Sulfone Copolymers Research Articles

Studies on the Relationship of Polymer Backbone Rigidity and Properties for Proton Exchange Membranes Derived from Sulfonated Polys(Arylene Ether Sulfone)

A series of novel sulfonated poly(arylene ether sulfone) (SPAES) copolymers were successfully synthesized from hexafluoro bisphenol A (6F-BPA), 9,9’-bis(4-hydroxyphenyl) fluorene (BHPF), 4,4’-difluorodiphenyl sulfone (DFDPS) and 3,3’-disulfonate-4,4’-difluorodiphenyl sulfone (SDFDPS) via aromatic nucleophilic substitution polymerization, and subsequently used to prepare proton exchange membranes. By adjusting the ratio of 6F-BPA to BHPF, the influence of the rigidity of polymer backbone on the properties of the prepared membranes was investigated in detail. The results indicated that the SPAES membranes had better stability towards water but lowered water uptake and proton conductivity with the increase in the polymer backbone rigidity.

Synthesis and Application of an Efficient and Stable Solid Acid Catalyst St-c-AS

Styrene/Sodium allyl sulfonate copolymer (St-c-SAS) were prepared using soap-free emulsion polymerization method and boiling at high-speed stirring, and it was acided to obtain an efficient, stable, reusable new solid acid catalyst styrene/acrylic acid copolymer (St-c-AS). Elemental analysis and acid–base titration techniques showed that St-c-AS have high concentration of sulfonic groups. Differential thermal analysis (DTA) and thermogravimetric analysis (TG) results showed that the sulfonic of copolymer was hard to fall off at high temperature. Esterifications of acetic acid with ethanol showed that St-c-AS has high catalytic activity, and the catalyst can be reused without separation of 10 times, the esterification yields close to or exceed 100%. The superior performance of St-c-AS is attributed to their unique features including large surface area, high content of sulfonic groups as well as high temperature resistance.

Synthesis of highly sulfonated poly(arylene ether sulfone)s with sulfonated triptycene pendants for proton exchange membranes

A series of poly(aryl ether sulfone)s containing triptycene groups PES-x-TPD (x refers to molar percentage of TPD) were firstly synthesized through nucleophilic aromatic substitution polycondensation by using 2,5-triptycenediol (TPD), bis(4-hydroxyphenyl) sulfone (BHPS) and 4,4′-difluorodiphenyl sulfone (DFDPS). The sulfonation of copolymers was conducted at room temperature by using a mild sulfonating reagent (98% H2SO4), and the degree of sulfonation was readily and accurately controlled by adjusting the ratio of TPD and BHPS. The structures of PES-x-TPD and SPES-x-TPD were characterized by IR, 1H NMR and 13C NMR spectra. These ionomers generally showed high thermal stability and mechanical strength at low humidity regardless of high IEC value. Meanwhile, it is noteworthy that these novel SPES-x-TPD membranes with high IEC value achieved high proton conductivity in a wide range of humidity at 80 °C. For example, SPES-60-TPD with the highest IEC value 2.86 mmol/g displays the conductivity of 2.5 × 10−1 S/cm which is much higher than that of the perfluorinated Nafion membrane (1.1 × 10−1 S/cm) at 80 °C and 94% RH. At 80 °C and 34% RH, SPES-60-TPD displays the conductivity of 4.5 × 10−3 S/cm which is also higher than that of the Nafion membrane (3.0 × 10−3 S/cm). Microscopic analyses revealed that well-defined phase separated structures and uniform ionic pathway was formed for SPES-45-TPD membrane with the IEC of 2.29 mmol/g. Moreover, a H2/O2 fuel cell using the SPES-55-TPD (IEC = 2.68 mmol/g) also showed better performance than that of Nafion 117 at 40 °C and 30% RH.

Novel side-chain-type cardo poly(aryl ether sulfone) bearing pendant sulfoalkyl groups for proton exchange membranes

A series of cardo poly(aryl ether sulfone) copolymers bearing pendant hydroxyl ethyl groups (−CH 2CH 2OH) were synthesized from a new biphenol monomer 2-(2-hydroxyethyl)-3,3-bis(4-hydroxyphenyl)isoindolin-1-one (PPH–OH), 4,4′-biphenol(BP), and 4,4′-difluorodiphenylsulfone (DFDPS). Sulfonic acid groups were readily grafted to the copolymers by reaction of the hydroxyl group with 1,3-propanesultone. The resulting sulfonated copolymers SPES-C-X (where X refer to the content of PPH–OH in the bisphenol monomers) contain side chain sulfoalkyl groups (–CH 2CH 2–O–CH 2CH 2CH 2SO 3H). TEM photographs revealed that SPES-C-100 membrane exhibited characteristic hydrophilic/hydrophobic microphase separated morphology with small interconnected and hydrophilic clusters (1.5–2 nm). Such microphase separated morphology renders the membrane high proton conductivity of 0.056 S/cm (IEC = 1.41 mequiv./g), and low dimensional changes of SPES-C-100 at room temperature. SPES-C-X membranes exhibited the methanol permeability in the range of 13.8–5.3 × 10 −8 cm 2/s, which were much lower than those of SBPES (8.7 × 10 −7 cm 2/s) and Nafion 117 (2.4 × 10 −7 cm 2/s).

Synthesis and characterization of poly(arylene ether ketone)s bearing pendant sulfonic acid groups for proton exchange membrane materials

AbstractA bisphenol monomer (2,5‐dimethoxy)phenylhydroquinone was prepared and further polymerized to obtain poly(arylene ether ketone) copolymers containing methoxy groups. After demethylation and sulfobutylation, a series of novel poly(arylene ether ketone)s bearing pendant sulfonic acid group (SPAEKs) with different sulfonation content were obtained. The chemical structures of all the copolymers were analyzed by 1H NMR and 13C NMR spectra. Flexible and tough membranes with reasonably good mechanical properties were prepared. The resulting side‐chain‐type SPAEK membranes showed good dimensional stability, and their water uptake and swelling ratio were lower than those of conventional main‐chain‐type SPAEK membranes with similar ion exchange capacity. Proton conductivities of these side‐chain‐type sulfonated copolymers were higher than 0.01 S/cm and increased gradually with increasing temperature. Their methanol permeability values were in the range of 1.97 × 10−7–5.81 × 10−7 cm2/s, which were much lower than that of Nafion 117. A combination of suitable proton conductivities, low water uptake, low swelling ratio, and high methanol resistance for these side‐chain‐type SPAEK films indicated that they may be good candidate material for proton exchange membrane in fuel cell applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Synthesis, Characterization and Photoluminescence Study of Novel Sulfobetaine Polyelectrolytes

A novel sulfobetaine copolymer is developed via polycondensation approach. The comonomers, melamine, condenses with a diketone, 5,5-dimethyl-1,3-cyclohexane (dimedone) to produce polyimine chain based on Schiff base chemistry. Dimedone-[N,N' melaminium] propane sulfonate copolymer crystals were obtained on treatment of the polyimine with sulfopropylating agent, 1,3-propane sultone with a crosslinker, di(ethylene glycol diacrylate) (DEGDA). This crosslinked sulfobetaine polymer yielded fine needle like single crystals and shows strong blue fluorescence and a week green phosphorescence. Multi-exponential fluorescence decay function indicates the presence of different conformers both in solution and crystalline phase. This easy straightforward protocol for synthesis of crystalline, soluble, and luminescent polymer could prove to be a landmark in development of next generation smart functional materials.

Synthesis and Characterization of Novel Sulfonated Hybrid Congo Red Membranes from Chlorofunctionalized Silsesquioxanes for Fuel Cell Application

AbstractA new sulfonated copolymers containing congo red groups were synthesized as a potential electrolyte for high temperature PEFCs. The resulting cross‐linked sulfonated hybrid congo red membranes showed greatly improved water stability in comparison with the uncrosslinked ones while high proton conductivity was maintained. sulfonated membranes have been tested with respect to fuel cell performance. Short term fuel cell test for 100 hr gave a stable performance. These membranes are less expensive compared to Nafion. New sulfonated proton exchange composites membranes were used biological fuel cells. Molasses which is the waste of sugar factory, was used in anode as fuel and different bacteria species was sowing. Potential change was reported in biological fuel cells.

Synthesis and characterization of sulfonated poly(styrene-isoprene-styrene): Effects of linear vs. branched morphology and counter-ion substitution

This investigation studied the resulting nanostructure of ionic membranes composed of sulfonated copolymers with thermoplastic and elastomeric blocks. Linear poly(styrene-isoprene-styrene) (L-SIS) and branched poly(styrene-isoprene) (B-SI) were sulfonated to various levels of ion exchange capacity (IEC). Since the sulfonation occurred in both the polystyrene (PS) blocks and the double bonds of the polyisoprene (PI) segments, the sulfonated polymer lost its elastomeric component. The latter is critical for blocking the transport of chemicals through the membrane; therefore, physical blends of sulfonated and unsulfonated L-SIS and B-SI were casted and analyzed. The newly developed membranes were characterized using several techniques including: elemental analysis (EA), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and small angle X-ray scattering (SAXS). These techniques were used to evaluate the thermal and physical properties of the membranes, which in turn, allowed for the comparison of resulting morphologies and selectivities. In addition, counter-ion substitution (Mg 2+, Ca 2+, Ba 2+) was used to cross-link the sulfonated polymers to further influence their selectivity. Vapor permeabilities were measured at 308 K using dimethyl methyl-phosphonate (DMMP), a chemical compound similar to Sarin Gas (GP), and water, in order to evaluate the selectivity of the membranes and their potential application for chemical and biological protective clothing (CBPC). Significant differences were observed between linear and branched morphologies.

Synthesis and characterization of sulfonated copolyethersulfones

AbstractThe present article deals with the synthesis and characterization of some sulfonated copolyethersulfones. The synthetic approach differs from the post sulfonation approach traditionally reported in the literature. The synthetic procedure is based on the use of sulfonated monomers which are then reacted with previously synthesized telechelic hydoxy‐ended poly (ether sulpnone)s. Combining the MALDI‐TOF MS and 1H NMR analyses, with SEC‐Viscometry and TGA measurements, we demonstrate a powerful tool for characterizing the chemical composition, end chains, degree of sulfonation (DS) and molecular mass distribution (MMD) of disulfonated poly(arylene ether‐sulfone) copolymers. The characterization techniques allowed to determine the exact nature of the copolymers synthesized and to reveal some interesting features about the reaction. DMA data show that the glass transition temperature of sulfonated copolymers with similar DS increase as raise their MMD. Copolymers with a DS of 10–11 mol % reach a Tg of 244–246 °C. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3010–3023, 2010

Synthesis and Characterization of UV Crosslinkable and Highly Sulfonated Block Copolymer by Living Radical Polymerization

UV crosslinkable sulfonated block copolymers of neopentyl p-styrene sulfonate (NSS) and 2-cinnamoylethyl acrylate (CEA) were synthesized by living radical polymerization. For this, the block copolymers of 2-(trimethylsilyl)ethyl acrylate (TMSEA) and NSS were first synthesized by sequential CuBr catalyzed living radical polymerization with 2-bromopropionate (EBP) initiator and N,N,N′,N′-pentamethylethyleneamine (PMDETA) ligand. Obtained well defined block copolymers (polydispersity <1.21) were then hydrolyzed with an acid to give the block copolymer of 2-hydroxylethyl acrylate (HEA) and NSS. Cinnamoyl chloride as a crosslinking moiety reacted with the hydrolyzed block copolymers to give final UV crosslinkable sulfonated block copolymers. Theses block copolymers were successfully crosslinked under UV irradiation and generated sulfonic acid groups by thermolysis of the PNSS.

STUDY ON SYNTHESIS AND PERFORMANCES OF SULFONATED POLY(ARYLENE ETHER KETONE SULFONE)COPOLYMERS FOR PROTON EXCHANGE MEMBRANES MATERIAL

A series of sulfonated SPEEKKS copolymers with different DS were synthesized by aromatic nucleophilic polycondensation of disodium 3,3′-disulfonate4,4′-dichloro-diphenylsulfone(SDCDPS),tertbutylhydroquione(TBHQ)and 1,4-bi(4′-fluorobenzoyl)benzene.Synthesized sulfonated copolymers were characterized by FTIR,TGA and DSC.Moreover,the microstructure of membranes was investigated by TEM,and the relationship between structure and performance was established.Physical and electrochemical performances of all membranes were studied thoroughly.The results showed that the proton conductivity of SPEEKKS-4 membrane reached 0.061 S/cm,which was close to that of Nafion 117 at 80℃.However,the methanol diffusion of SPEEKKS-4 membranes only reached 3.4×10~(-7) cm~2/s and was much lower than that of Nafion 117.The new membrane displayed good potential in application as proton exchange membranes(PEM) in PEMFC and DMFC.

Novel side-chain-type sulfonated poly(arylene ether ketone) with pendant sulfoalkyl groups for direct methanol fuel cells

Abstract Novel side-chain-type sulfonated poly(arylene ether ketone) with pendant sulfoalkyl groups (SPAEK-xx) were synthesized by post-sulfonation method. Their structures were confirmed by FT-IR and NMR spectra. The all obtained membranes had excellent thermal stability and mechanical properties. The side-chain-type SPAEK films showed good dimensional stability, and their water uptake and swelling ratio were lower than those of the main-chain-type SPAEK with similar ion exchange capacity (IEC) value. It should be noted that the most highly sulfonated copolymer, SPAEK-100 (DS = 1.0) with IEC of 1.54 meq./g, showed proton conductivity of 0.083 S/cm and water swelling ratio of only 9.74% at 80 °C. Moreover, the methanol permeability of SPAEK-100 membrane was 3.95 × 10 −7 cm 2 /s, which was much lower than 23.80 × 10 −7 cm 2 /s of Nafion 117.

DIRECT SYNTHESIS AND PROPRTIES OF SULFONATED POLY(ARYLENE ETHER SULFONE) COPOLYMERS FOR PROTON EXCHANGE MEMBRANES IN FUELCELLS

A series of sulfonated poly(arylene ether sulfone)(SPAES) copolymers with different degree of sulfonation(D_s) were synthesized by aromatic nucleophilic polycondensation of 3,3'-disulfonate-4,4'-dichlorodiphenylsulfone(SDCDPS),4,4'-dichlorodiphenylsulfone(DCDPS) and 4,4'-biphenol(BP).Synthesized sulfonated copolymers were characterized by FT-IR,TGA and DSC.Moreover,the microstructure of membranes was investigated by TEM,and the relationship between structure and performance was established.The influence of different D_s on the properties of SPAES membranes was studied,and it showed that the increase of sulfonated groups in the polymers led to the increase of water uptake,ion exchange capacity(IEC),methanol diffusion coefficient and proton conductivitie of the membranes.Physical and electrochemical performances of all membranes were studied thoroughly.The results showed that the proton conductivity of SPAES-2 membrane was 0.116 S/cm at 80℃ and 0.126 S/cm at 100℃,which were higher than those of Nafion 117 membrane(0.114 S/cm and 0.117 S/cm).However,the methanol diffusion coefficient of SPAES-2 membrane only reached 8.4×10-7 cm2/s and was much lower than that of Nafion 117 membrane(2.1×10-6 cm2/s).The new synthesized membranes displayed good potential in application as proton exchange membranes(PEM) in proton exchange membrane fuel cells(PEMFC) and direct methanol fuel cells(DMFC).

Carbonyl Groups in Sulfonated Styrene−Divinylbenzene Macroporous Resins

The generation of carbonyl groups during sulfonation of porous styrene−divinylbenzene copolymers is reported. The carbonyl groups and sulfonic acid groups were verified by infrared spectroscopy and quantified by acid−base titrations. A gradual change in sulfonation reaction conditions from 70 °C/30 min to 98 °C/60 min resulted in a gradual increase in sulfonic acid group concentration from ∼1.85 to ∼3.13 mol/kg and in the carboxylic acid group concentration from ∼0 to ∼0.34 mol/kg. Data on the swelling coefficients in water indicate a slight increase in cross-linking during sulfonation. Conversion of ethyl or residual vinyl groups to carboxylic acid groups, followed by conversion of some of the acid groups to cross-links through an acid-catalyzed acylation reaction, is proposed. The proposed reactions also explain the pH-dependent color change of the resins. Sulfonation of copolymers with varied cross-linkages further supports our assertion that, as the concentrations of ethyl and residual vinyl groups increase, the concentration of —COOH groups also increases and the resin color becomes darker.

Preparation and properties of bisphenol A‐based sulfonated poly(arylene ether sulfone) proton exchange membranes for direct methanol fuel cell

AbstractNovel bisphenol A‐based sulfonated poly(arylene ether sulfone) (bi A‐SPAES) copolymers were successfully synthesized via direct copolymerization of disodium 3,3′‐disulfonate‐4,4′‐dichlorodiphenylsulfone, 4,4′‐dichlorodiphenylsulfone, and bisphenol A. The copolymer structure was confirmed by Fourier transform infrared spectra and 1H NMR analysis. The series of sulfonated copolymers based membranes were prepared and evaluated for proton exchange membranes (PEM). The membranes showed good thermal stability and mechanical property. Transmission electron microscopy was used to obtain the microstructures of the synthesized polymers. The membranes exhibit increased water uptake from 8% to 66%, ion exchange capacities from 0.41 to 2.18 meq/g and proton conductivities (25°C) from 0.012 to 0.102 S/cm with the degree of sulfonation increasing. The proton conductivities of bi A‐SPAES‐6 membrane (0.10–0.15 S/cm) with high‐sulfonated degree are higher than that of Nafion 117 membrane (0.095–0.117 S/cm) at all temperatures (20–100°C). Especially, the methanol diffusion coefficients of membranes (1.7 × 10−8 cm2/s–8.5 × 10−7 cm2/s) are much lower than that of Nafion 117 membrane (2.1 × 10−6 cm2/s). The new synthesized copolymer was therefore proposed as a candidate of material for PEM in direct methanol fuel cell. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Copoly(arylene ether)s Containing Pendant Sulfonic Acid Groups as Proton Exchange Membranes † NRCC Publication No. 50899.

A poly(arylene ether) (PAE) with high fluorine content and a poly(arylene ether nitrile) (PAEN) with high nitrile content, each containing pendant phenyl sulfonic acids were synthesized. The PAE and PAEN were prepared from decafluorobiphenyl (DFBP) and difluorobenzonitrile (DFBN) respectively, by polycondensation with 2-phenylhydroquinone (PHQ) by conventional aromatic nucleophilic substitution reactions. The sulfonic acid groups were introduced by mild postsulfonation exclusively on the para-position of the pendant phenyl ring in PHQ. The membrane properties of the resulting sulfonated copolymers sPAE and sPAEN were compared for fuel cell applications. The copolymers sPAE and sPAEN, each having a degree of sulfonation (DS) of 1.0 had high ion exchange capacities (IECv(wet) (volume-based, wet state)) of 1.77 and 2.55 mequiv/cm3, high proton conductivities of 135.4 and 140.1 mS/cm at 80 °C, and acceptable volume-based water uptake of 44.5−51.9 vol % at 80 °C, respectively, compared to Nafion. The data poin...

Physical and electrochemical behaviors of directly polymerized sulfonated poly(arylene ether ketone sulfone)s proton exchange membranes with different backbone structures

AbstractSulfonated poly(ether ether ketone sulfone) (SPEEKS) and sulfonated poly(ether ether ketone ketone sulfone) (SPEEKKS) copolymers with different degree of sulfonation (DS) were synthesized by aromatic nucleophilic polycondensation of disodium 3,3′‐disulfonate‐4,4′‐dichloro‐diphenylsulfone (SDCDPS), tertbutylhydroquione, and 4,4′‐difluorobenzophenone or 1,4′‐bi(4‐fluorobenzoyl) benzene. Prepared sulfonated copolymers were characterized by Fourier transform infrared spectra, thermogravimetric analysis, and differential scanning calorimetry. The transmission electron microscope was used to investigate the microstructure of membranes. The different distance between two adjacent sulfonic groups in two series of membranes resulted in different physical and electrochemical properties between two kinds of membranes with the same DS. The proton conductivity, ionic exchange capacity and water uptake of SPEEKS membranes were higher than those of SPEEKKS membranes while the mechanical strength of SPEEKS membranes was lower than that of SPEEKKS membranes at the same DS. Moreover, the SPEEKKS membranes with DS equals to 0.8 showed a good combination of a high proton conductivity (0.046 S/cm at 25°C, 0.061 S/cm at 80°C), acceptable water uptake (33–65 wt %), excellent mechanical strength (tensile strength reached 49.7 MPa), and good thermal properties (Tg above 250°C, Td5% above 300°C). It suggested that this could be a promising membrane for proton exchange membrane fuel cell application. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

PREPARATION AND PROPERTIES OF SPAES-TiO2 HYBRID MEMBRANES FOR DIRECT METHANOL FUEL CELL

Sulfonated poly(arylene ether sulfone) (SPAES) copolymer with degree of sulfonation of 1.0 was synthesized and characterized. A series of SPAES-TiO2 hybrid membranes with various contents of nano-sized TiO2 particles were prepared and characterized through sol-gel reactions. Scanning electron microscopy (SEM) images indicated the TiO2 particles were well dispersed within polymer matrix. These composite membranes were evaluated for proton exchange membranes (PEMs) in direct methanol fuel cell (DMFC). These membranes showed good thermal stability and mechanical properties. It was found that the water uptake of these membranes increased with the increase of the TiO2 contents in the hybrid membranes. Meanwhile, the introduction of inorganic particles increased the proton conductivity and reduced the methanol permeability. The proton conductivities (0.118–0.162 S/cm) of SPAES-TiO2 hybrid membranes with 8% TiO2 particles are much higher than those of Nafion 117 membrane (0.095–0.117 S/cm) and pure SPAES membrane (0.100–0.124 S/cm) with degree of sulfonation of 1.0 at all temperatures (25–100°C). Especially, the methanol diffusion coefficient (8.4 × 10–7cm2/s) of SPAES-TiO2 hybrid membranes with 8% TiO2 is much lower than that of Nafion 117 membrane (2.1 × 10–6cm2/s). SPAES-TiO2 hybrid membranes were therefore proposed as candidates of material for PEM in DMFC.

Comparative study of liquid uptake and permeation characteristics of sulfonated cation-exchange membranes in water and methanol

Liquid permeation and uptake measurements of pure water and methanol were carried out using three commercial cation-exchange membranes: Nafion-117 (perfluorinated polyethylene with pendant ether-linked side chains terminated with sulfonated groups), MK-40 (microparticles of polystyrene–divinylbenzene with sulfonic groups randomly dispersed in a polyethylene matrix) and CR61-CZL-412 (crosslinked sulfonated copolymer of styrene–divinylbenzene). Methanol uptake by the Nafion-117 membrane was higher than that of water, in contrast, for MK-40 and CR61-CZL-412 membranes the opposite behavior is observed. Differences in the water and methanol liquid uptakes by the membranes were discussed in terms of the chemical interaction between the liquids and the polymers, and also on the size of the liquid molecules. On the other hand, the methanol permeation flow values through the membranes were higher than those of water for all the studied membranes.

Positron and Positronium Annihilation in Polymers Studied by Age-Momentum Correlation Spectroscopy

Positron (e) and positronium (Ps) annihilation processes in polymers are studied by positron age-momentum correlation spectroscopy, which can sensitively probe momentum distributions of e, p-Ps, and o-Ps. For polyether sulfone and ethylene tetrafluoroethylene copolymer belonging to oxygen-containing polymers (O group) and fluorine-containing polymers (F group), respectively, significant effects of positron trapping by polar element are observed. The Doppler profile of o-Ps pick-off annihilation is strongly influenced by F atoms, giving rise to anomalous broadening. The results are discussed together with our previous data of the S−I3 correlation in order to explore the feasibility of chemical analysis around the free volumes by age-momentum correlation spectroscopy.