WO2022225744A1

WO2022225744A1 - Chlorinated polyvinyl chloride composition

Info

Publication number: WO2022225744A1
Application number: PCT/US2022/024392
Authority: WO
Inventors: Thomas S. CORRIGAN; Amy L. SHORT; Christopher M. RASIK; Tyler PETEK; John S. Manka
Original assignee: The Lubrizol Corporation
Priority date: 2021-04-20
Filing date: 2022-04-12
Publication date: 2022-10-27

Abstract

The disclosed technology relates to a conductive composition containing chlorinated poly(vinyl) chloride ("CPVC") and a conductive filler, such as, for example, a graphitic material. More particularly, the technology includes bipolar plates prepared from the conductive composition for use in electrochemical devices, such as fuel cells, flow batteries, electrolyzers, and the like.

Description

TITLE

CHLORINATED POLYVINYL CHLORIDE COMPOSITION BACKGROUND OF THE INVENTION [0001] The disclosed technology relates to a conductive composition containing chlorinated poly(vinyl) chloride (“CPVC”) and a conductive filler, such as, for example, a graphitic material. More particularly, the technology includes bipolar plates prepared from the conductive composition for use in electrochemical de- vices, such as fuel cells, flow batteries, as well as electrolysis processes and the like. [0002] Bipolar plates (BPPs) perform a critical function in electrochemical sys- tems, such as fuel cells (e.g., PEMFCs) and redox flow batteries, as well as elec- trolysis processes, such as chlor-alkali and water electrolysis. In a fuel cell, the channeled bipolar plates are responsible for directing the fuel (hydrogen) and ox- idant gas (air/oxygen) to the anode and cathode catalysts. The most important role of the BPPs is to connect individual cells of the PEMFC in series via electrical conductivity of electrons from the anode of one cell, to the cathode of the adjacent cell. Similar to a fuels cell, in redox flow batteries bipolar plates, or “current collectors” separate individual cells and transfer electrons. In a specific type of flow battery, the vanadium redox flow battery (VRFB), the BPPs come in direct contact with a highly corrosive liquid electrolyte, including strong acid (e.g., sul- furic acid and/or hydrochloric acid) and varying oxidation states of vanadium. In these VRFB systems, component corrosion resistance is of the utmost importance in durability and longevity of the battery. [0003] Several types of BPPs have been investigated, including nonporous graph- ite, coated and non-coated metallics, and composite materials. Each of these ap- proaches has advantages and disadvantages. Thermoplastic composites offer sev- eral attractive advantages including low cost, low weight and ease of manufacture relative to traditional graphite, and they can be tailored through resin system and conductive fillers. [0004] Within composite BPPs, the polymeric binder is chosen based on chemical compatibility with the system environment, mechanical and thermal stability, pro- cessability (especially when compounded with conductive material) and cost. Both thermosets and thermoplastics have been used for BPPs. Thermosets such as phenolics, epoxies, polyester, and vinyl esters are often choses for their com- patibility with high loadings of conductive filler, and good chemical resistance. [0005] Thermoplastic resins such as polypropylene, polyethylene, poly(vinyli- dene fluoride) (PVDF), and phenylene sulfide are used less often due to generally lower chemical and thermal resistivity. However, thermoplastics can be injection molded making them much more favorable for automated manufacturing pro- cesses. [0006] It would be desirable to prepare a conductive composition from a more easily manufacturable thermoplastic with improved chemical stability that could be employed, for example, as a bipolar plate. SUMMARY OF THE INVENTION [0007] Owing to the superior properties of thermoplastic chlorinated polyvinyl chloride (“CPVC”), such as high glass transition temperature, high heat distortion temperature, robust chemical resilience, strong mechanical properties, and fire resistivity, provided is a superior thermoplastic binder for fabrication of conduc- tive compositions, such as bipolar plates. The CPVC binder can be molded or extruded or otherwise impregnated with a conductive filler such as graphite, car- bon black, graphene, carbon nanotubes, or other electronically conductive mate- rials to achieve a desired specifications for use in an electrochemical devices, such as a flow cell battery or fuel cell application or electrolysis applications. The combination of CPVC physical properties with the ease and scalability of manu- facturing of thermoplastic type composites gives CPVC BPPs an advantage over current BPP systems used today. [0008] In one embodiment, the disclosed technology, solves the problem of ease of manufacturability by providing an extrudable and injection moldable compo- sition that is also chemically stable. [0009] The disclosed technology provides a conductive composition of a chlorin- ated polyvinyl chloride (“CPVC”), and a conductive filler. In embodiments, the conductive composition can also include an acid neutralizer. [0010] The technology also provides an electrochemical device containing the conductive composition, such as, for example, a fuel cell or an electrolyzer. The electrochemical device can contain a layer of a cathode, an ionic conducting layer and an anode, the layer being held between two bipolar plates prepared from the conductive composition. DETAILED DESCRIPTION OF THE INVENTION [0011] Various preferred features and embodiments will be described below by way of non-limiting illustration. [0012] One aspect of the technology is directed to a conductive composition in- cluding chlorinated poly(vinyl) chloride (“CPVC”) polymer and a conductive filler. [0013] CPVC polymer is known to the art and to the literature and is commercially available. CPVC polymer can be prepared by chlorinating poly(vinyl) chloride (“PVC”) polymer, which has a chlorine content of about 56 wt%. The CPVC polymer employed in the conductive composition can have a chlorine content of from about 60 to about 72 wt. % based on the weight of the polymer, or from about 61 to about 71 wt. %, or about 62 to about 70 wt. %, and even from about 63.0 to about 68.0 or 69.0 wt. %, or between about 64.0 or 65.0 and 67.5 wt. %. [0014] The molecular weight of the CPVC is often indicated in the industry by reference to the inherent viscosity (I.V.) of the underlying PVC from which it was prepared. The CPVC polymer employed in the conductive composition can have an I.V., as measured on the underlying PVC polymer from which it was prepared per ASTM D1243, in the range of from about 0.4 to about 1.4. In some embodi- ments, the I.V. of the CPVC polymer, as measured on the underlying PVC poly- mer from which it was prepared per ASTM D1243, can be within a range of from about 0.4 to about 1.4, or from about 0.5 to 1.3, or even from about 0.54 to 1.2, or about 0.6 to 1.1, and in some embodiments from about 0.65 to 0.90 or 0.92, or even from about 0.65 to 1. While the I.V. is measured on the underlying PVC polymer, in the art and in the industry, the the I.V. is most often simply referred to in terms of the CPVC itself. In other words, one would refer to CPVC having an I.V. of 0.4 to 1.4, even though it is known the I.V. is measured on the under- lying PVC. This norm of reference to I.V. of the CPVC will be used herein. [0015] The CPVC polymer can be a homopolymer; that is, 100% of the repeat units making up the polymer backbone are derived from vinyl chloride monomers (i.e., ClCH=CH₂). The CPVC polymer can also be a copolymer in which a portion of the repeat units in the polymer backbone are derived from some other monomer besides vinyl chloride. As a copolymer, from about 90% to about 99.99 mole% of the repeat units in the CPVC polymer backbone can be vinyl chloride mono- mers. In some embodiments, the CPVC polymer can include from about 91mol%, or 92mol% to about 99.9mol%, or 99.5mol% vinyl chloride monomers. Notice that reference here to vinyl chloride encompasses both vinyl chloride as the mon- omer and vinyl chloride as incorporated into the polymer backbone. In come embodiments, the CPVC polymer can include from about 93mol%, or 94mol% to 99mol% vinyl chloride monomers, and often from about 95mol% to 98mol% vi- nyl chloride monomers (i.e., repeat units derived from vinyl chloride monomer). [0016] As a copolymer, the remainder of the co-monomers in the CPVC polymer can be one or more vinyl component co-monomers, or mixtures thereof. That is, from about 0.01mol% to about 10mol% of the co-monomers in the vinyl chloride copolymer resin can be vinyl component monomers, or from about 0.1mol%, or 0.5mol% to about 9mol%, or 8mol% vinyl component monomers. In certain em- bodiments, the vinyl component co-monomer can be from about 1mol% to about 6mol%, or 7mol%, or more preferably, from about 2mol% to about 5mol% of the total co-monomers in the vinyl chloride copolymer resin. [0017] By the term "vinyl component co-monomer" it is meant a vinyl type mon- omer other than vinyl chloride. Such monomers are well known to the art and to the literature and include esters of acrylic acid wherein the ester portion has from 1 to 12 carbon atoms, for example, methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, cyanoethyl acrylate, and the like; vinyl acetate; and vinyl aliphatic esters containing from 3 to 18 carbon atoms; esters of methacrylic acid wherein the ester portion has from to 12 carbon atoms, such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and the like; styrene and styrene derivatives having a total of from 8 to 15 carbon atoms such as alpha-methylstyrene, vinyl toluene, chlorostyrene; vinyl naphthalene; diolefins having a total of from 4 to 8 carbon atoms such as butadiene, isoprene, and including halogenated diolefins such as chloroprene; monoolefins having from 2 to 10 carbon atoms and prefera- bly 2 to 4 carbon atoms such as ethylene, propylene and isobutylene; and mixtures of any of the above types of monomers and other vinyl monomers co-polymeriz- able therewith known to the art and to the literature. In a preferred embodiment, the vinyl component co-monomer can be ethylene, propylene or isobutylene, and most preferably, ethylene. [0018] The CPVC polymer can be included in the conductive composition at from about 20 to 85 vol%. In some instances, the CPVC polymer can be included in the conductive composition at from about 25 to 80 vol.%. In embodiments, the CPVC polymer can be included in the conductive composition at from about 30 to about 75 vol.% or from about 35 to about 70 vol.%. In embodiments, the CPVC polymer can be included at less than 50 vol.%. In embodiments, the CPVC pol- ymer can be included at 40 to about 50 vol.%. [0019] The conductive filler employed in the conductive composition can be any material suitable to conduct an electrical charge, such as metals, intrinsically con- ducting polymers (“ICP”), conductive polymeric composites (“CPC”), carbona- ceous compounds, such as graphitic materials, and the like or any combinations thereof. [0020] Any of the conductive metals now employed or developed for use in con- ductive compositions in the future may be employed in the instant conductive composition. Conductive metals known to be employed in conductive type com- position can include, for example, stainless steel, aluminum, titanium, copper, nickel, and really any of the transition metals, and alloys thereof. [0021] Any of the ICPs now known or developed in the future may be employed in the conductive composition. ICPs can include, for example, aromatic polymers such as poly(fluorene)s, polyphenylenes, polypyrenes, polyazulenes, polynaph- thalenes and the like, as well as poly(p-phenylene vinylene), polypyrrole, poly- thiophene, and polyaniline. ICPs also include poly(acetylene)s and other poly- mers containing double bonds. [0022] Any of the CPCs now known or developed in the future may be employed in the conductive composition. CPCs are known in the art and can be formed from dispersing ion-conductive materials in a matrix of ion-conductive polymers having ion exchange groups. Ion-conductive polymers can include, for example, perfluorosulfonic acid polymers, polyamide, polyamide-imide, polyimide, poly- ether ketone, polyether ether ketone, polyphenylene, polyphenylene ether, poly- ester, polycarbonate, polyethylene, polypropylene, polyester, polystyrene, polya- cetal, polysulfone and poly(meth)acrylic acid derivatives, which all have ion ex- change groups; and block copolymers composed of ion-conductive blocks and ion-nonconductive blocks, all of which may be used. [0023] Carbonaceous compounds can include, for example, carbon black. Carbon black is a material produced by the incomplete combustion of heavy petro- leum products such as FCC tar, coal tar, or ethylene cracking tar. Carbon black is a form of paracrystalline or amorphous carbon that has a high surface-area-to- volume ratio, albeit lower than that of activated carbon. In particular, the carbon black may be an "acetylene black" or a "furnace black" or any commercial grade of conducting carbon black, the acetylene blacks being superior in producing con- ducting blends. "Furnace blacks" are lower quality carbon blacks and are inferior in their ability to produce conducting blends when compared to "acetylene blacks", which are fabricated from the pyrolysis of acetylene. [0024] Graphite is a well-known carbonaceous compound and may be employed in the present technology in any of its various forms, including natural or syn- thetic, crystalline or amorphous. When used, graphite may be employed in the plethora of particle shapes, such as spherical, ovular, etc., as flakes, powders, fibers or aggregates. As used herein, the term graphitic material covers graphite in its many different forms. Graphitic material, as used herein, can include a single sheet of graphene plane, also referred to as mono-layer graphene, or mul- tiple sheets of graphene stacked and bonded together, which also may be referred to as multi-layer graphene for platelets having from 2 to 10 layers, graphite nano- platelets for compositions having more than 10 layers of graphene plane, or graph- ite for compositions having more than 100 layers of graphene plane. [0025] The graphitic material may also be in the form of an intercalated compound having ions inserted between the oppositely charged carbon layers of the graphite. The graphitic material may also be in the form of a substituted graphite, such as graphene oxide or graphene fluoride. Substituted graphite, such as graphene ox- ide, is formed by the treatment of graphite with a substituent, such as oxidizing agents, and intercalants or other substituting means and has a high substituent content. Graphene oxide for example can have carbon to oxygen molar ratios of between about 2:1 and 25:1, or 1.5:1 and 20:1, or 1.25:1 and 15:1 or 1:1 and 5:1 to 10:1. As used herein, the term "carbon to oxygen ratio" refers to molar ratios of carbon to oxygen in the substituted graphite. Carbon to oxygen ratio is deter- mined by elemental analysis and the resulting weight ratios are converted to molar ratios. [0026] In some instances, it is preferred to employ a graphitic material that is substantially free of substituents, such as oxygen, meaning a carbon to substituent ratio of 25:1 or greater, and preferably completely free of substituent. [0027] In the graphitic material, each graphene plane encompasses a two-dimen- sional hexagonal structure of carbon atoms. Individual platelets in the graphitic material can have a length and a width parallel to the graphene plane and a thick- ness orthogonal to the graphene plane. The thickness of a graphene platelet can be 100 nanometers (nm) or smaller and more typically thinner than 10 nm with a single-sheet graphene platelet being as thin as 0.34 nm. The length and width of a graphene platelet is typically between 1 μm and 20 μm, but could be longer or shorter. For certain applications, both length and width may be smaller than 1 μm. [0028] Generally, the carbonaceous compounds are characterized in terms of par- ticle size, as measured by sifting the particles through U.S. Standard test sieves to determine what size particles fall through the test sieve. For smaller particles, some sort of microscopy may be employed to determine the average diameter of the particle. In terms of microscopy, any known method may be used. For exam- ple, an electron dual beam microscopy or scanning probe microscopy may be used. Raman spectroscopy, X-ray diffraction or an atomic force microscope may also be used to measure the particle size or optical microscopy. [0029] The carbonaceous compounds can have particle sizes of about 5 to 250 µm. The particles can also have a particles size of about 10 to 225 µm. Particle sizes for the carbonaceous compounds of about 15 to 200 µm are also contem- plated, as well as particle sizes of 20 to 175 µm. [0030] As a caveat, in terms of graphene, graphene sheet is more commonly meas- ured in terms of surface area due to its smaller scale. Surface are of graphene sheets can be measured according to standard BET nitrogen adsorption lab prac- tices as would be well-known to those of ordinary skill in the art, or in some instances according to ASTM D6556. Graphene sheet carbonaceous compounds can have surface areas of about 200 to 2600 m²/g, or even from about 250 to 2000 m²/g, or in some cases 300 to 1500 m²/g, or even 350 to 1000 m²/g or 400 to 800 m²/g. [0031] The carbonaceous compounds can also include carbon fibers, fullerenes, carbon nanotubes. [0032] Carbon fibers may also be used as the carbonaceous compound. Carbon fibers are fibers of carbon bonded together in crystals to form a long fiber. Carbon fibers as such have two dimensions, a length and a diameter. The diameter of carbon fibers may be from 1 to 30 µm, or, for example, 2.5 to 25 µm, or 5 to 20 µm, or even 7 to 15 µm. Carbon fiber lengths can vary from 50 to 2000 µm or even 100 to 1500 µm. In embodiments the carbon fiber length can be 80 to 350 µm, or 90 to 250 µm, or even 100 to 200 µm. In some embodiments, the carbon fiber length can be 200 to 2000 µm, or even 300 to 1500 µm, or 400 to 1000 µm. [0033] Nanotubes and fullerenes may also be used as the carbonaceous com- pound. Such compounds have particle sizes in the nm range. [0034] The conductive filler can be a combination of any of the foregoing carbo- naceous compounds. Combinations of any of the conductive fillers may be em- ployed as well. [0035] The conductive filler can be included in the conductive composition at from about 20 to 85 vol%. In some instances, the conductive filler can be included in the conductive composition at from about 25 to 80 vol.%. In embodiments, the conductive filler can be included in the conductive composition at from about 30 to about 75 vol.% or from about 35 to about 70 vol.%. In embodiments, the con- ductive filler can be included at greater than 50 vol.%. In embodiments, the con- ductive filler can be included at 50 to about 60 vol.%. [0036] In addition to the conductive filler, the composition can include one or more additives. Examples of additives which can be used include dispersants, antioxidants, lubricants, stabilizers, impact modifiers, pigments, glass transition enhancing additives, processing aids, fusion aids, fillers, fibrous reinforcing agents and antistatic agents. [0037] Particularly useful dispersants can include those of formula 1, including salts thereof. Formula 1: (T-(O-A-CO)_n(O-B-CO)_m)_pZ wherein T is H or a polymerisation terminating group; A is C_16-20-alkenylene; B is C_10-20-alkylene; Z is the residue of a polyamine or polyimine; n is 0 to 50; m is 0 to 25; and p is not less than 2. [0038] The polymer chain represented by T-(O-A-CO)_n (O-B-CO)_m— may be block or preferably random. It should be noted that either the moiety represented by —(O-A-CO)— or —(O-B-CO)— may be attached to T. [0039] Preferably the ratio of n to m is not less than 2:1, more preferably not less than 4:1 and especially not less than 10:1. It is particularly preferred that m is 0. [0040] When T is a polymerisation terminating group, it is preferably the residue of a carboxylic acid of formula T′-COOH wherein T′ may be aromatic, heterocy- clic, alicyclic or preferably aliphatic which is optionally substituted by halogen, C_1-4-alkoxy, hydroxy and/or ether groups. Preferably, T′ is unsubstituted. When T′ is aliphatic, it may be linear or branched, saturated or unsaturated but is pref- erably linear, saturated alkyl. [0041] The total number of carbon atoms in T can be as high as 50 but it is pre- ferred that T contains not less than 8, more preferably not less than 12 and espe- cially not less than 14 carbon atoms. It is also preferred that T contains not greater than 30, more preferably not greater than 25 and especially not greater than 20 carbon atoms. [0042] Preferably (O-A-CO) is the residue of ricinoleic acid. [0043] B is preferably C_10-16-alkylene. Examples of hydroxycarboxylic acids from which —(O-B-CO) is derivable are 12-hydroxydodecanoic acid, 5-hy- droxydodecanoic acid, 5-hydroxydecanoic acid, 4-hydroxydecanoic acid and es- pecially 12-hydroxystearic acid. [0044] n+m is not less than 2. It is also preferred that n+m is not greater than 10 and especially not greater than 6. [0045] The integer p is preferably not greater than 2000 and especially not greater than 1000. [0046] The weight ratio of T-(O-A-CO)_m (O-B-CO)_n to Z is preferably from 8:1 to 30:1 and especially from 8:1 to 20:1. [0047] Z is preferably the residue of polyallylamine, polyvinylamine, more pref- erably poly(C_2-4-alkyleneimine) (hereinafter PAI) and particularly poly(ethylene- imine) (PEI). The PAI may be linear or branched. [0048] The polyamine or polyimine preferably has a weight-average molecular weight from 500 to 600,000, more preferably from 1,000 to 200,000, even more preferably from 1,000 to 100,000 and especially from 1,000 to 70,000. [0049] Particularly useful effects have been obtained with dispersants of formula 1 wherein the TPOAC acid is obtained from ricinoleic acid, optionally containing 12-hydroxystearic acid and optionally containing stearic acid as polymerisation terminating group with a number-average molecular weight between 800 and 2,000 and Z is the residue of PEI having a number-average molecular weight of from 1,000 to 70,000. [0050] Commercial examples of such dispersants can include, but are not limited to, Solplus K251/K242/K241/K240, Solsperse 11000 and Ircosperse 2155, avail- able from Lubrizol Advanced Materials, Inc. [0051] Exemplary lubricants are polyglycerols of di- and trioleates, polyolefins such as polyethylene, polypropylene and oxidized polyolefins such as oxidized polyethylene and high molecular weight paraffin waxes. Since several lubricants can be combined in countless variations, the total amount of lubricant can vary from application to application. In an embodiment, oxidized polyethylene is used. A paraffin wax may also be included in conductive composition alone, or in ad- dition to the oxidized polyethylene. [0052] Suitable processing aids include acrylic polymers such as methyl acrylate copolymers. A description of other types of processing aids which can be used in the compound can be found in The Plastics and Rubber Institute: International Conference on PVC Processing, Apr.26-28 (1983), Paper No.17. [0053] The compositions can also include a stabilizer system. Organotin stabi- lizers are currently the most recognized heat stabilizers. These stabilizers include alkyl tin mercaptides, alkyl tin carboxylate and alkyl tin maleate. Stabilizers based on a composition of mono and dialkyl tin (2-ethyl hexyl mercapto acetate systems) are suitable. Optionally, a co-stabilizer can be used in conjunction with the stabilizer. Co-stabilizers, if used in conjunction with the main stabilizer, are used in small amounts, such as from 0.1 to 1.0 part by weight per 100 parts by weight of polymer resin, and preferably from 0.1 to 0.5 parts by weight. Suitable co-stabilizers include salts of carboxylic acids (e.g., C₁-C₆ metal carboxylates such as mono or disodium carboxylates), disodium phosphate, tetrasodium pyro- phosphate, sodium citrate, zeolite and hydrotalcite. The amount of heat stabilizer used is at least 1.0 part by weight and preferably at least 1.5 parts by weight. [0054] The stabilizer can also be an organic based stabilizer. In simplest terms, organic based stabilizers (OB-Stabilizers) are non-metal containing stabilizers based on organic chemistry. While the OB-Stabilizers suitable for the stabilizer system herein are not particularly limited, the most prevalent OB-Stabilizer com- pounds today include uracil and its derivatives. A common derivative of uracil suitable as an OB-Stabilizer for the composition herein is 6-amino-1,3-dimethylu- racil. Other commercially available OB-Stabilizers suitable for the present com- position include, for example, the Mark™ OBS™ line of stabilizers available from Galata™. [0055] In general, the OB-Stabilizers can be included in the composition at levels required to meet physical properties, such as color. The OB-Stabilizers can be present in an amount of from about 0.05 or 0.1 to about 2.0 parts by weight per 100 parts by weight of said polymer resin. In some embodiment, the OB-Stabi- lizers can be present from about 0.15 to about 1.75 phr, or from about 0.2 to about 1.5 phr, or even from about 0.25 or 0.5 to about 1.25 phr. [0056] Zeolite and/or C₆ to C₁₂ metal carboxylates, or combinations thereof may also be employed as stabilizers, or co-stabilizers alongside tin or OBS stabilizers. As a sole stabilizer, the zeolite can generally be present at from about 0.1 to about 4.0 phr. In some embodiments, the zeolite can be present from about 0.25 to about 3.5 phr, or 0.5 to about 3.0 phr. In another embodiment, the zeolite can be present from about 0.75 to about 1.5 or 2.5 phr. [0057] The C₆ to C₁₂ metal carboxylate can be a metal salt of a saturated C₆, or C₇, or C₈ to C₁₁, or C₁₂ aliphatic carboxylate or di-carboxylate, an unsaturated C₆ to C₁₂ aliphatic carboxylate or di-carboxylate, a saturated C₆ to C₁₂ aliphatic car- boxylate or di-carboxylate substituted with at least one OH group, or whose chain is interrupted by at least one oxygen atom (oxyacids), or a cyclic or bicyclic car- boxylate or di-carboxylate containing from 6, or 7, or 8 to 11 or 12 carbon atoms. Suitable metals for the metal carboxylate can include Li, K, Mg, Ca, and Na. [0058] Preferably the C₆, or C₇ or C₈ to C₁₁ or C₁₂ metal carboxylate is a sodium carboxylate, most preferably a disodium carboxylate, such as disodium sebacate, disodium dodecanedioate or disodium suberate, and combinations thereof. Other examples of C₆ to C₁₂ metal carboxylates that may be employed include disodium adipate, disodium azelate, and disodium undecanedioate. [0059] The C₆ to C₁₂ metal carboxylate can be present from about 0.1 to about 4.0 phr. In some embodiments, the C₆ to C₁₂ metal carboxylate can be present from about 0.25 to about 3.0 phr, or 0.5 to about 2.5 phr. In a preferred embodiment, the C₆ to C₁₂ metal carboxylate can be present from about 1.0 to about 2.0 phr. The metal carboxylate can be dry blended with other ingredients of a compound or the polymer resin can be coated with a metal carboxylate solution by a wet coating process followed by drying to obtain a metal carboxylate coated polymer resin. [0060] In one embodiment, other co-stabilizers beside zeolite and carboxylate may also be employed in the co-stabilizer system. In an embodiment, the stabi- lizer system is essentially free of, or free of heavy metal stabilizers, such as tin stabilizers. By essentially free of it is meant that a minor portion may be present in amounts that do not contribute or contribute an insignificant amount to stabili- zation. [0061] The conductive composition can also include flow enhancing polymers or oli- gomers. Flow enhancing polymer or oligomers include those made from various hy- drocarbon substituted styrene monomers having the following formula:

wherein R is generally an aliphatic group having from 1 to 5 carbon atoms. R can be an alkyl having from 1 to 4 carbon atoms and can also be methyl, such as, for example, alpha-methyl. The number of such substitutions, that is "n" is generally from 1 to about 3, or 1 to 2, or 1. Alpha-methyl styrene is an example compound encompassed by the formula. The molecular weight of the flow enhancing polymer made from monomers of the above formulation can be from about 400 to about 2,000, or from about 650 to about 1,000. [0062] The flow enhancing polymer or oligomer can be included in the conductive composition at from about 10 or 12 to about 40 parts by weight per 100 parts of CPVC, or from about 14 to about 30 parts by weight, or even from about 16 to about 26 parts by weight. [0063] Flow enhancing polymers such as alpha-methyl styrene can be difficult to in- corporate with CPVC and therefore compatibilizing agents may be employed. Gener- ally, any such compound can be utilized in effective amounts which yield a suitable increase in compatibility of the flow enhancing polymer or oligomer. A practical indi- cation of compatibility is the capability to develop useful impact resistance in the alloy. An effective amount of the compatibilizing agent copolymer can be from about 2 parts to about 10 parts by weight, of from about 3 parts to about 6 parts by weight based upon 100 parts by weight of the CPVC resin. Compatibilizing agents include the vari- ous styrene-acrylonitrile (SAN) copolymers or resins. SAN resins are random, amor- phous copolymers of styrene and acrylonitrile produced by emulsion, suspension, or continuous mass polymerization as known to the art as well as to the literature. The amount of styrene therein as well as the molecular weight of the copolymer can be varied to achieve different properties of the overall CPVC alloy. Generally, higher molecular weight styrene-acrylonitrile copolymers are desired with regard to optimum properties. [0064] Other compatible polymers that may be included in the mixture that may form an alloy with CPVC can include, for example, polyvinylchloride (PVC), styrene-acry- lonitrile (SAN), alpha-methyl styrene-acrylonitrile (AMSAN), styrene-maleic anhy- dride (SMA), polymethylmethacrylate (PMMA), acrylonitrile-butadiene-styrene (ABS), and acrylonitrile-butadiene-alpha-methyl styrene (ABAMS). The choice of polymer will depend upon the desired outcome (improved polymer melt processing, improved physical properties, etc.) [0065] The conductive composition can be prepared by mixing the CPVC resin and conductive filler along with the desired additives. Mixing of the CPVC resin, filler and additives can be completed according to known methods. In an embodiment, the CPVC resin, filler and additives can be extruded. [0066] The conductive composition can be molded into useful structures to be em- ployed in electrochemical devices, such as, for example, fuel cells, flow batteries, elec- trolyzers, and other applications requiring a chemically inert yet conductive separator. In an embodiment, the conductive composition can be compression molded. In another embodiment, the conductive composition can be injection molded. [0067] The conductive composition can be employed in energy generating devices. In an embodiment, the conductive composition can be employed as a bipolar plate in a fuel cell. In an embodiment, there is provided a fuel cell with a layer of a cathode, an ionic conducting layer, such as, for example, a proton exchange membrane, and an anode, the layer being held between two bipolar plates, and the bipolar plates being enclosed in an enclosure, where the bipolar plates comprise a conductive composition comprising A) CPVC, and B) a conductive filler, and the enclosure comprises CPVC. By “ionic conducting layer” it is meant a layer that is not electrically conducting, but is ionically conducting. [0068] The conductive composition can be employed in energy storage devices. In an embodiment, the conductive composition can be employed as a bipolar plate in an electrolyzer. In an embodiment, there is provided an electrolyzer with a layer of a cathode, an ionic conducting layer and an anode, the layer being held between two bipolar plates, and the bipolar plates being enclosed in an enclosure, where the bipolar plates comprise a conductive composition comprising A) CPVC, and B) a conductive filler, and the enclosure comprises CPVC. [0069] The amount of each chemical component described is presented exclusive of any solvent or diluent oil, which may be customarily present in the commercial material, that is, on an active chemical basis, unless otherwise indicated. How- ever, unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are nor- mally understood to be present in the commercial grade. [0070] It is known that some of the materials described above may interact in the final formulation, so that the components of the final formulation may be different from those that are initially added. For instance, metal ions can migrate to other acidic or anionic sites of other molecules. The products formed thereby, including the products formed upon employing the composition of the present invention in its intended use, may not be susceptible of easy description. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses the composition prepared by admixing the components described above. EXAMPLES Materials suitable for use as bi-polar plates were prepared by combining a series of carbonaceous solids (Table 1 below) with CPVC powders (Table 2) and eval- uated for their suitability as bi-polar plates. Table 1 – Carbonaceous Materials

Table 2 – CPVC Materials

[0071] Composites were prepared by the following general procedure: [0072] Carbon powder and CPVC powder were combined in amounts to provide at least about 125 g of composite mixture. Each example was prepared in a similar manner. For Instance, Example 1 (EX1) was prepared by combining solid carbon (C-2, 94.6 g) with CPVC1 (155.4 g). Carbon and graphite were mixed through use of a Resodyn™ Acoustic mixer at 70-g power level for 2 times 2 minutes with 1-2 minute interval between mixing cycles. The resulting solid mixture (10 g) was compressed into disks (1.9 cm radius and 5 to 6 mm thick) at 150°C and 5000 psi pressure. Composite disk compositions are summarized below (Table 3). [0073] Mechanical integrity of composite materials may be evaluated according to several standard industry tests, including the Standard Test Method for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Ma- terials (ASTM D790-10) and the Standard Test Methods for Tension Testing of Metallic Materials (ASTM E8M-01). All composite disks displayed acceptable mechanical integrity when subjected to routine handling and transfer. [0074] Efficacy of the materials to function as bi-polar plates was assessed by measuring the conductivity of the materials. The material disks were suspended between two copper plates with a thin sheet of graphitic carbon paper inserted between the electrodes and the test material to minimize contact resistance. Po- tential was applied across the sample necessary to generate a current of 1 ampere (A). The experimental results are compared to a current commercial vinyl-ester material used in bi-polar plates. Table 3 – Composite Formulations¹

1 T t t i l t l th i td

Table 3 (cont’d)¹

Table 3 (cont’d)¹

( ) Table 3 (cont’d)¹

[0075] The results indicate that CPVC/carbon composite materials display both mechanical and electrical properties suitable for use as bi-polar plates in fuel cell applications. Conductivity measurements of the inventive materials are compara- ble to and in some cases superior to industry standard materials used in fuel cells. [0076] Each of the documents referred to above is incorporated herein by refer- ence. The mention of any document is not an admission that such document qualifies as prior art or constitutes the general knowledge of the skilled person in any jurisdiction. Except in the Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, reac- tion conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word "about." It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be inde- pendently combined. Similarly, the ranges and amounts for each element of the invention can be used together with ranges or amounts for any of the other ele- ments. [0077] As used herein, the transitional term “comprising,” which is synonymous with “including,” “containing,” or “characterized by,” is inclusive or open-ended and does not exclude additional, un-recited elements or method steps. However, in each recitation of “comprising” herein, it is intended that the term also encom- pass, as alternative embodiments, the phrases “consisting essentially of” and “con- sisting of,” where “consisting of” excludes any element or step not specified and “consisting essentially of” permits the inclusion of additional un-recited elements or steps that do not materially affect the essential or basic and novel characteristics of the composition or method under consideration. [0078] A conductive composition comprising, consisting essentially of, consist- ing of A) chlorinated polyvinyl chloride (“CPVC”), and B) a conductive filler. [0079] The conductive composition of any previous sentence, wherein the CPVC has a chlorine content of from 60 to 72 wt.%. [0080] The conductive composition of any previous sentence, wherein the CPVC has a chlorine content of from 61 to 71 wt.%. [0081] The conductive composition of any previous sentence, wherein the CPVC has a chlorine content of from 62 to 70 wt.%. [0082] The conductive composition of any previous sentence, wherein the CPVC has a chlorine content of from 63 to 69 wt.%. [0083] The conductive composition of any previous sentence, wherein the CPVC has a chlorine content of from 63 to 68 wt.%. [0084] The conductive composition of any previous sentence, wherein the CPVC has a chlorine content of from 64 to 67.5 wt.%. [0085] The conductive composition of any previous sentence, wherein the CPVC has a chlorine content of from 65 to 67.5 wt.%. [0086] The conductive composition of any previous sentence, wherein the CPVC is prepared by chlorinating a vinyl chloride resin having an inherent viscosity of from 0.4 to 1.4. [0087] The conductive composition of any previous sentence, wherein the CPVC is prepared by chlorinating a vinyl chloride resin having an inherent viscosity of from 0.5 to 1.3. [0088] The conductive composition of any previous sentence, wherein the CPVC is prepared by chlorinating a vinyl chloride resin having an inherent viscosity of from 0.54 to 1.2. [0089] The conductive composition of any previous sentence, wherein the CPVC is prepared by chlorinating a vinyl chloride resin having an inherent viscosity of from 0.6 to 1.1. [0090] The conductive composition of any previous sentence, wherein the CPVC is prepared by chlorinating a vinyl chloride resin having an inherent viscosity of from 0.65 to 0.90. [0091] The conductive composition of any previous sentence, wherein the CPVC is prepared by chlorinating a vinyl chloride resin having an inherent viscosity of from 0.65 to 0.92. [0092] The conductive composition of any previous sentence, wherein the CPVC is prepared by chlorinating a vinyl chloride resin having an inherent viscosity of from 0.65 to 1. [0093] The conductive composition of any previous sentence, wherein the CPVC is a homopolymer. [0094] The conductive composition of any previous sentence, wherein the com- position comprises from 20 to 85 vol.% of the conductive filler. [0095] The conductive composition of any previous sentence, wherein the com- position comprises from 25 to 80 vol.% of the conductive filler. [0096] The conductive composition of any previous sentence, wherein the com- position comprises from 30 to 75 vol.% of the conductive filler. [0097] The conductive composition of any previous sentence, wherein the com- position comprises from 35 to 70 vol.% of the conductive filler. [0098] The conductive composition of any previous sentence, wherein the con- ductive filler comprises a metal. [0099] The conductive composition of any previous sentence, wherein the con- ductive filler comprises an intrinsically conducting polymer (“ICP”). [00100] The conductive composition of any previous sentence, wherein the conductive filler comprises a conductive polymeric composite (“CPC”). [00101] The conductive composition of any previous sentence, wherein the conductive filler comprises a carbonaceous compound. [00102] The conductive composition of any previous sentence, wherein the conductive filler comprises a graphitic material. [00103] The conductive composition of any previous sentence, wherein the graphitic material comprises graphite. [00104] The conductive composition of any previous sentence, wherein the graphitic material comprises graphene. [00105] The conductive composition of any previous sentence, wherein the graphitic material comprises carbon black. [00106] The conductive composition of any previous sentence, wherein the composition comprises carbon fibers. [00107] The conductive composition of any previous sentence, wherein the composition comprises an acid neutralizer. [00108] The conductive composition of any previous sentence, wherein the acid neutralizer comprises disodium phosphate. [00109] A method of preparing a bipolar plate comprising preparing a com- position as claimed in any previous sentence and injection molding the composi- tion into the form of a bipolar plate. [00110] An electrochemical device comprising a layer of a cathode, an ionic conducting layer, such as, for example, a proton exchange membrane, and an an- ode, the layer being held between two bipolar plates, and the bipolar plates being enclosed in an enclosure, where the bipolar plates comprise a conductive compo- sition comprising A) CPVC, and B) a conductive filler, and the enclosure com- prises CPVC. [00111] While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. In this regard, the scope of the invention is to be limited only by the following claims.

Claims

What is claimed is: 1. A conductive composition comprising, consisting essentially of, consisting of A) chlorinated polyvinyl chloride (“CPVC”), and B) a conductive filler. 2. The conductive composition of claim 1, wherein the CPVC has a chlorine content of from 60 to 72 wt.% and is prepared by chlorinating a vinyl chloride resin having an inherent viscosity of from 0.4 to 1.4. 3. The conductive composition of claim 1, wherein the CPVC is a homopolymer. 4. The conductive composition of claim 1, wherein the composition comprises from 20 to 85 vol.% of the conductive filler. 5. The conductive composition of claim 1, wherein the conductive filler com- prises a graphitic material. 6. The conductive composition of claim 5, wherein the graphitic material com- prises graphite. 7. The conductive composition of claim 5, wherein the graphitic material com- prises graphene. 8. The conductive composition of claim 5, wherein the graphitic material com- prises carbon black. 9. The conductive composition of claim 5, wherein the composition comprises carbon fibers. 10. The conductive composition of claim 1, wherein the composition comprises an acid neutralizer. 11. The conductive composition of claim 10, wherein the acid neutralizer com- prises disodium phosphate. 12. A method of preparing a bipolar plate comprising preparing a composition as claimed in claim 9 and injection molding the composition into the form of a bipolar plate. 13. An electrochemical system comprising a layer of a cathode, a ionic conducting layer and an anode, the layer being held between two bipolar plates, and the bipolar plates being enclosed in an enclosure, where the bipolar plates com- prise a conductive composition comprising A) CPVC, and B) a conductive filler, and the enclosure comprises CPVC.