Aryl Ether Ketone Research Articles

Characterization of the thermomechanical and aging behaviour of PAEK and CF/PAEK composites under long-term high-temperatures

The growing use of poly(aryl ether ketone) (PAEK) polymers reinforced with carbon fiber (CF) aims to meet the increasing demand for thermoplastic composites in applications that require excellent mechanical properties and thermal stability at higher temperatures. This study investigated the physicochemical properties of PAEK and CF/PAEK composites under long-term high-temperature exposure (150 °C, 200 °C and 250 °C) for durations of 15, 30, and 45 days, aiming to elucidate the durability mechanisms and enhance understanding of their performance. Specifically, the changes in the flexural properties and dynamic thermo-mechanical properties of the materials were evaluated after long-term high-temperature treatment. The results indicated that both PAEK and CF/PAEK composites possess substantial potential for long-term high-temperature applications, with CF not significantly altering the fundamental high-temperature response of the PAEK matrix. Regarding durability mechanisms, at 150 °C, PAEK's amorphous region undergoes chain reorientation, while temperatures of 200 °C and 250 °C induce significant secondary crystallization, which significantly improved the high-temperature mechanical properties of these materials. Additionally, at temperatures up to 250 °C, shorter linear chain fragments form through oxidative scission in PAEK's amorphous molecular chains. This work not only enriches the existing data on the properties of PAEK and CF/PAEK composites after long-term high-temperature treatment, but also provides further insights into their durability mechanisms.

Cross-Linking of Bromo-Pillar[5]arenes and Sulfonated Poly(Aryl Ether Ketone Sulfone) Enhances Proton Conductivity of Membranes at Low Ion Exchange Capacity

Cross-Linking of Bromo-Pillar[5]arenes and Sulfonated Poly(Aryl Ether Ketone Sulfone) Enhances Proton Conductivity of Membranes at Low Ion Exchange Capacity

Synergistic Effects of Liquid Rubber and Thermoplastic Particles for Toughening Epoxy Resin

This study aims to investigate the toughening effects of rubber and thermoplastic particles on epoxy resin (EP), and to understand the mechanism underlying their synergistic effect. For this purpose, three EP systems were prepared using diglycidyl ether of bisphenol-A (DGEBA) epoxy resin (E-54) and 4,4-Diamino diphenyl methane (Ag-80) as matrix resin, 4,4-diaminodiphenyl sulfone (DDS) as a curing agent, and phenolphthalein poly (aryl ether ketone) particles (PEK-C) and carboxyl-terminated butyl liquid rubber (CTBN) as toughening agents. These systems are classified as an EP/PEK-C toughening system, EP/CTBN toughening system, and EP/PEK-C/CTBN synergistic toughening system. The curing behavior, thermal properties, mechanical properties, and phase structure of the synergistic-toughened EP systems were comprehensively investigated. The results showed that PEK-C did not react with EP, while CTBN reacted with EP to form a flexible block polymer. The impact toughness of EP toughened by PEK-C/CTBN was improved obviously without significantly increasing viscosity or decreasing thermal stability, flexural strength, and modulus, and the synergistic toughening effect was significantly higher than that of the single toughening system. The notable improvement in toughness is believed to be due to the synergistic energy dissipation effect of PEK-C/CTBN.

Enhancing the interlaminar property of carbon fiber/poly(aryl ether ketone) composites with water‐soluble polyimide oligomer sizing agent

AbstractNovel water‐soluble polymer‐based sizing agents for carbon fiber/poly(aryl ether ketone) composites (CF/PAEK) have gained attention. However, a challenge remains: the sized CF bundles lack flexibility, and the effect of this on the properties of the composite has not been discussed. Herein, a water‐soluble polyimide oligomer (OL) sizing agent was developed, and the sizing effect was comprehensively evaluated. The conventional molecular weight polyimide (HP) sizing agent was also assessed for comparison. Although the interfacial shear strength of the sized CF monofilaments is enhanced due to improved surface roughness and wettability, the effect of the OL sizing agent on the composite's interlaminar shear strength (ILSS) and tow's flexibility differed from that of the HP sizing agent. Compared with HP‐CF, the yarn spreading rate of OL‐CF tow is increased by about eight times, and the ILSS of OL‐CF/PAEK composites with 2 and 5 MPa molding pressure is increased by 69% and 222%, respectively. The HP sizing agent weakens the tow's flexibility and yarn spreading ability, which is not conducive to the resin penetration in the tow, resulting in lower ILSS. In contrast, the OL sizing agent considers the tow's flexibility and composite's interlaminar property, showing great application potential.Highlights Two PI‐based sizing agents with diverse film‐forming capacities were prepared. The ILSS of CF/PAEK with OL sizing agent was significantly improved. HP sizing agent weakened the tow flexibility and interlaminar property. The interaction of sizing layer—resin penetration—ILSS was proposed.

Bifunctionalized MOFs modified poly (aryl ether ketone sulfone) ultrafiltration membranes with high-efficient BSA separation and dye adsorption

In this study, by connecting the amino ligand in ZIF-8-NH2 with an alkyl side chain containing sulfonic acid groups in a one-step method, a novel nanofiller (ZIF-8-NS) with bifunctional amino and sulfonic acid groups was formed. Sulfonated poly (aryl ether ketone sulfone) containing fluorene group (F-SPAEKS) was chosen as the polymer matrix. The nanofiller not only had good hydrophilicity but also had electrostatic interaction with the polymer matrix, which effectively promoted the compatibility problem among the polymer matrix and the filler. The nanofillers were characterized by XRD, FT-IR, SEM and XPS. The composite membranes were prepared by the NIPs method. The antifouling and separation properties of the prepared mixed matrix membranes (MMMs) were investigated using positively charged dye (RHB) and negative charge bovine serum albumin (BSA) as model contaminants. The water flux of the pure membrane achieved 529.16 L/m2 h. When the addition amount of ZIF-8-NS was 0.1 %, the water flux of M4 (F-SPAEKS/ZIF-8-NS-0.1 %) could reach 838.84 L/m2 h. The retention rate of the BSA solution could reach 99.06 %, and the FRR value was kept at a high level (81.45 %). Meanwhile, the dynamic retention of M4 on the primary adsorption of the dye RHB could even reach 99.89 %. Therefore, the innovative design of the novel MMMs not only improved the flux, retention, and other separation properties but also enhanced their excellent adsorption capacity for RHB dyes. This result indicated that the nanofiller ZIF-8-NS provided an interesting reference for the study of ultrafiltration membranes.

An effective strategy to enhance phosphoric acid retention and proton conductivity stability: Construction of proton transfer channels with starch rather than H3PO4

To enhance the phosphoric acid (PA) retention as well as maintain high proton conductivity of phosphoric acid doped proton exchange membranes at high temperature, we successfully design a series of phosphoric acid doped biobased composite membranes by incorporation of starch and graphene oxide (GO) into poly arylene ether ketones (PAEK). Proton transfer channels should be mainly built through dense hydrogen bonds formed from massive oxygen-containing groups of starch mainchain, which is confirmed by Molecular dynamics (MD) simulation, FT-IR and XRD analysis. The dense hydrogen-bond structure could construct fast proton transfer channels with extreme low doping level (0.00484 molH3PO4). The excellent PA retention properties with almost unchanged proton conductivity at high temperature (200 °C) for 600 min indicates that PA molecules are firmly fixed into membranes. Thus, in this study, we suggest a novel strategy for stablizing proton conductivity at high temperature and improving PA retention properties of PA doped membranes, which is building dense hydrogen-bond structure with low PA doping level.Based on the results in this study and the Grotthuss proton transfer mechanism, dense hydrogen-bonds from oxygen-containing groups in polymer backbones should be more stable than hydrogen-bonds from massive H3PO4 molecules with high acid doping levels to promote proton conduction.

Introduction of Bifunctionalized UIO-66-NH2 for Highly Conductive and Long-Term Stable Fluorene-Based Sulfonated Poly(aryl ether ketone sulfone) PEMs

Introduction of Bifunctionalized UIO-66-NH₂ for Highly Conductive and Long-Term Stable Fluorene-Based Sulfonated Poly(aryl ether ketone sulfone) PEMs

Molecular-Level Modification of Sulfonated Poly(arylene ether ketone sulfone) with Polyoxovanadate-Ionic Liquid for High-Performance Proton Exchange Membranes.

In this work, a proton-conductive inorganic filler based on polyoxovanadate (NH4)7[MnV13O38] (AMV) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (EMIM TFSI) was synthesized for hybridization with sulfonated poly(aryl ether ketone sulfone) (SPAEKS) to address the "trade-off" between high proton conductivity and mechanical strength. The novel inorganic filler AMV-EMIM TFSI (AI) was uniformly dispersed and stable within the polymer matrix due to the enhanced ionic interaction. AI provided additional proton transport sites, leading to an elevated ion exchange capacity (IEC) and improved proton conductivity, even at low swelling ratios. The optimized SPAEKS-50/AI-5 (50 for degree of sulfonation of SPAEKS and 5 for weight percentage of AI filler) membrane exhibited the highest proton conductivity of 0.188 S·cm-1 at 80 °C with an IEC of 2.38 mmol·g-1. The enhancement of intermolecular forces improved the mechanical strength from 35 to 55 MPa and improved the elongation at break from 17 to 45%, indicating excellent mechanical properties. The hybrid membrane also demonstrated reinforced methanol resistance due to the hydrogen bonding network and blocking effect, making it suitable for direct methanol fuel cell (DMFC) applications, which exhibited a power density of 15.1 mW·cm-2 at 80 °C. The possibility of further functionalizing these hybrid membranes to tailor their properties for specific applications presents exciting new avenues for research and development. By modification of the type and distribution of fillers or incorporation of additional functional groups, the membranes could be customized to meet the unique demands of various energy storage and conversion systems, enhancing their performance and broadening their application scope. This work provides new insights into the design of polymer electrolyte membranes through inorganic filler hybridization.

Dual synergies of functionalized hydrophilic MOFs based poly (aryl ether ketone sulfone) ultrafiltration membranes: Electrostatic action and pore size screening

In this paper, amino monomer (4Am-PH) and the sulfonated poly (arylene ether ketone sulfone) involving amino groups (Am-SPAEKS) were successfully prepared by diazotization reaction and direct polycondensation, respectively. The polyethyleneimine-modified UiO-66-NH2 (P-MOFs) were prepared as fillers. Composite membranes were fabricated by incorporating different contents of P-MOFs into Am-SPAEKS polymer matrix using non-solvent-induced phase separation. The morphology, chemical structure and properties of the polymers, fillers and composite membranes were proved by FT-IR, 1H NMR, FE-SEM, XPS and etc. The final experimental results showed that the introduction of hydrophilic fillers, P-MOFs, substantially improved the hydrophilicity, water flux and antifouling capabilities of the membranes. The water contact angle decreased from 78.5° to 56.4°. The flux of water from a pure membrane was 333.68 L/m2 h. When the content of P-MOFs was 0.1 %, the water flux could attain to 830.23 L/m2 h, the retention rate of bovine serum albumin (BSA) solution could attain to 98.6 % and the flux recovery rate (FRR) values of the composite membrane remained high (86.1 %) for BSA solution. In addition, after three cycles, the pure water flux of the composite membrane could still attain 595.49 L/m2 h. The results demonstrated that P-MOFs have significant potential for utilization in the preparation of composite ultrafiltration membranes and provided an effective idea for the modification and design of other hydrophilic MOFs applied in the study area of ultrafiltration membranes.

Preparation of sulfonated poly(arylene ether ketone sulfone) PEMs with enhanced proton conductivity by introducing ionic liquid impregnated MOFs

In this research, sulfonated poly(arylene ether ketone sulfone) containing -COOH groups (C-SPAEKS) was chosen as the substrate, and ionic liquid functionalized MOFs (UiO-66-AS@ILs) were selected as fillers to prepare C-S-U-AS@ILs hybrid membranes (The term “C-S-U-AS@ILs” signifies C-SPAEKS with an incorporated ionic liquid functionalized UiO-66-AS@ILs). The UiO-66-AS@ILs and C-S-U-AS@ILs hybrid membranes were characterized by 1H NMR, FT-IR, PXRD and SEM. The prepared membranes exhibited suitable water uptake and swelling ratios, and the C-S-U-AS@ILs-5 % hybrid membrane possessed superior proton conductivity (0.197 S cm−1 at 90 °C) was much higher than C-SPAEKS (0.156 S cm−1 at 90 °C) and Nafion 117 (0.110 S cm−1 at 90 °C). Moreover, the C-S-U-AS@ILs-5 % hybrid membranes’ power density up to 474.24 mW cm−2, significantly higher than that of C-SPAEKS (220.88 mW cm−2) under the same conditions. These results reflect that the hybrid membranes exhibited superior properties and fit the standards of proton exchange membranes.

Novel soluble N-heterocyclic poly(aryl ether ketone)s containing pendant biphenyl groups performing excellent thermal and mechanical performance

The enhancement of thermal resistance and mechanical properties for the soluble poly(aryl ether ketone)s is an important research topic. Based on the idea of introducing twisted N-heterocyclic structure and utilizing the restriction of intramolecular chain rotation by bulky pendant groups, the thermo-resistance, mechanical properties, and surface properties of polymers are modulated while ensuring their solubility. A novel bisphenol-like monomer 1′,4-di(biphenyl)-6,6′-biphthalazin-1,4(2H,3H)-dione (DBBD) and corresponding N-heterocycle copoly (aryl ether ketone)s with pendant biphenyl groups (PDPEKs) are prepared. PDPEKs exhibit good thermal stability in air and nitrogen, and the glass transition temperature (Tg) is in the range of 288–347 °C. In addition, the storage modulus retention rate of PDPEKs reaches 60.6 % at 250 °C. PDPEKs exhibit good solubility in N-methylpyrrolidone and 1,1,2,2-tetrachloroethane, performing good film-formation properties. The tensile strength of PDPEKs films is between 102 and 121 MPa, the Young's modulus is between 2.01–2.30 GPa, and the water contact angle of PDPEKs is in the range of 79°–84°.

Impact of stacking sequence on the thermal and electrical properties of Poly (aryl ether ketone)/glassfiber/buckypaper composites

AbstractThe current market's imperative demand necessitates the research and development of advanced polymer composites, especially those incorporating nanofillers. Carbon nanotubes, in particular, have attracted significant attention within research and development for their potential in creating multifunctional composites. This study aims to evaluate the impact of incorporating carbon nanotube buckypapers (BP) on the thermal and electrical properties of poly (aryl ether ketone) (PAEK)/glass fiber (GF) composites. The BP was prepared through vacuum filtration and integrated into PAEK/GF composites with varying stacking sequences, followed by hot compression processing. The degradation behavior of the laminates was investigated using thermogravimetric analysis (TGA). The viscoelastic properties, evaluated by dynamic mechanical analysis (DMA), suggested an increase in stiffness with the inclusion of BP in two of the analyzed stacking sequences. Thermal conductivity, measured via the pulse laser method, showed results comparable to the base laminate (0.153 W/m·K). Meanwhile, electrical conductivity, assessed using the four‐point probe method in the in‐plane direction, revealed semiconductor properties, achieving a mean value of 3.162 S/cm for one of the samples, indicating electrical anisotropy within the multifunctional composite material.

Tandem one‐pot synthesis of block copolymers for anion exchange membranes

AbstractThe anion exchange membrane (AEM) suffered from poor mechanical properties and low ionic conductivity in fuel cells. Herein, a series of novel block fluorene‐contained poly(arylene ether ketone)s backbones are synthesized by a tandem one‐pot process and then grafted with alkyl chains to form comb‐shaped structure for preparing AEMs. The one‐pot synthesis of block copolymer avoids the multiple purifications of oligomers. The membranes' structure–property relationship is studied by changing the ratios of hydrophilic and hydrophobic segments. The designed comb‐shaped structures grafted on fluorene‐containing block backbones can widen the space between chains and form clear microphase separation patterns, as determined by atomic force microscope (AFM) and small angle x‐ray scattering (SAXS). Hence, resulting AEMs have a high ionic conductivity (117.4 mS cm−1, 80°C). Meanwhile, they also present low swelling rate (SR) from 12.76% to 18.51% at 30°C, 16.84% to 24.36% at 60°C, and 18.33% to 25.81% at 80°C. In addition, excellent mechanical properties, that is, an elongation at break of 29.63% and a tensile strength of 28.72 MPa, are achieved and showed the promise of as‐fabricated AEMs in fuel cell applications.

Conductivity-enhanced swelling-induced triphenylphosphine-functionalized adamantane-containing poly(aryl ether ketone) membranes for vanadium redox flow batteries

To develop highly conductive membranes for VRFB, triphenyl quaternary phosphonium cationic groups were introduced into unique adamantane-containing poly(aryl ether ketone) to prepare TAPEK membranes. The selective swelling-induced microphase separation strategy was also adopted to strengthen membrane conductivity. The quaternary phosphonium groups give the membrane the Donnan repulsion effect, so the TAPEK membrane exhibits low area resistance and a good barrier to cross-mixing vanadium ions. The TAPEK-100 membrane exhibited a low area resistance of 0.12 Ω cm−2, lower than the current state-of-the-art Nafion212 membrane (0.14 Ω cm−2). TAPEK membranes were used for VRFB for the first time, and the TAPEK-100 exhibited excellent energy efficiency in VRFB (EE=91.0 % at 80 mAcm−2, EE=85.1 % at 200 mAcm−2, EE=80.36 % at 280 mAcm−2, and EE=79.32 % at 300 mAcm−2). TAPEK membrane showed insufficient stability in in-situ and ex-situ stability tests. The battery efficiency of VRFB with TAPEK-90 membrane dropped significantly after more than 823 cycles in the cycling test. Given the high conductivity of TAPEK membranes, more work related to enhancing the stability of quaternary phosphonium groups-containing membranes needs further study.

Study on the Application Performance of Polymer Electrolyte Membrane Functionalized with Triethyl Phosphite-Modified Graphene Oxide in Fuel Cells.

In this paper, we successfully synthesize phosphoric acid functionalized graphene oxide (PGO) based on acid modification of graphene oxide. The composite membrane is further prepared by adding PGO into sulfonated poly(aryl ether ketone sulfone) containing carboxyl groups matrix (C-SPAEKS). The PGO as well as the composite membranes were characterized by a series of tests. The prepared composite proton exchange membranes (PEMs) have good mechanical and electrochemical properties. Compared to the C-SPAEKS membrane, the best composite membrane has a tensile strength of 40.7 MPa while exhibiting superior proton conductivity (110.17 mS cm-1 at 80 °C). In addition, the open-circuit voltage and power density of C-SPAEKS@1% PGO are 0.918 V and 792.17 mW cm-2, respectively. Compared with C-SPAEKS (0.867 V and 166 mW cm-2), it can be seen that our work has a certain effect on the improvement of the single cell performance. The above results demonstrate that the functionalized graphene oxide has greatly improved the electrochemical performance and even the overall performance of PEMs.

Enhanced high-temperature capacitive performance through introduction of polar groups in poly(aryl ether ketone) dielectric polymer

High-temperature poly(aryl ether ketone) dielectrics have attracted application prospects in the field of polymer film capacitors. However, the investigations on improving the capacitive properties of poly(aryl ether ketone) based on molecular structure design strategies were absent. Herein, a series of poly(aryl ether ketone) bearing phthalazinone moiety were synthesized, and the effect of chemical structures on the capacitive properties of the resultant polymers was investigated by experimental data and density functional theory calculation. The introduction of the sulfone group could not only improve the permittivity but also construct deep carrier traps to enhance the breakdown strength, leading to high discharge energy density (Ue) value of the poly(phthalazinone ether sulfone ketone) (PPESK). For the poly(phthalazinone ether nitrile ketone) (PPENK), the introduction of the nitrile group could improve the Ue at room temperature, but reduce the value at elevated temperatures. As a result, at room temperature, the maximum Ue of both the PPESK (4.56 J/cm3) and the PPENK (3.40 J/cm3) was higher than that of the PPEK (3.02 J/cm3). Notably, the maximum Ue of the PPESK reached 3.07 J/cm3 at 150 °C, which is twice that of commercially bi-oriented polypropylene (BOPP) film (1.5 J/cm3 at 70 °C). Additionally, at the electric field of 200 MV/m and 150 °C, the PPESK films exhibited the Ue of 0.72 J/cm3 with charge-discharge efficiency (η) of 97.2 %, which was obviously superior to those of the BOPP (Ue = 0.4 J/cm3 with η of 96 % at 70 °C). This study presents an in-depth analysis regarding the relationship between the sulfone and nitrile groups and the capacitive performance of poly(aryl ether ketone) bearing phthalazinone moiety, which is informative for designing high-temperature dielectric polymers.

Poly (arylene ether ketone sulfone)s functionalized with diethylenetriamine-modified graphene oxide as proton exchange membranes for fuel cells

In this paper, composite proton exchange membranes (PEMs) based on functionalized graphene oxide (NGO) and carboxylated sulfonated poly aryl ether ketone sulfone (C-SPAEKS) were successfully synthesized. Functionalized graphene oxide was synthesized using graphene oxide as a substrate, and then diethylenetriamine (DETA) was chemically bound to the graphene oxide. The 1H NMR, FT-IR and XPS were used to characterize the NGO and composite membranes. The results show that the composite membranes have good proton conductivity, dimensional stability and electrochemical performance. The swelling rate of all the composite membranes was less than 18%, which indicates that they have good dimensional stability. Compared to C-SPAEKS membrane (34.8 mS cm-1 at 20 °C, 109.8 mS cm-1 at 90 °C), the proton conductivities of C-SPAEKS/GO-0.75 membrane (52.4 mS cm-1 at 20 °C, 171.1 mS cm-1 at 90 °C) were significantly improved. Meanwhile, the C-SPAEKS/NGO-0.75 achieved peak power density of 407.77 mW cm-2 at high OCV of 0.9576 V. Such a result is much superior to the C-SPAEKS membrane (0.8973 V, 190.72 mW cm-2) and the Nafion 117 (0.99 V, 302 mW cm-2), and demonstrated good single-fuel cell performance. In summary, it can be well concluded that functionalized GO as filler makes an significant contribution in improving the overall performance of the composite membranes.

Low-Temperature Deposited Amorphous Poly(aryl ether ketone) Hierarchically Porous Scaffolds with Strontium-Doped Mineralized Coating for Bone Defect Repair.

In recent years, the demand for clinical bone grafting has increased. As a new solution for orthopedic implants, polyether ether ketone (PEEK, crystalline PAEK) has excellent comprehensive performance and is practically applied in the clinic. In this research, a noteworthy elevated scheme to enhance the performance of PEEK scaffolds is presented. The amorphous aggregated poly (aryl ether ketone) (PAEK) resin is prepared as the matrix material, which maintains high mechanical strength and can be processed through the solution. So, the tissue engineering scaffolds with multilevel pores can be printed by low-temperature deposited manufacturing (LDM) to improve biologically inert scaffolds with smooth surfaces. Also, the feature of PAEK's solution processing is profitable to uniformly add the functional components for bone repair. Ultimately, A system of orthopedic implantable PAEK material based on intermolecular interactions, surface topology, and surface modification is established. The specific steps include synthesizing PAEK that contain polar carboxyl structures, preparing bioinks and fabricating scaffolds by LDM, preparation of scaffolds with strontium-doped mineralized coatings, evaluation of their osteogenic properties in vitro and in vivo, and investigation on the effect and mechanism of scaffolds in promoting osteogenic differentiation. This work provides an upgraded system of PAEK implantable materials for clinical application.

High-performance aqueous organic redox flow battery enabled by sulfonated anthrone-containing poly(aryl ether ketone) membranes

Aqueous organic redox flow batteries (AORFBs) have become a promising electrochemical energy storage technology due to their low cost, high safety, and sustainability. As key components of emerging AORFBs, membranes face challenges such as scarcity of available membranes and high prices. Moreover, currently available membranes have low battery performance because these membranes are not optimized for specific AORFBs. In this work, a new cation exchange membrane sulfonated anthrone-containing poly(aryl ether ketone) (SAnPEK) membrane was prepared for the first time and achieved significantly improved performance in (SPr)2V/K4[Fe(CN)6] AORFBs. SAnPEK membrane has excellent selectivity and high mechanical strength (>50 MPa). SAnPEK membranes exhibit high conductivity in 1 M NH4Cl solution. For example, SAnPEK-4 membranes exhibit low surface resistance (0.176 Ωcm2) in 1 M NH4Cl solution, which is significantly better than Nafion117 (1.02 Ωcm2) and Nafion212 membranes (0.276 Ωcm2). SAnPEK membrane exhibtis impressive performance in (SPr)2V/K4[Fe(CN)6] AORFB. The SAnPEK-4 membrane exhibits high coulombic efficiency (CE) and excellent energy efficiency (EE) (CE = 99.1 %, EE = 83.4 % at 100 mAcm−2), and the EE for SAnPEK-4 membrane is significantly better than that for the Nafion117 membrane (CE = 99.3 %, EE = 62.4 %) and Nafion212 membrane (CE = 99.1 %, EE = 80.8 %, 100 mAcm−2). In addition, the SAnPEK-4 membrane exhibits excellent cycle stability over 3000 cycles in AORFB. As a high-performance, easy-to-prepare, low-cost cation exchange membrane, SAnPEK membranes have good application potential in AORFBs.

Isosorbide-based Poly(arylene ether) biopolymer membranes for gas separation

Efforts to utilize biopolymer membranes to diminish the carbon footprint of separation processes are ongoing. Herein, we report the fabrication of isosorbide (ISB)-based poly(arylene ether) biopolymer membranes, including ISB-based poly(arylene ether sulfone) (I-PAES) and ISB-based poly(arylene ether ketone) (I-PAEK) for gas separation. The robust mechanical properties and amorphous nature of ISB-based biopolymers allow for their application to gas separations. Both positron annihilation lifetime spectroscopy (PALS) and free volume analysis using density measurements reveal that replacing bisphenol A (BPA) in polysulfone (PSF) with ISB results in a significant reduction in free volume owing to the absence of bulky dimethyl groups and the presence of polar aliphatic ether groups. Substituting the sulfone group for a ketone group further decreased free volume. Solid-state CP/MAS 13C NMR analysis discloses that substituting ISB and replacing sulfonyl moieties with carbonyl groups restricts the rotational motion of internal rings, resulting in inhibited gas diffusion. Consequently, the I-PAEK membrane exhibited H2/CO2 and H2/CH4 selectivities more than three times and five times higher, respectively, compared to the PSF counterpart. Our present study demonstrates the feasibility of ISB-based poly(arylene ether) biopolymer membranes for gas separation.