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The reactor fouling is a notorious obstacle in managing continuous synthetic processes of polyketones. The fouling raises synthetic costs and reduces the bulk density of polymers. Thus, efficient seed materials are required for antifouling performance. Hollow microporous organic polymers (HMOPs) were prepared using ZIF-8 nanoparticles as templating materials. Sulfonic groups were incorporated into HMOP via a post synthetic approach. The resultant HMOP–SO3H (20–90 μg/mL in methanol) showed successful catalyst activation and antifouling performance in polyketone synthesis.

Acetic anhydride (AA) is usually considered a stable molecule but is shown here to be able to polymerize in closed reactors to a cross-linked polyketone condensate. By using this chemistry, it was ...

Six promising biologically active polymers based on a 4-tert-butylcyclohexanone moiety have been synthesized through the Friedel–Crafts reaction as new polyketone derivatives. The polymerization occurred by the interaction of three different arylidene-based monomers, with adipoyl and sebacoyl diacid chlorides. The role of such arylidene linkages on the overall performance of these new polyketones was investigated with a special attention to its antimicrobial enhancement probability. The resulting polyketones were characterized by common characterization techniques including solubility, FTIR, X-ray diffraction, and morphological properties. The thermal properties of all the resulting polyketones were evaluated using TGA and associated with their structural units. The PDTmax results indicated that all the polymers had almost similar PDTmax patterns, which appeared in the range from 440 to 630 °C. The biological activity of all the synthesized polyketones was examined and showed that most of the synthesized polyketones had antibacterial activity against microbial strains. The role of the arylidene linkage on the antimicrobial enhancement of these new polyketone derivatives was also evaluated. The tested polyketones showed significant activity against most microbial strains, and the maximum activity was observed against E. coli and P. Aeruginosa. Polymer 5b showed the maximum inhibition zone of 13 mm amongst the other polymers. Furthermore, the tested polyketones showed no significant activity against B. subtilis or the fungus C. albicans. Furthermore, molecular docking studies were applied to all polymers with the “5FSA” protein, and the results have been investigated. Polymer 5b also showed the highest docking score of − 5.84 kcal/mol. Therefore, polymer 5b was classified as a promising biologically active polymer.

In this study, polyketone anion exchange fibers were synthesized by the amination of polyketone via a Paal-Knorr reaction and a quaternization reaction. The amination reaction proceeded at different reaction times and amine N,N-dimethylethylene diamine (DME) concentrations. The ion exchange capacity (IEC) and water uptake (W.U.) increased with increasing amination reaction time and DME concentration, and the maximum IEC and W.U. were 1.03 meq/g and 19.2%, respectively. The tensile strength decreased significantly with increasing amination time and amine concentration. TGA showed that the thermal decomposition temperature of the fibers was 220 °C. The HCl gas adsorption properties of the aminated polyketone ion exchange fibers were evaluated, and the HCl gas removal efficiency remained at 100% in 40 min at 300 ppm.

Graphical abstract, Six new polyketone metabolites, compounds (1–6) and seven known polyketone compounds (7–13) were isolated from Rhodiola tibetica endophytic fungus Alternaria sp. The structural elucidation of five new polyketone metabolites were elucidated on the basis of spectroscopic including 2D NMR and HRMS and spectrometric analysis. Inhibition rate evaluation revealed that compounds 1(EC50 = 0.02 mM), 3(EC50 = 0.3 mM), 6(EC50 = 0.07 mM), 8(EC50 = 0.1 mM) and 9(EC50 = 0.04 mM) had inhibitory effect on the SARS-CoV-2 virus.

In this study, sulfonated polyketone (SPK) cation exchange fibers were prepared by direct sulfonation with various concentration of sulfonating agent and sulfonation time. Fourier-transform infrared (FTIR) spectrum analysis was performed to confirm the structure of the sulfonated polyketone cation exchange fibers. The degree of sulfonation (DOS) and water uptake (W.U) of SPK cation exchange fibers were measured by gravimetric method and ion exchange capacity (IEC) was measured by titration method, respectively. The DOS of the SPK cation exchange fibers increased with sulfonation time and concentration of sulfonating agent. The SPK cation exchange fibers sulfonated for 15 min at a mole ratio of 1:2 of polyketone to chlorosulfonic acid had the DOS of 47%, ion exchange capacity 3.36 meq/g, and water content 35.1%, showing the best performance.

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.

A novel Diels–Alder polymerization system was developed, using an azodicarbonyl compound as the dienophile. A bis(azodicarbonyl) monomer was prepared by quantitative oxidation of bis(diacylhydrazine) with tBuOCl in the presence of pyridine. Diels–Alder polymerization was carried out with a bisdiene monomer, using AgOTf as the catalyst. High thermal stability of the polymer is characteristic for the products of this Diels–Alder polymerization system, in which the Diels–Alder reaction is irreversible. The C=C bond in the Diels–Alder polymer can be cleaved by ozonolysis to give a polyketone.

Polymers crosslinked via furan/maleimide thermo-reversible chemistry have been extensively explored as reprocessable and self-healing thermosets and elastomers. For such applications, it is important that the thermo-reversible features are reproducible after many reprocessing and healing cycles. Therefore, side reactions are undesirable. However, we have noticed irreversible changes in the mechanical properties of such materials when exposing them to temperatures around 150 °C. In this work, we study whether these changes are due to the self-reaction of maleimide moieties that may take place at this rather low temperature. In order to do so, we prepared a furan-grafted polyketone crosslinked with the commonly used aromatic bismaleimide (1,1′-(methylenedi-4,1-phenylene)bismaleimide), and exposed it to isothermal treatments at 150 °C. The changes in the chemistry and thermo-mechanical properties were mainly studied by infrared spectroscopy, 1H-NMR, and rheology. Our results indicate that maleimide self-reaction does take place in the studied polymer system. This finding comes along with limitations over the reprocessing and self-healing procedures for furan/maleimide-based reversibly crosslinked polymers that present their softening (decrosslinking) point at relatively high temperatures. On the other hand, the side reaction can also be used to tune the properties of such polymer products via in situ thermal treatments.

This study describes a straightforward post-polymerization modification (PPM) methodology from polyketone via chlorodimethylsilane (CDMS)-mediated reductive etherification reaction (RER). The polyketone platform was prepared via acyclic diene metathesis (ADMET) polymerization and reacted with a variety of alcohols in the presence of CDMS to create a wide range of polymers possessing pendant functional-alkoxy structures under mild conditions. The effect of parameters such as solvents and the amount of reactants on RER were studied. We have also explored the effect of other silane compounds on RER, none of which provided as high efficiency as the CDMS-mediated one. It has been found that the primary alcohols yielded corresponding alkoxy structures in high efficiencies, high isolated yields, and a wide range of functional group tolerance. It was also found that the formation of polyalcohol was inevitable, to some extent, during the RERs in addition to the alkoxy-functional polymers. All the polymers obtained were characterized in detail by various spectroscopic measurements, and a mechanistic aspect was also presented to evaluate the product distributions. Since operationally simple chemical methods, with a high yield and functional group tolerance, that can be easily adapted to the macromolecular level are always desired in synthetic polymer chemistry, this study promises remarkable opportunities for synthesizing functional polymers and may pave a way for the development of a novel metal-free PPM method.

Polyketone compounds play an important role in organic chemistry as a prominent source of reactivity and functionality. Their chemical properties vary widely depending on the ketone sequence in carbon chains. Although vicinal and β-polyketones have been used for more than 150 years, the recent development of new ketone sequences composed of alternating 1,3- and 1,4-diketones has demonstrated the further potential of polyketones as structurally flexible molecular ropes capable of derivatization to π-conjugated chromophores and molecular assemblies. In this Feature Article, we review the synthetic strategies and reactivities of polyketones with respect to their ketone sequence. Furthermore, recent research on polyketones with hybrid ketone sequences is also discussed, focussing on their structural diversity in chemical transformations including intramolecular cyclization and stereoselective oxidation.

International audience; The control of the stereochemistry of macromolecules is a very important goal, and coordination-insertion polymerization is superior with respect to the other polymerization methods for its achievement. In this contribution, we focus on Pd(II) homogeneous catalysts for the stereocontrolled synthesis of CO/vinyl arene polyketones. We developed a library of aldo- and keto-iminopyridine ligands N-N′ that feature an α- or β-naphthyl or anthracenyl moiety on the imino nitrogen atom (Nimm). With such ligands, the Pd(II) monocationic complexes [Pd(CH3)(CH3CN)(N-N′)][PF6] were synthesized. NMR spectroscopy shows that in solution, each complex exists as an equilibrium mixture of cis and trans stereoisomers, the latter having the CH3 ligand opposite to the Pd–Nimm bond. The isomeric population depends on the N-N′ ligand: an almost 1:1 ratio is found for the ketimine complexes, whereas those with the aldimines show a preference for the trans geometry. These complexes generate very efficient catalysts for the CO/vinyl arene copolymerization. Catalyst performances depend both on the nature of N-N′ and of the vinyl arene comonomer. The ketimine-based catalysts are more stable and more productive than the aldimine counterpart, leading to prevailingly syndiotactic macromolecules of high Mw (up to 280 kDa). The aldimine derivatives produce copolymers with isotactic and syndiotactic stereoblocks of different lengths depending on the vinyl arene. The effect of the prochiral monomer on the copolymer tacticity is steric in nature as demonstrated by the stereochemistry of the obtained CO/4-fluorostyrene polyketone, whose synthesis is reported here for the first time. As a conclusion, we have now demonstrated that when catalysts with nonsymmetric ancillary ligands are used, and stereoisomers are present, the stereochemistry of the copolymerization is driven by both the catalyst isomeric distribution and the prochiral comonomer.

In this study, we attempt to prepare a new blending system of poly(vinylidene fluoride) (PVDF) and aliphatic polyketone (POK) by melt compounding. The latter is a promising engineering plastic with comprehensive mechanical performances. When POK acted as minor phase to homogeneously disperse in and intimately contact with PVDF matrix, the brittle tensile behavior of neat PVDF transferred into a remarkably flexible manner (the elongation at break increased for 20 times), and more interestingly, the room-temperature durability of β-form PVDF in the uniaxially drawn blend film was obviously better than that in the neat PVDF film. Fourier transform infrared spectroscopy revealed that specific dipole interaction existed between CF2 group of PVDF and C=O group of POK. The intermolecular dipolar interaction induced good compatibility in the PVDF/POK blends, as evidently proved by fine two-phase morphology and decreased melting points of POK crystals. Therefore, the good compatibility and interfacial enhancement are responsible for the improvement of the stretch ductility and β-form room-temperature durability of the PVDF/POK blends.

Polyketone is a thermoplastic polymer known for its strong mechanical properties and chemical resistance. Such superiorities make it difficult to process and chemically modify for further functionalizations and applications. In this work, we introduce a novel method for functionalizing the alpha carbon of polyketone. We succeeded to attach allyl groups to the backbone of polyketone by a heterogeneous reaction between polyketone enolate and allyl bromide. Allylated polyketone is not soluble in common solvents. Since we started with a membrane of polyketone, there is no need to cast again. Further functionalization is possible through pending allyl groups via alkene addition reactions and ionic or radicalic polymerization. FTIR, elemental analysis, solid NMR, FT-Raman, SEM and XPS methods were employed to confirm the elemental composition, molecular structure and morphology. In addition, X-ray diffractometer (XRD), UV–Visible spectroscopy and thermal analysis were used to investigate the crystal structure, physical and electronic properties.

We report herein a new methodology for the rapid and selective reduction of carbonyls in the solid phase. By exploiting mechanical energy and using a cheap and air-stable silane, polymethylhydrosiloxane (PMHS), we can reduce a variety of carbonyl compounds, with catalytic amounts of fluorides. A scope of 19 substrates was explored to probe the generality of the method. In addition, an important biomass-based platform chemical, 5-hydroxymethylfurfural (5-HMF), and an insoluble polymer, polyketone, could be reduced with this methodology. A mechanistic study is also presented, suggesting the active role of volatile silane species. This method is particularly appealing to overcome substrate solubility issues and reduce solvent reliance in organic synthesis.

Using the radiation grafting technique, polyketone membranes were graft copolymerized with sodium styrene sulfonate (SSS) in the presence of additives such as Mohr’s salt and H2SO4. Fourier-transform infrared (FT-IR) spectroscopy was used to characterize the grafted membranes. Water uptake (WU), ion exchange capacity (IEC) and electrical resistance (ER) of the prepared membranes were measured in order to evaluate their physical properties The prepared membranes were applied to the membrane capacitive deionization (MCDI) process, in which their salt removal rates were evaluated and compared to those of CDI (capacitive deionization) process. The degree of grafting rose from 14.4% to 81.4% as the irradiation dose and the monomer concentration were increased. The water uptake ranged from 7.9% to 34.2%. The ionexchange capacity was observed between 0.43 meq/g and 1.1 meq/g, and the electrical resistance had values ranging from 12.2 Ω·cm2 to 2.1 Ω·cm2. The electrical resistance decreased as the ion-exchange capacity was extended. When the prepared cation exchange membrane was used in the MCDI process, the salt removal rate reached 87.6%, which was much higher than 28.8% of CDI process.

A novel anion exchange membrane composed of aminated polyketone-g-vinylbenzyl chloride was synthesized via 60Co γ-ray irradiation grafting technique. Total irradiation dose and concentration of monomers were set as variables to determine degree of grafting. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy equipped with energy dispersive X-ray spectrometer (SEM-EDS) were used to characterize the grafted membranes. Water uptake (WU) and swelling ratio (SR) were measured with a gravimetric method. A titration method was used to detect ion exchange capacity (IEC), whereas electrical resistance (ER) and ion conductivity (IC) were measured with a LCR meter. Our method has boosted the degree of grafting up to 97.6% from 3.7% as total irradiation dose and monomer concentration have been increased. WU and SR were in the ranges 1.5%-35.6% and 0.35%-20.9%, respectively. Also, IEC has taken values ranging between 0.2 and 1.19 meq/g. IC has varied within the range 0.01-0.3 S cm-1, and it has shown a rising trend as IEC increased. In this study, the optimum synthesis conditions have been 70 kGy of total irradiation dose and 50wt% of monomers. The membrane synthesized here is potentially superior to Nafion membrane in terms of several properties.

In this research, the morphologies, isothermal-crystallization kinetics, and spherulite growth of aliphatic polyketone/polyamide-6 blends were studied. A single glass-transition temperature (T g) was determined, and the composition dependence of T g for these blends was well described by the Kwei equation. The strong intermolecular interaction between the two polymer components was confirmed by melting-point depression. The isothermal-crystallization kinetics were analyzed on the basis of the Avrami approach. A linear increase in the radii of the spherulites with time was observed for all compositions. All the spherulites continued to grow at nearly identical growth rates. With increasing polyamide-6 content, the size of the spherulites in the polyketone/polyamide-6 blends gradually decreased, and the number of spherulites in the blends increased.

A new zwitterionic nickel(II) catalyst that comprises a partially fluorinated tetrakis(aryl)borate center in a bidentate phosphine ligand and a cationic Ni center has been developed and studied for CO–ethylene copolymerization in the context of comparison with a previously reported zwitterionic catalyst that carries a nonfluorinated borate anion. The crystal structures of several zwitterionic and related nickel compounds are characterized. Partial fluorination of the tetrakis(aryl)borate only brings a modest increase in productivity (2700 vs 1600 g of polyketone per gram of Ni, g (g of Ni)−1). Like the nonfluorinated catalyst, the fluorinated zwitterionic catalyst is extremely active at the beginning of the polymerization but deactivates rapidly. Deactivation of the two catalysts apparently follows different mechanisms. Stoichometric decomposition studies show that the partially fluorinated tetrakis(aryl)borate in the Ni compounds is stable under acidic conditions either directly introduced by addition of...

The effect of polyketone (PK) γ-irradiation dose on the energy characteristics of the PK surface, the specific free surface energy, and the interfacial energy at the boundary between polar (water) and nonpolar (octane) liquids has been studied for the first time. The most significant changes in the energy characteristics of the surface occur at doses up to 100 kGy, and improvement in PK adhesion to the polar and nonpolar phases is observed at doses above 75 and 200 kGy, respectively.

This paper aims to design new aliphatic polyketones based on dimethylketene, by cationic polymerization. Previous works showed that the polyketone type of polydimethylketene presents excellent oxygen barrier properties even in the presence of humidity, enabling this material to compete with the polymers currently used in the food packaging industry. However, PDMK has a degradation temperature close to its melting temperature which may make processability uneasy. PDMK structure is thus modified to broaden the gap between these two temperatures: for the first time, a dimethylketene/ethylketene random copolymer and a star-shaped polydimethylketene are targeted by cationic polymerization. The obtained polymers are studied by 1H and 13C NMR, FTIR, and capillary viscosimetry, the thermal properties are more particularly analyzed by TGA and DSC, and the oxygen permeability is measured.

Tensile properties such as Young's modulus and ultimate tensile force are important properties in understanding the characteristics of nanocomposites. Besides, the importance of functionalization methods in modification of the unique mechanical and elastic properties of carbon nanotubes (CNTs) is being widely recognized. In this paper, the tensile properties of CNTs functionalized with carbene under physisorption of polymer chains, i.e., aramid and polyketone chains, are investigated by using a series of molecular dynamics (MD) simulations. The results illustrated that Young's modulus of carbene-functionalized CNTs (cfCNTs) decreases by rising the weight percentage of carbene. By contrast, Young's modulus of cfCNTs under physisorption of polymer chains (cfCNTs/polymers) increases as the carbene weight rises. In a particular carbene weight, Young's modulus of cfCNTs/polymers decreases by increasing the chains of non-covalent functional groups. Moreover, it is shown that similar to Young's modulus, ultimate tensile force of cfCNTs reduces by increasing the weight percentage of carbene whereas the ultimate tensile force of cfCNTs/polymers has an increasing trend with raising the carbene weight.

The chemo- and stereo-selective two-step transformation of aliphatic polyketones composed of 3,3-dimethylpentane-2,4-dione units was achieved to generate π-conjugated polyimines. Upon treatment with hydrazine, discrete oligoketones with 4-8 carbonyl groups afforded ethylene-bridged oligoisopyrazoles in 80-89% yields. These oligoisopyrazoles underwent stereoselective oxidation at the ethylene bridge to give fully π-conjugated oligo(isopyrazole-3,5-diyl-trans-vinylene)s in 73-87% yields. Oxidation of the oligoimines drastically changed their absorption and metal-coordination behaviors. Finally, this two-step transformation was applied to polydisperse polymers. Imine formation proceeded almost quantitatively, even for longer polyketones, including docosamer. Subsequent oxidation of the polyimines furnished a virtually insoluble material that showed broad and red-shifted solid-state absorption over the whole visible region resulting from extended π-conjugation.

A series of amphiphilic polymers bearing aliphatic secondary amines and hydroxyl groups have been synthesized showing different hydrophilic/hydrophobic balance. The synthesis is performed through the Paal-Knorr modification of a polyketone comprising both ethylene and propylene comonomers with N-(2-hydroxyethyl)ethylenediamine. The values of dicarbonyl conversion achieved were 19, 35, 51, and 63%, which allowed controlling the amphiphilia of the polymers: a lower carbonyl conversion degree implies a higher hydrophobia. On the other hand, photodegradation studies of a model nanosized pollutant pigment comprised of 1,3,5-triphenylformazan nanoparticles stabilized by poly(sodium 4-styrenesulfonate) have been performed in the absence and in the presence of the photocatalyst 5,10,15,20-tetrakis-(4-sulfonatophenyl)porphyrin, showing no catalytic action, since electrostatic repulsion minimize molecular contacts between the reactants. However, the synthesized polymers allow overcoming this problem. Due to their amphiphila, the polymers showing dicarbonyl conversion values of 35, 51, and 63% form complexes with the porphyrin and stabilize its non-self-aggregated tetraanionic form in water from basic pH up to pH 1.74, 1.82, and 2.76, respectively, the differences related with the polymeric relative hydrophilic/hydrophobic balance. Only the amphiphilic polymer showing a conversion degree of 35% acts as an adequate vehicle for the dye to photocatalyze the oxidation of 1,3,5-triphenylformazan confined in the nanoparticles, highlighting the potential of the Paal-Knorr modification of polyketones to achieve a fine tunning of polymeric properties to obtain a specific functionality: the positive charge of the complex and the high hydrophobia of the tuned polymer allow, respectively, attractive long-range electrostatic interactions with the nanoparticles and diffusion of the reactants into the nanoparticle hydrophobic environment.

Soluble polyhydrofurans with chromophoric end-groups have been synthesized via post-polymerization modifications of polyketones. The absorption intensity in solution and molecular weight were controlled by manipulation of reaction time after addition of HBr gas, and the chromophoric end-groups exhibited blue emission with a maximum quantum yield of ca. 14%. Precise addition of a dopant decreased chromophore emission quantum yield, presumably by energy transfer from the polymer end-groups to the polymer backbone. Given their solubility, tunability with regard to photophysical properties and molecular weight, the resulting polymers may have applicability to organic-based electronic devices and studies of the solution-processability thereof.

As a widely-used engineering thermoplastic, polyamide 6 (PA6) is prone to hydrolysis in acidic and alkaline solvents, precluding its application in both acidic and alkaline environments. Polymer blending is an interesting strategy to fabricate high-performance polymer composites, while it is of challenge to achieve satisfactory properties via simple polymer blending technologies. Here, we report a chemical-resistant PA6/Polyketone (PK) composite with gradient encapsulation structures that is available by both high-pressure capillary extrusion and injection molding. Processing conditions including interfacial tension, viscosity ratio of polymer pairs, and shear rate during melt processing were taken into account to study the formation mechanism of such a special structure. It was revealed that the gradient encapsulation structure can be formed at a critical shear rate of beyond 200 s−1 and the critical viscosity above 5.8. Owing to the interesting gradient encapsulation structure (PK sheath and PA core), the obtained PA6/PK composites showed superior chemical-resistant performance upon formic acid immersion due to the formation of PK “sheath”. This work provides a facile strategy to fabricate PA6 materials with outstanding chemical resistance and mechanical properties by rapid and scalable melt processing methods.

Novel cationic resins were synthesized for a direct application in automotive industry. A previous patent protocol with lower bath toxicity (i.e. no catalyst neither harmful compounds were employed), as compared to the current industrial methods based on polyurethane chemistry, was implemented. This includes the use of aliphatic polyketones as cross-linking agents for epoxy-based resins in electro-deposition (EPD) processes. Cross-linking takes place through the Paal-Knorr reaction of the amino groups on the epoxy-based materials with 1,4-dicarbonyl groups present on the polyketone backbone. The reaction kinetics can be finely tuned by the steric hindrance on both components. This was preliminarily investigated by using 2,5,8-nonanetrione as model compound. The used amines (i.e. 4-aminopiperidine (AP) and 4-aminomethyl piperidine (AMP)) display higher steric hindrance with respect to the primary ones used in the original protocol. Application of these components during electro-deposition coating yields the desired high-quality coating layers on several metallic substrates as shown by optical microscopy and image processing. All the produced coatings scored higher adhesion and chemical resistance rating than the amine-based ones used in the previous protocol (i.e. diethylenetriamine, DETA). Afterwards, the same electro-deposition baths showed to have stable performance even after being re-used 21 and 56 days later. Keywords: Aliphatic polyketones, Electrodeposition, Green-oriented formulation, Automotive, Thin films

The terpolymerization of CO, ethylene, and additional olefins varies the properties of polyketones depending on olefins. In this study, monomer candidates for the terpolymerization of polyketones were expanded to alkynes, in addition to olefins. Thermal properties of polyketones were modified by adding aromatic alkynes during Pd-catalyzed terpolymerization with CO and ethylene. The Tm values of terpolymers were reduced to 192–215°C.

The synthesis and characterization of regioregular aliphatic polyketones is reported. Poly(1-oxoheptamethylene), a semicrystalline polyketone, was prepared via ruthenium-catalyzed ring-opening metathesis polymerization (ROMP) of a ketal-protected 7-membered cyclic ketone followed by subsequent hydrogenation and deprotection. Temperature and catalyst studies of the ROMP reaction guided the preparation of polyketones with high monomer conversions, molecular weights as high as 30 kDa, and dispersities as low as 1.4. Because of the symmetric nature of the monomer, the polymer has ketones spaced every six methylene units apart. The thermal properties of this polyketone were investigated by differential scanning calorimetry, revealing a peak melting range of 160–165 °C. A related polymer, poly(1-oxooctamethylene), was also prepared in a similar fashion, and a peak melting range of only 130–133 °C was observed. This difference in melting range is attributed to the lack of the regioregularity in poly(1-oxooctamet...

In this work we present a reversible and toughened thermoset system based on the covalent incorporation of a furane functionalized ethylene-propylene rubber (EPM-Fu) into a thermoset furane functionalized polyketone (PK-Fu) via Diels-Alder (DA) reversible cross-linking with bismaleimide (b-MA). FT-IR and DSC analyses proved the reversible interaction between PK-Fu and EPM-Fu with b-Ma via DA and r-DA sequence. Likewise, thermo-mechanical experiments (DMTA) indicated the re-workability of the material with no evident differences in elastic and loss modulus after several heating cycles and recycling procedures. Moreover, a considerable increase in the softening point (tangent 6) was also found for the higher toughened system containing 12 wt% of EPM-Fu (neat thermoset T = 137 degrees C whereas toughened thermoset T = 155 degrees C). A two-fold increase in IZOD impact strength compared to the neat thermoset (up to 27 J/m) was also recorded by the toughened system. Overall, this approach clearly indicates that fully thermally reversible and toughened thermosets can be realized starting from mixtures of furan functionalized polyketone and EPM rubber, cross-linked via reversible Diels-Alder chemistry. (C) 2015 Elsevier Ltd. All rights reserved.

Polyvinyl alcohol (PVA) is a reactive polymer since there are abundant hydroxyl groups so various chemical transitions are feasible for PVA. In this study, we utilized the oxidation of PVA followed with a ketalization to achieve the configuration of reversible polyketal networks. The oxidation of PVA was performed by using a benign oxidation system in which hydrogen peroxide acts as the green oxidant and p-toluene sulfonic acid (TSA) as the catalyst. Both fully oxidized PVA (polyketone, PK) and partially oxidized PVA (PVA-OXI) were obtained by controlling the oxidation time. Polyketals (PKLs) were prepared by ketalization of PVA with PK, or by self-ketalization of PVA-OXI. Under the catalysis TSA, only dark PKLs were obtained. However, with ionic liquid [BMIm]HSO4 as the catalyst, PKLs were colorless and transparent. The PKLs originated from a feed ratio of PVA/PK = 4/1 (w/w) seems tougher than other samples. When the PKL films were hydrolysed at 90 °C and recasted, the recycled (or reprocessed) PKL films appears the same as the fresh one, from the appearance to the chemical structure, and further to the mechanical properties. PKLs can be prepared by self-ketalization as well from PVA-OXI but the mechanical properties of the obtained PKLs seem not as good as those from ketalization of PVA and PK. The discoveries in this work open a door to easy but efficient modification of OH-abundant polymers, especially for polysaccharides.

Nanostructured polyketone (PK)/polyamide 6 (PA6) blends can be readily prepared via melt blending technologies and exhibit ultra-high toughness when PA6 is present as the nanoscale phase domains. When PA6 content is 30 vol%, the impact strength of the blends increases from 21.4 kJ/m2 of pure PK to 103.2 kJ/m2. The impact strength of the PK/PA6 blends with a 5:5 composition ratio reaches as high as 113 kJ/m2. The strong intermolecular force between PK and PA6 molecular chains enables the PA6 nanophase to cavitate to dissipate a significant amount of impact energy and effectively prevents the crack propagation or even terminates the cracks. The fracture mechanism of the PK/PA6 blends was further examined by the essential work of fracture method which proves that PK/PA6 blends show improved ability to prevent crack propagation. This work may deepen the understanding of polymer blend systems with strong hydrogen bonding interaction.

In the present work, microfibrillated cellulose (MFC) suspensions were produced by high-pressure homogenization and subsequently used to fabricate MFC membranes (C-1) by vacuum filtration followed by hot-pressing. A polyketone (PK50) was chemically modified by Paal-Knorr reaction to graft imidazole (IM) functional groups along its backbone structure. The resulting polymer is referred to as PK50IM80. By solution impregnation, C-1 was immersed in an aqueous solution of PK50IM80 and subsequently hot pressed, resulting in the fabrication of MFC/PK50IM80 composite membranes (C-IMP). Another method, referred to as solution mixing, consisted in adding MFC into an aqueous solution of PK50IM80 followed by vacuum filtration and hot-pressing to obtain MFC/PK50IM80 composite membranes (C-MEZC). C-IMP and C-MEZC were characterized by a wide range of analytical techniques including, X-ray photoelectron spectroscopy, Fourier-transform infrared chemical imaging, scanning electron microscopy, atomic force microscopy, dynamical mechanical analysis, tensile testing as well as streaming zeta potential, and compared to C-1 (reference material). The results suggested that C-IMP possess a more homogeneous distribution of PK50IM80 at their surface when compared to C-MEZC. C-IMP was found to possess significantly enhanced Young's modulus compared to C-1 and C-MEZC. The tensile strength of C-IMP was found to improve significantly compared to C-1, whereas C-1 possessed significantly higher tensile index than C-IMP and C-MEZC. Furthermore, the presence of PK50IM80 at the surface of MFC was found to significantly shift the isoelectric point (IEP) of the membranes from pH 2.3 to a maximum value of 4.5 for C-IMP. Above the IEP, C-IMP and C-MEZC were found to possess significantly less negative electrical surface charges (plateau value of −25 mV at pH 10) when compared to C-1 (plateau value of −42 mV at pH 10). Our approach may have implication to broaden the range of filtration applications of MFC-based membranes.

Polyolefins attract considerable attention due to their vast consumption and wide application. In this study, cross-metathesis polymerization (CMP) is demonstrated to be an efficient and feasible method for the synthesis of aliphatic polyketones. The synthetic route features good yield, mild condition and easy operation. The success of CMP relies on the high cross-metathesis tendency between α-olefin and vinyl ketone units of monomer 2. Optimization of polymerization condition was conducted to generate unsaturated polyketone P0 (Mn,GPC = 14 kDa), and the results of kinetic study verified high efficiency and structural integrity of this system. Furthermore, post-polymerization modification of P0 by using thiol-Michael chemistry furnished functional polyketones P1–P6, and full conversion of the internal vinyl ketone groups of P0 was observed in each case. The pristine and functional polyketones P0–P6 were virtually soluble in most common organic solvents. In particular, hydrophobic and fluorescent polyketones (P5 and P6) were also obtained by this means. Therefore, this synthetic strategy shows promising future and exemplifies huge potential for the synthesis of a diverse range of functional polyketones.

The exploitation of the Paal-Knorr reaction as a postmodification tool of ethene/propene/CO polyketone terpolymers to produce thermoset beads for metal ion uptake is hereby presented. Its prominent green character (i.e., no catalyst or a solvent employed, biocompatible polymer precursor) renders this class of functional polymers highly competitive in terms of low environmental impact compared to commercial biosorbents. Different cross-linking protocols are implemented for the four polymer resins, all involving formation of imine and/or pyrrolic bridges between the macromolecules. Functional thermosets bearing piperazine (X-PICPip), primary amine (X-PICDap) or glycine-type (X-PKLys) functional groups are synthesized. Qualitative correlation has been attempted with the metal ion-functional group interaction evaluation through FT-IR measurements and the correspondent uptake performances. During batch studies, the three resins indicated a robust uptake of Ni(II), Ag(I), and Cr(III), whereas in competitive adsorption during selectivity studies they showed a different reactivity pattern in the presence of the same metal ions.

We report on a novel synthetic route to synthesize relatively large quantities of polystyrene (PS) star polymers with targeted arm functionality and molar mass and their theological properties in the molten state. The synthetic route involves grafting styrene monomers onto a modified (aliphatic, alternating) polyketone backbone with a specific number of initiating grafting sites using controlled atom transfer radical polymerization (ATRP). Several polyketone precursors were used. This resulted in a large array of star polystyrenes with nonspherical cores and varying average arm length and number of arms. Their linear viscoelasticity was investigated and discussed in the context of the known response of anionically synthesized stars. Using a powerful characterization toolbox, including state-of-the-art interaction chromatography, rheometry, and tube modeling via the branch-on-branch (BoB) algorithm, we have assessed the viscoelasticity of these star polymers quantitatively. In particular, we have demonstrated a variability in molecular structure, which differs substantially from their anionically synthesized counterparts. Hence, whereas this new family of star polymers is not recommended for fundamental studies of polymer physics such as the molecular origin of relaxation mechanisms without prior extensive fractionation, they could be used in studies of mixtures as well as industrially relevant processing operations that require large amounts of polymeric stars.

This paper describes the synthesis and characterization of a high molecular weight cross-conjugated polyketone synthesized via scalable Friedel Crafts chemistry. Cross-conjugated polyketones are precursors to conjugated polyions; they become orders of magnitude more conductive after a two-electron reduction and demonstrate reversible spinless doping upon protonation with acids. Cross-conjugated polyketones are a new polymer platform that possess the same optoelectronic tunability as conventional polymers but with excellent thermal and oxidative stability. We constructed a proof-of-concept organic light-emitting diode device and demonstrate that a cross-conjugated polyketone can be successfully used as an n-dopable semiconducting material.

The reactive compatibilization of polyketone (PK) and maleic anhydride (MA)-grafted ethylene-octane rubber (mEOR) blends by addition of 1,10-diaminodecane (DA) was studied. Effects of DA were evaluated through the Fourier transform infrared (FTIR) spectroscopy, melt flow index (MFI), morphology, thermal, and mechanical properties. FTIR spectra indicated that DA reacted with PK and mEOR during melt blending and produced the PKmEOR inter-polymers at the interface. The addition of DA was found to decrease the MFI value, diminished the size of the dispersed phase, and enhanced its adhesion with PK matrix. For PK/mEOR/DA system, while the tensile properties were changed little, the impact strength was three times those of PK/mEOR blends. SEM observations of the blend morphology indicated that the impact strength of PK/mEOR blend was primarily controlled by the matrix ligament thickness. Open image in new window