Proton-exchange Sulfonated Poly（ether ether ketone）/Sulfonated Phenolphthalein Poly（ether sulfone） Blend Membranes in DMFCs

A sulfonated poly（ether ether ketone） （SPEEK） membrane with fairly high degree of sulfonation （DS） swells excessively and even dissolves at high temperature. To solve these problems, sulfonated phenolphthalein poly（ether sulfone） （SPES-C, DS= 53.7%） is blended with the SPEEK matrix （DS= 55.1%, 61.7%） to prepare SPEEKJSPES-C blend membrane. The decrease in swelling degree and methanol permeability of the membrane is dose-dependent. Pure SPEEK （DS = 61.7%） membrane dissolves completely in water at 70℃, whereas the swelling degree of the SPEEK （DS = 61.7%）/SPES-C （40%, by mass） membrane is 29.7% at 80℃. From room temperature to 80℃, the methanol permeability of all SPEEK （DS = 55.1%）/SPES-C blend membranes is about one order of magnitude lower than that of Nafion 115. At higher temperature, the addition of SPES-C polymer increases the dimensional stability and greater proton conductivity can be achieved. The SPEEK （DS = 55.1%）/SPES-C （40%, by mass） membrane can withstand temperatures up to 150℃. The proton conductivity of SPEEK （DS = 55.1%）/SPES-C （30%, by mass） membrane approaches 0.16 S·cm^-1, matching that of Nafion 115 at 140℃ and 100% RH, while pure SPEEK （DS = 55.1%） membrane dissolves at 90℃. The SPEEK/SPES-C blend membranes are promising for use in direct methanol fuel cells because of their good dimensional stability, high proton conductivity, and low methanol permeability.

Synthesis and characterization of quaternized poly(phthalazinone ether sulfone ketone)for anion-exchange membrane

Chloromethylated poly（phthalazinone ether sulfone ketone） （CMPPESK） was prepared from poly（phthalazinone ether sulfone ketone） （PPESK） using chloromethyl octyl ethers （CMOE） with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone （NMP）, N,N-dimethylacetamide （DMAc） and chloroform. Quaternized poly（phthalazinone ether sulfone ketone） （QAPPESK） was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance, which was only partly soluble in sulfuric acid （98%） and swollen in N,N-dimethylformamide （DMF）. The vanadium redox flow battery （V-RFB） using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.

Proton-Exchange Sulfonated Poly （ether ether ketone） （SPEEK）/SiOx-S Composite Membranes in Direct Methanol Fuel Cells

A sulfonated poly（ether ether ketone） （SPEEK） membrane with a fairly high degree of sulfonation （DS） can swell excessively and even dissolve at high temperature. To solve these problems, insolvable functionalized silica powder with sulfonic acid groups （SiOx-S） was added into the SPEEK matrix （DS = 55.1%） to prepare SPEEK/ SiOx-S composite membranes. The decrease in both the swelling degree and the methanol permeability of the membranes was a dose-dependent result of addition of the SiOx-S powder. Pure SPEEK membrane swelled 52.6% at 80℃, whereas the SPEEK/SiOx-S （15%, by mass） membrane swelled only 27.3% at the same temperature. From room temperature to 80℃, all SPEEK/SPEEK/SiOx-S composite membranes had methanol permeability of about one order of magnitude lower than that ofNafion115. Compared with pure SPEEK membranes, the addition of the SiOx-S powder not only leads to higher proton conductivity, but also increases the dimensional stability at higher temperatures, and greater proton conductivity can be achieved at higher temperature. The SPEEK/SiO4-S （20%, by mass） membrane could withstand temperature up to 145℃, at which in 100% relative humidity （RH） its proton conductivity exceeded slightly that of Nafion 1 15 membrane and reached 0.17 S·cm^-1, while pure SPEEK membrane dissolved at 90℃. The SPEEK/SiOx-S composite membranes are promising for use in direct methanol fuel cells because of their good dimensional stability, high proton conductivity, and low methanol permeability.

Synthesis and characterization of novel poly(aryl ether sulfone ketone)s containing phthalazinone and biphenyl moieties

A novel series of poly（aryl ether sulfone ketone）s （PPESKs） containing phthalazinone and biphenyl moieties were prepared by two-step nucleophilic polycondensation reaction. The ^-Mw values of these copolymers were between 38,330 and 67,900. The glass transition temperatures （Tg） and 5% decomposition temperatures were ranged in 253-269 ℃ and 488-500 ℃, respectively, The structures of these copolymers were confirmed by FT-IR and ^1H NMR. Moreover, all the resultant copolymers were amorphous determined by wide angle X-ray diffraction （WAXD）.

SYNTHESIS AND PROPERTIES OF SULFONATED POLY(ARYLENE ETHER) CONTAINING TRIPHENYL METHANE MOIETIES FROM ISOCYNATE MASKED BISPHENOL

A novel sulfonated poly（arylene ether） containing triphenylmethane moieties was synthesized by the sulfonation of a designed parent polymer using chlorosulfonic acid as sulfonation agent. The sulfonation took place at the para position of the pendant phenyl rings because of the specially designed parent polymer. The position and degree of sulfonation were characterized by ^1H-NMR and elemental analysis. The sulfonated polymers are highly soluble in common organic solvents, such as dimethylsulfoxide, N,N＇-dimethylacetamide, dimethylformamide, ethylene glycol monomethyl ether, and can be readily cast into tough and smooth films from solutions. The films showed good thermal and hydrolysis stabilities. Moreover, Fenton＇s reagent test revealed that the films exhibited superior stability to oxidation. The proton conductivities of the films were comparable with Nation 117 under same conditions. The membrane electrode assembly （MEA） prepared with the asmade film （706 EW, 100 μm dry thickness） shows better cell performance than Nation 115-MEA in the whole current density range.

Synthesis and properties of soluble poly（aryl ether sulfone ether ketone）s copolymers containing pendant methyl groups

A series of Poly（arly ether sulfone ether ketone）s containing pendant methyl groups were synthesized by the reaction of 4,4＇-[sulfonylbis （1,4-phenylene）dioxy] dibenzoyl chloride （SODBC） with 4,4＇- diphenoxy diphenylsulfone （DPODPS）, 4,4＇- di（2-methylphenoxy） diphenylsulfone （o-Me-DPODPS）, 4,4＇- di（3-methylphenoxy） diphenylsulfone （m-Me-DPODPS）, 4,4＇- di （2,6-bimethylphenoxy） biphenylsulfone（o-Me2-DPODPS） respectively, in a mixture of 1,2-dichloroethane （DCE） and N-methylpyrrolidone （NMP）. These reactions were catalyzed by anhydrous aluminum chloride （AlCl）. The characteristic of copolymers were studied by means of advanced analytical techniques such as FT-IR,1H-NMR, DSC, TGA and WAXD. The results show glass transition temperature （Tg） in the range of 193-206℃, thermally stable in excess of 434℃ and excellent solubility in polar solvents. Methyl-substituted Poly（aryl ether sulfone ketone）s had higher glass transition temperatures, lower initial decomposition temperatures than the unsubstituted ones.

Sulfonated fluorinated multi-block copolymer hybrid containing sulfonated(poly ether ether ketone) and graphene oxide: A ternary hybrid membrane architecture for electrolyte applications in proton exchange membrane fuel cells

A ternary hybrid membrane architecture consisting of sulfonated fluorinated multi-block copolymer （SFMC）, sulfonated （poly ether ether ketone） （SPEEK） and I or 5 wt% graphene oxide （GO） was fabricated through a facile solution casting approach. The simple, but effective monomer sulfonation was performed for SFMC to create compact and rigid hydrophobic backbone structures, while conventional random sulfonation was carried-out for SPEEK. Hydrophilic-hydrophobic-hydrophilic structure of SFMC enhances the compatibility with SPEEK and GO and allows for an unprecedented approach to alter me- chanical strength and proton conductivity of ternary hybrid membrane, as verified from universal test machine （UTM） curves and alternating current （AC） impedance plots. The impact of GO integration on the morphology and roughness of hybrid membrane was scrutinized using field emission scanning electron microscope （FE-SEM） and atomic force microscope （AFM）. Ternary hybrid showed uniform intercalation of GO nanosheets throughout the entire surface of membrane with an increased surface roughness of 8.91 nm. The constructed ternary hybrid membrane revealed excellent water absorption, ion exchange capacity and gas barrier properties, while retaining reasonable dimensional stability. The well-optimized ternary hybrid membrane containing 5 wt% GO revealed a maximum proton conductivity of 111.9 mS/cm, which is higher by a factor of two-fold with respect to that of bare SFMC membrane. The maximum PEMFC power density of 528.07mW/cm2 was yielded by ternary hybrid membrane at a load current density of 1321.1 mA/cm2 when operating the cell at 70 ℃ under 100% relative humidity （RH）. In comparison, a maximum power density of only 182.06 mW/cm2 was exhibited by the bare SFMC membrane at a load current density of 455.56 mA/cm2 under same operating conditions.

SYNTHESIS AND CHARACTERIZATION OF PHTHALAZINONE POLY(ARYL ETHER SULFONE KETONE)WITH CARBONYL GROUP

A kind of novel heat-resistant, high performance engineering thermoplastic phthalazinone poly(aryl ether sulfone ketone) (PPESK) containing a carboxyl group in its side chain was prepared by the nucleophilic displacement reaction of 4-(4-hydroxylphenyl)- 1 (2H)-phthalazinone with di(4-chlorophenyl) sulfone, 4,4'-difluoro-benzophenone and phenolphthalin in sulfolane in the presence of K2CO3 to produce high molecular weight polymers which can be dissolved in some polar solvents such as chloroform and nitrobenzene at room temperature and can be easily cast into flexible, yellowish and transparent films. PPESK is an amorphous polymer having a decomposition temperature above 400degreesC, which indicates that it has high thermal stability. At the same time, the thermal properties of PPESKs with dicyandiamide (DICY) as curing agent indicated that the heat-resistance properties of the PPESKs are improved after curing. The apparent activation energy (A-E) of the cross-linking reaction and the reaction order (n) of PPESK/DICY were found to be 52.2 kJ/mol and ca. 1.0, respectively. Therefore, the cross-linking reaction is approximately a first order reaction.

Ex situ aging effect on sulfonated poly(ether ether ketone) membrane:Hydration-dehydration cycling and hydrothermal treatment

Prolonged hydrothermal treatment for sulfonated poly(ether ether ketone) membranes induces mechanical degradation and developing hydrophilic-hydrophobic phase separation, simultaneously. The enhanced phase separation provides incremental proton conductivity to the membranes, whereas mechanical degradation drastically reduces device stability. On this basis, we describe here the effects of two different ex situ aging processes on sulfonated poly(ether ether ketone) membranes: hydrationdehydration cycling and prolonged hydrothermal treatment. Both aged membranes exhibited enhanced phase separation under the hydrated conditions, as characterized by small angle X-ray scattering.However, when the aged membranes were dried again, the nanostructure of the membranes aged via the hydration-dehydration cycling was recoverable, whereas that of the membranes aged via prolonged hydrothermal treatment was irreversible. Furthermore, the two differently aged membranes showed clear differences in thermal, mechanical, and electrochemical properties. Finally, we implemented both aged membranes in fuel cell application. The sample aged via hydration-dehydration cycling maintained its improved cell performance, whereas the sample aged via hydrothermal treatment showed drastically reduced cell performance after durability test for 50 h.

Synthesis and Characterization of Poly (Ether Sulfone Ketone) Containing the Phthalazinone Moiety

A novel poly (ether sulfone ketone) containing the phthalazinone moiety was prepared by the reaction of 4-)4-hydroxyphenyl) (2H) phthalazin-1-one with activated dichloro-monomers. The polymer was characterized by FT-IR, H-1-NMR, DSC, TGA and X-ray diffraction.

Sulfonated poly(aryl ether ketone sulfone)modified by polyoxometalates LaW_(10) clusters for proton exchange membranes with high proton conduction performance

Polyoxometalates(POMs)are classified as solid superacids which can exhibit notable proton conductivity,making them a promising functional inorganic filler for enhancing the proton conductivity of proton exchange membranes(PEMs).In this study,a series of hybrid membranes were obtained by molecular-level hybridization of Weakley-type POM Na_(7)H_(2)LaW_(10)O_(36)(LaW_(10))clusters into sulfonated poly(aryl ether ketone sulfone)(SPAEKS).All hybrid membranes exhibited greater proton conductivity than the pristine membrane in the 30–80℃temperature range.When the doping amount of LaW 10 reached 7 wt.%,the proton conductivity of M-LaW 10^(-7)achieved 64 mS·cm^(−1)at 80℃.Lanthanide ions'high coordination number property and variable coordination environment can aid to attract more water molecules from the environment.LaW 10 and these bound water can construct denser hydrogen bonds with–SO_(3)H of SPAEKS.These intensive hydrogen bonds will facilitate the constitution of more continuous proton transport channels,and improve the proton conductivity of the hybrid membrane.This work off ers a fresh approach to using POMs containing rare-earth components in PEMs.

Synthesis of Poly(phthalazinone ether ketone) Containing Sodium Sulfonate Groups via Direct Polymerization

1, 2-Diliydro-4-(4-hydroxyphenyl)(2H)phthalazin-1-one(DHPZ) was sulfonated in concentrated Sulfuric acid. Poly(phthalazinone ether ketone) containing pendant sodium sulfonate group was synthesized from sulfonated and pure 1,2-dihydro-4-(4-hydroxyphenyl)(2H)phthalazin-1-one, and 4,4'-difluorodiphenylketone. The sulfonated monomer and sulfonated polymer were characterized with FT-IR and H-1-NMR.

Properties of Multiblock Sulfonated Poly(arylene ether sulfone)s Synthesized by Precise Controllable Post-sulfonation for Proton Exchange Membranes

A series of multiblock sulfonated poly(arylene ether sulfone)s(SPAES)with various block lengths and predictable ion exchange capacity were synthesized from 4,4’-difluorodiphenyl sulfone,4,4’-dihydrodiphenyl sulfone and 4,4’-biphenol by one-pot and two-pot polymerization.;H-NMR and FTIR spectra confirmed the structure that sulfonic acid groups were introduced precisely on the poly(arylene ether sulfone)s by post-sulfonation which resulted in controllable sulfonation degree.The proton exchange membranes(PEMs)-based SPAES displayed excellent dimensional,thermal,antioxidant stability,proton conductivity and mechanical properties(maximum tensile stress>35 MPa).Thermogravimetric analysis indicated the prepared SPAES began to degrade above 310℃.The effects of polymerization processes,those were,one-pot hydrophobic segment process,one-pot hydrophilic segment process and two-pot process,on the properties of polymers were investigated.The proton conductivity and microphase separation of SPAES PEMs increased in order of those prepared by one-pot hydrophobic segment process,two-pot process and one-pot hydrophilic segment process.The highest conductivities of SPAES synthesized by the above processes under 80℃ and 100%relative humidity were 213(MS4),297(MB3)and 360 mS·cm^(-1)(MQ2),respectively.

Preparation and Properties of Poly(aryl ether sulfone ketone)Ultrafiltration Membrane Containing Fluorene Group for High Temperature Condensed Water Treatment

Novel poly（aryl ether sulfone ketone）s （PAESK） were synthesized from bisphenol A （BPA）, 9,9＇-bis（4-hydroxyphenyl） fluorene （BHPF）, 4,4＇-dichlorodiphenylsulfone （DCS） and 4,4＇-difluorobenzophenone （DFB） via nucleophilic substitution polymerization, which were subsequently used to fabricate ultrafiltration membrane by phase-inversion method for high temperature condensed water treatment. The obtained high molecular weight co-polymers with fluorene group with good solubility and good thermal stability, can be easily cast into flexible, white and non-transparent fiat films. The influence of molar ratio of BPA and BHPF on the properties of the prepared co-polymers and membranes was investigated in detail. SEM study of the morphology of the membranes indicated that the prepared membranes possessed homogeneous pores on the top surface and were sponge-like or finger-like in cross-section. Pure water flux of the membranes increased from 71.87 L·m-2.h-1 to 247.65 L·m-2.h-1, while the retention of BSA decreased slightly, and the water contact angle decreased from 82.1 ° to 55.6° with the PVP concentration from 0 wt% to 10 wt%. With increasing concentration of PVP, the mechanical properties of membranes decreased, while the thermal stability increased. The permeate flux measurement showed that the PAESK membrane had the potential for high temperature condensed water treatment.

SYNTHESIS AND PROPERTIES OF SULFONATED POLY(ETHER KETONE)S CONTAINING 3,5-DIMETHYL PHTHALAZINONE MOIETIES AS PROTON EXCHANGE MEMBRANE MATERIALS

Sulfonated poly（ether ketone）s containing 3,5-dimethyl phthalazinone moieties （SPPEK-DMs） with different degrees of sulfonation （DS） were synthesized via direct polycondensation from 4-（3,5-dimethyl-4-hydroxyphenyl）-2,3- phthalazinone, 4,4＇-difluorobenzophenone and 3,3＇-disulfonate-4,4＇-difluorobenzophenone. The chemical structure of SPPEK-DMs was characterized by FTIR and 1H-NMR. Thermal stability of SPPEK-DMs was characterized by the thermogravimetric analysis. The membranes prepared from SPPEK-DMs exhibited ion exchange capacities （IEC） ranging from 0.93 mmol.g-1 to 1.86 mmol.g-1. Water uptake, swelling, oxidative stability and methanol permeability of SPPEK- DMs membranes were investigated. SPPEK-DMs membranes exhibited high oxidative stability. The methanol permeability values of SPPEK-DMs membranes were in the range 5.15× 10^-8-6.61×10^-7 cm^2.s-1, which was much lower than those of Nafion117. The proton conductivity of SPPEK-DM40 membranes was 1.1 ×10^-2 S.cm^-1 at 70℃.

Semi-interpenetrating polymer networks toward sulfonated poly(ether ether ketone) membranes for high concentration direct methanol fuel cell

Low methanol permeability of proton exchange membranes (PEMs) is greatly important for direct methanol fuel cells (DMFCs). Here, sulfonated poly (ether ether ketone) (SPEEK) based semiinterpenetrating polymer networks (semi-IPNs) are successfully prepared by interpenetrating SPEEK into the in-situ synthesized crosslinking networks. The polymeric networks are formed by the covalent bonds between bromobenzyl groups of bro mo methylated poly (phenylene oxide) and amine groups of diamine linkers as well as the ionic bonds between amine species and sulfonated groups. Two linkers without and with sulfonated groups are applied to fabricate the semi-IPNs. The core properties of the membranes, like phase separation, water uptake, proton conductivity and methanol permeability, are systematically studied and compared. The DMFCs assembled by using the semi-IPN membranes display better performance than Nafion 117 in high concentration methanol solutions. The present work provides a facile way to prepare PEMs with enhanced DMFC performance.

Precise modification of poly(aryl ether ketone sulfone)proton exchangemembranes with positively charged bismuth oxide clusters for high proton conduction performance

In the field of proton exchange membranes(PEMs),it is still a great challenge to explore new Nafion alternatives,maintaining the high proton conductivity and lowering the cost of practical application.In this work,a series of low sulfonated poly(aryl ether ketone sulfone)(SPAEKS)membranes hybridized by[Bi_(6)O_(5)(OH)_(3)]_(2)(NO_(3))10⋅6H_(2)O(H_(6)Bi_(12)O_(16))have been successfully fabricated.When the doping amount of H6Bi12O16 reaches 5 wt%,the DS15-Bi12-5 showing the best proton conductive ability and mechanical properties.The proton conductivity can achieve 72.8 mS⋅cm−1 at 80℃ and the tensile strength can reach 43.57 MPa.Confirmed by experimental data and activation energy(Ea)calculations,the existence of Bi cluster makes more hydrogen bonds,providing additional proton hopping sites and offers more proton transport vehicles,leading to a high proton conduction performance.This work proved that polyoxometalates(POMs)can replace the role of sulfonate groups in SPAEKS to a certain extent and work out the defects of high sulfonation,making a remarkable contribution to the practical application of low sulfonated SPAEKS.

Preparation and Properties of Hybrid Silane-crosslinked Sulfonated Poly(aryl ether ketone)s as Proton Exchange Membranes

A series of novel organic-inorganic hybrid proton-conducting electrolyte membranes with silane-crosslinked sulfonated poly(aryl ether ketone)(SC-SPAEK) networks was prepared via a simple procedure that includes solution casting and acid treatment. The organosilicon pendants of the silane-grafted SPAEK, which were expected to serve as coupling and crosslinking agents, were found to play a key role in the homogenous dispersion of inorganic particles and improved the performance of hybrid membranes. The hybrid membranes exhibited enhanced proton conductivity, and SC-SPAEK/TiO2-4 showed an extremely high proton conductivity of 0.1472 S/cm at 100℃. The crosslinked hybrid membranes also demonstrated good chemical resistance, oxidative stability, and mechanical properties. The crosslinked hybrid membranes with excellent comprehensive performance may be a promising material for proton exchange membrane fuel cells.

Comb-shaped 2-Methylimidazolium Poly(arylene ether sulfone) Anion Exchange Membranes with High Alkaline Stability

A series of comb-shaped poly(arylene ether sulfone)s containing pendant 2-methyl-3-alkylimidazolitun group(ImPAES-Cx,x=1,6,10)was prepared and characterized as novel anion exchange membranes.These Im-PAES-Cx membranes were obtained by benzylic bromination and imidazolium functionalization.The characteristic nano-phase separation structure was formed in membranes with longer alkyl side chains,as confmned by small-angle X-ray scattering.The nano-phase separation structures endowed ImPAES-Cx membranes with improved ionic conductivity,dimensional stability(at least 60% decrease water uptake and swelling ratio at 60℃)and mechanical properties,together with excellent alkaline stability.Especially,ImPAES-C6 membranes possessed enhanced hydroxide conductivity and chemical stability simultaneously.These results suggest that it is a feasible strategy to introduce appropriate length of alkyl side chains into anion exchange membranes(AEMs)to improve the performance.