Aryl Ether Ketone Research Articles

Study of novel nonlinear optical material based on Poly(aryl ether ketone) and its application in SHG imaging

Novel nonlinear optical polymer based on poly(aryl ether ketone) was designed and prepared. Such kind of materials showed excellent water solubility and thermal properties, its onset decomposition temperature can reach 314 °C; glass transition temperature can reach 170 °C. Though the nonlinear optical coefficients (d33) is not very large at 1310 nm, just about 13.9 pm/V; such kind of materials show us a low absorption spectral window at red and infrared light area (wavelength longer than 650 nm). Under the laser of 1310 nm, the morphology of the poled films can be detected by second harmonic generation (SHG) scanning microscopy.

Comparative potential assessment of solid lubricants on the performance of poly aryl ether ketone (PAEK) composites

Poly aryl ether ketone (PAEK) is known as a high performance polymer superior to PEEK (poly ether ether ketone) in many aspects such as temperature stability, tribo-performance etc. Recently few efforts are put to enhance the tribo-potential of PAEK by developing composites containing short fibers of carbon and glass and most favored lubricants such as graphite, PTFE (poly tetrafluoroethylene), hexa boron nitride (hBN) etc. The wear and friction got significantly reduced to the extent that the composites showed very high potential as bearing materials for harsh operating conditions.Mica and boric acid (BA) are known as very good solid lubricants (SLs) with layer lattice structures. Potassium titanate (KT) powder also has been very popular ingredient of friction materials responsible for increasing wear resistance (WR) and reducing friction fluctuations. It is, however, never explored in bearing materials for enhancing tribo-potential.Keeping this in view, a series of composites was prepared by injection molding with identical parent composition but differing in type of solid lubricants (hBN, KT, BA and Mica). The tribo-performance was evaluated in adhesive wear mode on tribometer under severe operating conditions (700–900 N, velocity 1.63–3.5m/s). Composites exhibited very low specific wear rates (K0) (2–8×10–16m3/Nm) and very low coefficient of friction (µ) (0.04–0.08), which decreased with load and velocity. KT proved to be the most performing filler, while Mica was least effective followed by BA. Worn surface analysis by SEM (Scanning electron microscopy) and EDAX (energy dispersive x-ray) helped to understand wear mechanisms.

In situ surface crosslinked tight ultrafiltration membrane prepared by one-step chemical reaction-involved phase inversion process between activated PAEK-COOH and PEI

Carboxylated cardo poly(arylene ether ketone)s (PAEK-COOH) is a thermally stable and hydrophilic membrane fabrication material. Herein, PAEK-COOH was employed as membrane material, being dissolved in N-methyl-2-pyrrolidone (NMP) and 1,4-dioxane (DO) mixed solvent and activated by adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) to prepare polymer casting solution. Then the activated polymer film was immersed into polyethylenimine (PEI) aqueous solution that served as coagulation bath for taking the one-step chemical reaction-involved phase inversion process. As illustrated by the SEM images, the fabricated crosslinked tight ultrafiltration membrane had a dense and integrally skinned separation skin layer. Chemical composition and hydrophilicity of membrane surface were studied by ATR-FTIR and water contact angle, respectively. Those results revealed that, via the in situ crosslinking of activated carboxylic acid group and PEI along with the phase inversion process, the PEI molecules had been covalently bonded onto membrane surface and resulted in the increase of membrane hydrophilicity. The optimized membrane had a molecular weight cut off (MWCO) of 12.7kDa and an isoelectric point of 7.4, indicating which is slightly positively charged. The one-step chemical reaction involved phase inversion between reactive macromolecules, i.e., activated PAEK-COOH original polymer film and PEI crosslinker in coagulant, was an efficient and convenient approach for fabrication of highly permeable and selective tight ultrafiltration membranes. Membrane had a dye solution permeability of 80–84Lm−2h−1bar−1 and Congo red (CR) rejection of 99.9% in 100h long-term filtration testing, being capable for dye removal from textile wastewater.

Correction to: β-Adrenergic Signaling Inhibits Gq-Dependent Protein Kinase D Activation by Preventing Protein Kinase D Translocation and Multimodal SHG-2PF Imaging of Microdomain Ca2+-Contraction Coupling in Live Cardiac Myocytes.

HomeCirculation ResearchVol. 120, No. 8Correction to: β-Adrenergic Signaling Inhibits Gq-Dependent Protein Kinase D Activation by Preventing Protein Kinase D Translocation and Multimodal SHG-2PF Imaging of Microdomain Ca2+-Contraction Coupling in Live Cardiac Myocytes Free AccessCorrectionPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessCorrectionPDF/EPUBCorrection to: β-Adrenergic Signaling Inhibits Gq-Dependent Protein Kinase D Activation by Preventing Protein Kinase D Translocation and Multimodal SHG-2PF Imaging of Microdomain Ca2+-Contraction Coupling in Live Cardiac Myocytes Originally published14 Apr 2017https://doi.org/10.1161/RES.0000000000000143Circulation Research. 2017;120:e32This article corrects the followingβ-Adrenergic Signaling Inhibits Gq-Dependent Protein Kinase D Activation by Preventing Protein Kinase D TranslocationMultimodal SHG-2PF Imaging of Microdomain Ca2+-Contraction Coupling in Live Cardiac MyocytesIn the article by Nichols et al, “β-Adrenergic Signaling Inhibits Gq-Dependent Protein Kinase D Activation by Preventing Protein Kinase D Translocation,” which published in the April 25, 2014 issue of the journal (Circ Res. 2014;114:1398–1409. DOI: 10.1161/CIRCRESAHA.114.303870.), and in the article by Awasthi et al, “Multimodal SHG-2PF Imaging of Microdomain Ca2+-Contraction Coupling in Live Cardiac Myocytes,” which published in the January 22, 2016 issue of the journal (Circ Res. 2016;118:e19-e28. DOI: 10.1161/CIRCRESAHA.115.307919.), corrections were needed.In both articles, the author Brittani Wood has been changed to Brent M. Wood.These corrections have been made to the current online version of the articles, which are available at http://circres.ahajournals.org/content/114/9/1398 and http://circres.ahajournals.org/content/118/2/e19, respectively. Previous Back to top Next FiguresReferencesRelatedDetailsCited By Liu Y, Liu H, Qin G, Gui Z, Yang Z and Liu J (2017) Study of novel nonlinear optical material based on Poly(aryl ether ketone) and its application in SHG imaging, Optical Materials, 10.1016/j.optmat.2017.06.032, 72, (392-396), Online publication date: 1-Oct-2017. Related articlesβ-Adrenergic Signaling Inhibits Gq-Dependent Protein Kinase D Activation by Preventing Protein Kinase D TranslocationC. Blake Nichols, et al. Circulation Research. 2014;114:1398-1409Multimodal SHG-2PF Imaging of Microdomain Ca2+-Contraction Coupling in Live Cardiac MyocytesSamir Awasthi, et al. Circulation Research. 2016;118:e19-e28 April 14, 2017Vol 120, Issue 8 Advertisement Article InformationMetrics © 2017 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000143PMID: 28408457 Originally publishedApril 14, 2017 PDF download Advertisement

Integrated antimicrobial and antifouling ultrafiltration membrane by surface grafting PEO and N-chloramine functional groups

Ultrafiltration membranes with integrated antimicrobial and antifouling properties were fabricated using an engineering thermoplastic (carboxylated cardopoly(aryl ether ketone, PEK-COOH). Different molecular weights of PEO (Mw: 120, 350, 550) were grafted to the PEK-COOH membrane surface via EDC/NHS methodology. N-chloramine modified membranes then were prepared by simple exposure to dilute sodium hypochlorite solution. The surface grafting processes were all performed in water (i.e. without organic solvent). With this surface modification, the hydrophilicity of membranes improved significantly and the pure water flux increased compared to the unmodified PEK-COOH membrane. Furthermore, the PEO and N-chloramine modified membranes were resistant not only to both protein adsorption and bacterial adhesion, but also to microbial proliferation. The results of this work suggest that PEO and N-chloramine modified membranes are promising as fouling-resistant membranes.

Ionic conducting membranes based on new sulfonated poly(arylene ether ketone)s for fuel cell applications

ABSTRACTThe synthesis and characterization of new di‐ and tetra‐sulfonated ether diketone monomers are described. From these monomers, a wide series of sulfonated poly(arylene ether ketone)s (SPAEK) are synthesized by varying the sulfonic acid repartition along the polymer backbones. Their chemical structures are thoroughly characterized by NMR. From these polymers tough membranes are obtained from solution casting method and their water uptake, ionic conductivity, and water/gas permeation properties are determined and compared with those of Nafion membrane. Preliminary fuel cell tests show that SPAEK membranes are promising candidates for fuel cell application. This work brings new insights concerning the beneficial effects of introducing densely sulfonated monomers in a polyarylether macromolecular structure along with fluorinated groups improving conductivity while reducing unwanted excessive swelling. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 771–777

Poly(arylene ether ketone) with pendant pyridinium groups for alkaline fuel cell membranes

Using the step-growth polycondensation reaction, poly(arylene ether ketone) (PAEK) and activated poly(arylene ether ketone)-NHS intermediates (PAEK-N) were synthesized. PAEK-NHS intermediates with pyridinium groups (PAEK-PYR) were obtained by adding different amounts of PYR groups. The successful syntheses of PAEK, PAEK-N, and PAEK-PYR were confirmed by nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. Several important membrane properties (e.g., ionic exchange capacity (IEC), water uptake, anion conductivity, and thermal and mechanical stability) were investigated for their applications in alkaline fuel cells. Water uptake, swelling ratio, anion conductivity, and IEC increased with increasing PYR contents, while the mechanical properties decreased. Among a series of prepared membranes, the PAEK-PYR100 and PAEK-PYR125 membranes showed IEC and anion conductivity values that were higher than those of a commercial AHA membrane. Also, all of the prepared membranes were thermally stable up to 255 °C and show excellent chemical stability in alkaline conditions.

Influence of hydrophobic block length and ionic liquid on the performance of multiblock poly (arylene ether) proton exchange membrane

The present article includes the synthesis of nanophase-separated poly (arylene ether) multiblock copolymers. A series of poly (arylene ether sulfone) hydrophobic oligomers consisting of bisphenol-A groups were reacted with a disulfonated poly (arylene ether ketone) hydrophilic oligomer containing 4, 4′- bis (4-hydroxyphenyl) valeric acid moieties to prepare multiblock copolymers. The synthesized oligomers and block copolymers were characterized by using FT-IR, 1H NMR spectra and Gel Permeation Chromatography. The membranes obtained by solution casting method exhibited good dimensional and thermal stability. The increase in hydrophobic block length reduced the water uptake and methanol permeability of the membranes. The complexation of multiblock copolymer with ionic liquid (1-butyl-3-methyl-imidazolium tetrafluoroborate) resulted into novel hybrid membranes. These showed enhanced proton conductivity without affecting the mechanical stability. The Fenton's test revealed that the hybrid multiblock membranes were stable towards radical oxidation. The hydrophobic-hydrophilic phase separation was characterized by using tapping mode Atomic Force Microscopy (AFM). The hybrid membranes showed better fuel cell performance than that of pristine membrane.

Ionic crosslinking of imidazolium functionalized poly(aryl ether ketone) by sulfonated poly(ether ether ketone) for anion exchange membranes.

Two N3-substituted imidazoles 1,2-dimethylimidazole and 1-butyl-2-methylimidazole were chosen to functionalize poly(aryl ether ketone), respectively. The generated imidazolium cations could electrostatically react with sulfonate ions of the sulfonated poly(ether ether ketone) forming the ionic crosslinking structure of the membranes. The changes in crosslinking degree and the alkyl chain-length on N3 site of the imidazoliums could highly affect the properties of the anion exchange membranes (AEMs). The AEMs functionalized by 1-butyl-2-methylimidazole exhibited superior properties compared to those functionalized by 1,2-dimethylimidazole according to the tolerance tests of the AEMs towards hot alkaline solutions. After exposed to 1M KOH at 80°C for 200h, the 1-butyl-2-methylimidazole modified AEMs maintained the ion exchange capacity of above 85%, the conductivity of about 70%, and the tensile stress at break of around 80%, respectively. The hydrophile-lipophile balance of the polymer membranes was calculated and proposed to better understand the correlation between structures and properties of the AEMs. The degradation of the imidazolium functional groups of the AEMs under the attack of hydroxide ions was evidenced by FT-IR analysis.

Pyrene-functionalized PAEKs prepared from C–H borylation and Suzuki coupling reactions for the dispersion of single-walled carbon nanotubes

The distribution of pyrene-functionalized single-walled carbon nanotubes (f-SWCNTs) within PEEK was investigated. Poly(aryl ether ketone)s with various contents of pyrene (PAEK-Py) were synthesized through iridium-catalyzed C–H borylation followed by Suzuki coupling. PAEK-Pys were characterized using UV–Vis, 1H NMR and gel permeation chromatography. The polymers were then used for non-covalent functionalization of pristine single-walled carbon nanotubes (SWCNTs). The functionalization efficiency was assessed by measuring the SWCNT dispersibility in chloroform. The maximal dispersion effect of the SWCNTs was obtained with the optimized conditions. In the presence of PAEK-Py-10, the dispersibility was as high as 272 mg L−1, and the dispersions containing 1.25 mg mL−1 of PAEK-Py-10 were very stable for 24 h with no solid deposits observed after being centrifuged at 5000 rpm for 15 min. Finally, pristine single-walled carbon nanotubes (SWCNTs) and non-covalently functionalized single-walled carbon nanotubes (f-SWCNTs) were used to prepare poly(ether ether ketone) (PEEK) composites (SWCNT/PEEK and f-SWCNT/PEEK) via co-blending in solution. The SWCNTs in the f-SWCNT/PEEK composite were dispersed better than those in the SWCNT/PEEK composite. These results suggest that PAEK-Pys could be used as an excellent dispersant for subsequent preparation of PEEK/SWCNT composites.

In-situ template synthesis of a polymer/nanoparticles nanohybrid using hyperbranched poly(aryl ether ketone)

Nanostructured ZnS/hyperbranched poly(aryl ether ketone) (ZnS/HPAEK) hybrid material was synthesized by a facile hydrothermal reaction of HPAEK–Zn(Ac)2⋅2H2O in DMF. ZnS nanoparticles were prepared by heterogeneous stirring of carboxylic-functionalized hyperbranched poly(aryl ether ketone) (PCA-HPAEK)–Zn(Ac)2⋅2H2O in DMF with DMF solution of thiourea. The obtained nanocomposites were characterized using various techniques such as Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), UV–Vis spectroscopy and photoluminescence. FTIR and HRTEM studies confirmed the formation of ZnS QDs with small particle size. And the results of photoluminescence measurement showed that the nanocomposites exhibited distinct luminescence properties. Differential scanning calorimetry and thermogravimetric analysis studies indicated that the nanocomposites exhibited excellent heat resistance. In general, a new ZnS/PCA-HPAEK nanohybrid was synthesized without ligand exchange, and had good optical properties and excellent heat resistance.

Transparent conductive polymers for laminated multi-wire metallization of bifacial concentrator crystalline silicon solar cells with TCO layers

Replacing expensive silver with inexpensive copper for the metallization of silicon wafer solar cells can lead to substantial reductions in material costs associated with cell production. A promising approach is the use of multi-wire design. This technology uses many wires in the place of busbars, and the copper wires are “soldered” during the low-temperature lamination process to the fingers (printed or plated) or to the transparent conductive oxide (TCO) layer, e.g. in the case of the a-Si:H/c-Si heterojunction cells. Here we describe a solar cell design in which wires are attached to TCO layers using transparent conductive polymer (TCP) films. To this end, we have synthesized a number of thermoplastics, poly(arylene ether ketone) copolymers (co-PAEKs), containing phthalide in their main chain. The fraction of phthalide-containing units in the copolymers was p=3, 5, 15, and 50mol%. With increasing p, the peak strain temperature of the co-PAEKs rises from 205 to 290°C and their optical band gap and refractive index increase from 3.12 to 3.15eV and from 1.6 to 1.614, respectively. The copolymers have a negligible absorption coefficient in the wavelength range 400–1100nm. When exposed to an excess pressure of 1atm or above, co-PAEK films less than 30µm in thickness undergo a transition from a dielectric to a conductive state. The resistivity (ρС) of wire/TCP/TCO (ITO=In2O3:Sn and IFO=In2O3:F) contacts ranges from 0.37 to 1.43mΩcm2. The polymer with the highest phthalide content (p=50mol%) has the lowest ρС. The average work of adhesion per unit area determined by pulling off the wires from the polymer surface depends on both the phthalide content of the co-PAEKs and their reduced viscosity, ranging from 14.3 to 43.5N/cm. The highest value was obtained for the co-PAEK with p=50mol%. We have fabricated low-concentration bifacial IFO/(n+pp+)Cz-Si/ITO solar cells with a wire contact grid attached to IFO and ITO using a co-PAEK film. The efficiency of the best cell under 1× to 7× front/rear illumination was determined to be 18.3–18.9%/15.0–15.6%.

Poly(2,6-dimethyl-1,4-phenylene oxide) blends with a poly(arylene ether ketone) for gas separation membranes

Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) is utilized for gas separation membranes. It has a relatively high free volume with high gas permeabilities but suffers from low selectivities. PPO polymers with Mn's from 2000 to 22,000 g/mole were synthesized and blended with a poly(arylene ether ketone) derived from bisphenol A and difluorobenzophenone (BPA-PAEK). DSC showed that the blends with all but the lowest molecular weight PPO had two Tg's, thus suggesting that two phases were present. The ketone carbon and benzylic methyl groups on the BPA-PAEK and the PPO polymers crosslinked upon exposure to UV light. The gel fractions after UV exposure were high and the tensile properties were similar to the PPO control polymer that is currently used as a gas separation membrane. The crosslinked blends had improved gas selectivities over their linear counterparts. The 90/10 wt/wt 22k PPO/BPA PAEK crosslinked blends gained the most O2/N2 selectivity and maintained a high permeability.

Organic-inorganic composite membrane based on sulfonated poly (arylene ether ketone sulfone) with excellent long-term stability for proton exchange membrane fuel cells

Organic-inorganic composite membranes based on sulfonated poly (arylene ether ketone sulfone) (SPAEKS) and 1-ethyl-3-methyl imidazolium phosphotungstate (PWA-IL) have been prepared. PWA-IL with three imidazole cations per unit is prepared successfully through molecular modification of phosphotungstic acid with ionic liquid (IL). The obtained PWA-IL is introduced into SPAEKS matrix aiming to enhance the proton conductivity and decelerate the leakage of ionic liquid. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and scanning electron microscope (SEM) are used to characterize and confirm the interaction between PWA-IL and SPAEKS. Higher degree of sulfonation benefits both dispersion and retention of PWA-IL in the SPAEKS matrix significantly. In particular, the obtained SPAEKS-80/PWA-IL membrane shows excellent long-term stability with 98.4% of PWA-IL residue after 132h in water due to the intensely interaction between SPAEKS and PWA-IL. It is found that PWA-IL causes a higher IEC value, resulting in higher proton conductivity compared to pristine SPAEKS membranes. Simultaneously, the PWA-IL plays a positive role in improving methanol resistance. The individual membrane SPAEKS-80/PWA-IL exhibits good proton conductivity (0.127Scm−1) under fully hydrated conditions at 80°C.

Poly Aryl Ether Ketones (PAEKs) and carbon-reinforced PAEK powders for laser sintering

This paper discusses various methods of fabrication of plain and carbon-reinforced composite powders, as well as a range of powder characterisation test methods suitable for defining powders for laser sintering. Two milling processes (based on disc blades and rotatory cutting knives) were used as methods of fabrication of powders, starting from injection moulding granule grades, for comparison with current powders obtained directly from polymerisation processes. It was found that the milling process affects the particles properties. The rotary milling produced powders with superior properties in comparison with the disc milling method. Tests including particle size distribution, angle of repose, aspect ratio, sphericity and roundness of particles were employed to compare and assess the suitability of powders for laser sintering. The Brunauer–Emmett–Teller test was identified as a useful method to define surface roughness and porosity of the particles. The carbon fibre (Cf) Poly Ether Ketone (PEK) granules milled well and after an additional sieving process created a good quality powder. This is the first attempt to investigate properties of PEK powder with encapsulated Cf and follow their sintering profile through hot-stage microscopy. It is expected that this type of composite powder will create isotropic structures in comparison with the highly anisotropic properties given by the known dry mix composite powders, currently used in laser sintering.

Tight ultrafiltration membrane: Preparation and characterization of thermally resistant carboxylated cardo poly (arylene ether ketone)s (PAEK-COOH) tight ultrafiltration membrane for dye removal

Cardo poly (arylene ether ketone)s bearing hydrophilic carboxylic acid groups (PAEK-COOH) was successfully synthesized by condensation polymerization of 2-[bis(4-hydroxyphenyl)methyl] benzoic acid and 4,4′-bisfluorodiphenylketone. TGA and DSC analyses demonstrated that the material has an initial decomposition temperature and glass transition temperature of 360°C and 220°C respectively, which revealed the excellent thermal stability of PAEK-COOH. Then PAEK-COOH was employed to fabricate tight ultrafiltration membrane by the nonsolvent induced phase inversion process (NIPS). The water contact angle of the prepared membrane is 61.5°, indicating its good hydrophilicity. The PAEK-COOH tight ultrafiltration membrane possesses a pure water flux of 119.6±2.6Lm−2h−1, dye permeation flux of 100.9±4.3Lm−2h−1 and rejection of 99.8±0.33% for Congo red at dye concentration of 100ppm and operation pressure of 0.4MPa. Membrane has a molecular weight cut off of 9260Da and gives complete penetration of monovalent inorganic salt NaCl but a slight rejection of divalent inorganic salt Na2SO4 (less than 10%). Thus, the membrane could be used in the decolorization of wastewater or fractionation of dye and salt mixture for dye purification. The membrane also exhibits excellent antifouling performance and anti-dye adsorption properties with a flux recovery ratio of 91.5% for BSA and dye adsorption rate below 5.0% for four kinds of studied dyes, respectively.

Correlation of the polymer hydrophilicity and membrane fabrication process on the properties of asymmetric membranes in a vapor‐induced phase‐inversion process

ABSTRACTIn this study, we sought a better understanding of how the hydrophilicity of a polymer affects the morphology and performance of membranes. Three types of polymer with different hydrophilicity solution systems were considered: poly(aryl ether ketone) bearing a hydroxyl group (PEK–OH‐100) with N,N‐dimethylformamide (DMF); poly(aryl ether ketone) bearing a 50% fraction hydroxyl group with DMF, and cardo poly(aryl ether ketone) with DMF. These systems were used to investigate the evolution of the morphology and variation in performance versus a change in the hydrophilicity of the polymer. In addition, the fundamental thermodynamic influence of the solution systems on the phase‐inversion process was investigated by cloud‐point measurement and Hansen solubility parameter theory to determine the role of polymer hydrophilicity on the stability of the polymer solution in humid surroundings. The performance of the membranes was tested via testing of the pure water flux, porosity, and rejection of bovine serum albumin (BSA) with respect to variations in the polymer hydrophilicity, evaporation time, relative humidity, and molecular weight of the polymer. The resulting optimal membrane exhibited a flux of 329.3 L m−2 h−1 and a 99.3% rejection of BSA at a relative humidity of 90% and an evaporation time of 3 s. The hydrophilic PEK–OH‐100 membranes have promising applications in protein separation and the porous support of reverse‐osmosis membranes and so on. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44701.

Chemically stable thioether cross-linked membranes derived from sulfonated poly(arylene ether ketone)s for direct methanol fuel cells

A series of thioether cross-linked membranes based on sulfonated poly(arylene ether ketone)s containing propenyl groups were prepared to solve the problem of high methanol permeability for proton electrolyte membrane in direct methanol fuel cells (DMFCs). For this purpose, 4,4′-thiobisbenzenethiol was selected as cross-linker, and the cross-linked structure was formed via thiol-ene click chemical reaction between propenyl and thiol groups. Compared with pristine membrane, the thioether cross-linked membranes exhibited improved mechanical properties and dimensional stabilities. As the cross-linker increased, the swelling ratio decreased from 11.01% to 8.64% at 20°C and from 15.18% to 10.69% at 80°C. Furthermore, the modified membranes exhibited reduced methanol permeability coefficients (down to 4.03 × 10−7 cm2 s−1), which was nearly half of the pristine membrane (7.66 × 10−7 cm2 s−1). Due to the thioether units, the cross-linked membranes showed enhanced oxidative stabilities, and the longest elapsed time in Fenton’s reagent was 225 min, which was 2.5 times longer than that of pristine polymeric membrane. Although the proton conductivity decreased upon the addition of cross-linker agent, the selectivity value increased due to the lower methanol permeability. Thus, all the results implied that the thioether cross-linked membranes were promising alternative materials for DMFCs application.

Preparation and characterization of an antibacterial ultrafiltration membrane with N-chloramine functional groups

In this study, a cardo poly(aryl ether ketone) ultrafiltration membrane containing an N-chloramine functional group (PEK-N-Cl membrane) was easily obtained via exposure of a cardo poly(aryl ether ketone) ultrafiltration membrane (PEK-NH membrane) to dilute sodium hypochlorite solution. The chlorination process did not harm membrane performance. In addition, the PEK-N-Cl membrane was stable in both air and water. The PEK-N-Cl membrane exhibited excellent antimicrobial properties against both Gram-negative and Gram-positive bacteria (i.e. E. coli and Bacillus subtilis, respectively). The PEK-N-Cl membrane provided 94.2% and 100% reduction of E. coli and Bacillus subtilis, respectively, within 30min of contact times. Moreover, nearly 100% of the E. coli was killed after 2h during the filtration process for the PEK-N-Cl membrane. In addition, the water flux decreased by 42% for the PEK-N-Cl membrane compared to 77.6% for the PEK-NH membrane after filtration of the E. coli solution and incubation on LB nutrient agar plate, indicating that the PEK-N-Cl membrane enhibits antifouling. Furthermore, the PEK-N-Cl membrane is recyclable via subsequent exposure to a sodium hypochlorite solution.

Durability of Sulfonated Phenylene Poly(Arylene Ether Ketone) Semiblock Copolymer Membrane in Wet-Dry Cycling for PEFCs

The mechanical durability of sulfonated poly (phenylene) (SPP) membrane, used for polymer electrolyte fuel cells (PEFCs), is evaluated by the United States Department of Energy (USDOE) stress protocol involving wet-dry cycling, and the degradation is analyzed specifically by comparing with sulfonated poly(arylene ether ketone) (SPK) membrane. Initially, the SPP membrane exhibits 2-fold higher stiffness and 50% lower dimensional change ratio than the SPK membrane. In durability cycling, the SPP membrane lasts more than 20,000 wet-dry cycles without mechanical failure, which is more than 5-fold better durability than that for the SPK membrane. Higher mechanical strength and lower dimensional change can reduce both irreversible membrane deformation and mechanical stress attributed to the membrane swelling and shrinking. In post-test analyses, the SPP membrane is found to rupture in the peripheral region of the membrane electrode assemblies. The SPP membrane maintains only 10% of the elongation at break in the peripheral region but 50% in the electrode region, compared with the pristine condition. It is most likely that the membrane deteriorates in the peripheral region due to stress concentration by cell compression and membrane deformation during wet-dry cycling. (185 words)