituents of che same structure) but having long (12-carbon) chain substituents are also shown in Table III. It is seen that changing he propyl substituents of Sample 11 to dodecyl substicuents to gec Sample 10 has a dramatic effect on melt flow rate, strength, softness (modulus), and elongation. The material neutralized with the amine containing the 12 carbon substituents (tridodecylamine) has over 5 times the melt flow rate of the sample neutralized with tripropylamine; a lso, Sample 10 is much softer and has much higher elongation and much lower tensile strength. The much higher melt flow rate and greacer softness of the material neurralized with the long chain amine make it useful where high processing rates are desirable, such as in injection molding or extrusion. Also, these properties would be useful in caulking compounds and hoc melt sealancs. TABLE III COMPARISON OF A LONG CHAIN WITH A SHORTER CHAIN AMINE AS NEUTRALIZING AGENTS FOR A SUFLONATED EPDM Melt Flow Tensile Properties at Room Temperatur Sample Rate 150 C Strenght Elongation Initial Modul Number Neutralizing Agent 250 psi (g/10 min.) (psi) (%) (psi) 11 (C3H7)3N 0.37 970 720 320 12 (C12H25)3N 2.1 220 1480 175

Claims: 1. A polymer having the general formula: [C - A-]p+1 R3N+ #Q-R2N+#pR wherein C is one of a plurality of carbon atoms comprising a portion of the pol ymer backbone chain of carbon atoms or is an acyclic, alicyclic or aromatic radical which is pendant to the backbone chain and wherein said C is in a single polymer molecule: A is an anionic radical covalently bonded to one or more of said C carbon atoms; and wherein the R groups represent substituents of the nitrogen atom(s) which are each independently selected from hydrogen, C1 to C50 straight or branched chain acyclic, alicyclic, aryl, alkaryl, aralkyl radicals or a substituted functional derivative thereof, provided at least one of the R groups is a C12 to C50 straight or branched chain acyclic, alicyclic, aryl, alkaryl, aralkyl radical or a substituted functional derivative thereof, and wherein each Q is independently selected from C1 to C40 divalent straight or branched chain alkylene, cycloalkylene, arylene, dialkylenearylene radicals, a substituted functional derivative thereof or a -(C8Y)n-Zm-(CHY)n, wherein Z is the hetero atom oxygen or sulphur, -m is zero or one, Y is hydrogen, said C1 to C50 radical or a substituted functional derivative of said radical and n is an integer of from 1 to 10, wherein p is from zero (for a monoammonium counterion) to 10, and wherein said ammonium counterion at least partially neutralizes said anionic acid radicals0 2. A polymer according to claim 1 wherein said backbone polymer is an onomer, 3o A polymer according to claim 1 wherein said backbone polymer is an elastomers '*. A polymer according to claim 3 wherein said backbone polymer is an EPDM or Butyl rubber, 5. A polymer according to claim 1 wherein said polymer backbone is: (a) a homopolymer or interpolymer of one or more acyclic and alicyclic mono-olefins; (b) a homopolymer or interpolymer of one or more alkenyl aromatic hydrocarbon monomers; (c) an interpolymer of one or more C4 to C10 conjugated diolefins with one or more C8 to C12 vinyl aromatic hydrocarbons; (d) an interpolymer of one or more C8 to C12 vinyl aromatic hydrocarbons with one or more C4 to C10 Type III mono-olefins; (e) an elastomeric interpolymer of one or more C4 to C10 conjugated diolefins with one or more C4 to C10 Type III mono-olefins; (f) a homopolymer or interpolymer of one or more C10 acyclic and alicyclic monoterpenes and Cl5 sesquiterpenes; (g) a homopolymer or interpolymer of one or more C4 to C10 conjugated diolefins; or (h) an interpolymer of one or more C2 to C18 Type I mono-olefins and one or more C6 to C12 acylic and alicyclic non-conjugated diolefins. 6. A polymer according to claim 2 wherein said anionic radical is a sulfonate group covalently bonded to said C carbon atoms in an amount of from about 0.2 to about 8 mole percent. 7. A polymer according to claim 2 wherein said ionomer is water insoluble. 8. A polymer according to either of claims 1 and 2 wherein C is a portion of a polymeric backbone which is an interpolymer of ethylene and propylene. 90 A polymer according to any one of the preceding claims further including a filler, an oil, an extender or a mixture thereof.

Inventors: BRENNER, DOUGLAS, OSWALD, ALEXIS A.
Applicants: EXXON RESEARCH AND ENGINEERING COMPANY
Application year: 1979
Main classification: C08F8
IPC codes: C08F8, C08G85, C08C19