Polymer Compositions

RELATED APPLICATIONS

This application claims priority to U.S. provisional patent application No. 62/670,040, filed May 11, 2018, the whole content of this application being incorporated herein by reference for all purposes.

FIELD OF THE INVENTION

The present invention relates to a polymer composition including a PEDEK- PEEK copolymer and a friction and wear additive, methods of making the polymer composition, shaped articles comprising the polymer composition, and their use in friction and wear applications.

BACKGROUND

Thermoplastics are increasingly displacing metals as tribological components in, for example, radial and axial bearings, engines, gears, and seal rings, which are used in automotive and industrial applications and which require materials having the strength and wear resistance found in lubricated metals. It is generally desirable to replace metals with polymers in these applications because of their ease of fabrication, higher performance, lower or little dependence on external lubrication, and lower overall cost; however, such thermoplastics must be able to withstand the loads and speeds that are common in such environments while also retaining suitable wear performance.

Poly(aryl ether ketone) (PAEK) polymers, including in particular

poly(etheretherketone) (PEEK), poly(etherketone) (PEK) and

poly(etherketoneketone) (PEKK) polymers are well known for their exceptional balance of technical properties, such as excellent heat resistance, mechanical properties and wear resistance. Nevertheless, the performance capabilities of some PAEKs have restricted their suitability for use in applications requiring the highest friction and wear performance.

There is thus a continuous need for new PAEK compositions with improved wear capabilities without loss of other advantageous properties at high

temperatures. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plot illustrating the results of wear resistance testing of the polymer compositions of Comparative Example 6 and Example 7.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Exemplary embodiments are generally directed to a polymer composition including at least one PEDEK-PEEK copolymer having a PEDEK/PEEK mole ratio ranging from 55/45 to 80/20, and at least one friction and wear additive, methods of making the polymer composition, and shaped articles including the polymer composition.

Applicants have unexpectedly found that the polymer compositions of the present invention are effective in providing shaped articles having improved wear resistance and retention of mechanical properties at relatively high temperatures. In particular, Applicants have discovered that polymer compositions including at least one PEDEK-PEEK copolymer having a PEDEK/PEEK mole ratio ranging from 55/45 to 80/20 and at least one friction and wear additive surprisingly exhibit 1) increased dynamic elastic modulus at high temperatures (e.g. 175 °C) and 2) markedly improved wear performance, as compared with similar PEEK-containing polymer compositions.

Thus, in some embodiments, the polymer composition exhibits a Dynamic Mechanical Analysis (DMT A) shear modulus of at least 1,000 MPa, preferably at least 1,200 MPa, 1,300 MPa, 1,400 MPa, and most preferably at least 1450 MPa, when measured in accordance with D5279, torsional strain mode, at a temperature of 175 °C and a strain frequency of 10 rad/s.

In some embodiments, the polymer composition exhibits a decrease in average cumulative thickness of at most 90 pm, preferably at most 85 pm, for “Cycle 1;” at most 150 pm, 140 pm, 130 pm, 125 pm for“Cycle 2;” at most 180 pm, 170 pm, 165 pm for“Cycle 3;” or a combination thereof, when tested according to the Wear Protocol described in the Examples below.

In some embodiments, the polymer composition does not reach 250 °C until at least 16.5 h, preferably at least 17.0 h, when tested according to the Wear Protocol described in the Examples below.

As used herein, the term“wear” generally refers to the amount of the polymer composition removed from a bearing surface as a result of the relative motion of the bearing surface against a surface with which the bearing surface interacts. In some embodiments, the polymer composition exhibits a tensile modulus ranging from 1,500 ksi to 3,000 ksi, preferably from 1,700 ksi to 2800 ksi as measured according to ASTM D638.

In some embodiments, the polymer composition exhibits a tensile strength ranging from 20 ksi to 25 ksi as measured according to ASTM D638.

In some embodiments, the polymer composition exhibits a flexural modulus of 1500 ksi to 2400 ksi as measured according to ASTM D790.

The polymer composition comprises at least one PEDEK-PEEK copolymer, as detailed below, at least one friction and wear additive, as detailed below, and optionally, one or more additional ingredients, as detailed below. Preferably, the at least one PEDEK-PEEK copolymer, the at least one friction and wear additive, and the optional one or more additional ingredients collectively represent greater than 50 wt.%, preferably greater than 70 wt. %, 80 wt. %, 90 wt. %, 95 wt. % of the polymer composition, based on the total weight of the polymer composition.

The polymer composition preferably consists essentially of the at least one

PEDEK-PEEK copolymer, as detailed below, the at least one friction and wear additive, as detailed below, and the optional one or more additional ingredients, as detailed below.

For the purpose of the present invention, the expression“consisting essentially of’ is to be understood to mean that any additional component different from the recited components is present in an amount of at most 1 % by weight, based on the total weight of the polymer composition, so as not to substantially alter the advantageous properties of the composition. PEDEK-PEEK Copolymer

As used herein, a“PEDEK-PEEK copolymer” denotes a polymer comprising greater than 50 mol %, collectively, of repeat units (RPEDEK) and repeat units (RPEEK), relative to the total number of moles of repeat units in the PEDEK-PEEK copolymer. In some embodiments, the total number of repeat units (RPEDEK) and (RPEEK) in the PEDEK-PEEK copolymer is at least 60 mol %, 70 mol %, 80 mol %, 90 mol %, 95 mol %, and most preferably at least 99 mol %, relative to the total number of repeat units in the PEDEK-PEEK copolymer.

Repeat units (RPEDEK) are represented by formula:

re icat units (RPEEK) are represented by formula : (B), where each R ¹ and R ² , equal to or different from each other, is independently at each occurrence selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium; and

each a and b is independently selected from the group consisting of integers ranging from 0 to 4.

Preferably, repeat units (RPEDEK) are selected from units of formula :

(A-l),

Preferably, repeat units (RPEEK) are selected from units of formula:

(B-l), where each of R ¹ , R ² , a’, and b’ is independently selected from the groups described above for R ¹ , R ² , a, and b, respectively.

Preferably, repeat units (RPEDEK) are repeat units of formula (A-l), and repeat units (RPEEK) are repeat units of formula (B-l).

In some embodiments, each a’ is zero, such that the repeat units (RPEDEK) are re )eat units of formula: In some embodiments, each b’ is zero, such that the repeat units (RPEEK) are repeat units of formula : (B-2).

Preferably, repeat units (RPEDEK) are repeat units of formula (A-2), and repeat units (RPEEK) are repeat units of formula (B-2).

The PEDEK-PEEK copolymer of the present invention may additionally comprise repeat units (RPAEK) different from repeat units (RPEDEK) and (RPEEK), as above detailed. In such case, the amount of repeat units (RPAEK) is generally comprised between 0 and 5 mol %, with respect to the total number of moles of repeat units of PEDEK-PEEK copolymer.

In some embodiments, the PEDEK-PEEK copolymer includes repeat units (RPAEK) different from repeat units (RPEEK) and (RPEDEK). Repeat units (RPAEK) are selected from the group consisting of units of formulae:

wherein in each of formulae (K-A) to (K-M) above, each of R’, equal to or different from each other, is independently selected at each occurrence from a Ci-Ci ₂ group optionally comprising one or more than one heteroatom; sulfonic acid and sulfonate groups; phosphonic acid and phosphonate groups; amine and quaternary ammonium groups; and each of j’, equal to or different from each other, is independently selected at each occurrence from 0 and an integer of 1 to 4, preferably j’ being equal to zero.

It is nevertheless generally preferred for the PEDEK-PEEK copolymer of the present invention to be essentially comprised of repeat units (RPEDEK) and (RPEEK), as above detailed. Thus, in some embodiments, the PEDEK-PEEK copolymer consists essentially of repeat units RPEDEK and RPEEK- AS used herein, the expression“consists essentially of repeat units RPEDEK and RPEEK” means that any additional repeat unit different from repeat units RPEDEK and RPEEK, as above detailed, may be present in the PEDEK-PEEK copolymer in amount of at most 1 mol %, relative to the total number of moles of repeat units in the PEDEK-PEEK copolymer, and so as not to substantially alter the advantageous properties of the PEDEK-PEEK copolymer.

Repeat units (RPEDEK) and (RPEEK) are present in the PEDEK-PEEK copolymer in a (RPEDEK)/(RPEEK) molar ratio ranging from 55/45 to 80/20, preferably 60/40 to 80/20, more preferably from 60/40 to 75/25. The

“PEDEK/PEEK mole ratio” is used interchangeably herein with the

“(RPEDEK)/(RPEEK) molar ratio.”

The PEDEK-PEEK copolymer preferably exhibits a melt viscosity (MV) ranging from 0.1 to 5 kN-s/m ² , preferably 0.11 to 2 kN-s/m ² , more preferably 0.12 to 1.5 kN-s/m ² . measured pursuant to ASTM D3835 at 410 °C and a shear rate of 46 s ¹ using a tungsten-carbide die with the following characteristics: diameter = 1.016 mm, length = 20.32 mm, cone angle = 120°.

The PEDEK-PEEK copolymer is present in the polymer composition in an amount of at most 99.5 wt.%, preferably at most 99 wt.%, 98 wt.%, 95 wt.%,

90 wt.%, 80 wt.%, based on the total weight of the polymer composition. In some embodiments, the PEDEK-PEEK copolymer is present in the polymer composition in an amount of at least 50 wt.%, preferably at least 60 wt.%, 70 wt.%, 80 wt.%, 90 wt.%, 95 wt.%, based on the total weight of the polymer composition.

In some embodiments the amount of PEDEK-PEEK copolymer ranges from

50 wt.% to 99 wt.%, from 60 wt.% to 98 wt.%, from 70 wt.% to 97 wt.%, from 80 wt.% to 96 wt.% or from 90 wt.% to 95 wt.%, based on the total weight of the polymer composition.

In some embodiments, the amount of PEDEK-PEEK copolymer ranges from 40 wt.% to 95 wt.%, preferably from 50 wt.% to 90 wt.%, more preferably from

55 wt.% to 85 wt.%, and most preferably from 60 wt.% to 80 wt.%, based on the total weight of the polymer composition.

Friction & Wear Additives

The polymer composition includes at least one friction and wear additive. As used herein, a“friction and wear additive” denotes a component that provides the polymer composition with a decreased coefficient of friction as compared to a comparable polymer composition not including the friction reducing component. Thus, the friction and wear additive causes the resultant polymer composition and articles comprising the polymer composition to have a more slippery, silky, or slick feel, with reduced friction between the polymer composition (or articles comprising the polymer composition) and materials that come into contact with the polymer composition.

The polymer composition preferably includes the at least one friction and wear additive in an amount of at least 0.5 wt.%, preferably at least 1 wt.%, 2 wt.%,

5 wt.%, 10 wt.%, 20 wt.% based on the total weight of the polymer composition.

In some embodiments, the polymer composition includes the at least one friction and wear additive in an amount of at most 50 wt.%, preferably at most 40 wt.%, based on the total weight of the polymer composition.

In some aspects the polymer composition includes the at least one friction and wear additive in an amount ranging from 1 wt.% to 50 wt.%, preferably from 10 wt.% to 45 wt.%, 15 wt.% to 40 wt.%, 20 wt.% to 35 wt.%, 25 wt.% to 35 wt.%, based on the total weight of the polymer composition. Most preferably, the polymer composition includes about 30 wt.% of the at least one friction and wear additive, based on the total weight of the polymer composition. Any of the friction and wear additives known to those of skill in the art can be used in the polymer composition. In addition, the friction and wear additive can be present in the polymer composition in a variety of forms such as, for example, powders, fibers, beads, and oils.

In some embodiments, the friction and wear additive is selected from the group consisting of fluoropolymers, siloxane polymers, silicone oils, silicon carbide, silicon dioxide, mica, aluminum oxide, zirconium oxide, molybdenum disulfide, certain nitrides (as described below), carbon fiber, and graphite. Of these, fluoropolymers, carbon fibers, graphite, and the nitrides described below are most preferred.

Fluoropolymers suitable for use in the invention may be any of the

fluoropolymers known in the art for use as lubricants, including, for example, polytetrafluoroethylene (PTFE) and perfluoroalkoxy polymers (PFA, MFA).

Fluoropolymer resins are readily available from a variety of commercial sources.

Among the fluoropolymers, PTFE is most preferred. The PTFE polymers suitable for use in the polymer composition are generally polymers of

tetrafluoroethylene. However, the PTFE may also comprise minor amounts of one or more co-monomers such as hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(propyl vinyl ether), perfluoro-(2, 2-dimethyl- l,3-dioxole), and the like, provided, however that the latter do not significantly adversely affect the unique properties, such as thermal and chemical stability of the tetrafluoroethylene homopolymer. Preferably, the amount of such co-monomer is less than 3 mol%, preferably less than 1 mol %, more preferably less than 0.5 mol %. Most preferred are PTFE homopolymers.

In some embodiments, the PTFE has a mean particle size of at most 75 pm, preferably at most 60 pm, more preferably at most 50 pm. The mean particle size of the PTFE is preferably at least 1 pm, more preferably at least 2 pm, most preferably at least 3 pm.

In some embodiments, the fluoropolymer (preferably PTFE) may be present in a concentration of 1 wt.% to 20 wt.%, or preferably 2 wt.% to 15 wt.%, preferably 7 wt.% to 12 wt.%, most preferably about 10 wt.%, based on the total weight of the polymer composition.

Carbon fibers useful for the present invention can be obtained by heat treatment and pyrolysis of different polymer precursors such as, for example, rayon, polyacrylonitrile (PAN), aromatic polyamide or phenolic resin; suitable carbon fibers may also be obtained from pitchy materials. A variety of carbon fibers known to those of skill in the art are available from commercial sources.

In some embodiments, the carbon fiber may be present in a concentration of 1 wt.% to 40 wt.%, preferably 2 wt.% to 20 wt.%, preferably 5 wt.% to 15 wt.%, most preferably about 10 wt.% based on the total weight of the polymer composition.

Nitrides suitable for use as the at least one friction and wear additive are selected from the group consisting of aluminum nitride, antimony nitride, beryllium nitride, boron nitride, chromium nitride, copper nitride, gallium nitride,

trigermanium dinitride, trigermanium tetranitride, hafnium nitride, iron nitrides, mercury nitride, niobium nitride, silicon nitride, tantalum nitride, titanium nitride, tungsten dinitride, vanadium nitride, zinc nitride, and zirconium nitride. Of these, silicon nitride and boron nitride are preferred. Boron nitride is most preferred.

In some embodiments, the polymer composition includes one or more of the above nitrides (preferably boron nitride) in an amount of 1 wt.% to 20 wt.%, preferably 2 wt.% to 15 wt.%, preferably 3 wt.% to 10 wt.%, preferably 3 wt.% to 6 wt.%, most preferably about 5 wt.%, based on the total weight of the polymer composition.

In certain embodiments, the graphite may be present in a concentration of 1 wt.% to 55 wt.%, preferably 2 wt.% to 20 wt.%, preferably 5 wt.% to 15 wt.%, most preferably about 10 wt.% based on the total weight of the polymer composition.

The polymer composition may include any combination of the friction and wear additives described herein, and, in some embodiments, may comprise two, three, or more friction and wear additives.

In some embodiments, the polymer composition includes at least one of a fluoropolymer (preferably PTFE), graphite, carbon fiber, and a nitride as described above (preferably boron nitride). For example, in some embodiments, the polymer composition includes as friction and wear additives:

(i) PTFE, preferably in an amount of 5 to 15 wt.%, preferably about 10 wt.%;

(ii) graphite, preferably in an amount of 5 to 15 wt.%, preferably about 10 wt.%; and

(iii) carbon fiber, preferably in an amount of 5 to 15 wt.%, preferably about 10 wt.%, where the weight percents are based on the total weight of the polymer composition. In an alternative embodiment, the polymer composition includes as friction and wear additives:

(i) graphite, preferably in an amount of 5 to 15 wt.%, preferably about 10 wt.%;

(ii) carbon fiber, preferably in an amount of 10 to 20 wt.%, preferably about

15 wt.%, and

(iii) boron nitride, preferably in an amount of 1 to 10 wt.%, preferably about 5 wt.%, where the weight percents are based on the total weight of the polymer composition.

Optional Additional Ingredients

Optionally, one or more ingredients other than the PEDEK-PEEK copolymer and friction and wear additives may be incorporated in the polymer composition. These ingredients may be polymeric or non-polymeric in nature.

For example, reinforcing or filling additives, may be incorporated into the polymeric composition to improve certain of properties of the polymer composition such as: short-term mechanical capabilities (e.g. mechanical strength, toughness, hardness, stiffness), thermal conductivity, creep strength, fracture resistance, high temperature dimensional stability, and fatigue resistance. Additives other than friction and wear additives may include, for example, glass fibers; asbestos fibers ; boron fibers, metal fibers; calcium silicate fibers; metal borides fibers (e.g. TiB ₂ ) and mixtures thereof. Pigments, such as titanium dioxide and/or ultramarine blue, may also be incorporated into the polymeric composition.

The polymer composition may also optionally include additional additives such as zinc sulfide, zinc oxide, ultraviolet light stabilizers, heat stabilizers, antioxidants such as organic phosphites and phosphonites, acid scavengers, processing aids, nucleating agents, flame retardants, smoke-suppressing agents, anti-static agents, anti-blocking agents, and conductivity additives such as carbon black.

When one or more additional ingredients are present, their total concentration is preferably less than 10 wt. %, more preferably less than 5 wt. %, and most preferably less than 2 wt. %, based on the total weight of polymer composition.

Methods of Making the Polymer Composition

The polymer composition can be prepared by melt-mixing the at least one

PEDEK-PEEK copolymer, the at least one friction and wear additive, and, optionally, the one or more additional ingredients to provide a molten mixture, followed by extrusion and cooling of the molten mixture.

The polymer compositions described herein are advantageously provided in the form of pellets, which may be used in injection molding, compression molding, or extrusion processes known in the art.

The preparation of the polymer composition can be carried out by any known melt-mixing process that is suitable for preparing thermoplastic molding

compositions. Such a process is typically carried out by heating the thermoplastic polymer above the melting temperature of the thermoplastic polymer thereby forming a melt of the thermoplastic polymer. The process for the preparation of the polymer composition can be carried out in a melt-mixing apparatus as known to those of skill in the art. Suitable melt-mixing apparatus include, for example, kneaders, Banbury mixers, single-screw extruders, and twin-screw extruders.

Preferably, use is made of an extruder fitted with means for dosing all the desired components to the extruder, either to the extruder's throat or to the melt. In the process for the preparation of the polymer composition, the components of the polymer composition can be fed to the melt-mixing apparatus and melt-mixed in the apparatus. The components may be fed simultaneously as a powder mixture or granule mixture, also known as a dry-blend, or may be fed separately.

Thus, in some embodiments, the invention concerns a method for making the polymer compositions as described herein, comprising melt mixing the at least one PEDEK-PEEK copolymer, the at least one friction and wear additive, and, optionally, the one or more additional ingredients.

The polymer composition can be further processed following standard methods for injection moulding, extrusion, blow moulding, foam processing, compression molding, casting, coating and the like to form shaped articles comprising the polymer composition.

Shaped Articles and Methods of Making

Exemplary embodiments are also directed to shaped articles including the polymer composition described above and methods of making the shaped articles.

The total weight of the polymer composition in the shaped article is preferably at least 50 wt.%, 80 wt.% , 90 wt.% , 95 wt.%, and most preferably at least 99 wt.%, based on the total weight of the shaped article.

Preferably, the shaped article is an injection moulded article, an extrusion moulded article, a machined article, a coated article, or a casted article. In some embodiments, the shaped article is a single part formed from the polymer composition. In alternative embodiments, the shaped article includes two or more parts, at least one of which includes the polymer composition.

Preferably, the shaped article is a friction and wear article. As used herein, a “friction and wear article” means an article including at least one surface (“bearing surface”) adapted to interact with another surface in relative motion, for example, by sliding, pivoting, oscillating, reciprocating, rotating, or the like. The bearing surface of the friction and wear article may be subjected to relatively high loads, relatively high speed motion, or both, which may result in the generation of heat through friction. Examples of such articles include, but are not limited to, thrust bearings, sleeve bearings, journal bearings, thrust washers, rub strips, bearing pads, needle bearings, ball bearings, including the balls, valve seats, piston rings, valve guides, compressor vanes, and seals, both stationary and dynamic. Thus, in some embodiments, the friction and wear article is an article for use in automotive or oil and gas applications, for example: seal rings for hydraulically actuated clutch components, axial thrust bearings, gears, labyrinth seals for turbo compressors, compressor plates for oil/gas compressors, compressor poppets and discharge valves for reciprocating and linear AC compressors, CMP rings for semiconductor manufacturing, vanes or vane tips for vacuum assist brakes, bearing cages for needle and ball bearings, and turbo compressor vanes for turbocharging

applications.

In some embodiments, the friction and wear article can be used with a lubricant. As used herein, the term“lubricant” refers to a substance, such as a liquid, that may be disposed between two moving surfaces, one of which may include a surface of the friction and wear article, to reduce friction between the surfaces. In some embodiments, the lubricant may include an oil, such as a motor oil or transmission oil.

In alternative embodiments, the friction and wear article is adapted to be used without a lubricant.

In some embodiments, the friction and wear article (or a surface thereof) is adapted to be subjected to temperatures of at least 150 °C, preferably at least 175 °C, 200 °C, 225 °C, 250 °C without, e.g., deformation, or loss of ability to perform its designated function.

In some aspects, the invention also includes a method of making the shaped articles (e.g. a friction and wear article) comprising the polymer composition as described above. Preferably, the method includes at least one step of injection moulding, extrusion moulding, blow moulding, compression moulding, casting, or coating the polymer composition as above detailed. In some embodiments, the shape article is milled from a stock shape including the polymer composition. Non limiting examples of stock shapes include plates, rods, slabs or the like.

Exemplary embodiments will now be described in the following non-limiting examples.

EXAMPLES

Raw Materials

KetaSpire ^® KT-820 P (“KT-820P” herein) is an aromatic

polyetheretherketone (PEEK) polymer available from Solvay Specialty Polymers USA, LLC.

Kitamura KT-300M is a PTFE micropowder available from Kitamura Limited in Japan.

Sigrafil C30 S006 APS is a Carbon fiber available from SGL Group in Germany.

Superior Graphite grade 4735FF is a graphite powder available from Superior

Graphite in Chicago, IL, USA.

Boronid Sl-SF Boron Nitride powder is available from ESK Ceramics GmbH and Co, KG in Germany.

Hostanox P-EPQ is a thermal stabilizer available from Clariant in

Switzerland.

Hydroquinone photo-grade was procured from Eastman.

4,4’-biphenol, polymer grade, was procured from SI, USA.

4,4’-difluorobenzophenone, polymer grade, was procured from Jintan, China. Diphenyl sulfone (polymer grade) was procured from Proviron (99.8% pure). Sodium carbonate, light soda ash, was procured from Solvay S.A., France.

Potassium carbonate with a dyo < 45 pm was procured from Armand products. Lithium chloride was procured from Acros. Preparation of Copolymers

Comparative Example 1: Poly(ether ether ketone) (PEEK)

KetaSpire® PEEK KT-820P was used as Comparative Example 1.

Example 2 : Preparation of PEDEK-PEEK Copolymer 60/40

In a 500 mL 4-neck reaction flask fitted with a stirrer, a N ₂ inlet tube, a Claisen adapter with a thermocouple plunging in the reaction medium, and a Dean- Stark trap with a condenser and a dry ice trap were introduced 127.70 g of diphenyl sulfone, 9.894 g of hydroquinone, 25.103 g of 4,4’biphenol and 50.130 g of

4,4’-difluorobenzophenone. The flask content was evacuated under vacuum and then filled with high purity nitrogen (containing less than 10 ppm 0 ₂ ). The reaction mixture was then placed under a constant nitrogen purge (60 mL/min).

The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 25.097 g of Na ₂ C0 ₃ and 0.155 g of K ₂ C0 ₃ was added via a powder dispenser to the reaction mixture over 30 minutes. At the end of the addition, the reaction mixture was heated to 320 °C at l°C/minute. After 2 minutes at 320°C, 5.892 g of

4,4’-difluorobenzophenone were added to the reaction mixture while keeping a nitrogen purge on the reactor. After 5 minutes, 0.384 g of lithium chloride were added to the reaction mixture. Ten minutes later, another 1.964 g of

4,4’-difluorobenzophenone were added to the reactor and the reaction mixture was kept at temperature for 15 minutes.

The reactor content was then poured from the reactor into a SS pan and cooled. The solid was broken up and ground in an attrition mill through a 2 mm screen. Diphenyl sulfone and salts were extracted from the mixture with acetone and water at pH between 1 and 12. The powder was then removed from the reactor and dried at l20°C under vacuum for 12 hours yielding 74 g of a white powder.

The structure of the obtained copolymer can be represented by its repeat units as follows:

The melt viscosity, measured by capillary rheology at 4lO°C, 46 s ¹ was found to be 0.18 kN-s/m ² .

Example 3 : Preparation of PEDEK-PEEK Copolymer 75/25 (MV =

4.2 kN s/m ² )

In a 500 mL 4-neck reaction flask fitted with a stirrer, a N ₂ inlet tube, a Claisen adapter with a thermocouple plunging in the reaction medium, and a Dean- Stark trap with a condenser and a dry ice trap were introduced 212.10 g of diphenyl sulfone, 5.637 g of hydroquinone, 28.602 g of 4,4’biphenol and 45.426 g of 4,4’-difluorobenzophenone. The flask content was evacuated under vacuum and then filled with high purity nitrogen (containing less than 10 ppm 0 ₂ ). The reaction mixture was then placed under a constant nitrogen purge (60 mL/min).

The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 22.391 g of Na ₂ C0 ₃ and 0.141 g of K ₂ C0 ₃ was added via a powder dispenser to the reaction mixture over 30 minutes. At the end of the addition, the reaction mixture was heated to 340 °C at l°C/minute. After 44minutes at 340 °C, 3.127 g of 4,4’-difluorobenzophenone were added to the reaction mixture while keeping a nitrogen purge on the reactor. After 5 minutes, 0.868 g of lithium chloride were added to the reaction mixture. 10 minutes later, another 1.787 g of

4,4’-difluorobenzophenone were added to the reactor and the reaction mixture was kept at temperature for 15 minutes.

The reactor content was then poured from the reactor into a SS pan and cooled. The solid was broken up and ground in an attrition mill through a 2 mm screen. Diphenyl sulfone and salts were extracted from the mixture with acetone and water at pH between 1 and 12. The powder was then removed from the reactor and dried at 120 °C under vacuum for 12 hours yielding 62 g of a white powder. The structure of the obtained copolymer can be sketched, in terms of repeat units, as follows:

The melt viscosity measured by capillary rheology, at 410 °C, 46 s ¹ was found to be 4.2 kN-s/m ² .

Example 4: Preparation of PEDEK-PEEK Copolymer 75/25 (MV =

0.32 kN s/m ² )

The copolymer of Example 3 was prepared following the same procedure as

Example 2 but the reaction was held at 340 °C for 2 min before the addition of the termination charge of 4,4’-difluorobenzophenone. The melt viscosity measured by capillary rheology at 410 °C, 46 s ¹ was 0.32 kN-s/m ² . Example 5 : Preparation of PEDEK-PEEK Copolymer 75/25 (MV =

0.18 kN-s/m ² )

The copolymer of Example 4 was prepared following the same procedure as Example 2 but the reaction was not held at 340 °C before the addition of the termination charge of 4,4’-difluorobenzophenone. The melt viscosity measured by capillary rheology at 410 °C, 46 s ¹ was 0.18 kN-s/m ² .

Comparative Example 6 : Preparation of PEDEK-PEEK Copolymer 30/70 (MV = 0.48 kN-s/m ² )

In a 500 mL 4-neck reaction flask fitted with a stirrer, a N ₂ inlet tube, a Claisen adapter with a thermocouple plunging in the reaction medium, and a Dean- Stark trap with a condenser and a dry ice trap were introduced 128.21 g of diphenyl sulfone, 18.724 g of hydroquinone, 13.526 g of 4,4’-biphenol and 53.707 g of 4,4’- difluorobenzophenone. The flask content was evacuated under vacuum and then filled with high purity nitrogen (containing less than 10 ppm 0 ₂ ). The reaction mixture was then placed under a constant nitrogen purge (60 mL/min).

The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 26.626 g of Na ₂ C0 ₃ and 0.167 g of K ₂ C0 ₃ was added via a powder dispenser to the reaction mixture over 30 minutes. At the end of the addition, the reaction mixture was heated to 320 °C at l°C/minute. After 13 minutes at 320 °C, 3.697 g of 4,4’- difluorobenzophenone were added to the reaction mixture while keeping a nitrogen purge on the reactor. After 5 minutes, 1.026 g of lithium chloride were added to the reaction mixture. 10 minutes later, another 2.112 g of 4,4’-difluorobenzophenone were added to the reactor and the reaction mixture was kept at temperature for 15 minutes.

The reactor content was then poured from the reactor into a SS pan and cooled. The solid was broken up and ground in an attrition mill through a 2 mm screen. Diphenyl sulfone and salts were extracted from the mixture with acetone and water at pH between 1 and 12. The powder was then removed from the reactor and dried at 120 °C under vacuum for 12 hours yielding 74 g of a white powder.

The melt viscosity measured by capillary rheology at 410 °C, 46 s ¹ was 0.48 kN-s/m ² . Comparative Example 7 : Preparation of PEDEK-PEEK Copolymer 30/70 (MV = 0.16 kN s/m ² )

In a 500 mL 4-neck reaction flask fitted with a stirrer, a N ₂ inlet tube, a Claisen adapter with a thermocouple plunging in the reaction medium, and a Dean- Stark trap with a condenser and a dry ice trap were introduced 128.21 g of diphenyl sulfone, 18.724 g of hydroquinone, 13.526 g of 4,4’-biphenol and 53.285 g of 4,4’- difluorobenzophenone. The flask content was evacuated under vacuum and then filled with high purity nitrogen (containing less than 10 ppm 0 ₂ ). The reaction mixture was then placed under a constant nitrogen purge (60 mL/min).

The reaction mixture was heated slowly to 150 °C. At 150 °C, a mixture of 26.626 g of Na ₂ C0 ₃ and 0.167 g of K ₂ C0 ₃ was added via a powder dispenser to the reaction mixture over 30 minutes. At the end of the addition, the reaction mixture was heated to 320 °C at l°C/minute. After 17 minutes at 320 °C, 3.697 g of 4,4’- difluorobenzophenone were added to the reaction mixture while keeping a nitrogen purge on the reactor. After 5 minutes, 1.026 g of lithium chloride were added to the reaction mixture. 10 minutes later, another 2.118 g of 4,4’-difluorobenzophenone were added to the reactor and the reaction mixture was kept at temperature for 15 minutes.

The reactor content was then poured from the reactor into a SS pan and cooled. The solid was broken up and ground in an attrition mill through a 2 mm screen. Diphenyl sulfone and salts were extracted from the mixture with acetone and water at pH between 1 and 12. The powder was then removed from the reactor and dried at 120 °C under vacuum for 12 hours yielding 74 g of a white powder.

The melt viscosity measured by capillary rheology at 410 °C, 46 s ¹ was 0.16 kN-s/m ² .

Preparation of Polymer Compositions

The polymer compositions of Comparative Examples 8, 11, 14, and 15, and Examples 9, 10, 12, and 13, described in Tables 1 and 1A below, were compounded using a Coperion ZSK 26mm intermeshing co-rotating twin-screw extruder having 12 barrel sections and an overall L/D ratio of 48. The raw materials were fed to the extruder in two streams. A pre-blend of the resin, graphite, and PTFE was fed at the main hopper as a powder mixture into barrel section 1 using a gravimetric feeder. The carbon fiber was fed further downstream, also with a gravimetric feeder, at a rate of 10 wt.% (C8, E9, E10, C14, C15) or 15 wt.% (Cl l, E12, E13) of the total throughput rate of the overall composition. The total throughput rate for the compounding was 35 lb/hr. The melt extrudate was stranded and pelletized to produce pellets approximately 3 mm long by 3 mm in diameter.

The polymer compositions were injection molded to produce standard Type I ASTM tensile specimens and flexural bars with a thickness of 3.2 mm for use in the analysis that follows.

Assessment of Thermal and Mechanical Properties Determination of the Melt Viscosity

The melt viscosity (MV) was measured using a capillary rheometer pursuant to ASTM D3835 standard. Readings were taken after lO-minute dwell time at 4lO°C and a shear rate of 46 s ¹ using a tungsten-carbide die with the following characteristics: diameter = 1.016 mm, length = 20.32 mm, cone angle = 120° Mechanical Property Analysis of Polymer Compositions

Specimens for the following tests were produced from ASTM tensile (Type I) or flexural bars. The test specimen geometries that were used conformed to the ASTM test standards employed. Molded test specimens were annealed at 230 °C for 2 hours prior to testing. Tensile testing was performed at room temperature following ASTM D638 at 0.2”/min. Flexural tests followed ASTM D790.

Dynamic Mechanical Analysis (DMTA)

Dynamic Mechanical Analysis (DMTA) in torsional strain mode was conducted on specimens cut from the ASTM flexural bars injection molded from the polymer compositions shown in Table 1, below. This testing was conducted in accordance with ASTM test standard D5279 over a temperature range from 23 °C to 300 °C and at a strain frequency of 10 rad/s. The test provides dynamic elastic modulus data as a function of temperature. The modulus at a temperature of 175 °C was recorded and compared between the different compositions tested.

Results

Table 1 : Mechanical and Thermal Properties of Polymer Compositions

Note: All base resin melt viscosities were assessed a 410 °C and a shear rate of 46 s ¹ . All component amounts are provided in wt.% based on the total weight of the composition. “N/A” indicates test results were not available.

Table 1A : Mechanical and Thermal Properties of Polymer Compositions

Note: All base resin melt viscosities were assessed a 410 °C and a shear rate of 46 s ¹ . All component amounts are provided in wt.% based on the total weight of the composition. “N/A” indicates test results were not available. As shown above, the inventive polymer compositions of Examples, 9, 10, 12, and 13 exhibited similar tensile modulus, tensile strength, and flexural modulus as did the analogous PEEK compositions of Comparative Examples 8 and 11 and the analogous PEDEK-PEEK compositions of Comparative Examples 14 and 15; however, the PEDEK- PEEK copolymer compositions of the invention shown in Examples 9 and 10 unexpectedly exhibited markedly superior performance at elevated temperature as shown by their significantly higher DMA elastic modulus values at 175 °C. Wear Testing

Thrust washer test specimens, approximately one inch in diameter, and having an initial wear contact area of 0.02 in ² , were injection molded from the polymer compositions of Comparative Examples 8, 14 and 15 and Examples 9 and 10 in Tables 1 and 1 A. The test specimens were annealed at 230 °C for 2 hours. A Falex Thrust Washer Friction & Wear Testing Machine from Faville-LeVally Corp., affixed with a counter surface consisting of a steel washer, was used to wear the unlubricated test specimens at ambient temperature and a linear velocity of V = 400 ft/min according to the protocol in Table 2 below:

Table 2: Wear Protocol

After each cycle, the thickness of the washer was recorded at four

representative locations. A thermocouple was used to measure the specimen temperature throughout the test, and the final cycle was stopped when the specimen temperature reached 250 °C.

Results for the average cumulative change in the thickness of the washer after each wear step are shown in the bar graph of Fig. 1. The data shows that the thrust washer molded from the polymer composition of Example 9, according to the invention, surprisingly both exhibited significantly less wear and remained below the cut-off temperature of 250 °C for a longer time than did the washer molded from the polymer composition of Comparative Example 8.

Further wear testing was also performed for C8, E9, E10, C14, and C15. Testing involved initially subjecting the samples to cycle 1. Subsequently, the samples were subjected to the conditions of cycle 2, with the exception that the total time was the earlier of 24 hours or the time of sample failure (cycle 2’). For each sample, the wear rate was calculated: (T ₀ -Ti)/t _c where T ₀ is the washer thickness subsequent to cycle 1 and prior to cycle 2’; Ti is thickness of the washer subsequent to cycle 2’; and t _c is the cycle time for cycle 2’ (i.e. the earlier of 24 hours and the time to sample failure). Results are shown in Table 2 A.

Table 2A: Wear Results

Referring to Table 2 A, surprisingly, E9 and E10 had significantly reduced wear rates relative to C 8 , C 14 , and C 15.

Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.