Fact-checked by Grok 2 weeks ago

Polyketone

Polyketones are a family of high-performance thermoplastic polymers featuring ketone (carbonyl) groups in their main chain, which provide strong dipole-dipole interactions that enhance mechanical strength, chemical resistance, and thermal stability.^[1] They are broadly classified into aliphatic and aromatic variants, with aliphatic polyketones (often denoted as POK) consisting of perfectly alternating copolymers of carbon monoxide (CO) and olefins such as ethylene or propylene, resulting in a semi-crystalline structure with a density of approximately 1.24 g/cm³ and crystallinity of 30–40%.^[1] Aromatic polyketones, in contrast, incorporate aromatic rings connected via ether and ketone linkages, exemplified by polyether ether ketone (PEEK), and exhibit even higher thermal performance due to the rigid aromatic backbone.^[1] Aliphatic polyketones are synthesized through copolymerization of CO and α-olefins using palladium-based catalysts, a process first patented in the 1970s and refined in the 1980s to overcome early challenges with thermal stability from catalyst residues.^[2] Commercial production began in 1996 when Shell launched Carilon, a terpolymer of CO, ethylene, and propylene with a melting point of 200–220°C, though it was discontinued in 2000 due to market challenges; Hyosung revived the material in 2015 under the POKETONE brand, emphasizing its eco-friendly synthesis from abundant feedstocks like CO derived from syngas.^[3] Aromatic polyketones, developed earlier in the 1970s by ICI, are produced via nucleophilic aromatic substitution or other step-growth methods, yielding materials with melting points exceeding 300°C for some grades.^[1] These polymers exhibit notable properties that position them as alternatives to materials like nylon, acetal, and polybutylene terephthalate. Aliphatic POK offers high tensile strength (around 60 MPa), exceptional impact resistance (no break in notched Izod tests), low moisture absorption (<0.5%), and superior chemical resistance to hydrocarbons, acids, and bases, alongside a glass transition temperature of about 15°C and excellent barrier properties against gases and moisture.^[2]^[1] Aromatic variants like PEEK provide even greater heat resistance (continuous use up to 260°C), low flammability, and biocompatibility, with minimal degradation in aggressive environments.^[1] Both types demonstrate good processability via injection molding, extrusion, and fiber spinning, though aliphatic POK's lower cost (about one-tenth that of PEEK) makes it attractive for broader use.^[3] Applications of polyketones leverage their balanced performance in demanding sectors. Aliphatic POK is widely used in automotive components such as fuel lines, gears, bushings, and under-hood parts due to its wear resistance, low friction, and fuel barrier capabilities; it also finds roles in electrical connectors, railway interiors for flame-retardant compliance (e.g., meeting EN 45545 standards with limiting oxygen index >32%), and packaging films.^[2]^[1] Aromatic polyketones excel in aerospace (e.g., structural composites), medical implants, oil and gas seals, and high-temperature electronics, where their rigidity and dimensional stability under load are critical.^[1] Ongoing research focuses on blends and composites to further tailor properties like flame retardancy and recyclability, expanding their eco-friendly potential.^[2]

Overview

Definition and Types

Polyketones are a family of high-performance thermoplastic polymers distinguished by the presence of polar ketone groups (-CO-) in the backbone, resulting from the copolymerization of carbon monoxide (CO) with olefins such as ethylene or propylene.^[1] These materials exhibit a unique combination of properties due to the alternating incorporation of CO, which introduces strong intermolecular forces while maintaining a flexible carbon-carbon chain structure.^[4] The primary types of polyketones are alternating copolymers and terpolymers. Alternating copolymers, such as poly(ethylene-alt-carbon monoxide), feature a strictly regular repeating unit of -(CH₂-CH₂-CO)ₙ- and possess a high melting point of approximately 255°C, attributed to their high crystallinity and symmetry.^[1] Terpolymers incorporate a third monomer, typically around 6 mol% propylene alongside ethylene and CO, which disrupts the regularity slightly to lower the melting point to about 220°C and improve melt processability without significantly compromising mechanical performance.^[1] In general, polyketones are semicrystalline thermoplastics with 30-40 wt% crystallinity, a density of 1.235 g/cm³, and a glass transition temperature (T₉) of approximately 15°C, enabling applications requiring thermal stability and dimensional consistency.^[1]^[5] Commercial variants are marketed under trade names including POK (polyketone), Carilon, and Poketone, reflecting their availability from various producers for engineering uses.

Historical Development

The earliest synthesis of polyketone polymers dates to 1941, when researchers at Farbenfabriken Bayer achieved the first radical copolymerization of carbon monoxide (CO) and ethylene under high pressure, yielding random copolymers with limited carbonyl incorporation (less than 50%).^[6] In the late 1940s, DuPont independently advanced this work, with H.C. Brubaker demonstrating free radical polymerization of ethylene and CO using peroxide initiators, producing low-molecular-weight polyketones unsuitable for practical applications due to poor mechanical properties and processing challenges.^[7] These early efforts established the fundamental reactivity of CO in olefin copolymerization but highlighted the need for controlled microstructures to achieve viable materials.^[7] A major breakthrough occurred in the 1980s through the development of palladium-catalyzed alternating copolymerization, pioneered by researchers at Shell, including E. Drent, who in 1982 identified catalyst systems enabling strictly alternating, high-molecular-weight linear polyketones from ethylene and CO.^[1] This method produced semicrystalline polymers with superior thermal and mechanical performance, marking the transition from laboratory curiosities to industrially promising thermoplastics.^[7] By the early 1990s, Shell's innovations in bidentate phosphine ligands for palladium catalysts, as detailed in key patents, significantly improved reaction yields, selectivity, and polymer quality, facilitating scale-up efforts. Shell commercially launched the first aliphatic polyketone under the trade name Carilon in 1996, with initial production capacity of 20 million pounds per year at its Carrington, UK facility, targeting applications in automotive and industrial components for its chemical resistance and low wear.^[3] However, due to insufficient market demand and competition from established engineering plastics, Shell discontinued Carilon production in 2000 and donated related patents to SRI International.^[1] The field revived in the 2010s amid growing emphasis on sustainable materials, leveraging CO's potential as a low-cost, carbon-efficient monomer from syngas or industrial waste gases; South Korea's Hyosung Corporation initiated commercial production in 2015 with a 50,000-ton-per-year plant in Ulsan, reintroducing polyketone (branded POKETONE) to global markets.^[8] As of 2024, Hyosung remains the primary producer, with ongoing capacity expansions driven by demand in eco-friendly applications.^[9]

Chemical Structure

Monomer Composition

Aliphatic polyketones are primarily synthesized from two key monomers: carbon monoxide (CO), a simple diatomic gas that introduces the ketone functionality into the polymer, and ethylene (\ce{CH2=CH2}), which provides the aliphatic carbon chains forming the backbone. This copolymerization yields linear alternating polyketones with the repeating unit -[\ce{(CH2-CH2-C(O))}]_n-.^[7] In many commercial and advanced formulations, propylene (\ce{CH3CH=CH2}) serves as an optional comonomer in terpolymers, incorporated at levels typically ranging from 3 to 10 mol% to introduce short branches that enhance flexibility and reduce crystallinity without compromising overall mechanical integrity. For instance, the commercial polyketone Carilon employs approximately 6 mol% propylene to improve processability while preserving the alternating CO-olefin structure.^[10]^[11] The optimal monomer ratio for achieving a strictly alternating polyketone microstructure is 1:1 (CO:olefin), which promotes regular insertion and minimizes structural defects. Excess olefin relative to CO, such as ratios of 9:1 or higher, results in reduced ketone incorporation (e.g., as low as 6 mol%) and non-alternating sequences, leading to polymers with polyethylene-like characteristics rather than distinct polyketone properties.^[6]^[12] High-purity carbon monoxide, exceeding 99% purity, is essential in polyketone synthesis to prevent catalyst deactivation or poisoning, particularly with palladium-based systems sensitive to impurities like oxygen or sulfur compounds. Industrially, CO is derived from syngas through processes such as steam reforming of natural gas, ensuring the necessary purity for effective polymerization.^[13]^[7]

Aromatic Polyketones

Aromatic polyketones, such as polyether ether ketone (PEEK), are synthesized via step-growth polymerization methods, including nucleophilic aromatic substitution of difluorobenzophenone with hydroquinone, yielding a backbone with repeating units like -[\ce{(C6H4-O-C6H4-O-C(O)-C6H4-C(O))}]_n-, where aromatic rings are linked by ether (–O–) and ketone (–C(O)–) groups. These rigid structures incorporate bisphenol and diacid monomers or equivalents, resulting in fully aromatic chains with high thermal stability.^[1]

Polymer Backbone and Microstructure

The polymer backbone of aliphatic polyketones, particularly in ethylene-carbon monoxide copolymers, consists of strictly alternating -[CH₂-CH₂-CO]- units, resulting in a linear chain with ketone functionalities spaced every third atom. This alternating microstructure is highly regioregular, characterized by predominant head-to-tail enchainment of monomers, which promotes crystallinity and structural uniformity. Confirmation of this backbone architecture comes from ¹³C NMR spectroscopy, which reveals distinct resonance peaks for the carbonyl carbon (around 210 ppm) and the adjacent methylene groups (approximately 40-50 ppm for CH₂ adjacent to CO and 30-35 ppm for the terminal CH₂), indicating the absence of significant irregularities in the copolymer sequence. The selective migratory insertion kinetics in the palladium-catalyzed process ensure low enchainment defect rates, maintaining the alternating sequence.^[14] In terpolymers incorporating propylene alongside ethylene and carbon monoxide, the microstructure incorporates propylene units primarily as -[CH(CH₃)-CH₂-CO]-, following 1,2-insertion regiochemistry. These branched insertions disrupt the regularity of the alternating chain, leading to reduced crystallinity compared to the ethylene-CO copolymer, as the methyl side groups hinder close packing of polymer chains. ¹³C NMR analysis of such terpolymers shows additional peaks for the methine (CH) and methyl (CH₃) carbons (typically 40-45 ppm and 15-20 ppm, respectively), quantifying the propylene content and confirming its impact on chain perfection. The ketone groups (C=O) within the backbone impart polarity, fostering strong interchain dipole-dipole interactions between adjacent carbonyl moieties, which contribute to enhanced cohesion and mechanical integrity of the polymer matrix. These interactions are evident in the denser packing observed in crystalline phases, where carbonyl dipoles align to minimize energy.^[15]

Properties

Physical and Thermal Properties

Aliphatic polyketones, as semi-crystalline thermoplastic materials, possess notable thermal properties that enhance their utility in demanding environments. The pure ethylene-carbon monoxide copolymer exhibits a high melting point of approximately 255°C, attributed to its regular alternating structure, while the terpolymer variant with roughly 6% propylene incorporation displays a reduced melting point of about 220°C to improve processability.^[4] The glass transition temperature (Tg) is low, around 15°C, which allows the polymer to remain flexible at ambient temperatures.^[16] Thermal decomposition begins above 300°C, indicating robust thermal stability suitable for high-temperature applications. Key physical characteristics include a density of 1.235 g/cm³; the ketone polarity in the backbone elevates both the density and the melting temperature significantly above that of polyethylene (typically 110–130°C).^[4] The polymer achieves high crystallinity levels of 30–40 wt%, fostering a semi-crystalline morphology that balances rigidity and toughness.^[17] Moisture absorption remains minimal, under 0.5% at 50% relative humidity, ensuring excellent dimensional stability in humid conditions.^[4] Processing of aliphatic polyketone benefits from its melt viscosity, enabling efficient injection molding within a temperature range of 200–260°C.^[4] The thermal conductivity is approximately 0.25 W/m·K, supporting heat dissipation in molded parts.^[4]

Mechanical and Chemical Properties

Aliphatic polyketones exhibit robust mechanical properties suitable for engineering applications, with tensile strength typically ranging from 50 to 70 MPa at yield, depending on the grade and processing conditions.^[4] Elongation at break varies from 20% to over 200% in unreinforced grades, providing a balance of ductility and toughness, while Young's modulus lies between 1.4 and 1.7 GPa, indicating semi-rigid behavior under load.^[4] These attributes stem from the alternating ethylene-carbon monoxide backbone, which contributes to high impact resistance even at low temperatures.^[4] Chemically, aliphatic polyketones demonstrate strong resistance to hydrolysis, maintaining dimensional stability in aqueous environments due to low water absorption of approximately 0.5% at 50% relative humidity.^[4] They remain inert to hydrocarbons, alcohols, and ketones at temperatures up to 100°C, with minimal swelling or degradation, but are susceptible to attack by strong acids or bases that can cleave the polymer chain.^[4] Solubility is limited, occurring primarily in aggressive solvents like hexafluoro-isopropanol, while chlorinated solvents show only partial interaction without full dissolution.^[4] Tribologically, aliphatic polyketones offer excellent wear resistance, with wear factors as low as 0.0007 mm³/N·km in self-mating configurations, attributed to the self-lubricating nature of polar ketone groups that reduce adhesion.^[4] The dynamic friction coefficient ranges from 0.1 to 0.3 against steel or similar counterparts, enabling low-energy sliding and superior performance under dynamic loads compared to many polyamides.^[4] This fatigue resistance supports prolonged cyclic stressing without significant property loss.^[4] Regarding aging, aliphatic polyketones display moderate UV stability, undergoing photooxidative degradation upon prolonged exposure that reduces elongation at break, though stabilized grades with additives retain mechanical integrity for extended periods in accelerated weathering tests.^[4]

Synthesis

Catalytic Polymerization Process

The catalytic polymerization of polyketone involves the alternating copolymerization of carbon monoxide (CO) and ethylene using palladium(II) (Pd(II)) catalysts, typically conducted in solvents such as methanol or toluene under elevated pressures of 20–60 bar and temperatures of 80–120°C.^[7] This process yields linear polyketones with the repeating unit -[CH₂-CH₂-C(O)]-, where the strict alternation arises from the preferential insertion of CO after ethylene in the catalytic cycle.^[10] The catalyst system generally consists of a Pd(II) salt, such as palladium acetate (Pd(OAc)₂), coordinated to bidentate ligands like 1,3-bis(diphenylphosphino)propane (dppp) or 1,10-phenanthroline, along with an acid promoter such as p-toluenesulfonic acid (p-TsOH) to generate the active cationic species.^[18] The bidentate ligands play a crucial role in stabilizing the Pd center and enforcing regioselectivity, as detailed in subsequent mechanistic studies.^[7] Process variants include slurry polymerization in methanol, which facilitates high yields due to the solvent's role in stabilizing the catalyst and aiding product precipitation, and gas-phase polymerization using immobilized Pd catalysts on supports like silica for continuous operation.^[19] These approaches allow scalability from laboratory to pilot scales while maintaining control over polymer morphology.^[7] Catalytic activities can reach up to 10⁵ g polyketone per mol Pd per hour, depending on ligand choice and conditions, with molecular weights (M_w) typically ranging from 50,000 to 200,000 g/mol.^[10] Molecular weight is tuned primarily through hydrogen as a chain transfer agent, which promotes β-hydride elimination to terminate chains without introducing defects.^[20]

Industrial Production Methods

Industrial production of polyketone primarily involves the terpolymerization of carbon monoxide (CO), ethylene, and propylene using palladium-based catalysts in a continuous solution polymerization process conducted in stirred-tank reactors.^[21] This method allows for high-volume output while maintaining control over molecular weight and microstructure, typically operating under elevated pressures (around 50-100 bar) and temperatures (80-120°C) in a solvent like methanol.^[21] Following polymerization, the reaction mixture undergoes separation to recover unreacted monomers, with the polymer precipitated using an anti-solvent such as acetone, followed by filtration, thorough washing to remove residual catalyst and solvent, and drying to yield a powder or granule form suitable for further processing.^[21] These post-polymerization steps ensure product purity exceeding 99% while minimizing environmental discharge of volatile organics.^[21] Global production capacity for polyketone stands at approximately 50,000 tons per year as of 2024, dominated by a single commercial-scale plant operated by Hyosung in Ulsan, South Korea.^[22] Production costs range from $3 to $5 per kg, largely influenced by the sourcing of CO, which constitutes about half the monomer mass and can be obtained economically from industrial waste gases or syngas processes.^[23] The process is energy-efficient due to the direct incorporation of CO, which avoids energy-intensive oxidation steps in traditional hydrocarbon-based polymers.^[23] Polyketone production contributes to sustainability by utilizing CO—a potent greenhouse gas often derived from waste streams in steel or syngas facilities—thereby converting an environmental liability into a valuable monomer and reducing CO₂ emissions by 61% compared to polyamide 66 (PA66) on a life-cycle basis.^[23] The polymer itself is highly recyclable through standard melt processing techniques, such as extrusion and injection molding, without significant degradation in properties after multiple cycles.^[24] However, challenges persist in catalyst recovery, where processes like ion-exchange or precipitation enable recycling of over 95% of the palladium component, minimizing metal waste and supporting economic viability.^[25] Quality control in industrial production emphasizes end-group analysis via techniques like NMR spectroscopy to ensure low defect levels (typically <1% unsaturated or branched ends), which directly impacts thermal stability and processability.^[26] The resulting material is pelletized under controlled conditions to form uniform thermoplastic pellets (2-3 mm diameter) optimized for downstream applications, with specifications targeting melt flow indices of 5-50 g/10 min for versatility in extrusion and molding.

Polymerization Mechanism

Initiation and Termination

In the palladium-catalyzed synthesis of polyketones, initiation involves activation of the Pd(II) precatalyst by counterion exchange, often promoted by an acid additive like p-toluenesulfonic acid, to generate a cationic Pd(II) species.^[7] This active species typically starts chain growth via migratory insertion of an olefin into a Pd-hydride or Pd-alkoxy bond, forming an initial Pd-alkyl or Pd-acyl intermediate.^[7] The kinetics of initiation are characterized by an induction period lasting on the order of minutes, during which the precatalyst is activated and the first active centers form, influencing the overall polymerization rate.^[7] This step is crucial for establishing the number of growing chains. Termination or chain transfer in polyketone polymerization primarily occurs through β-hydride elimination from the Pd-alkyl species, yielding a Pd-hydride and an α-olefin end-group on the polymer chain.^[7] An alternative pathway is hydrogenolysis, where the Pd-alkyl complex reacts with hydrogen: Pd-alkyl + H₂ → Pd-H + alkane, producing a saturated alkane end-group.^[7] Low rates of these termination processes are essential for achieving high molecular weight polymers, as they minimize premature chain cessation.^[7] Polyketone chains typically have two end-groups, either alkyl (from olefin insertion) or acyl (from CO coordination), which can affect the polymer's thermal stability and reactivity in post-polymerization modifications.^[7] Recent studies (up to 2024) confirm this mechanism via DFT calculations for alternating copolymers.^[27]

Propagation

The propagation step in the palladium-catalyzed synthesis of polyketones proceeds via a series of migratory insertion reactions, alternating between olefin coordination and carbon monoxide (CO) insertion into the Pd–C bond. The cycle commences with a Pd–alkyl species, formed from prior initiation, which coordinates an olefin monomer for 1,2-migratory insertion. This extends the growing polymer chain and regenerates a Pd–alkyl intermediate. Subsequently, CO coordinates to the palladium center and undergoes insertion into the Pd–alkyl bond, yielding a Pd–acyl species that sets the stage for the next olefin coordination and insertion. This alternating mechanism ensures the characteristic perfectly regular backbone of –[CH₂CHR–C(O)]–_n units in the polyketone, where R is H or alkyl depending on the olefin used.^[7]^[28] The rate-determining step in propagation is the CO insertion, characterized by an activation barrier of approximately 15 kcal/mol.^[28] This step's regioselectivity, governed by the 1,2-insertion preference of the olefin, promotes head-to-tail enchainment, minimizing branched or irregular structures in the polymer chain. The overall propagation rate follows the expression \text{rate} = k [\ce{CO}] [\text{olefin}] [\ce{Pd-active}], highlighting its dependence on monomer concentrations and the concentration of active palladium species; high CO pressure is crucial for suppressing defects like consecutive olefin enchainments, which would disrupt alternation.^[7]^[28] Stereochemical control during propagation results in atactic microstructures for terpolymers incorporating propylene, arising from non-stereoselective insertion of the chiral propylene units amid the dominant ethylene sequences. In contrast, binary copolymers, such as those from CO and ethylene, exhibit no stereoregularity due to ethylene's symmetry, though certain olefin/CO copolymers display isotactic tendencies influenced by the monomer symmetry and catalyst geometry.^[7]

Importance of Bidentate Ligands

Bidentate ligands play a crucial role in palladium-catalyzed polyketone polymerization by stabilizing the metal center and directing the alternating insertion of carbon monoxide (CO) and ethylene monomers. These ligands, typically nitrogen- or phosphorus-based, coordinate to Pd(II) in a chelating fashion, enforcing a square-planar geometry that is essential for efficient migratory insertion steps. Without such ligands, the catalyst tends to favor random copolymerization, leading to irregular microstructures with reduced molecular weights and thermal stability.^[7]^[29] Common bidentate nitrogen ligands include 2,2'-bipyridine and 1,10-phenanthroline, which provide strong σ-donation and π-acceptor properties to stabilize cationic Pd species. Phosphorus-based ligands, such as 1,3-bis(diphenylphosphino)propane (DPPP) and 1,4-bis(diphenylphosphino)butane (DPPB), offer tunable steric and electronic effects through their backbone length. The bite angle—the P-Pd-P or N-Pd-N angle, ideally between 85° and 100°—is critical, as it influences the insertion barriers and favors CO coordination over competing pathways. For instance, DPPB with its wider bite angle (~98°) promotes higher catalytic activity compared to narrower analogs like DPPP (~91°).^[29]^[30]^[31] These ligands prevent β-hydride elimination, a deactivation pathway that would introduce defects like ethyl branches and terminate chain growth, thereby ensuring >99% regioselectivity for alternating CO/ethylene enchainment. Additionally, hemilabile coordination in certain bidentate systems—where one donor arm temporarily dissociates—facilitates CO activation by creating a vacant site for monomer binding during the propagation cycle. This synergy extends catalyst lifetime, achieving turnover numbers exceeding 10^6 g polyketone per g Pd under mild conditions (e.g., 85°C, 45 bar), far surpassing monodentate ligand systems.^[29]^[32]^[33]

Applications

Engineering and Industrial Uses

Polyketone, particularly the aliphatic variant known as POK, is widely utilized in automotive applications for components requiring durability under harsh conditions. Gears and bushings benefit from its exceptional wear resistance, with a low wear factor of approximately 0.07 mm³/N·km when tested against steel, while fuel system parts leverage its chemical inertness to resist degradation from fuels, oils, and coolants.^[4] Under-hood components, such as fluid connectors and housings, can operate reliably at temperatures up to 150°C without significant loss of mechanical integrity, making it suitable for engine compartments exposed to heat and vibration.^[34]^[4] In industrial manufacturing, polyketone serves in demanding roles like conveyor belts, where its abrasion resistance ensures longevity in material handling; seals and gaskets, which rely on its low dynamic coefficient of friction (around 0.13–0.60 against steel) for smooth operation; and electrical connectors, which capitalize on its dimensional stability to maintain tight tolerances in humid or chemically aggressive environments.^[35]^[4] These properties stem from its semi-crystalline structure, providing hydrolytic stability and minimal warpage even after prolonged exposure to moisture or temperature fluctuations.^[4] One key advantage of polyketone in engineering contexts is its ability to replace metals in tribological applications, such as bearings and sliding parts, achieving up to 50% weight reduction while preserving strength and reducing noise and energy loss.^[4] Additionally, it offers a cost-effective alternative to PTFE for low-friction needs, delivering comparable wear performance at a lower material cost and better processability for injection molding.^[4] Case studies highlight polyketone's efficacy in oil-exposed systems; for example, it is integrated into hydraulic hoses as a barrier layer to prevent permeation and swelling from hydrocarbons, enhancing safety and service life in heavy machinery.^[4] Similarly, pump components like impellers and housings utilize its oil resistance and impact toughness to withstand continuous fluid contact without degradation, as demonstrated in industrial fluid transfer applications.^[35]^[4]

Packaging and Specialty Applications

Polyketone's utility in packaging stems from its inherent barrier properties, particularly low oxygen permeability attributed to the polar carbonyl groups in its backbone, which interact favorably with permeants like water vapor and hydrocarbons. In food packaging applications, polyketone films and blends exhibit oxygen transmission rates (OTR) as low as 0.16 cm³·20 μm/m²·day·atm at 23°C and 0% relative humidity when combined with ethylene-vinyl alcohol (EVOH) copolymers at 30–70 wt%, outperforming pure EVOH in moisture resistance after retorting processes. These properties enable the use of polyketone in barrier films, bottles, and trays that resist oils, greases, and gases, extending shelf life for perishable goods while maintaining structural integrity under mechanical stress.^[36] In specialty applications, polyketone serves as a high-performance material in fibers, membranes, adhesives, and coatings due to its combination of chemical resistance, low moisture absorption, and mechanical toughness. For fibers, gel-spun polyketone variants achieve high tenacity and modulus comparable to p-aramid, making them suitable for tire cords and industrial textiles where durability and adhesion to rubber matrices are critical.^[37] Membranes fabricated from polyketone via phase inversion or co-extrusion demonstrate high permeance for separations, with applications in filtration and potential gas processing. Adhesives and coatings based on polyketone resins provide robust corrosion protection on metallic substrates, enhancing adhesion across diverse surfaces and resisting hydrolysis in harsh environments like marine or chemical exposure settings.^[38]^[39] Emerging developments focus on polyketone blends to address sustainability demands, including composites for eco-packaging to enhance sustainability while preserving barrier performance.^[40] Additionally, polyketone-based filaments are explored for 3D printing in prototyping protective enclosures and custom packaging molds, leveraging their low warpage and chemical stability. Regulatory compliance supports these uses, with specific polyketone terpolymer grades (CAS No. 88995-51-1) approved under FDA Food Contact Notification (FCN) 2380 for single- and repeated-use articles in cooking applications above 250°F, excluding infant formula, and featuring low extractables to ensure food safety.^[41]

Aromatic Polyketone Applications

Aromatic polyketones, such as polyether ether ketone (PEEK), are employed in high-performance applications requiring superior thermal and chemical resistance. In aerospace, they are used for structural composites and components that withstand extreme conditions. Medical applications include implants and prosthetics due to their biocompatibility and sterilizability. In the oil and gas industry, seals and bearings benefit from their dimensional stability under high pressure and temperature. High-temperature electronics utilize aromatic polyketones for insulators and housings capable of continuous use up to 260°C.^[1]

References

[1]
Polyketone - an overview | ScienceDirect Topics
Aliphatic polyketones offer toughness, chemical resistance, and wear resistance and was competing with polyamides, thermoplastic polyesters, and syndiotactic ...
[2]
Improving Flame Retardant Properties of Aliphatic Polyketone (POK)
Mar 1, 2023 · According to the literature data, the melting temperature for aliphatic polyketone polymers was found to be around 200 °C. (17) The melting ...
[3]
Tracing the History of Polymeric Materials: Aliphatic Polyketone
Jun 7, 2022 · The term aliphatic refers to a chain structure that does not employ aromatic rings, the six-sided structures that are an essential part of ...
[4]
None
### Summary of Polyketone Properties from PK Technical Guidebook
[5]
Transparent package with aliphatic polyketone oxygen-scavenger
The density of the terpolymer at room temperature is 1.235g/cm 3 with an amorphous density of 1.206g/cm 3. [0033]. At room temperature and in dry conditions ...
[6]
Versatile, degradable, non-alternating polyketones - ScienceDirect
Mar 13, 2024 · These copolymers were patented in 1941 by Farbenfabriken Bayer and in 1950 by DuPont. These methods obtained less than 50% carbonyl ...
[7]
Palladium-Catalyzed Alternating Copolymerization of Alkenes and ...
These catalysts made possible the essential technological advances in the synthesis and processing of alternating polyketones which enabled Shell to move these ...
[8]
History - HYOSUNG POLYKETONE : POKETONE
2015. POKETONE Plant start (50,000 ton/year, Ulsan Yongyeon Plant) · 2013. POKETONE Plant Engineering design Completed. POK Biz. · 2012. POKETONE Pilot Plant ...
[9]
Newsroom I I A Product of 10 Years of Work, POKETONE™
Oct 5, 2023 · In 2015, Hyosung's establishment of the new POKETONE™ production site with an annual capacity of 5 million tons elevated the entire ...
[10]
Synthesis and Characterization of Ethylene/Carbon Monoxide ...
Synthesis and Characterization of Ethylene/Carbon Monoxide Copolymers, A New Class of Polyketones ... carbon monoxide polyketone based on a renewable α ...
[11]
Recent Advances in Synthesis of Non-Alternating Polyketone ... - NIH
Jan 22, 2024 · This review aims to enlighten the design of ethylene/CO non-alternating polymerization catalysts for the development of new polyketone materials.Missing: composition | Show results with:composition
[12]
Structure of aliphatic polyketone based on ethylene-ketone and...
This is an ethyleneketone-propyleneketone copolymer, poly- merised from ethylene, propylene (6 mol%) and carbon monoxide. The propylene ketone is to lower the ...Missing: monomers | Show results with:monomers
[13]
[PDF] Alternating Olefin/Carbon Monoxide Polymers
CARILON polymers are semicrystalline thermoplastics derived from the simple and abundant raw materials of carbon monoxide and ethylene (or other a-olefins),.
[14]
Copolymerization of Carbon Monoxide and Norbornene with a ...
Carbon monoxide (99.3% purity) was purchased (Air. Products and Chemicals Inc.). Norbornene (Merck) was distilled twice from calcium hydride under dry nitrogen.
[15]
Crystalline structure in aliphatic polyketones - ScienceDirect.com
Thus, while WAXS measures a crystallinity value for quenched EVOH of 35% and for slow cooled samples of 55%, in good agreement with data reported in the ...Missing: percentage | Show results with:percentage
[16]
https://pmc.ncbi.nlm.nih.gov/articles/PMC8002582/
[17]
Comparative Studies on Crystallinity, Thermal and Mechanical ... - NIH
Mar 17, 2021 · The aliphatic PK with the repeating unit of ‒(CH2‒CH2‒C=O)n‒ has relatively high melting temperature (Tm) between 255 and 260 °C [2]. Although ...<|control11|><|separator|>
[18]
On the Crystalline Structure and Morphology of Aliphatic Ketone ...
The degree of crystallinity (∼40%) of the solution- crystallized material, although higher than that of the melt-quenched, is relatively low. A simple two-phase ...
[19]
Progress in polyketone materials: blends and composites
May 8, 2018 · This review presents various developments of POK binary and ternary blends and composites with traditional reinforcements, micro- and/or ...
[20]
https://www.nature.com/articles/pj200121.pdf
[21]
Anchoring sulfonic acid on silica surface through SiC bond for ...
May 1, 2016 · Anchoring sulfonic acid on silica surface through Si single bond C bond for immobilization of catalyst for polyketone synthesis.
[22]
Effects of Anion and Solvent on Properties of Alternating Ethylene ...
In this system, mo- lecular weight of copolymer depends on the nature of anions and solvent as well as hydrogen. ... polyketone/g-Pd · h and from 582 up to 975 g- ...
[23]
method for preparing aliphatic polyketone by continuous solution ...
Nov 14, 2024 · The present disclosure provides a method for preparing aliphatic polyketone by continuous solution polymerization process and aliphatic ...
[24]
HYOSUNG POLYKETONE : POKETONE
After developing proprietary technologies, Hyosung Corporation is producing POKETONE in the 50,000 tons per annum commercial plant located in Yongyeon, Ulsan, ...Missing: process | Show results with:process
[25]
Could polyketone be the next-generation nylon alternative? - Avient
Jun 21, 2024 · Polyketone has similar properties to nylon, is less hygroscopic, more thermally stable, and has a reduced environmental impact, making it a ...
[26]
Thermally stable and highly recyclable carbon fiber-reinforced ...
PK has superior impact strength, flame retardancy, chemical resistance, tribological, and barrier properties [1], [2], [3].
[27]
Study of the Mechanical Recycling on the Properties of Glass Fiber ...
This study aims to evaluate the effects of repeated mechanical recycling on the properties of a novel aliphatic polyketone composite reinforced with 15 wt% ...Missing: Pd | Show results with:Pd
[28]
The use of ion exchange resins in the recycle of palladium catalysts ...
The catalytic activity of reused catalyst can reach 474 g/g h. The ion exchange resin can adsorb Pd2+, Cu2+, etc., in the after-treatment solution of the ...
[29]
Characterization of Polyketone Copolymer by High Speed DSC
Application Note using PerkinElmer HyperDSC® to analyze polyketone copolymer samples commonly used in automotive and industrial applications because of its.Missing: group | Show results with:group
[30]
Mechanistic Studies of the Palladium(II) - ACS Publications
We have examined the microscopic steps responsible for copolymerization of ethylene and CO initiated by the (phen)Pd(CH3)(NCCH3)+ precatalyst. The study has ...
[31]
https://pubs.rsc.org/en/content/articlelanding/2003/dt/b300322c
[32]
[PDF] Ligand Bite Angle Effects in Metal-catalyzed C−C Bond Formation
Bidentate ligands have played an important role in the development of catalytic applications of metal organic complexes. The synthesis of dppe (1b) was.
[33]
Bite angle effects in diphosphine metal catalysts: steric or electronic?
Bite angle affects selectivity and rate in catalytic reactions. Hydroformylation regioselectivity is steric, while rate is electronic. Selectivity in palladium ...<|separator|>
[34]
[PDF] Ligand and Solvent Effects on the Catalytic Activity and Lifetime of ...
Cationic Pd(II) catalysts with bidentate phosphine ligands are highly active and highly productive for the alternating copolymerization, with the activity ...<|control11|><|separator|>
[35]
None
### Summary of Bidentate Ligands in Pd-Catalyzed Polyketone Synthesis
[36]
https://onlinelibrary.wiley.com/doi/full/10.1002/app.49537
[37]
[PDF] POKETONE (Polyketone) What is it? - PolySource
• Industrial – Rail Fastening System, Conveyor Belts, Cosmetic Containers, Industrial Wheels, Helmet components, Cable Ties, Oil. Seal, Pipe and Tubing.Missing: uses | Show results with:uses
[38]
Oxygen barrier properties of polyketone/EVOH blend films and their ...
Jun 4, 2020 · In addition to good gas barrier properties, PK has excellent impact strength, chemical resistance, and abrasion resistance, which are also ...
[39]
Basic study of PK fiber tire cord - ResearchGate
Aug 6, 2025 · This time we have focused on a new high-tenacity and high-modulus "polyketone" fiber obtained by gel-spun technology and performed a basic study ...
[40]
Fabrication of high-permeance polyketone (PK) hollow fiber ...
In this study, co-extrusion technology was employed to modify the outer surface structure of the polyketone (PK) hollow fiber membrane to enhance membrane ...
[41]
Paal-Knorr kinetics in waterborne polyketone-based formulations as ...
Oct 15, 2016 · This technique is characterized by several advantages, such as high efficiency, no drag-out, and easiness of control and optimization [4].
[42]
Progress in polyketone materials: blends and composites
May 8, 2018 · Polyketone (POK), a new environment-friendly engineering plastic produced from carbon monoxide (CO), can be used for various applications ...Missing: definition | Show results with:definition<|control11|><|separator|>
[43]
[PDF] Environmental Assessment for Food Contact Notification FCN 2380
May 30, 2024 · Finished food-contact articles produced from the polyketone terpolymers will be used nationwide. Therefore, food-contact articles produced ...