Search

Water soluble bis(acetonitrile) diphospalladium (II) complexes cis‐[Pd(L1–L5)(NCCH3)2][BF4]2 (C1–C5) were obtained by the reaction [Pd(NCCH3)4][BF4]2 with diphosphines ligands L1–L5 (CH2(CH2PR2)2: where R=(CH2)nP(O)(OEt)2, n=2–4, n=6 and n=8)) in dichloromethane–acetonitrile. The isolated complexes were characterized by elemental analysis, FTIR, 1H‐ and 31P‐NMR spectroscopy. The complexes were applied as catalysts for the copolymerization of 1‐butene with carbon monoxide in aqueous media. The present work emphasized on the effect of weakly coordinated solvent and counterion on the catalytic behavior of cis‐[Pd(L1–L5)(NCCH3)2][BF4]2 complexes compared to previously prepared cis‐[ Pd(L1–L5)(OAc)2] (A1–A5). The exchange of π‐bonding NCCH3 ligand with π‐bonding CO and alkene was more favored than the exchange of σ‐bonding OAc− as reflected by the much higher catalytic activity (TON) of the former compared to the latter. In order to compare the catalytic efficiency of water soluble complexes with the performance of a standard, the water insoluble complex, cis‐[Pd(CH2(CH2P(CH2CH3)2)2(NCCH3)2][BF4]2, C6, was prepared and incorporated in the investigations. The isolated alternating 1‐butene/CO copolymer exhibits glass transition temperature of Tg=−3–−15 °C, which is in the range desirable for latex emulsion application. The solid content is up to 21 % with high molecular weight (Mw=4×104 g mol−1) and narrow polydispersities (Mw/Mn=2–3). The C5 complex was found to be fourteen times more active in aqueous polymerization medium (6369 mol substr. mol Pd−1 h−1) than C6 complex in nonaqueous medium (441 mol substr. mol Pd−1 h−1). [ABSTRACT FROM AUTHOR]

The change in the surface morphology of polyketone, polypyromeltitimide, polyethylene naphthalate, and polyethylene terephthalate films under the influence of a direct current discharge has been studied. A significant increase in the roughness has been shown, which is more characteristic of films modified at the cathode. The adhesion properties (peel resistance) have been assessed using the T-test method according to ASTM1876-2001 with polyurethane glue. A significant increase in adhesion for the modified samples has been shown. The contribution of changes in surface morphology to the manifestation of this effect is discussed. [ABSTRACT FROM AUTHOR]

The copolymers of carbon monoxide (CO) and ethylene, namely aliphatic polyketones (PKs), have attracted considerable attention due to their unique property and degradation. Based on the arrangement of the ethylene and carbonyl groups in the polymer chain, PKs can be divided into perfect alternating and non-perfect alternating copolymers. Perfect alternating PKs have been previously reviewed, we herein focus on recent advances in the synthesis of PKs without a perfect alternating structure including non-perfect alternating PKs and PE with in-chain ketones. The chain structure of PKs, catalytic copolymerization mechanism, and non-alternating polymerization catalysts including phosphine–sulfonate Pd, diphosphazane monoxide (PNPO) Pd/Ni, and phosphinophenolate Ni catalysts are comprehensively summarized. This review aims to enlighten the design of ethylene/CO non-alternating polymerization catalysts for the development of new polyketone materials. [ABSTRACT FROM AUTHOR]

Today, polymeric drug delivery systems (DDS) appear as an interesting solution against bacterial resistance, having great advantages such as low toxicity, biocompatibility, and biodegradability. In this work, two polyketones (PK) have been post-functionalized with sodium taurinate (PKT) or potassium sulfanilate (PKSK) and employed as carriers for Vancomycin against bacterial infections. Modified PKs were easily prepared by the Paal–Knorr reaction and loaded with Vancomycin at a variable pH. All polymers were characterized by FT-IR, DSC, TGA, SEM, and elemental analysis. Antimicrobial activity was tested against Gram-positive Staphylococcus aureus ATCC 25923 and correlated to the different pHs used for its loading (between 2.3 and 8.8). In particular, the minimum inhibitory concentrations achieved with PKT and PKSK loaded with Vancomycin were similar, at 0.23 μg/mL and 0.24 μg/mL, respectively, i.e., six times lower than that with Vancomycin alone. The use of post-functionalized aliphatic polyketones has thus been demonstrated to be a promising way to obtain very efficient polymeric DDS.

X-ray photoelectron spectroscopy was used to study the change in the chemical composition of the surface of polyketone films as a result of exposure to a low-pressure direct-current (DC) discharge. The films were placed at the anode and cathode; filtered atmospheric air was used as a working gas. It was shown that a significant number of oxygen-containing groups is formed on the polymer surface. An atomic force microscopy study detected that plasma treatment leads to a considerable increase in the surface roughness of the films. Such changes improve the contact and adhesion properties of polyketone films. [ABSTRACT FROM AUTHOR]

Today, the high concentrations of copper found in water resources result in an urgent problem to solve since human health and aquatic ecosystems have been affected. Functionalized crosslinked polyketone resins (XLPK) have demonstrated high performance for the uptake of heavy metals in water solutions. In addition, its green chemical synthesis makes these resins very attractive as sorbents for metal ions contained in wastewater. XLPK are not soluble in aqueous media and do not require any catalyst, solvent, or harsh conditions to carry out the uptake process. In this paper, a series of functionalized XLPK with pending amino-derivatives namely; butylamine (BA), amino 2-propanol (A2P), 4-(aminomethyl) benzoic acid (HAMC), 6-aminohexanoic acid (PAMBA), and 1,2 diamino propane (DAP) directly attached to the pyrrole backbone of the polymers and crosslinked by di-amine derivatives was investigated using Density Functional Theory (DFT) calculations. Our computational analysis revealed that dipole-dipole interactions played a crucial role in enhancing the adsorption of Cu2+ ions onto XLPKs. The negatively charged ketone moieties and functional groups within XLPKs were identified as key adsorption sites for the selective binding of Cu2+ ions. Additionally, we found that XLPKs exhibited strong electrostatic interactions primarily through the –NH2 and –C=O groups. Evaluation of the adsorption energies in XLPK-Cu(II) complexes showed that the DAP-Cu(II) complex exhibited the highest stability, attributed to strong Cu(II)-N binding facilitated by the amino moiety (–NH2). The remaining XLPKs displayed binding modes involving oxygen atoms (Cu(II)-O) within the ketone moieties in the polymer backbone. Furthermore, the complexation and thermochemical analysis emphasized the role of the coordinator atom (N or O) and the coordinating environment, in which higher entropic effects involved in the adsorption of Cu2+ ions onto XLPKs describes a lower spontaneity of the adsorption process. The adsorption reactions were favored at lower temperatures and higher pressures. These findings provide valuable insights into the reactivity and adsorption mechanisms of functionalized and crosslinked polyketones for Cu2+ uptake, facilitating the design of high-performance polymeric resins for water treatment applications. [ABSTRACT FROM AUTHOR]

Electrospun nanofiber membranes derived from polyketone (PK) are precisely fabricated to exhibit an excellent separation efficiency for oil/water emulsions. The fiber diameter and pore size of the membrane are controlled by introducing NaOH to the precursor solution prior to electrospinning. The surface properties of the nanofibers are then controlled by the removal of NaOH with water and reduction of functional groups with sodium borohydride (NaBH4) to exhibit an air‐water superhydrophilicity and underwater superoleophobicity. This surface conversion process is easily monitored by the water contact angle and the underwater oil contact angle. Oil/water emulsions, including toluene, soybean oil, and hexadecane are filtered through the membranes to examine their separation efficiency and flux using total organic carbon and UV‐Vis measurements. The optimized membrane exhibits the minimum 97 % separation efficiency for all three oil/water emulsions and recyclability without notably losing its flux under gravity‐driven filtration conditions. [ABSTRACT FROM AUTHOR]

The copolymers of carbon monoxide (CO) and ethylene, namely aliphatic polyketones (PKs), have attracted considerable attention due to their unique property and degradation. Based on the arrangement of the ethylene and carbonyl groups in the polymer chain, PKs can be divided into perfect alternating and non-perfect alternating copolymers. Perfect alternating PKs have been previously reviewed, we herein focus on recent advances in the synthesis of PKs without a perfect alternating structure including non-perfect alternating PKs and PE with in-chain ketones. The chain structure of PKs, catalytic copolymerization mechanism, and non-alternating polymerization catalysts including phosphine–sulfonate Pd, diphosphazane monoxide (PNPO) Pd/Ni, and phosphinophenolate Ni catalysts are comprehensively summarized. This review aims to enlighten the design of ethylene/CO non-alternating polymerization catalysts for the development of new polyketone materials.

Anion-exchange membranes (AEMs) are involved in a wide range of applications, including fuel cells and water electrolysis. A straightforward method for the preparation of efficient AEMs consists of polymer functionalization with robust anion-exchange sites. In this work, an aliphatic polyketone was functionalized with 1-(3-aminopropyl)imidazole through the Paal–Knorr reaction, with a carbonyl (CCO %) conversion of 33%. The anion-exchange groups were generated by the imidazole quaternization by using two different types of alkyl halides, i.e., 1,4-iodobutane and 1-iodobutane, with the aim of modulating the degree of crosslinking of the derived membrane. All of the membranes were amorphous (Tg ∼ 30 °C), thermally resistant up to 130 °C, and had a minimum Young's modulus of 372 ± 30 MPa and a maximum of 86 ± 5 % for the elongation at break for the least-crosslinked system. The ionic conductivity of the AEMs was determined at 25 °C by electrochemical impedance spectroscopy (EIS), with a maximum of 9.69 mS/cm, i.e., comparable with that of 9.66 mS/cm measured using a commercially available AEM (Fumasep-PK-130). Future efforts will be directed toward increasing the robustness of these PK-based AEMs to meet all the requirements needed for their application in electrolytic cells. [ABSTRACT FROM AUTHOR]

Water electrolysis is by far the most appealing method to produce green hydrogen. Among the possible technologies, Anion Exchange Membrane (AEM) water electrolyzers are promising in the medium term, as they make it possible to avoid critical and noble materials as catalyst components. However, AEMs are still lacking in performance and stability, which has become the current research focus. Here, we report the facile and inexpensive chemical modification of polyketone (PK) with a functional unit encompassing morpholinium as the positively charged group, and the fabrication of self‐standing membranes. The synthesis products are investigated with an ensemble of physico‐chemical and spectroscopic techniques, including solid‐state and time‐domain NMR, FT‐IR, and thermal analysis. The membranes show good Ion Exchange Capacity values in the range 1.48–2.24 mmol g−1. A preliminary electrolysis test shows that the PK‐based membrane has performance comparable to that of a commercial one. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The introduction of carbonyl group with a high density in polyethylene backbone corresponds to polyketone materials, which features excellent mechanical strength, crystallinity, photodegradability, hydrophilicity, surface and barrier properties. Due to the extremely high binding affinity of carbon monoxide (CO) and kinetic preference for its subsequent insertion, the formation of nonalternating structure with extra ethylene insertion is exceptionally challenging, however, this nonalternating strategy is of significant importance for polymer modification in term of processing and solubility. Here, we have communicated our study on cationic palladium coordinated diphosphazane monoxide (PNPO) for the nonalternating copolymerization of ethylene with CO, the systematical investigation on the amine and phosphine oxide moieties in PNPO platform in term of electronic and steric modulation has been performed. It is discovered that the installation of aliphatic structure on amine moiety favors the improvement of catalyst activity and longevity, while the amino groups on phosphine oxide moiety promotes the nonalternating copolymerization. In particular, we have computationally investigated herein the aspects of the nonalternating degree by comparing with PNPO platform and 1,3‐bis(diphenylphosphanyl)propane ligands based palladium catalysts. These mechanistic studies can help to understand the catalyst structure and polyketone property relationships and shed light on future design of high‐performance copolymerization catalysts. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The introduction of carbonyl group with a high density in polyethylene backbone corresponds to polyketone materials, which features excellent mechanical strength, crystallinity, photodegradability, hydrophilicity, surface and barrier properties. Due to the extremely high binding affinity of carbon monoxide (CO) and kinetic preference for its subsequent insertion, the formation of nonalternating structure with extra ethylene insertion is exceptionally challenging, however, this nonalternating strategy is of significant importance for polymer modification in term of processing and solubility. Here, we have communicated our study on cationic palladium coordinated diphosphazane monoxide (PNPO) for the nonalternating copolymerization of ethylene with CO, the systematical investigation on the amine and phosphine oxide moieties in PNPO platform in term of electronic and steric modulation has been performed. It is discovered that the installation of aliphatic structure on amine moiety favors the improvement of catalyst activity and longevity, while the amino groups on phosphine oxide moiety promotes the nonalternating copolymerization. In particular, we have computationally investigated herein the aspects of the nonalternating degree by comparing with PNPO platform and 1,3‐bis(diphenylphosphanyl)propane ligands based palladium catalysts. These mechanistic studies can help to understand the catalyst structure and polyketone property relationships and shed light on future design of high‐performance copolymerization catalysts. [ABSTRACT FROM AUTHOR]

The compatibility of polyketone (PK)/polyamide 6 (PA) polymer blends was studied to expand the use of PK polymers with polyamide 6 blends. Tensile strength showed negative deviation, but flexural modulus and Izod impact strength showed positive deviation with composition according to the linear mixing law. Differential scanning calorimetry and X-ray diffraction analyses showed that little shift in the glass transition temperature (Tg) and diffraction angles of the blends. Tg shifts were observed in the PK-rich and PA-rich compositions in dynamic mechanical tests, but a broadened bandwidth of tanδ peak and shoulder peaks were present in the PK30/PA70 and PK50/PA50 ranges. The blend morphology showed good interfacial adhesion and appeared as submicron domains in the PK-rich and PA-rich blends. Interfacial adhesion and the domain sizes larger than the critical size of the blend contributed to the improved impact strength of the PK/PA blend. Infrared spectroscopy showed that the hydrogen bonds in each polymer chain were reduced in blending, indicating a certain level of molecular blending between the PK and PA polymers. The results of this study suggest that PK/PA blends are partially miscible. [ABSTRACT FROM AUTHOR]

Abstract Water electrolysis is by far the most appealing method to produce green hydrogen. Among the possible technologies, Anion Exchange Membrane (AEM) water electrolyzers are promising in the medium term, as they make it possible to avoid critical and noble materials as catalyst components. However, AEMs are still lacking in performance and stability, which has become the current research focus. Here, we report the facile and inexpensive chemical modification of polyketone (PK) with a functional unit encompassing morpholinium as the positively charged group, and the fabrication of self‐standing membranes. The synthesis products are investigated with an ensemble of physico‐chemical and spectroscopic techniques, including solid‐state and time‐domain NMR, FT‐IR, and thermal analysis. The membranes show good Ion Exchange Capacity values in the range 1.48–2.24 mmol g−1. A preliminary electrolysis test shows that the PK‐based membrane has performance comparable to that of a commercial one.

Transition metal‐catalyzed copolymerization of CO and ethylene has a strong inherent propensity to produce the strictly alternating copolymer. In this work, nickel catalysts capable of both homopolymerization of ethylene and alternating copolymerization of CO and ethylene are developed to explore the possibility of non‐alternating copolymerization of CO and ethylene under the assumption that comonomer incorporation in the polymer chain can be adjusted by the concentrations of the comonomers. Both polyketones with slightly more than 50 % ethylene and "polyethylenes" with a small amount of CO incorporation are obtained but only under carefully controlled conditions and in low yields. [ABSTRACT FROM AUTHOR]

Homopolymerization of styrenic monomer featuring different functional group and their copolymerization with carbon monoxide were investigated by imine-pyridine palladium complex with the assistance of AgSbF 6. Poly(4-vinylbenzyl chloride) and poly(4-N,N-dimethylaminostyrene) were produced probably according to coordination-insertion mechanism. In the presence of carbon monoxide, substituted styrenes except for the 4-N,N-dimethylaminostyrene were copolymerized with CO to yield polyketones by the same catalysts. Thus, polyketones featuring chloromethyl group, diphenylaminomethyl group and quaternary ammonium salt were produced for the first time by direct alternating copolymerization. DSC results disclosed that glass transition temperature of the resulting polyketones was significantly affected by the substituents. The T g of polyketone featuring quaternary ammonium salt was 160 °C. [Display omitted] • Homopolymerization of 4-vinylbenzyl chloride or 4-N,N-dimethylaminostyrene catalyzed by imine-pyridine palladium catalyst according to coordination-insertion mechanism for the first time. • Alternating copolymerization of a series of substituted styrenes with carbon monoxide by palladium catalyst to yield polyketones featuring different functional groups. • High glass transition of polyketones featuring quaternary ammonium salt produced by direct copolymerization. [ABSTRACT FROM AUTHOR]

Today, the high concentrations of copper found in water resources result in an urgent problem to solve since human health and aquatic ecosystems have been affected. Functionalized crosslinked polyketone resins (XLPK) have demonstrated high performance for the uptake of heavy metals in water solutions. In addition, its green chemical synthesis makes these resins very attractive as sorbents for metal ions contained in wastewater. XLPK are not soluble in aqueous media and do not require any catalyst, solvent, or harsh conditions to carry out the uptake process. In this paper, a series of functionalized XLPK with pending amino-derivatives namely; butylamine (BA), amino 2-propanol (A2P), 4-(aminomethyl) benzoic acid (HAMC), 6-aminohexanoic acid (PAMBA), and 1,2 diamino propane (DAP) directly attached to the pyrrole backbone of the polymers and crosslinked by di-amine derivatives was investigated using Density Functional Theory (DFT) calculations. Our computational analysis revealed that dipole-dipole interactions played a crucial role in enhancing the adsorption of Cu2+ ions onto XLPKs. The negatively charged ketone moieties and functional groups within XLPKs were identified as key adsorption sites for the selective binding of Cu2+ ions. Additionally, we found that XLPKs exhibited strong electrostatic interactions primarily through the –NH2 and –C=O groups. Evaluation of the adsorption energies in XLPK-Cu(II) complexes showed that the DAP-Cu(II) complex exhibited the highest stability, attributed to strong Cu(II)-N binding facilitated by the amino moiety (–NH2). The remaining XLPKs displayed binding modes involving oxygen atoms (Cu(II)-O) within the ketone moieties in the polymer backbone. Furthermore, the complexation and thermochemical analysis emphasized the role of the coordinator atom (N or O) and the coordinating environment, in which higher entropic effects involved in the adsorption of Cu2+ ions onto XLPKs describes a lower spontaneity of the adsorption process. The adsorption reactions were favored at lower temperatures and higher pressures. These findings provide valuable insights into the reactivity and adsorption mechanisms of functionalized and crosslinked polyketones for Cu2+ uptake, facilitating the design of high-performance polymeric resins for water treatment applications.

In this paper, the polyketone (POK) extrusion cast film is manufactured by melt stretching method, and the evolution process of the crystal morphology and mechanical properties with the increase of melt drawing ratio (MDR) are followed. The results show that the melt stretching process produces many micro shish‐kebab crystals in the POK. The length of the shish crystal and the thickness of the kebab crystal hardly increase with MDR, but the lateral length of the kebab crystal shows linear growth when MDR exceeds 40. The crystalline morphology of POK is mainly affected by melt relaxation. The molecular chain has sufficient relaxation during cooling at a low MDR (20–40). At this time, micro shish‐kebab crystals are mainly randomly arranged. When MDR exceeds 40, the rapid melt stretching shortens the relaxation time of the tie chain between the neighborhood shish crystal, and the atomic force microscopy image shows a typical shish‐kebab structure. This experimental result indicates that the formation of the oriented lamella structure may be related to the relaxation of the molecular chains between the micro‐shish. When the length of the shish axis and the thickness of the kebab lamellae are similar, it is difficult to distinguish the two. [ABSTRACT FROM AUTHOR]

Transition‐metal‐catalyzed copolymerization of ethylene with carbon monoxide affords polyketones materials with excellent mechanical strength, photodegradability, surface and barrier properties. Unlike the widely used and rather expensive Pd catalysts, Ni‐catalyzed carbonylative polymerization is very difficult since the strong binding affinity of CO to Ni deactivates the highly electrophilic metal center easily. In this study, various cationic P,O‐coordinated Ni complexes were synthesized using the electronic modulation strategy, and the catalyst with strong electron‐donating substituents exhibits an excellent productivity of 104 g polymer (g Ni)−1, which represents a rare discovery that a Ni complex could operate with such exceptional efficiency in comparison with Pd catalysts. Notably, those Ni catalysts were also efficient for terpolymerization of ethylene, propylene with CO for producing commercial polyketone materials with low melting temperatures and easy processibility. [ABSTRACT FROM AUTHOR]

Today, polymeric drug delivery systems (DDS) appear as an interesting solution against bacterial resistance, having great advantages such as low toxicity, biocompatibility, and biodegradability. In this work, two polyketones (PK) have been post-functionalized with sodium taurinate (PKT) or potassium sulfanilate (PKSK) and employed as carriers for Vancomycin against bacterial infections. Modified PKs were easily prepared by the Paal-Knorr reaction and loaded with Vancomycin at a variable pH. All polymers were characterized by FT-IR, DSC, TGA, SEM, and elemental analysis. Antimicrobial activity was tested against Gram-positive Staphylococcus aureus ATCC 25923 and correlated to the different pHs used for its loading (between 2.3 and 8.8). In particular, the minimum inhibitory concentrations achieved with PKT and PKSK loaded with Vancomycin were similar, at 0.23 μg/mL and 0.24 μg/mL, respectively, i.e., six times lower than that with Vancomycin alone. The use of post-functionalized aliphatic polyketones has thus been demonstrated to be a promising way to obtain very efficient polymeric DDS.

Anion-exchange membranes (AEMs) are involved in a wide range of applications, including fuel cells and water electrolysis. A straightforward method for the preparation of efficient AEMs consists of polymer functionalization with robust anion-exchange sites. In this work, an aliphatic polyketone was functionalized with 1-(3-aminopropyl)imidazole through the Paal–Knorr reaction, with a carbonyl (CCO %) conversion of 33%. The anion-exchange groups were generated by the imidazole quaternization by using two different types of alkyl halides, i.e., 1,4-iodobutane and 1-iodobutane, with the aim of modulating the degree of crosslinking of the derived membrane. All of the membranes were amorphous (Tg ∼ 30 °C), thermally resistant up to 130 °C, and had a minimum Young’s modulus of 372 ± 30 MPa and a maximum of 86 ± 5 % for the elongation at break for the least-crosslinked system. The ionic conductivity of the AEMs was determined at 25 °C by electrochemical impedance spectroscopy (EIS), with a maximum of 9.69 mS/cm, i.e., comparable with that of 9.66 mS/cm measured using a commercially available AEM (Fumasep-PK-130). Future efforts will be directed toward increasing the robustness of these PK-based AEMs to meet all the requirements needed for their application in electrolytic cells.

Polyketone (PK) has attracted wide attention owing to its direct utilization of carbon monoxide, excellent properties, and photodegradation performance. However, the commercialized PK is produced using Pd‐based catalysts, which accounts for the largest part of the production cost. Herein, [Ni(2‐tol)(PPh3)(N,O)] is used as the main catalyst for its high productivity and good tolerance to CO. Effects of the cocatalyst (Ni(COD)2), the aging method in CO atmosphere, and the polarity of solvent are investigated. When Ni(COD)2 is employed as the cocatalyst, the catalytic activity and molecular weight of PK are increased by 29% and 42.6%, respectively. Aging of catalyst system with Ni(COD)2 in CO atmosphere leads to significant decrease in activity and molecular weight, while aging has almost no effect on the copolymerization without Ni(COD)2. Different catalytic mechanisms are proposed for the catalyst system with and without cocatalyst. Furthermore, it is found that the polar solvent (CH2Cl2) significantly increases the activity by 119.2% compared to that in the nonpolar solvent (toluene). However, the thermal stability of the catalyst is much better in toluene. The study on the understanding of catalytic mechanism and improvement of activity will promote the practical application of nonprecious metal catalysts for preparation of PK. [ABSTRACT FROM AUTHOR]

The effect of addition of a chain extender (ADR) creating branches on nylon 6 (PA6) by reactive extrusion on the isothermal crystallization behavior is studied. The effect of addition of small amounts of polyketone (PK) capable of forming strong hydrogen bonds with PA6 chains as an additive in reactive extrusion on the isothermal crystallization behavior is also studied. Addition of chain extender to PA6 results in a decrease in the degree of crystallization and the crystallization rate due to the formation of branches, and the increase in the chain extender content or reaction temperature speeds up the reaction forming branches to result in a greater decrease in the degree of crystallization and the crystallization rate. Addition of PK to PA6 results in a decrease in the degree of crystallization and the crystallization rate, and the degree of decrease is dependent on the amount of added PK. Addition of PK along with the chain extender results in a greater decrease in the degree of crystallization and the crystallization rate due to the additional formation of hydrogen bonds between branched PA6 and PK chains. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pd catalysts are used for nonalternating copolymerization of ethylene with CO. • Alkyl substituents on phosphorus moiety exhibits 29.2 mol% extra C2 incorporation. • T m value of nonalternating polyketone was reduced to 162 °C. • Such Pd catalyst exhibits high thermally robust nature in this copolymerization. Production of polyketone realizes the direct conversion of cost effective and abundant olefin and carbon monoxide (CO) monomers. However, copolymerization of ethylene with CO shows a high tendency for the formation of strictly alternating structures, and they feature a high melting temperature (T m) of 260 °C that impedes the processing by using the conventional injection molding and extrusion. Nonalternating preference in such copolymerization is a very promising method to circumvent the processability issues. In this study, we present a series of phosphine-sulfonate Pd catalysts for nonalternating copolymerization of ethylene and CO, since rare study has investigated the electronic and steric nature systematically in such ligand platform in this field. The usage of dicyclohexyl substituents on phosphorus moiety exhibits unexpected nonalternating preference with up to 29.2 mol% extra ethylene incorporation, thus lowing the T m values to 162 °C. Notably, such alkyl substituted phosphine sulfonate Pd catalyst exhibits high thermally robust nature in this nonalternating copolymerization. [ABSTRACT FROM AUTHOR]

Palladium catalysts modified with iminopyridine ligands were employed for ethylene/CO and styrene/CO copolymerization and ethylene/styrene/CO terpolymerization. Our studies revealed that the steric and electronic effects of the catalysts play key, yet distinct roles in these polymerization reactions. The thermal properties of the polyketones were engineered by varying the styrene content in terpolymers derived from ethylene, styrene, and CO sources, with increased styrene ratios yielding reduced polyketone crystallinity. [ABSTRACT FROM AUTHOR]

An isopyrazole (4H‐pyrazole)‐embedded nonane‐2,4,6,8‐tetraone derivative was synthesized as a masked‐tetraketone for stepwise and multiple functionalization. The masked‐tetraketone has six possible tautomers, but exists predominantly as a 12π‐electron conjugated keto‐enamine‐imine‐enol form, which was also observed in the solid state by single crystal X‐ray analysis. Stepwise functionalization to introduce metal‐coordination and fluorescence‐enhancement sites into the masked tetraketone furnished a fluorescent chromophore that indicates metal coordination on a microgram scale by considerably changing the solid‐state emission. [ABSTRACT FROM AUTHOR]

Metal ion adsorbents are indispensable materials for the recovery of noble metal ions in a sustainable society. Herein, we report that poly(isopyrazole-3,5-diyl-trans-vinylene) (1) effectively adsorbed group 10 metal ions from solution in acetonitrile. Owing to its fully π-conjugated and rigid structure, polyimine 1 was virtually insoluble in common organic solvents and water, making it advantageous for metal ion adsorption via a solid/liquid interface. Inductively coupled plasma (ICP) analysis showed that ≥90% of Ni2+, Pd2+, and Pt2+ ions were adsorbed at a concentration of 10 µM (order of ≤2 ppm) after stirring suspensions at room temperature. Metal ion desorption was achieved by treatment with ethylenediaminetetraacetic acid disodium salt (EDTA⋅ 2Na), and the adsorbent was reused. Theoretical calculations supported that the desolvation energy was an important factor for effective adsorption in acetonitrile. [ABSTRACT FROM AUTHOR]

Due to the excellent solvent resistance properties of polyketone (PK), the traditional non-solvent induced phase separation (NIPS) preparation process is both highly toxic and complex. In this work, we successfully and efficiently prepared PK hollow fiber membranes using the thermally induced phase separation (TIPS) method, capitalizing on a low-toxicity diluent system of polyethylene glycol 300 (PEG300) and triethylene glycol (TEG). Moreover, by simply adding TEG to the diluent, we achieved a reduction in the spinning temperature, resulting in membranes that display an interconnected structure formed through the liquid-liquid phase separation process. We systematically investigated the impact of the TEG ratio in the diluent, PK concentration, and propylene carbonate (PC) ratio in the bore liquid on the phase diagram, membrane morphology, and characteristics of PK membranes. Increasing the PC ratio in the bore liquid significantly improves the inner surface porosity due to PC penetration into the dope solution, leading to high water permeability. Additionally, the resulting PK membrane exhibits exceptional resistance to organic solvents. This work introduces a novel approach to lower the spinning temperature for PK membrane preparation in the TIPS process while preserving the membrane structure and properties. [Display omitted] • PK HFMs was prepared with low-toxic mixed diluent system via TIPS method. • The spinning temperature was significantly lowered with the addition of TEG. • The effects of PK concentration and bore liquid on membrane preformance were studied. • The resultant PK HFMs exhibited high water permence and good solvent resistance. [ABSTRACT FROM AUTHOR]

Several modified terpolymer polyketones (MPK) with N-substituted pyrrole moieties in the main chain and quaternized amine in the side group were synthesized for use as anion exchange membranes for fuel cells. The moieties were carried by SiO2 nanoparticles through surface functionalization (Si–N), which were added to the membranes to enhance their overall properties. On increasing the amount of modified silica from 10% to 60% wt/of MPK, there was an increase in Si–N and a corresponding threefold increase in the hydroxide conductivity of the membrane. The MPK–SiN (60%) exhibited a superior ionic conductivity of 1.05 × 10−1 S.cm−1 at 120 °C, a high mechanical stability, with a tensile strength of 46 MPa at 80 °C. In strongly alkaline conditions (1 M KOH, 216 h at 80 °C), the membranes maintained about 70% of the conductivity measured in a usual environment. Fuel cell performance at 80 °C showed a peak power density of 133 mW·cm−2, indicating that using surface-functionalized SiO2 is a simple and effective way to enhance the overall performance of anion exchange membranes in fuel cell applications.

To enhance impact strength of polyketone (PK) without loss of stiffness, PK was blended with polycarbonate (PC) via melt mixing. Three types of polyamides (PAs) with varying structures, — polyamide 6 (PA6), polyamide 612 (PA612), polyamide 12 (PA12) — were employed as polymeric compatibilizers. To elucidate the effect of the structure of PAs on the compatibilization, morphology, mechanical properties, and fracture behavior of the blends were investigated. The addition of PA6 and PA612 reduced the size of dispersed particles by encapsulating the PC phase, while PA12 was found not to affect the morphology of the PK/PC blend. The change in particle size, glass transition temperature (Tg), and elongation at break exhibited that PA6 was the most effective compatibilizer for the PK/PC blends of this study. These results were interpreted with the change in interfacial tension between PK and PA due to the difference in polarity of the PAs. It was found that the impact strength was not highest in the blend with the smallest particle size. The observation of sub-surface damage zone also indicated that effective toughening by intensive crazing in polymer blends requires dispersed particles of optimum size. [ABSTRACT FROM AUTHOR]

Effect of the oligomeric unsaturated polyketone (UPK) additive on the rheological properties, vulcanization, and structural characteristics of elastomeric compositions based on butadiene and nitrile-butadiene rubbers containing N-cyclohexyl-2-benzothiazolylsulfenamide (sulfenamide C) as vulcanizing accelerator is investigated. It was demonstrated using IR and NMR spectroscopy that sulfenamide C reacts with polyketone. A mechanism for such interaction, which includes the sequential addition of benzothiazyl sulfide and amine fragments to the oligomeric chain, was proposed. [ABSTRACT FROM AUTHOR]

In this study, two polymeric materials were tested in a dry rotating “pin-on-disc” configuration against differently coated surfaces, to evaluate their tribological response under conditions, such as those of rotary lip seals, and to identify the wear mechanism of each coupling. A PTFE based material, reinforced with glass fibers and a solid lubricant, and unreinforced polyketone were tested against a chromium oxide coating deposited by plasma thermal spraying, a CrN/NbN superlattice coating deposited by Physical Vapor Deposition (PVD), and a Diamond-Like Carbon (DLC) coating obtained through a hybrid PVD/PECVD (Plasma-Enhanced Chemical Vapor Deposition) process. The PTFE matrix composite offers better overall performance, in terms of specific wear rates and friction coefficients than polyketone. Although the tribological behavior of this material is generally worse than that of the PTFE matrix composite, it can be used without reinforcing fillers. Our analysis demonstrates the importance of transfer-film formation on the counter-surfaces, which can prevent further wear of the polymer if it adheres well to the counterpart. However, the tribofilm has opposing effects on the friction coefficient for the two materials: its formation leads to lower friction for PTFE and higher friction for polyketone.

Polyketones (PKs) having strong hydrogen bonding properties and a chain extender are used as additives in the melt processing of nylon 6 (PA6). Their effect on the chain structure and properties of PA6 is studied to enhance the processability of PA6 in melt processing. The addition of the chain extender to PA6 increases the melt viscosity by forming branches on the backbone. The addition of PKs results in an additional increase in viscosity through the hydrogen bonding between N–H of PA6 and C=O of PK. The change in the N–H bond FT-IR peak of PA6 and the swelling data of the PA6/PK blend containing a chain extender, styrene maleic anhydride copolymer (ADR), suggest that incorporation of chain extender and PK in the melt processing of PA6 results in physical crosslinks through hydrogen bonding between the branched PA6 formed by the addition of chain extender and PK chains. This change in the chain structure of PA6 not only increases the melt strength of PA6 but also increases randomness resulting in decreased crystallinity.

The efficiency of using an oligomeric unsaturated polyketone prepared by ketonization of cis-1,4-butadiene rubber with nitrogen(I) oxide (N2O) for the modification of physicomechanical properties of elastomer compounds based on Keltan 512 and SKEPT-50 ethylene–propylene–diene rubbers was demonstrated. The modification leads to a decrease in the viscosity of filled rubber stocks, facilitating their processing on the process equipment, and to more uniform dispersion of the silica filler (BS-1290 white soot); it enhances the elastic and strength characteristics of the vulcanizates by a factor of up to 2–2.5 relative to the unmodified compounds. [ABSTRACT FROM AUTHOR]

A kind of side-chain type anion exchange membranes (AEMs) with high ionic conductivity and good comprehensive stability was prepared via direct modification of commercial engineering plastic polyketone with diamines through Paal-Knorr reaction and quaternization reaction. It was found that the amount of diamine can effectively tune the microphase morphology and properties of the prepared quaternized functionalized-polyketone anion exchange membranes (QAFPK-AEMs). The tensile strength was increased from 18.6 MPa to 38.6 MPa, and the ion exchange capacity (IEC) was increased from 1.11 mmol/g to 2.71 mmol/g depending on the amount of added diamine. The QAFPK-1-6-AEM with the IEC of 1.43 mmol/g showed the highest hydroxide conductivity of 65 mS/cm at 25 °C and 96.8 mS/cm at 80 °C. The high ionic conductivity was achieved through the establishment of effective ionic channels, and it maintained 70% of the initial ionic conductivity after the 192 h treatment in 2 mol/L KOH (aq) at 80 °C. Moreover, a peak power density of 129 mW/cm2 was achieved when the assembled single cell with QAFPK-1-6-AEM was operated at 50 °C. Thus, the prepared QAFPK-AEMs showed great potential applications for the anion exchange membrane fuel cells (AEMFCs). [ABSTRACT FROM AUTHOR]

A polyketone-b-poly[N-(4 methyl-methylpyridium)-ethylenepyrrole+][X−], with X− = I− or OH−, is investigated as an example of anion-exchange membrane with potential applications in fuel cells. The polyketone starting material PK and the functionalized polyketones Pyr-FPKmI and Pyr-FPKmOH are investigated via Broadband Electrical Spectroscopy (BES) to understand the conductivity mechanism. BES signals are collected in the frequency range of 10−2 – 107 Hz and from −100° to 120 °C. BES measurements reveal the presence of up to three interdomain polarizations phenomena, one electrode polarization event and two β dielectric relaxation modes for both wet Pyr-FPKmI and Pyr-FPKmOH. Ion conductivity for Pyr-FPKmI and Pyr-FPKmOH is found to be 0.0086 and 0.0105 S cm−1 at 80 °C, respectively. The overall conductivity mechanism is attributed to the superposition of two conduction pathways, via delocalization bodies and via interdomain percolation pathways, which are associated with two different physical phenomena. [ABSTRACT FROM AUTHOR]

Reverse osmosis (RO) is a widely used pressure-driven membrane process for desalination. Advancements in membrane materials have driven RO technologies' development and widespread application. Thin-film composite (TFC) membranes of a thin polyamide (PA) layer, porous substrate, and nonwoven fabric support are considered the gold standard in desalination technology. These membranes exhibited excellent separation performance and mechanical strength. Recently, TFC membranes with PA layers have been successfully employed in organic solvent reverse osmosis (OSRO) to differentiate organic liquids molecularly. Developing TFC membranes with improved solvent resistance and permeance is required to expand the applications of TFC membranes beyond solvent-solute systems. This study explored polyketone (PK) membranes as porous substrates in TFC membranes for general reverse osmosis processes. PK membranes offer excellent solvent resistance and are easier to prepare than other membranes. Furthermore, a surface modification approach was proposed to enhance the interfacial polymerization (IP) of the polyamide layer on both PK and polysulfone (PSf) substrates, resulting in improved TFC membranes with enhanced water permeance for RO and increased organic liquid permeance for OSRO while maintaining permselectivity. These findings highlight surface chemistry's significance in controlling crumpled PA layers' formation, ultimately improving the filtration efficiency for general RO applications. This study provides an example of the design of composite structures of TFC membranes for broader RO applications. [Display omitted] • Thin-film composite membrane with solvent resistance were fabricated. • A versatile substrate surface modification method was developed. • Reverse osmosis and organic solvent reverse osmosis were evaluated. • The membranes exhibited enhanced permeance for water and organic solvents. [ABSTRACT FROM AUTHOR]

[Display omitted] • Interface-reinforced PK/CNT-g-PK composites were prepared via reactive melt-mixing. • CNT-g-PK was formed by the reaction between hydroxyl-CNT and GMA-grafted PK. • CNTs were dispersed well in the PK matrix with good interfacial adhesion. • Elastic modulus and tensile strength of the composites were highly enhanced. • EMI shielding effectiveness of the composite with 5 wt% CNT was ∼ 22.4 dB. We report the impacts of polyketone-grafted multiwalled carbon nanotube (CNT-g-PK) on the thermal, mechanical, electrical, and electromagnetic interference (EMI) shielding performance of polyketone (PK) composites. For this purpose, a masterbatch of 10 wt% hydroxylated CNT (CNT-OH) with 90 wt% glycidyl methacrylate-grafted PK (PKGMA) is manufactured by solution mixing and drying. It is then composited with neat PK to fabricate a series of PK/CNT-g-PK composites with varying CNT amounts of 0.5–5.0 wt% via reactive melt-compounding. Infrared spectral results confirm the successful formation of CNT-g-PKs in the melt-compounded composites through the reaction between the hydroxy group of CNT-OH and the epoxy group of PKGMA. Electron microscopic images of PK/CNT-g-PK composites reveal that CNTs are evenly distributed and tightly encapsulated in the composite matrices, indicating good interfacial adhesion between the reinforcing CNT filler and the PK matrix. Accordingly, the melt-crystallization temperature of the PK/CNT-g-PK composites increases as the CNT content increase owing to the nucleating agent role of CNTs, while the melt-crystallization/melting enthalpies decrease due to the mobility hindrance in the PK chains anchored by CNTs. The elastic storage modulus and tensile strength of PK/CNT-g-PK composites are significantly enhanced with increasing CNT content. The 1-mm-thick PK/CNT-g-PK composite with 5.0 wt% CNT exhibits high electrical conductivity of 6.98 × 10−4 S/cm and EMI shielding effectiveness of ∼22.4 dB in the X-band radio frequency range. [ABSTRACT FROM AUTHOR]

In this work, we report a facile way to control crystalline structures of polyketone (PK) films by combining plasma surface treatment with chemical vapor deposition (CVD) technique. The crystalline structure of PKs grown on plasma-treated graphene and the resulting thermal and mechanical properties were systematically discussed. Every graphene sheet used in this work was produced by CVD method and the production of PKs having different crystallinity were performed on the O2- and N2-doped graphene sheets. It was evident that the CVD-grown graphene sheets acted as the nucleating agents for promoting the crystallization of β-form PK, while suppressing the growth of α-form PK crystals. Regardless of the increase in surface roughness of graphene, surface functionality of the CVD-grown graphene was found to be an important factor in determining the crystalline structure of PK. N2 plasma treatment of the CVD-grown graphene promoted growth of the β-form PK, whereas the O2 plasma treatment of CVD graphene led to transformation of the unoriented β-form PK into the oriented α-form PK. Thus, the resulting thermal and mechanical properties of the PKs were highly dependent on the surface functionality of the CVD graphene. The method of controlling crystalline structure of the PKs suggested in this study, is expected to be very effective in realizing the PK with good processability, heat resistance and mechanical properties.

Among smart materials, self-healing is one of the most studied properties. A self-healing polymer can repair the cracks that occurred in the structure of the material. Polyketones, which are high-performance thermoplastic polymers, are a suitable material for a self-healing mechanism: a furanic pendant moiety can be introduced into the backbone and used as a diene for a temperature reversible Diels-Alder reaction with bismaleimide. The Diels-Alder adduct is formed at around 50 °C and broken at about 120 °C, giving an intrinsic, stimuli-responsive self-healing material triggered by temperature variations. Also, reduced graphene oxide (rGO) is added to the polymer matrix (1.6–7 wt%), giving a reversible OFF-ON electrically conductive polymer network. Remarkably, the electrical conductivity is activated when reaching temperatures higher than 100 °C, thus suggesting applications as electronic switches based on self-healing soft devices.

For the purpose of enhancing the impact resistance of polyketone (PK) without lowering the stiffness, PK was blended with polycarbonate (PC). As a compatibilizer for the blend, poly(methyl methacrylate-co-maleic anhydride) [poly(MMA-co-MA)] was synthesized and introduced. The structure and maleic anhydride content of poly(MMA-co-MA) were investigated by spectroscopy analysis and titration method. In the compatibilized blends, it was observed that the particle size decreased with increasing amount of poly(MMA-co-MA) compatibilizer, and that the compatibilizer encapsulated the PC particles. Among the tensile and impact properties examined, elongation at break and impact strength were greatly enhanced by the compatibilization, while modulus and yield strength were not much affected. The amount of compatibilizer and the resulting particle size giving the highest impact strength were different from those for the highest elongation at break. It was observed that there existed an optimum particle size of about 1µm that caused the maximum crazing to toughen the blend most effectively. [ABSTRACT FROM AUTHOR]

To enhance the impact strength of polyketone (PK) without the decrease in its stiffness, PK was blended with polycarbonate (PC). For the effective toughening of PK/PC blends, polyamide 6 (PA6) and mixtures of unmodified poly[styrene-b-(ethylene-co-butylene)-b-styrene] (unSEBS) and maleic anhydride (MA)-grafted SEBS (SEBS-g-MA) were added to the blends as compatibilizers. Examining the fracture surface, it was observed that, by varying the SEBS-g-MA/unSEBS ratio in the compatibilizer, the phase morphology and interphase structure were changed. While PK/PC/SEBS-g-MA/PA6 blend had completely encapsulated PC domains, PK/PC/(SEBS-g-MA/unSEBS)/PA6 blends showed a morphology in which the PC was incompletely encapsulated by SEBS. Morphological differences, such as complete or incomplete PC encapsulation, led to differences in the impact strength. The impact strength of the blends with incomplete encapsulation of PC was higher than that with complete encapsulation of PC. Through the investigation of fracture behaviors, it was confirmed that the impact strength of PK/PC/(SEBS-g-MA/unSEBS)/PA6 was enhanced due to debonding around the incompletely encapsulated PC particles and matrix shear yielding. [ABSTRACT FROM AUTHOR]

Aliphatic polyketone (POK) is a new engineering plastic owning outstanding mechanics, chemical resistance, and gas/liquid barrier properties. However, analogous to other polymers, the nature of combustion severely restricts the widespread application of POK. Herein, the diethyl zinc phosphinate (ZnPi) was compounded with three grades of POKs, which were different among each other in viscosity as low (L), medium (M), and high (H) levels, by melt mixing. It is intriguing to suggest that increasing the viscosity of POK could remarkably improve the dispersion homogeneity of ZnPi, which was beneficial to superior flame retardancy, simultaneously with comprehensive mechanical properties. For the H‐POK matrix, only 10% well‐dispersed ZnPi resulted in a V0 ranking with a good maintenance of its notched impact strength, whereas the load of ZnPi for reaching V0 rank increased to 14% in L‐POKs and M‐POKs and the mechanical performances decreased mildly. By a combination of scanning electron microscopy (SEM), Fourier‐transform infrared (FTIR), thermogravimetric analysis (TGA), and cone calorimetry, it is well revealed that the flame retardancy induced by adding ZnPi could mainly ascribe to the formation of various zinc phosphate species. This work exploits a facile and feasible method for fabrication of antiflame engineering plastics, which will be promising for large‐scale applicability of high‐performance POK materials. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Enzymes play vital roles in biological transformations due to incomparable selectivity. Enzymatic membrane reactors (EMRs) combine enzymes with membranes, and many researchers have studied the synergistic effect of EMRs exerting on enzyme performance. Before the utility of EMRs can expand from natural aqueous media to organic solvents, robust membranes must be developed to promote enzyme protection from hostile forms of media. For this study, laccase was immobilized on an organic-solvent-resistant hydroxylated polyketone (PK-OH) membrane via covalent bonds and served as a model enzyme. Ketone groups facilitated the immobilization via hydrogen bonds, leading to a high immobilization density of 462 µg/cm2. In homogeneous aqueous-organic solvents, the activity of immobilized laccase was up to 3.5 times greater than that of free laccase towards 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid). In addition, the results also showed improved activity towards highly concentrated 2,4,6-trichlorophenol and bisphenol A (1.4 g/L). Furthermore, the activity in filtration mode showed a 240% increase over that in batch mode. The immobilized laccase maintained its activity after 40 days of storage, 10 reuse cycles, and 50 h of continuous reaction. These results show that robust polyketone based membrane support will create opportunities for the application of EMRs in aqueous-organic solvents. [ABSTRACT FROM AUTHOR]

Polyketone (POK), a new environment‐friendly engineering plastic produced from carbon monoxide (CO), can be used for various applications including packaging, fibers and technical items. Due to its exceptional balance of mechanical properties and high chemical resistance, POK holds great potential to be one of the most promising candidates for high‐performance and multifunctional polymer materials. The introduction of other polymer materials, reinforcing fibers or micro‐ and/or nanofillers into the POK matrix is a powerful method for obtaining new POK‐based materials with specific characteristics and satisfactory improvements in properties. This article summarizes and highlights the recent advances and efforts in research and development in the field of POK blends, POK composites and POK blend‐based composites. The applications of POK materials and outlook are also summarized and discussed. © 2018 Society of Chemical Industry Recent advances in the field of polyketone (POK) blends, composites and blend‐based composites are summarized, and discussions of the developing directions for POK materials with specific properties are presented. [ABSTRACT FROM AUTHOR]

• A fluorine-containing polymer, Teflon® AF2400, was coated on a support membrane. • Aliphatic hydrocarbons and aromatic hydrocarbons (nonpolar solvents) permeated. • No permeation of alcohols (polar solvents) was observed. • In solvent mixtures, hexane and toluene permeated preferentially over alcohols. • TIPB separation factor was 31.3, which is fairly higher than the reported values. An organic solvent reverse osmosis (OSRO) membrane was fabricated by spin-coating a copolymer of perfluoro-2,2-dimethyl-1,3-dioxole and tetrafluoroethylene (Teflon® AF2400) onto a polyketone support membrane. The purpose of this research was to develop an OSRO membrane with different separation properties from a polyamide membrane already published in the literature. The prepared membranes had a dense and smooth active layer on the support membrane. In the pure organic solvent permeation tests, aliphatic hydrocarbons (nonpolar solvents) and aromatic hydrocarbons (nonpolar solvents) permeated through the membrane, whereas almost no alcohol permeation (polar solvents) was observed under our evaluation conditions. The separation performances of the nonpolar/polar solvent mixture systems and nonpolar/nonpolar solvent mixture systems were investigated. In the separation of 1,3,5-triisopropylbenzene from toluene, a separation factor of 31.3 with a toluene permeance of 0.07 LMH/bar was obtained, suggesting the successful separation of nonpolar organic solvents from a mixture of nonpolar solvents. [ABSTRACT FROM AUTHOR]