JP2003503510A - Novel ion conductive material suitable for use in electrochemical applications and related methods - Google Patents

Abstract

  (57) [Summary] The present invention relates to a novel ion conductive material used as a solid polymer electrolyte membrane in electrochemical applications including fuel cell systems. More specifically, the novel ion-conducting polymers are based on sulfonated polyaryletherketone polymers and sulfonated polyphenylsulfone polymers, including copolymers or blends thereof. The invention also relates to a new method for producing these ion-conducting materials.

Description

Detailed Description of the Invention

The present invention is based on a consignment number DE-FC02-97EE50478 provided by the Ministry of Energy.
It is supported by the government under the consignment number DMI-9760978 under the National Science Foundation. The government has certain rights in this invention.

TECHNICAL FIELD This invention relates to novel ion-conducting materials suitable for use as solid polymer electrolyte membranes in electrochemical applications such as fuel cell systems. More specifically, the novel ion-conducting polymers are based on sulfonated polyaryletherketone polymers or copolymer-containing sulfonated polyphenylsulfone polymers or mixtures thereof. The present invention also relates to a novel method for producing these ion conductive materials.

BACKGROUND OF THE INVENTION Quiet, effective, lightweight power sources with improved power density are in great need in both the military and commercial sectors. Military applications include, but are not limited to, submarines, surface ships, portable / mobile electric field generating units, and low power units (ie, battery replacements). For example, the military has a strong interest in developing low-range power sources (a few watts to a few kilowatts) that could serve as an alternative to batteries. Commercial use includes transportation (ie automobiles,
Bus, truck and rail), telecommunications, local cogeneration and stationary generation.

Other areas of interest are household applications such as radios, video cameras and laptop computers. Further, there is also interest in a relatively large power source or a relatively high power density power source that can be used to drive a clean and efficient vehicle. In all cases where stationary power generation is required, a quiet and effective lightweight power source is needed.

Furthermore, the use of gasoline internal combustion engines poses significant environmental issues related to exhaust emissions. One possible solution to that environmental problem is the use of fuel cells. Fuel electricity is a highly efficient electrochemical energy conversion device that directly converts chemical energy derived from renewable fuels into electrical energy.

Considerable research and development efforts have been devoted to the development of proton exchange membranes for use in various electrochemical applications such as fuel cell systems. Proton exchange membrane fuel cells have a polymer electrolyte membrane disposed between an anode (cathode) and a cathode (anode). The polymer electrolyte membrane is made of an ion exchange polymer (ie ionomer). Its role is to provide a means of ion transport and prevent mixing of molecular fuels and oxidants.

The Solid Polymer Electrolyte Fuel Cell (SPEFC) is an ideal power source that is quiet, efficient and lightweight. The fuel cell operates continuously with air and hydrogen, although the cell structure contains reactants that will eventually be used up. Its fuel efficiency is high (45
-50%), it is noiseless, operates over a wide power range (10 Watts to hundreds of kilowatts) and is relatively simple to design, manufacture and operate. Furthermore, currently SP
EFC has the highest power density in any type of fuel cell. Furthermore SPEF
C does not generate environmentally harmful emissions such as NO _x and SO x _(typical combustion by-products).

A conventional SPEFC has a solid polymer ion exchange membrane between two gas diffusion electrodes, an anode and a cathode, each electrode commonly containing a metal catalyst supported by a conductive material. . These gas diffusion electrodes are exposed to the individual reaction gases reducing agent gas and oxidizing agent gas. An electrochemical reaction occurs at each of two branch points (three-phase boundary) where one of these electrodes, the electrolyte polymer film and the reaction gas come into contact.

During operation of the fuel cell, hydrogen interacts with the metal catalyst through the anode to generate electrons and protons. The electrons are conducted from the external circuit to the cathode through the conductive material, and the protons are simultaneously transferred to the cathode through the polymer electrolyte membrane through the ion path. Oxygen passes to the catalytic site of the cathode, where it receives electrons and reacts with protons to produce water. Consequently, the products of the SPEFC reaction are water, electricity and heat. In SPEFC, current is conducted simultaneously by the ionic and electronic paths. The efficiency of SPEFCs depends heavily on their ability to reduce both ionic and electronic resistance to current flow.

[0010]   Ion exchange membranes play a very important role in various electrochemical applications including SPEFC.
Fulfill For example, in SPEFC, the ion exchange membrane is (1) the ion between the anode and the cathode.
And (2) two reaction gases (eg O _Two And H_Two) Has the dual function of acting as a separator. Sanawa
While the ion exchange membrane serves as a good proton transport membrane,
Has a low permeability, which may reduce the performance of the fuel cell.
It must also avoid elephants. This is because the reaction gas is under pressure and burns.
It is especially important in fuel cell applications where the fuel cell is operated at high temperatures.

Fuel cell reactants are classified into oxidants and reducing agents based on their electron acceptor or electron donor properties. Oxidants include pure oxygen, oxygen-containing gases (eg air) and halogens (chlorine). Reducing agents include hydrogen, carbon monoxide, natural gas,
Examples include methane, ethane, formaldehyde and methanol.

Optimal proton and water transport of the membrane as well as proper water management are also very important for effective fuel cell applications. When the membrane is dehydrated, the proton conductivity is lowered, and excessive water may cause swelling of the membrane. If the removal efficiency of water, which is a by-product, is low, there is a case where the electrode overflows which obstructs gas invasion. Either of these conditions leads to poor battery performance.

Although promising for many applications, SPEFCs have not yet been commercialized due to unsolved technical problems and high overall costs. One of the major drawbacks affecting the commercialization of SPEFCs is the inherent limitations of today's mainstream membrane electrode assemblies. For SPEFCs to survive commercially (especially in automotive applications), the membranes used must operate at high temperatures (> 120 ° C) to increase power density and limit the catalyst's susceptibility to fuel impurities. This will enable applications such as on-site cogeneration (high-quality waste heat in addition to electricity). Excessive methanol crossover in liquid-fed direct methanol fuel cells also occurs with current membranes (depending on actual operating conditions but typically corresponds to about 50-200 mA / cm ² current density loss at 0.5V). . Generally, fuel crossover is a parasitic reaction that reduces efficiency, reduces performance, and generates heat in a fuel cell. Therefore, it is highly desirable to reduce the fuel crossover rate.

Several polymer electrolyte membranes have been developed over the years for use as solid polymer electrolytes used in electrochemical redox driven applications, including fuel cell systems. However, these membranes have significant limitations for use in liquid-fed direct methanol fuel cells and hydrogen fuel cells. For example, the most advanced SPEFC membranes today have the combination of ionic conductivity, mechanical strength, dehydration resistance, chemical stability and fuel impermeability (eg methanol crossover) required for high temperature operation. Do not have.

DuPont has developed a series of perfluorosulfonic acid membranes called Nafion® membranes. The Nafion® membrane method is known in the art and is described in US Pat. Nos. 3,282,875 and 4,330,654. Almost exclusively non-reinforced Nafion® membranes are used as ion exchange membranes in this SPEFC application. This film is composed of a copolymer of tetrafluoroethylene (TFE) and perfluorovinyl ether sulfonyl fluoride. The vinyl ether comonomer is copolymerized with TFE to form a melt moldable polymer. Once in the desired shape, the sulfonyl fluoride group is hydrolyzed to the ionic sulfonic acid type.

The fluorocarbon component and the ionic group are incompatible or immiscible (the former being hydrophobic and the latter hydrophilic). This results in phase separation, which forms interconnected hydrated ionic "clusters". Because protons “jump” from one ionic cluster to the other, they are conducted through the membrane,
The properties of this cluster determine the electrochemical properties of the polymer. To ensure the flow of protons, each ionic group surrounds and requires a minimal amount of water to form clusters. If the ionic group concentration is too low (or insufficient hydration), proton transport will not occur. Higher ionic group concentrations (or higher hydration levels) improve proton conductivity but at the expense of mechanical properties of the membrane.

As the film temperature rises, the swelling force (penetration force) becomes higher than the regulation force (fluorocarbon chain). This may cause the membrane to become more swollen and ultimately promote dehydration of the membrane. Peroxide radicals form more rapidly as the temperature increases. The radicals can attack and decompose the membrane.
At higher temperatures (230 ° C.), the fluorocarbon phase melts and the ionic regions become “melted” (Nafion® phase inversion).

There are several mechanisms that limit the performance of Nafion® membranes in fuel cell environments and other electrochemical applications. For example, Nafion® is sensitive to heat and can only be effectively used up to temperatures of about 100 ° C. In fact, the performance degradation phenomenon may start even at a temperature of about 80 ° C. Mechanisms that limit the performance of Nafion® include membrane dehydration, reduced ion conductivity, radical formation in the membrane (which can chemically destroy the solid polymer electrolyte membrane), and mechanical strength through softening. Loss and increased parasitic loss due to high fuel penetration.

The crossover problem for Nafion® is especially problematic in liquid fed direct methanol fuel cell applications where excessive methanol transport (which reduces efficiency and power density) occurs. Methanol crossover not only lowers fuel utilization efficiency, but also adversely affects oxygen cathode performance and significantly reduces cell performance. More specifically, this crossover causes a mixed reaction (oxidation and reduction), resulting in a decrease in reaction efficiency on the cathode side.

The Nafion® / electrode is so expensive to manufacture that it is not yet commercially viable as a result. Reducing membrane cost is essential to the commercialization of SPEFC. It is estimated from the Nafion® model that the SPEFC needs to reduce the membrane cost by an order of magnitude or more before it becomes commercially attractive.

Another type of ion conducting membrane, Gore-Select® (W.
(Commercially available from L. Gore) is currently under development for fuel cell applications. Regarding Gore Select (registered trademark), a series of US patents (US Pat.
47551 and 5599614).

Gore discloses a composite membrane consisting of a porous Teflon® membrane filled with Nafion® or Nafion®-like ion-conducting solution. Although it is reported to exhibit high ionic conductivity and greater dimensional stability than Nafion® membranes, the Teflon® and Nafion materials selected and used by Gore as the membrane material and ion exchange material, respectively. (Registered trademark)
The material may not be suitable for operation at high temperature SPEFC. Teflon (R) causes extensive creep at temperatures above 80 ° C, and Nafion (R)
And similar ionomers swell and soften above that temperature. As a result, the interconnecting channels in the membrane may expand, causing performance degradation, especially at high temperatures and pressures.

In addition, GoreSelect®, as well as many other perfluoroion conductive membranes (eg, Aciplex from Asahi Chemical of Japan)
Aciplex), Flemion® from Asahi Glass,
Due to the high percentage of perfluoroionomer used, Nafion (
It is as expensive as the registered trademark).

Aiming to reduce the cost of SPEFC and promote its possible industrialization and improve its performance in all suitable electrochemical applications, it can be manufactured cheaper for use in polymer electrolyte membrane fuel cells. Ion exchange membranes have been studied.

Polymer Electrolyte Membrane Poly (trifluorostyrene) as a membrane used in fuel cells
The copolymer was tested. See, for example, US Pat. No. 5,422,411. However, there is a concern that these films have poor mechanical properties and film forming properties. Moreover, these membranes are costly because the processing of fluorinated polymers is inherently difficult.

[0026]   Various sulfonated polymers have been tested for use in electrochemical applications.

Sulfonated polyaromatic based systems such as those described in US Pat. Nos. 3,528,858 and 3,226,361 were also investigated as membrane materials for SPEFC. However, their poor chemical and mechanical resistance limits their use in SPEFC applications.

Solid polymer membranes containing sulfonated poly (2,6-dimethyl-1,4-phenylene oxide) alone or as a blend with poly (vinylidene fluoride) have also been investigated. These membranes are disclosed in International Patent WO 97/24777. However, it is known that these films are particularly susceptible to decomposition by peroxide radicals.

Sulfonated poly (aryl ether ketone) (PEK) polymers developed by Hoechst AG are described in EP-A-574,891A2. These polymers can be crosslinked with primary and secondary amines. However, when used as a membrane in a polymer electrolyte membrane fuel cell and tested,
Only mediocre fuel performance is observed.

US Pat. No. 4,268,650 also describes sulfonated PEK polymers. The method disclosed in that patent relies on the copolymerization of PEK with polyetheretherketone (PEEK) to control the level of sulfonation in concentrated sulfuric acid. Sulfonation under these conditions is believed to occur only at the ether-phenyl-ether bond.

US Pat. No. 4,273,903 relates to a similar method using polyaryl ether sulfone copolymers. More specifically, the patent describes polyetherethersulfone (which is easily sulfonated) and polyethersulfone (which is difficult to sulfonate).
Disclosed is the tunable sulfonation of polyarylether sulfone copolymers in concentrated sulfuric acid using the copolymer with. The patent also reports that the use of sulfonic acid / fuming sulfuric acid, fuming sulfuric acid or chlorosulfonic acid results in complete sulfonation and / or degradation of the polyethersulfone polymer. The sulfonation procedure described in this reference is carried out in a homogeneous system (ie the polymer is brought into solution before adding the sulfonating agent).

US Pat. No. 5,795,496 discloses materials for use in fuel cells.
Disclosed are methods for making sulfonated polyetheretherketone (PEEK) polymers and sulfonated poly (p-phenylene ether sulfone) (PES) polymers. The target for an asymmetric film formed using the materials and methods of the patent is a target film thickness of 0.05-0.5 mm (equivalent to about 2-20 mil). The patent also reports that thinner films, such as films less than 0.05 mm, have reduced mechanical strength and dimensional stability. This reference also states that these sulfonated polymeric materials are cross-linked at a temperature of about 120 ° C. for an unspecified amount of time to minimize fuel crossover.

US Pat. No. 4,413,106 describes heterogeneous sulfonation of polyarylethersulfone (PES) polymers in chlorinated hydrocarbon solvents with sulfonating agents (eg precipitated polymer / solvent eutectic (co- A method for sulfonation of crystals) is provided. The patent states that it is well known that "sulfonation is difficult" for aromatic PES polymers because the electron-withdrawing effect of the sulfone bond deactivates electrophilic substitution on adjacent aromatic rings. The patent further states that when these polymers are sulfonated with chlorosulfonic acid or fuming sulfuric acid at room temperature, a huge excess of sulfonating agent is required, resulting in extremely decomposed products and the extent of sulfonation. Report that it is impossible to adjust.

The patent further states that once the easily sulphonatable PEES units are introduced into the PES polymer (PES / PEES copolymer), the sulphonation of the polymer can be successfully adjusted to the formula (PH-SO ₂ -Ph- O) PES polymer is CH ₂ C
It is known to crystallize from various solvents such as ₁₂ , DMF, DMAc. Crystallization is facilitated by stirring or addition of non-solvent and is highly dependent on reaction conditions. Polymer / solvent mutual crystallites (diameter <1 micron) are formed as a suspension in excess solvent. The amount of sulfonating agent added controls the degree of sulfonation. Preferred temperatures are specified to be in the range of -10 ° C to 25 ° C.

US Pat. No. 5,013,765 discloses sulfur trioxide (a sulfonating agent) and sulfuric acid (
Solvent) and the tunable sulfonation of aromatic PES polymers. The patent suggests that the sulfuric acid content must be less than 6% by weight (based on solvent) and the temperature must be <30 ° C. to control side reactions and decomposition. Chlorosulfonic acid and fuming sulfuric acid are not preferred as sulfonating agents because they lead to excessive sulfonation and / or polymer degradation. Citing another source, the patent suggests that controllable sulfonation using them as sulfonating agents is not possible. The patent also, the use of sulfur trioxide in concentrated sulfuric acid, in particular in the case of the polymers of O-Ph-SO 2 _-Ph bases, reported that can produce sulfonated polymer without byproducts or degradation products ing.

The desirability of using sulfonated poly (aryl ether) polymers for applications such as reverse osmosis has been found in the literature (D. Lloyd et al., Synthetic Mem).
branes: Desalination, pp. 327-350 (1981)
)It is described in. The reference reports that membranes using such polymers are highly desirable and worth continuing research. While the chemical structure corresponding to polyphenylsulfone (PPSU) polymers is listed in this document (among others) as a promising sulfonating agent candidate, no experimental evidence for sulfonation of PPSU is given.

Sulfonation of PPSU has also been reported in other literature (eg O. Sava
dogo, J .; New Mat. Electrochem. Systems 1
, 47-66 (1998)). However, neither this publication nor the references cited with respect to the PPSU study lacks experimental data showing the sulfonation of this particular polymer.

Despite extensive research on the use of sulfonated aromatic polymers that can replace perfluorinated ionomers, they provide novel ion-conducting materials suitable for a wide range of electrochemical applications. There is a great need to do so and to develop new manufacturing methods for such materials.

There is also a great need to develop improved solid polymer electrolyte membranes using these novel ion-conducting materials. Such membranes would be suitable for use in a variety of electrochemical applications such as hydrogen or methanol fuel cell systems.

SUMMARY OF THE INVENTION The main object of the present invention is to provide novel ion-conducting materials suitable for use in a wide range of electrochemical applications such as fuel cell systems.

In one embodiment of the invention, these novel ion-conducting materials are based on sulfonated polyaryl ether ketone (PEK) homopolymers or PEK copolymers or blends thereof. In another embodiment, these novel ion-conducting materials are based on sulfonated polyphenylsulfone (PPSU) homopolymers or PPSU copolymers or blends thereof.

The classes of homopolymers, copolymers and blends thereof of PEK and PPSU disclosed herein are of average skill in the art, provided that the substituents do not substantially impair the desired polymer properties for the intended application. Can include any desired substituents that can be readily determined. Such properties include ionic conductivity, chemical and structural stability, swellability, and the like. Therefore, the homopolymers, copolymers and blends of PEK and PPSU used in the present text can be substituted and substituted with P
Includes polymers of EK and PPSU.

Another object of the present invention is to provide a novel method for producing such an ion conductive material.

Another object of the present invention is to provide an improved solid polymer electrolyte membrane that is resistant to methanol crossover when used in direct methanol fuel cells.

Another object of the present invention is to substantially reduce the total manufacturing cost of solid polymer electrolyte membranes that enable the industrialization of SPEFC.

One preferred ion-conducting material according to the present invention is at least one polyaryletherketone (PEK) homopolymer or at least one PEK copolymer or blends thereof (hereinafter “PEK-based ionic”). Sometimes referred to as "conductive material"), the PEK homopolymer is sulfonated, and the ion conductive material does not contain ether-phenyl-ether bonds.

In one particularly preferred embodiment of the invention, the PEK homopolymer has the formula:

[0048]

[Chemical 3] The phenyl ring in the formula may be substituted or unsubstituted.

The PEK-based ionically conductive material is at least about 0.5 meq. / G to at least about 4 meq. It is preferred to have an IEC of / g.

In applications where stability is important, the PEK-based ion-conducting material may further include sulfone crosslinks and / or antioxidants.

The PEK-based ion-conducting material of the present invention may be halogenated, eg brominated or chlorinated, to further enhance stability.

The PEK-based ion-conducting material of the present invention is useful in the manufacture of solid polymer electrolyte membranes.

A preferred method of making an ether-phenyl-ether bond free ion conductive material suitable for use in the electrochemical applications of the present invention is at least one P
Preparing a solution of EK homopolymer, adding a sulfonating agent to the PEK homopolymer solution to form a sulfonated PEK homopolymer, and sulfonate P
Isolating the EK homopolymer from the solution. Preferred sulfonating agents for use in this method include at least one of sulfur trioxide, concentrated sulfuric acid and fuming sulfuric acid. In some methods, the sulfonating agent provides about 0% by weight of free sulfur trioxide.
It is preferably included at a content of (about 100% sulfuric acid) to about 30% by weight (about 70% sulfuric acid).

The PEK homopolymer solution is preferably maintained at a reaction temperature of about 10 ° C to about 60 ° C.

One preferred method of isolating the sulfonated PEK-based ionically conductive material is
It consists of reprecipitating the sulfonated PEK homopolymer in water, saturated saline, methanol or other non-solvent.

In another preferred method, an antioxidant is added to the sulfonated PEK homopolymer before or after isolation of the sulfonated PEK homopolymer. In another preferred method, the PEK-based ionically conductive material is crosslinked, especially when the ionically conductive material is in the H ⁺ (acid) form.

In yet another preferred method of the present invention, the PEK-based ionically conductive material is treated with a halogenation step.

Another ion-conducting material according to the present invention is at least one sulfonated polyphenyl sulfone (PPSU) homopolymer or PPSU copolymer or blends thereof (hereinafter “PPSU-based ion-conducting material”). "It is sometimes called).

[0059]   One preferred PPSU-based ionically conductive material has the formula:

[0060]

[Chemical 4] The phenyl ring in the formula may be substituted or unsubstituted.

The PPSU-based ion-conducting material of the present invention has at least about 0.5 meq. /
g to about 4 meq. It has an IEC in the range of / g. In some embodiments, these materials further include sulfone crosslinks and / or antioxidants.

The PPSU-based ion-conducting materials of the present invention can be used in the manufacture of solid polymer electrolyte membranes. Such solid polymer electrolyte membranes may contain sulfone crosslinks.

One method of making the PPSU-based, ionically conductive material of the present invention suitable for use in electrochemical applications comprises providing a PPSU polymer solution and precipitating the PPSU polymer from the solution. , Adding a sulfonating agent comprising sulfur trioxide to the solution to form a sulfonated PPSU polymer, characterized by the steps of diluting sulfur trioxide into a solvent comprising chlorinated hydrocarbons, Isolating the modified PPSU polymer from the solution. Methylene chloride is the preferred chlorinated hydrocarbon solvent for use in the present invention.

[0064] In some embodiments, the method further comprises purifying the ionically conductive material to produce PPS.
Removing the over-sulfonated or degraded fraction of the U-based ion-conducting material. In one preferred method this is done by redissolving the sulfonated PPSU polymer in a solvent and reprecipitating the sulfonated PPSU polymer in water, saturated saline solution, methanol or other non-solvent.

The method of forming the PPSU-based ion-conducting polymer of the present invention further comprises the step of cross-linking the ion-conducting material, especially when the ion-conducting material is in the H ⁺ form.

The preferred method also includes the step of adding an antioxidant to the sulfonated PPSU polymer before or after isolation of the sulfonated PPSU polymer. Yet another preferred method involves halogenating, eg, chlorinating or brominated, the PPSU-based ionically conductive material.

The above and other objects, features and advantages of the present invention will be more fully understood from the following description and claims.

DETAILED DESCRIPTION The present invention relates to novel ion-conducting materials that can be used in the manufacture of solid polymer electrolyte membranes (SPEM). These materials can also be used in composite SPEMs consisting of a base polymer and an ionically conductive material component.

The novel ion-conducting materials and SPEMs of the present invention can be found in current mainstream solid polymer electrolyte membranes such as Naflon® membranes or Gore-Select.
It is designed to address the drawbacks found in membranes such as another Naflon®-like membrane, such as t®.

The materials and membranes of the present invention are characterized by polarity-based chemical separations; electrolysis; fuel cells and accumulators; pervaporation; reverse osmosis-water purification, gas separations; dialysis separations; industrial electrolysis such as chloroalkali production. Chemical and other electrochemical applications; Separation of water from wastewater solutions and subsequent recovery of acids and bases; Use as superacid catalysts; for example as enzyme immobilization media; or as electrode separators in conventional accumulators Use; can be used for many electrochemical applications, including but not limited to.

Innovative methods of making the ionically conductive materials of the present invention are also disclosed. These methods can be designed to produce solid polymer electrolyte membranes useful for a range of process conditions and / or applications.

Such methods generally include polyaryl ether ketone (PEK) homopolymers, PEK copolymers or blends thereof, or polyphenyl sulfone (
PPSU) homopolymers, PPSU copolymers or blends thereof are provided, the addition of a sulfonating agent to the polymer solution and the separation of the sulfonated polymer from the solution. Post-treatment steps (eg purification, crosslinking, use of antioxidants, chlorination or bromination of the aromatic polymer backbone) in order to enhance or improve the stability of ion-conducting materials and membranes made of these materials. May be used.

In one embodiment of the invention, the ionically conductive material comprises a sulfonated PEK homopolymer, PEK copolymer or blends thereof.

[0074]   One example of a suitable PEK homopolymer has the following repeating units:

[0075]

[Chemical 5] The phenyl ring of the PEK homopolymer may or may not be substituted.

One feature of the present invention is that PEK homopolymers, PEK copolymers or blends thereof are prepared in the absence of ether-phenyl-ether bonds (eg PEK / PEEK).
Sulfonation (in the absence of copolymerization).

This is also achieved in part by increasing the sulfonation capacity of the sulfonation solution while preventing significant degradation of the polymer. The expectations of the prior art differ from this idea, and it was believed that, for example, aromatic groups adjacent to protonated ketones could not be sulfonated to a useful degree.

In one preferred embodiment, PEK homopolymer, for example commercially available from Victrex USA, is dissolved in concentrated sulfuric acid. Fuming sulfuric acid is added slowly to react with the water present in the solution (after all the water has reacted) to finally produce a more concentrated form of the sulfuric acid solvent with free SO ₃ . Further fuming sulfuric acid is added to increase the sulfonation capacity of the solution. (Water content reduces the increases the sulfone Kano solution.) SO ₃ concentration careful excess since or solution from overheating, it is necessary to minimize polymer degradation. Overhead stirring of the solution and a room temperature water bath are highly recommended.

Maintaining the concentration of the reactant acid solution is essential. Since these solutions are hygroscopic, the concentration is likely to change due to moisture absorption when exposed to air. Carefully monitor the opacity of the solution to confirm the concentration. Concentration may be monitored using titration.

Ion-conducting products based on sulfonated PEKs can be isolated by precipitation in water (methanol / water or water saturated with salt) provided that the product is not sulfonated enough to render the product water soluble. Also causes an increase in the degree of sulfonation). Sulfonation proceeds as the reaction time increases or the amount of sulfur trioxide increases.

A suitable temperature range for the reaction is the initial PEK before, after or during the addition of fuming sulfuric acid.
The temperature is 0 to 80 ° C including the cooling of the polymer solution. However, pure H ₂ SO ₄ solution is about 1
Since it solidifies at 0 ° C, it is preferable to maintain the temperature at 10 to 60 ° C.

Other suitable reaction conditions include about 0 (about 100% sulfuric acid) to about 30 wt% (about 70%).
Free SO ₃ concentration used in% sulfuric acid) and the like. The optimum concentration varies depending on other reaction conditions (that is, temperature), but generally, the SO ₃ concentration is preferably 1 to 25% by weight.

The final polymer concentration depends on the starting sulfuric acid concentration, the desired free SO ₃ concentration and the concentration of oleum added. Generally, the preferred concentration range is concentrated sulfuric acid (preferably 80-
100%, more preferably 90-99%) 10% by weight polymer (5-30% by weight).

Fuming sulfuric acid (SO ₃ / H ₂ SO ₄ ) is a preferred source of SO ₃ for sulfonation of PEK homopolymers, copolymers or blends thereof. The free SO ₃ concentration is preferably 10-60% by weight, more preferably about 20-30% by weight. However, pure SO ₃ can also be used under suitable conditions.

The above reaction conditions can be adjusted to produce an ion-conducting material based on sulfonated PEK with an IEC of at least about 0.5 to at least about 4 meq / g.

According to the present invention, ion-conducting materials comprising sulfonated PEK homopolymers, copolymers or blends thereof can be isolated by direct precipitation of water (or brine) depending on the degree of sulfonation.

Although the peroxide stability of sulfonated PEK is not sufficient for long-term use in fuel cells, for example, dialysis, electrodialysis or electrolysis systems, pervaporation or gas separation systems, acidification from waste aqueous solutions. Many electrochemical applications, such as water separation systems for recovering bases and bases, or battery electrode separators, do not require this level of hydrolytic stability.

In another preferred embodiment of the invention, the ionically conductive material comprises at least one of a sulfonated PPSU homopolymer, a PPSU copolymer or a blend thereof. This polymer has the following repeating units.

[0089]

[Chemical 6] The phenyl ring of the PPSU polymer may or may not be substituted.

According to the teachings of the prior art, PEES units are easily sulfonated, while PES units are very difficult to sulfonate (see, eg, US Pat. No. 5,013,765). P
Due to the chemical structure of the PSU polymer, it was expected that the sulfonation of PPSU could be carried out using a sulfuric acid (solvent) / sulfur trioxide (sulfonating agent) system. As a result of examination by the present inventors, it was considered that controllable sulfonation of PPSU cannot be performed with a sulfuric acid solvent.

An alternative method using a DMF / sulfur trioxide combination was investigated. It has been found that this method also fails to produce sulfonated PPSU polymer.

Further alternatives were investigated using the sulfonation method with chlorosulfonic acid (solvent) / sulfur trioxide (sulfonating agent). See, for example, U.S. Pat. No. 4,413,106. This method also proved to be inadequate.

It has been found in the present invention that controllable sulfonation of PPSU homopolymers, copolymers and blends thereof can be achieved using a methylene chloride (solvent) / sulfur trioxide (sulfonating agent) system.

To describe one preferred method of the present invention for making PPSU-based ionically conductive materials, first the polymer is treated with a suitable solvent, preferably methylene chloride or another non-reactive solvent such as halogenated carbon. Dissolve in hydrogen or nitrobenzene). The polymer solution is stirred until the polymer precipitates and a slush-like suspension is formed. The sulfonation is carried out by mixing the PPSU polymer suspension with a sulfonating agent, preferably sulfur trioxide. The degree of sulfonation is controlled by the addition amount of the sulfonating agent. The temperature is preferably maintained at -10 to 25 ° C.

The method for producing an ion-conducting material based on PPSU of the present invention can be further optimized by further diluting the polymer solution with a solvent and extending the addition time of the sulfonating agent.

According to the method of the present invention, addition of sulfur trioxide to the slush-like suspension did not result in agglomeration during sulfonation. The reaction product was maintained as a suspension (e.g., an ultrafine dispersed powder) and collected by filtration. The product was then washed with solvent (eg methylene chloride) and air dried. Surprisingly, the use of ClSO ₃ H / CH ₂ Cl ₂ was found to be incompatible with such suspensions.

A generally preferred concentration range of the PPSU-based ion-conducting material of the present invention is 5 to 30% by weight, preferably 10 to 20% by weight (initial polymer solution before dilution of excess solvent).

Using this method, a comparable high conductivity (at least about 0.01 to about 0.5) is used.
S / cm IC) and highly sulfonated polymer films with minimal polymer degradation (at least about 0.5 meq / g to at least about 4.0 meq / g IEC.
) Can be manufactured.

The sulfonation treatment may result in some inhomogeneities in the sulfonated PPSU-based ion-conducting polymer. The heterogeneity does not appear to be so great that the polymer precipitates during the sulfonation process, although some partitioning may be seen as the polymer crystallites are sulfonated from the outside to the inside. That is, a part of the sulfonated polymer may be strongly sulfonated to be water-soluble (it may be leached during the operation of the fuel cell) or may be decomposed in another form.

The over-sulfonated or degraded moieties of these polymers can be effectively removed using various purification methods. In one preferred embodiment, the ion-conducting polymer is redissolved in a suitable solvent (eg NMP) and reprecipitated in water or saturated NaCl solution as a purification treatment. It has been found that reprecipitation of the ion-conducting polymer in a saturated salt solution yields a high yield of ion-conducting polymer while removing excess sulfonated or degraded polymer.

Furthermore, the long-term stability (aqueous hydroperoxide groups) of the ionically conductive material of the invention can be improved by several methods.

For example, several post-treatment steps can enhance the stability of the ion conductive material of the present invention. These steps include (i) a step of cross-linking an ion-conductive polymer in the H + form to form a sulfone cross-link, (ii) a step of adding a small amount of an antioxidant (insoluble) to the ion-conductive polymer, and ( iii) A step of chlorinating / brominating the ion-conducting polymer main chain to reduce decomposition sites can be mentioned.

The cross-linking method can provide or enhance peroxide stability. Further, various methods for crosslinking a sulfonated polymer to further enhance the barrier property of an ion conductive polymer are described in the literature. For example, US Pat. No. 5,795,496; Kerres.
Et al., “New Ionomers and ther Applicatio”
ns in PEM Fuel Cells ”, ICE, Stuttgart,
Germany (1996); and Kerres et al., J. Am. Membrane S
ci. 139: 211-225 (1998).

For example, US Pat. No. 5,795,496 describes a method of crosslinking ion-conducting polymers via SO ₃ H groups (sulfonic acid groups) to form sulfone crosslinks between polymer chains. There is. This method uses concentrated sulfuric acid to polymer (eg PEEK
) Is sulfonated and the film is cast, the film is heated under vacuum to a temperature of 120 ° C. Crosslinking occurs in the heating process.

Although the barrier property is enhanced by the crosslinking, the ionic conductivity, water absorption and swelling property of the polymer are reduced as a result of the crosslinking treatment. However, the crosslinking treatment used can be adjusted to minimize the loss of ionic conductivity.

Additives can also be used to provide or enhance the peroxide stability of PEK and PPSU based ion conducting materials of the present invention. Polymer additives can be used as radical scavengers inside the ion conductive material or the ion conductive component of SPEM. Examples of these include Irganox 1135.
(Primary phenol antioxidant, Ciba Geigy commercial product) and DTTDP (di (tridecyl) thiodipropionate, secondary antioxidant, Hampshire commercial product).

The PEK- and PPSU-based ion-conducting materials of the present invention can be used to make SPEMs using standard membrane casting techniques. Such techniques are well known to those of ordinary skill in the art. For example, the polymer can be dissolved in a suitable solvent and cast onto a glass plate (or other surface) to form a film. More specifically, the ion conductive polymer can be dissolved in n-methylpyrrolidone (NMP), filtered, and then cast on a support. The film is slowly evaporated in a low humidity chamber and then dried in a vacuum oven until fully cured. When dry
The film can be peeled from the casting support by immersion in water.

Ion-conducting materials and SPEMs based on PEK and PPSU of the invention
Has low methanol permeability even at high temperature and high pressure (low methanol diffusion and solubility)
, Substantially stable to acids and free radicals, at least about 100 ° C
It is heat / hydrolysis stable up to the temperature of.

The ion-conducting membranes based on PEK and PPSU of the present invention are> 1.0 meq.
/ G dry membrane (preferably 1.5 to 2.0 meq / g) ion exchange capacity (IEC
), And has high ionic conductivity (preferably about 0.01 to about 0.5 S / cm,
More preferably> about 0.1 S / cm or resistivity <10 Ωcm).

The ion-conducting materials and SPEMs of the present invention are durable, substantially defect free, and preferably dimensionally stable at temperatures above at least about 100 ° C. (dimensions wet to dry). Change less than about 20%).

Particularly preferred PEK- and PPSU-based ion-conducting materials are capable of withstanding operation in fuel cells (ie H ₂ / O ₂ , methanol) for at least about 5000 hours (eg for automobiles).

The ion-conducting materials based on PEK and PPSU used in the present invention may be substituted or not. These materials can be present as homopolymers, copolymers or other blends. PEKs and Ps of the type disclosed herein
PSU homopolymers, copolymers and blends thereof can include any desired substituents, as will be readily appreciated by those skilled in the art, provided that they do not substantially impair the properties desired for the intended use of the polymer. Such properties include ionic conductivity, chemical and structural stability, swelling and the like.

Blending the polymers to form the PEK- and PPSU-based ion-conducting materials of the present invention is advantageous for optimizing each of their properties. Unlike simple mixing, the blend does not form a composite in which the two components are dispersed, but is homogeneous throughout. Blending a sulfonated polymer with a non-sulfonated polymer may be useful for optimizing swelling, fuel crossover resistance, conductivity, peroxide resistance, hydrolysis stability and the like. It is also believed that blending the two sulfonated polymers can improve properties over the individual components. This concept can also be used to improve the strength, cost, processability or stability of the ionically conductive materials of the present invention.

Use of the innovative PEK- and PPSU-based ion-conducting materials and membranes of the present invention results in improved power density and reduced sensitivity to carbon monoxide in hydrogen fuel. Costly ion conductive materials can be manufactured.

The ion-conducting materials of the present invention also alleviate water management issues that limit the efficiency of existing Nafion® membrane based fuel cells.

The ion conductive material of the present invention exhibits resistance to decomposition and hydrolysis and resistance to creep due to stress.

The ion conductive material of the present invention has high ionic conductivity, high dehydration resistance, high mechanical strength, is chemically stable at the time of oxidation and hydrolysis, and has low gas permeability, thus causing parasitic loss. Low, stable at high temperature and high pressure.

The ion conductive material of the present invention is resistant to methanol crossover when used in direct methanol fuel cells. As a result, efficiency is high and battery performance is improved.

The ion-conducting material of the present invention uses relatively low cost raw materials and manufacturing methods, so it is manufactured at a fraction of the cost of membranes using Nafion® and Nafion®-like ionomers. be able to.

The ion conductive material of the present invention acts as a shield for reactants (H ₂ , O ₂ and methanol permeation) in fuel cell applications.

To produce the ion conductive material of the present invention, a surfactant or a surfactant having a hydrophobic portion and a hydrophilic portion can be used. These materials are well known in the art and are described, for example, in Triton X-100 (Philadelphia, P.
A commercial product of Rohm & Haas located in A) can be mentioned.

Compatibilizers can also be utilized in making the membranes of the present invention. As used herein, a "compatibilizer" is a substance that enhances the blendability of two or more polymers that are normally difficult to blend. For example, a block copolymer including a bonding segment of each component may be mentioned.

Hereinafter, the PEK- and PPSU-based ion conductive material of the present invention, SPE
M and the method will be further described with reference to tables and examples.

[0124]   The following table details the ion conductive materials and SPEMs of the present invention.

[0125]

[Table 1]

[0126]

EXAMPLES Commercially available starting material Radel® polyphenylsulfone polymer is Ammo Copolymers (Am
commercially available from Oco Polymers). Victrex® poly (arylethyl ether) polymers are commercially available from Victrex USA.

General Procedures The following procedures were used in the fabrication and testing of samples prepared by the materials, membranes and methods of the invention.

IEC Procedure 1. Cut a small piece of sulfonated film (target weight 0.2g, target thickness 2mils
) Do. 2. Vacuum dry at 60 ° C. Record the dry weight and note whether the film is H + or Na + form. 3. Boil deionized water in a separate beaker on a hot plate. 4. Put the film in boiling water. 5. Boil the film vigorously for 1/2 hour. 6. Prepare 1.5 NH ₂ SO ₄ . 7. Place the film in H ₂ SO ₄ and soak for ½ hour. 8. Remove the film and rinse with deionized water. 9. Boil again in deionized water. By repeating this, the film is dipped in H ₂ SO ₄ three times. 10. Remove the film from boiling water, dab the surface of the film with a paper towel and carefully rinse with deionized water. 11. Place the film in another beaker of water and check the pH. 12. Continue washing the film with water until the pH is neutral to remove excess acid from the film fold. 13. Prepare a saturated NaCl solution. 14. The NaCl solution is boiled, poured into a vial with a screw-on lid, and a film is put into the vial and the lid is closed. 15. Place the covered beaker containing the film in a 90 ° C. water bath for 30 minutes. 16. Remove the covered beaker from the water bath and allow it to cool to room temperature. 17. The film is removed from the NaCl solution by pouring the salt solution into another beaker (storage) and washing the film with deionized water (store all wash water, use for titration). 18. The NaCl solution is titrated with 0.1 N NaCl. 19. Take the film and tap it with a paper towel to determine the wet weight (wet weight is used to measure the water content of the film). 20. The film is dried at 60 ° C. under vacuum until the weight becomes constant. 21. Dry weight is measured and used for IEC calculation.

Peroxide Test Procedure 22. The film is made H + type by the following steps 1-12. A peroxide solution is prepared by adding 23.4 ppm Fe to 3% hydrogen peroxide (
28.5 mg of iron (II) sulfate ammonium hexahydrate per 1 L of hydrogen peroxide (Aldrich
Obtained from)) 24. Place the peroxide solution in a 68 ° C. water bath. Place the film in the peroxide solution at 25.68 ° C. Perform a 26.8 hour peroxide test and record the film properties (mechanical, color, ease of handling). 27. Once the film passes the test, it is removed from the hydrogen peroxide and washed with water to remove traces of peroxide solution. 28. Perform steps 13-21 to obtain IEC after peroxide test.

Crosslinking Procedure The ion-conducting polymer sample was treated with acid (H +) to improve ICP stability.
) Molds can be crosslinked. Crosslinking is usually performed under vacuum to remove oxygen from the system (oxygen can cause ICP carbonization). The vacuum oven must be preheated to a temperature of at least about 200 ° C. The ICP sample is therefore heated in the vacuum oven for an extended period of time. ICP samples must be tested before and after crosslinking for IEC and peroxide stability to assess long term membrane stability. See, eg, Example 5 below.

Film Fabrication Procedure Film Molding The ion conductive materials of the present invention could be manufactured using standard membrane molding techniques. Such techniques are well known to those of ordinary skill in the art. For example, a film can be made by dissolving the polymer in a suitable solvent and then molding it on a glass plate (or other surface). More specifically, the ion-conducting polymer can be dissolved in n-methylpyrrolidone (NMP), filtered, and molded onto a substrate.
The film is dried slowly in a low humidity chamber and then in a vacuum oven to full density. Once dried, the film is removed from the substrate by water immersion.

Sulfonation Procedures Sulfonation Procedures I Aromatic PES polymers can be sulfonated with a degree of substitution controlled by a sulfonating agent. The degree of substitution is controlled by the choice of sulfonating agent and the molar ratio of sulfonating agent to aromatic rings of the polymer. This procedure provides a way to carry out the sulfonation in a heterogeneous manner, for example on precipitated polymer crystals.

The polymer (preferably polyether sulfone) is first dissolved in a suitable solvent (preferably methylene chloride) and then precipitated to give a finely crystalline suspension. The sulfonation can be carried out with a simple mixture of this suspension and the sulfonating agent. Suitable sulfonating agents include chlorosulfonic acid, and preferably sulfur trioxide (Sulfan B® stabilized in methylene chloride, Allied chemicals). The sulfonating agent used must be in a sufficient ratio to introduce the number of sulfonate groups on the polymer, which is not critical but 0.4: 1 to 5: per polymer unit.
It is within the range of 1. The temperature at which sulfonation occurs is important to limit side reactions, but varies with the type of polymer (preferred temperature is -50 to 80 ° C,
It is preferably in the range of -10 to + 25 ° C).

Once the desired degree of sulfonation is reached, the sulfonated polymer can be prepared by conventional means,
It can be separated from the reaction mixture by separating it from the reaction mixture, for example by filtration, washing and drying.

The polymer product of the process of the present invention can be neutralized by the addition of a base such as sodium hydrogen carbonate and, if necessary, its alkali salt. The alkali salt of the polymer product of this invention can be used for the same purpose as the parent acid polymer.

[0136]   See, for example, US Pat. No. 4,413,106.

Sulfonation Procedure II Concentrated sulfuric acid is used as solvent in this procedure. The amount of sulfonating agent, sulfur trioxide, is based on the total amount of pure (100% anhydrous) sulfuric acid present in the reaction mixture and is kept below 6% by weight for the entire duration of the sulfonation. Sulfur trioxide is in dissolved form (
Oleum, fuming sulfuric acid) can be mixed with concentrated sulfuric acid. The concentrations of starting sulfuric acid and oleum were determined by measuring their densities just before use in the reaction.

The temperature of the reaction mixture is kept below + 30 ° C. during the whole reaction. The sulfonation procedure is stopped by adding water to the reaction mixture or pouring the reaction mixture into water.

More specifically, the polymer is first dried at room temperature under high vacuum until constant weight and then dissolved in concentrated sulfuric acid. Next, stir the oleum constantly at + 30 ° C.
Add dropwise over the entire time, keeping below. Once all the oleum has been added,
The reaction mixture is stirred for a further hour at the same temperature. The viscous solution obtained is then placed in water and the precipitated polymer is filtered off. The polymer is then washed until it is not acidic and dried.

If these conditions are maintained, the sulfonation of the aromatic polyether sulfone can be controlled, and the deterioration of the polymer can be substantially or completely prevented.

Although less preferred, another modification of this procedure is to add sulfur trioxide in pure solid or gas state to a polymer solution in concentrated sulfuric acid.

[0142]   See, for example, US Pat. No. 5,013,765.

Ion Conductive Material-Test Method IEC,% Water Content, Membrane Degradation During this procedure, the film is immersed in distilled water and boiled for 30 minutes. The film is then placed at room temperature in a 1.5 NH ₂ SO ₄ solution and soaked for 30 minutes. This is repeated three times separately to ensure H + ion exchange in the membrane. The film is washed free of acid (wash water pH> 5.0) and placed in another beaker filled with another saturated NaCl solution. The salt solution is boiled for 3 hours. The film, now in the Na + form, is removed from the salt solution, washed with distilled water and tapped to remove excess water. Measure the wet weight and thickness of the sample. Although it is a Na + type, this film has 6
Dry in an air oven at a temperature of 0 ° C. The dry weight and thickness of this film is measured and the water content percentage is calculated. The salt solution is titrated with 0.1 N NaOH to the phenolphthalein endpoint and the IEC dry (meq / g) value is calculated.

Ionic Conductivity For film samples, transverse ionic conductivity is measured to determine the specific resistance (ohm ^* cm ² ). Prior to measurement of ionic conductivity, film samples are made H + type using the standard method described above. To measure ionic conductivity, the film sample is placed in a die consisting of a niobium plate with a platinum plate. The test sample size is 25 cm ² . Place the platinum black electrodes on both ends of the film sample and assemble the membrane-electrode assembly (ME
Make A). The MEA is pressed between 100 and 500 psi between two platinum-plated niobium steel rams so that they are in full contact during resistance measurements. The resistance of each film is measured with a 4-point probe resistance measuring device at 1000 Hz and 1 to 5 A, and converted into conductivity using Equation 1.

(1) C = t / RxA C = conductivity (S / cm) R = sample resistance (ohm) t = wet sample thickness (cm) A = sample area (cm ² ).

By calculating the ratio of thickness to conductivity (ohm ^* cm ² ) the measured value
Convert to resistivity.

Membrane Degradation A accelerated degradation test is performed using a 3% H ₂ O ₂ solution with 4 ppm Fe ++ added as an accelerator. The film is tested at a temperature of 68 ° C for 8 hours. After testing, the% IEC reduction of the film sample is measured. After 8 hours, the film is removed from the solution and reconverted with 1.5 NH ₂ SO ₄ . The IEC is recalculated and the test results are presented as% IEC loss. This test corresponds to a long time (thousands of hours) of actual fuel cell operation. For H ₂ O ₂ fuel cells, <10% IEC degradation in this test is considered acceptable.

Example 1 Sulfonation of RadelR® with SulfanB® (100% and 150% Sulfonation) Sulfonation Procedure I was used in the following examples.

A three-neck resin kettle (ribbed) fitted with N ₂ inlet, addition funnel and overhead stirrer was charged with 340 ml of dichloromethane and 50
． 00 g of RadelR® polyphenylsulfone polymer (beads)
I put it in. The mixture was stirred until a solution formed (about 0.25 hours). Once a solution had formed, the mixture was cooled in an ice-cold bath at a temperature of about 0 ° C (the ice-cold bath was kept during the addition and reaction). (Note that RadelR® was dried at 70 ° C. under full dynamic vacuum for about 12 hours to completely remove the absorbed water.) While cooling this solution, the following amount of Sulfan B (registered trademark) was added. ™) was combined with dichloromethane in two separate addition funnels. In Funnel # 1 (100% sulphonated) 10.00 g Sulfan B® was combined with 120 ml dichloromethane. In Funnel # 2 (150% sulphonated) 15.00 g Sulfan B® was combined with 120 ml dichloromethane.

Upon cooling the polymer solution, the polymer precipitated out of solution forming a viscous paste. The polymers were combined with 120 ml of dichloromethane so that the suspension was homogeneous. The diluted suspension was then cooled once again to ice bath temperature.

Sulfan B® was added dropwise to the rapidly stirred, cooled and diluted polymer suspension over 3.5 to 4 hours.

After the addition of the Sulfan B® / dichloromethane solution was complete, the reaction mixture was stirred for an additional 2.5 hours at ice-cold bath temperature, then the reaction was added to each reaction mixture with about 10 ml of distilled water. And then stopped.

The reaction mixture (white dispersion) was collected by filtration through glassware. product(
The white powder) was washed 3X with 100 ml portions of dichloromethane. The wash product was then air dried in a hood. A 20% solution of dry product in NMP was prepared and molded onto soda lime glass plates. The as-formed film was placed in a dry box with a specific humidity of 5% or less for 24 hours. The formed film was heated to 70 ° C. for 1 hour under full dynamic vacuum before being float-separated with distilled water. The floated film was then dried overnight.

The 100% and 150% sulfonated products swell significantly in water and become opaque, but when the film is dried it shrinks and becomes clear again. The mechanical strength of this film is such that it can be folded without tearing. 100
The% product film and the 150% product film are insoluble in boiling water and retain their mechanical properties under these conditions.

IEC: 100% sulfonated RadelR® crude = 1.39me
q / g 150% sulfonated RadelR® crude = 1.58 me
q / g.

These polymers were dissolved in NMP (at 20% by weight) for further purification and precipitated in excess saturated aqueous salt solution. The polymer obtained was dipped in sodium hydrogen carbonate, washed several times with water and dried under vacuum (-100 ° C). These polymers were cast into films as described above for characterization.

IEC: 100% Sulfonated RadelR® Purification = 1.26 meq
/ G 150% sulfonated RadelR® purification = 1.44 meq
/ G.

[0158]   Water pickup (% by weight)           100% Sulfonated RadelR® Purification = 56%           150% Sulfonated RadelR® Purification = 110%.

Example 2 200% of RadelR® with SulfanB®
Sulfonation Procedure with Stoichiometric Sulfonation The sulfonation reaction here is performed according to Example 1 (Sulfan B® 10
(0,150% sulfonation) was carried out in a manner very similar to that described above, with the following adjustments.

-After the first precipitation of the polymer from dichloromethane, only 200 ml of fresh solvent was added to facilitate stirring (an additional 350 ml was used in Example 1).

The above data suggests that not all SO ₃ has reacted with the polymer at 0-5 ° C. for 6 hours. Therefore, one reaction was run at ice bath temperature for 8 (or more) hours and then warmed to room temperature. The resulting sulfonated RadelR® was darker than the batch that was quenched in only 6 hours, but the polymer was still insoluble in water and showed good film properties. These ICP
Was as follows.

200% sulfonated RadelR (stopped at 0-5 ° C. after 6 hours): IEC = 1.67 meq / g, water pickup = 144%, conductivity = 0.073
S / cm 200% sulfonated Radel R (reaction stopped after warming): IEC = 1.90 meq / g, water pickup = 174%, conductivity = 0.091.
S / cm.

A similar reaction was carried out by reacting —SO ₃ for a longer time, cooling the temperature during the reaction (0-5 ° C.). The product isolated from this reaction has an IEC value (1.71 meq / g)
Had. This value was midway between the two batches mentioned above.

Note: Percent sulphonation in the stoichiometric sense, eg 200% sulphonation,
Refers to the use of a certain excess amount for each polymer repeat unit, for example 2 mol in the case of 200% sulphonation.

Example 3 Sulfonation of RadelR® with SulfanB® at 220% Stoichiometric Sulfonation Procedure Two sulfonation experiments were carried out by the method of Examples 1 and 2 below. The adjustments described were made and carried out.

-350 ml after precipitation of the polymer from the first solution to aid in stirring
Dichloromethane was added.

-22 g SulfanB was combined with approximately 115 ml dichloromethane (corresponding to 220% sulfonation of the monomer units). This solution was added dropwise to each polymer suspension (previously cooled in an ice-cooled bath) over 4 hours.

[0168]   -After addition, the reaction was packed in ice for about 10 hours and then warmed to room temperature.

After stopping the reaction with a few ml of water, the reaction mixture was filtered and washed with dichloromethane and tetrahydrofuran.

The sulfonated polymer was dried overnight, dissolved in NMP (at 20% by weight), then precipitated in a large excess of distilled water and then immersed in sodium hydrogen carbonate solution (to obtain the sodium salt form) To). After neutralization, the gel-like polymer precipitate was rinsed several times with deionized water.

-One reaction (Sample A) was filtered and dried. About 4 L of acetone was added to the second reactant (Sample B). Acetone causes the water swollen polymer to collapse. The polymer was then isolated by filtration. Acetone also dissolved a significant portion. The dissolved portion was isolated by drying the acetone / water mixture (Sample B
-1). Sample B and Sample B-1 contained approximately the same amount of polymer,
It showed different properties. In particular, the polymer that was not extracted in acetone showed slightly lower IEC and much lower water pickup.

[0172]   220% sulfonated RadelR:   Sample A: IEC = 2.08 meq / g,               Water pickup = 306% by weight,               IC = 0.179 (S / cm)   Sample B: IEC = 1.82 meq / g,               Water pickup = 128% by weight,               IC = 0.155 (S / cm)   Sample B-1: IEC = 2.12 meq / g,               Water pickup = 432% by weight,               IC = 0.132 (S / cm).

Example 4 Sulfonation of Victrex® poly (ether ketone) with H ₂ SO ₄ / SO ₃ Procedure II was used in the following examples.

Procedure 30.00 g PEK polymer was dissolved in 270 g concentrated sulfuric acid (93.5 wt%) under nitrogen and stirred with an overhead mechanical stirrer. The polymer was dispersed for several days to give a dark red concentrated solution.

176 g of this solution was placed in a three-necked flask with overhester and N ₂ etc. To this flask was added 208.4 g fuming sulfuric acid (25.5 wt% free SO ₃ ) over a few minutes with constant stirring to raise the solution's free SO ₃ content to 2 wt%. The resulting solution was placed in a room temperature bath to control the temperature.

Samples were taken after about 1 hour, 3 hours and 16 hours and quenched by precipitation in deionized water.

To make films, the 1 hour and 3 hour products were washed several times with deionized water, soaked in approximately 0.5 M NaOH overnight, and then washed until neutral. These were blotted dry and placed in a vacuum oven at 50 ° C. Dry sample to N
A 20 wt% solution was prepared by dissolving in MP. For this purpose it was heated to 60 ° C. overnight.
A film of about 6 mil was cast on a freshly cleaned glass plate. After drying for 2 days, the film was taken out by dipping in deionized water.

Soaking the film in water (at room temperature) caused a significant swelling, giving a cloudy gel-like density, but the 1 hour and 3 hour samples did not dissolve. 1
The time product film could be hydrated and dehydrated while maintaining tear resistance. The 1-hour sulfonated PEK film IEC was 2.3 meq / g.

Example 5 Crosslinking of Sulfonated PPSU Ion conducting polymer samples can be crosslinked in the acid (H +) form to improve IPC stability. Crosslinking is usually done under vacuum to remove oxygen from the system (which can cause IPC carbonization). For example, SPPSU was cross-linked for up to 8 hours in a vacuum oven preheated to temperatures of 200, 225 and 250 ° C. Under these conditions, the sample showed a slight IEC loss (-10%) and a slight improvement in long-term stability (peroxide test). More severe conditions were given by exposing the sample to full vacuum at 250 ° C. for 20 hours or more. In the peroxide test, until heated for at least 32 hours, the SPPU crosslinked film and SPP
No significant difference was seen with the U control film. The 32 hour and 72 hour crosslinked films at 250 ° C maintained the integrity of the film during the peroxide accelerated severe storage test. The IEC of these samples was greatly reduced. Specifically, 3
63% for 2-hour samples (1.90 meq / g to 0.69 meq / g)
Loss of 73% for a 72 hour sample (0.50 m for 1.90 meq / g)
eq / g) was calculated. Many SO ₃ H acid groups are aromatic sulfones (Ar
It is expected that -SO3-Ar) crosslinks were formed between the polymer chains. This tendency confirms that the cross-linking (H + type) of the sulfonated polymer can be used to improve long-term membrane stability.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08J 5/22 101 C08J 5/22 101 CEZ CEZ C08K 5/00 C08K 5/00 C08L 81/06 C08L 81 / 06 H01M 8/02 H01M 8/02 P (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW) , SD, SL, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AL, AM, AT, AU , AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH, GM, HR, HU, ID, IL, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO , RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZW (72) Inventor Aussner, Paul United States, Masachi Youtsutsu 02472, Watertown, Waltham Street No. 9/100 (72) Inventor Kovar, Robert F. USA, Masachi Yousets 02093, Wrentham, Beach Street 203 (72) Inventor Landrough, Nell United States, Masachi Youths 01752, Morbara, Poo Boxes 625 F Term (reference) 4F071 AA51C AA64C AE02C AE05C AH12 4J002 CH091 CN031 EJ016 EV106 FD076 GD01 4J005 AA24 BD04 BD06 4J030 BA0 BA0 BA42 BA42 BA42 BA42 BA42 BA42 BB10 CX05 EE18 HH00 HH05 HH08

Claims (39)

[Claims] 1. An ion conductive material comprising one or more polyaryletherketone (PEK) homopolymers, one or more PEK copolymers or a mixture thereof, wherein said PEK homopolymer, PEK copolymer or them. The ionic conductive material is characterized in that the mixture is sulfonated and the ion conductive material does not have an ether-phenyl-ether linkage. 2. The PEK homopolymer has repeating units of the formula:
The ion conductive material according to. [Chemical 1] (In the formula, the phenyl ring may be substituted or unsubstituted.) 3. At least about 0.5 meq / g to at least 4 meq / g
The ion conductive material according to claim 1, having an IEC of. 4. The ion conductive material according to claim 1, further comprising a sulfone cross-linking portion. 5. The ion conductive material according to claim 1, further comprising an antioxidant. 6. The ion conductive material according to claim 1, wherein the ion conductive material is halogenated. 7. The ion conductive material according to claim 6, wherein the ion conductive material is brominated or chlorinated. 8. A solid polymer electrolyte membrane comprising the ion conductive material according to claim 1. 9. The solid polymer electrolyte membrane according to claim 8, wherein the ion conductive material has a sulfone cross-linking portion. 10. A method of making an ionically conductive material free of ether-phenyl-ether linkages suitable for use in electrochemical applications, comprising one or more PEK homopolymers, PEK copolymers or mixtures thereof. Providing a solution; adding a sulfonating agent to the solution of the PEK homopolymer, PEK copolymer or a mixture thereof to form a sulfonated PEK homopolymer, PEK copolymer or a mixture thereof; And a step of isolating the sulfonated PEK homopolymer, PEK copolymer or a mixture thereof from a solution. 11. The method of claim 10, wherein the sulfonating agent comprises one or more of sulfur trioxide, concentrated sulfuric acid and fuming sulfuric acid. 12. The method of claim 11, wherein the sulfonating agent has a free sulfur trioxide content of about 0 (about 100% sulfuric acid) to about 30 wt% (about 70% sulfuric acid). 13. The method of claim 10, wherein the PEK polymer solution is maintained at a reaction temperature of about 10 ° C to about 60 ° C. 14. The method of claim 10, further comprising casting a membrane of the ion conductive material. 15. The method of claim 10, further comprising the step of crosslinking the ionically conductive material. 16. The method of claim 15, wherein the ionically conductive material is crosslinked in the H ⁺ form by a thermal process. 17. The step of isolating the sulfonated PEK homopolymer, PEK copolymer or a mixture thereof comprises adding the sulfonated PEK homopolymer, PEK copolymer or a mixture thereof with water, sodium chloride. 11. The method of claim 10, comprising reprecipitating in saturated water, methanol or other non-solvent. 18. The method of claim 10, further comprising the step of adding an antioxidant to the sulfonated PEK homopolymer, PEK copolymer, or mixture thereof. 19. The oxidant, the sulfonated PEK homopolymer, PEK
The method according to claim 18, which is introduced after isolation of the copolymer or a mixture thereof. 20. The method of claim 10, further comprising halogenating the aromatic backbone of the sulfonated PEK homopolymer, PEK copolymer, or mixture thereof. 21. The method of claim 10, further comprising the step of chlorinating or brominating the aromatic backbone of the sulfonated PEK homopolymer, PEK copolymer, or mixtures thereof. 22. An ion conductive material comprising one or more sulfonated polyphenyl sulfone (PPSU) homopolymers, PPSU copolymers or mixtures thereof. 23. The ion conductive material according to claim 22, having a repeating unit of the formula: [Chemical 2] (In the formula, the phenyl ring may be substituted or unsubstituted.) 24. At least about 0.5 meq / g to at least 4 meq / g.
23. The ion conductive material of claim 22, having an IEC of g. 25. The ion conductive material according to claim 22, further having a sulfone cross-linking portion. 26. The ion conductive material according to claim 22, further comprising an antioxidant. 27. A solid polymer electrolyte membrane comprising the ion conductive material according to claim 22. 28. The ion-conductive material has a sulfone cross-linking portion.
7. The solid polymer electrolyte membrane according to 7. 29. A method of making an ionically conductive material suitable for use in electrochemical applications, comprising providing a solution of PPSU homopolymer, PPSU copolymer or a mixture thereof; said PPSU homopolymer, Precipitating a PPSU copolymer or a mixture thereof from a solution; adding a sulfonating agent containing sulfur trioxide to the solution to form a sulfonated PPSU homopolymer, a PPSU copolymer or a mixture thereof. A step of diluting the sulfur trioxide with a halogenated hydrocarbon or nitrobenzene solvent; and isolating the sulfonated PPSU polymer from a solution. 30. The method of claim 29, wherein the halogenated hydrocarbon solvent comprises methylene chloride. 31. The method of claim 29, further comprising purifying the ionically conductive material to remove excess sulfonated or degraded portions of the ionically conductive material. 32. The step of purifying the ion-conducting material comprises:
32. The method of claim 31, comprising redissolving the SU polymer in a solvent and reprecipitating the sulfonated PPSU polymer in water, water saturated with sodium chloride, methanol or other non-solvent. 33. The method of claim 29, further comprising casting the membrane of ion conductive material. 34. The method of claim 29, further comprising cross-linking the ionically conductive material. 35. The method of claim 34, wherein the ionically conductive material is crosslinked in the H ⁺ form by a thermal process. 36. The method of claim 29, further comprising adding an antioxidant to the sulfonated PPSU polymer. 37. The method of claim 29, wherein the oxidizing agent is introduced after isolation of the sulfonated PPSU polymer. 38. The method of claim 29, further comprising halogenating the ionically conductive material. 39. The method of claim 29, further comprising chlorinating or brominating the ion conductive material.