The preparation of microporous membranes from blends of poly(2,6‐dimethyl‐1,4‐phenylene oxide) and sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) is a chemically resistant polymer and, therefore, an attractive material for the formation of membranes. However, membranes of unmodified PPO prepared by an immersion precipitation possess very low hydraulic permeabilities at the filtration processes. The membranes with higher hydraulic permeabilities can be prepared from sulfonated PPO and/or from blends of unsulfonated PPO and sulfonated PPO. In conclusion, the mechanism of the formation of membranes from blends of unsulfonated PPO and sulfonated PPO is suggested. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 161–167, 1999     

磺化聚醚醚酮的性能与应用

聚醚醚酮(PEEK)是一种性能优异的工程塑料。笔者简单地介绍了聚醚醚酮的特性,对近年来磺化聚醚醚酮的制备、SPEEK的性能及应用做了比较全面的归纳,并对磺化聚醚醚酮未来的发展前景进行了展望。     

Novel sulfonated poly(arylene biphenylsulfone ether) copolymers containing bisphenylsulfonyl biphenyl moiety: structural,thermal, electrochemical and morphological characteristics

A series of sulfonated poly(arylene biphenylsulfone ether) polymers containing up to two pendant sulfonic acid groups per repeat unit were successfully synthesized from 4,4′‐bis[(4‐chlorophenyl)sulfonyl]‐1,1′‐biphenyl (BCPSBP), disodium 3,3′‐disulfonate‐4,4′‐dichlorodiphenylsulfone (SDCDPS) and bisphenol A via aromatic nucleophilic displacement polycondensation. The resulting polymers were characterized by means of Fourier transform infrared and ¹H NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis (TGA). The number‐average molecular weight (M_n) of the synthesized polymers was in the range 15 300–22 900 g mol^?1, and the polydispersity indices (M_w/M_n) varied from 2.5 to 4.4. Tough membranes with SDCDPS/BCPSBP mole ratio up to 50:50 were successfully cast using N‐methyl‐2‐pyrrolidone (NMP). An increase of sulfonic acid groups in the polymer backbone resulted in increased solubility in aprotic polar solvents and glass transition temperature. The TGA curves of all the copolymers in acid form exhibited two distinct weight‐loss profiles. The influential characteristics of the polymer electrolyte membranes, such as tensile strength, water uptake, ion‐exchange capacity and proton conductivity, were characterized with respect to the pendant sulfonic acid groups. Atomic force microscopy phase images of the acid‐form membranes clearly showed the hydrophilic domains, with sizes increasing as a function of the degree of sulfonation. Copyright © 2010 Society of Chemical Industry     

Preparation and characterization of sulfonated poly(arylene‐co‐naphthalimide)s for use as proton exchange membranes

In this study, conductive porous composites were fabricated using the host substrate with an interconnected porous network, followed by the penetration and deposition of polypyrrole (PPy) to create a continuous conductive network. The open‐porous host substrate was processed using polylactide (PLA) with compression molding and salt leaching techniques. Three different salt contents were varied from 75 wt %, 85 wt %, and 90 wt %, which were referred to by their salt‐to‐polymer mass ratios of 3, 6, and 9, respectively. The porous network was made conductive by coating its interior surfaces through in situ polymerization of PPy using iron (III) chloride as the oxidant species. These porous composites were then characterized to analyze the relationships between their morphology and their physical, conductive, and mechanical properties. The mechanical properties were then fitted with numerically simulated results from finite element modeling (FEM). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

SPTES-b-PI质子交换膜的制备及表征

质子交换膜作为质子交换膜燃料电池的核心部件具有提供离子通道传递质子和隔绝两极气体的双重作用,其性能的好坏直接影响着电池性能的优劣。主链引入亲水和疏水段的嵌段芳香族共聚物,由于各嵌段之间具有热力学不相容性会产生微相分离结构,进而形成高效的质子传导通道。本文以磺化双（4-氟苯基）砜（SDFDPS）和4,4'-硫代双苯硫酚（TBBT）为单体,以间羟基苯胺为封端剂合成了带有氨端基的磺化聚芳硫醚砜（SPTES-NH₂）。嵌段聚合物SPTES-b-PI通过亲水段SPTES-NH₂与以1,4,5,8-萘四羧酸二酐（NDA）和4,4'-双（3-氨基苯氧基）二苯基砜（m-BAPS）为单体缩聚而成的疏水段聚酰亚胺（PI）的酰亚胺化偶联反应来合成,制备出了PI分子量不同的SPTES-b-PIx（x=5~20kg/mol）。SPTES-b-PIx膜显示出优异的热力学稳定性,SPTES-b-PIx膜的脱磺化反应开始于290℃高于260℃的SPTES膜,与SPTES-70相比吸水率降低。随着聚酰亚胺分子量的增大,热稳定性增加,质子传导率增加。SPTES-b-PIx的质子传导率25℃下达到0.045~0.124S/cm。     

Poly(arylene ether)s carrying pendant (3‐sulfonated) phenylsulfonyl groups

A series of poly(arylene ether)s with biphenyl units and pendant sulfonated phenylsulfonyl groups was prepared via nucleophilic aromatic substitution reactions of varying ratios of 3,5‐difluoro‐3′‐sulfonated diphenylsulfone and 4,4′‐difluorodiphenylsulfone with 4,4′‐biphenol. As such, the sulfonic acid moieties reside in the meta position of a pendant, electron‐poor phenylsulfonyl group. Mechanically robust proton‐exchange membranes with ion‐exchange capacities (IEC) ranging from 0.91 to 2.05 meq g^?1 were cast from dimethylacetamide. The thermal stability of the membranes was evaluated via thermogravimetric analysis and the 5% weight losses were found to be in excess of 330 °C in air. The glass transition temperatures were determined, via differential scanning calorimetry, to range from a low of 148 to a high of 209 °C at IEC values of 0.91 and 1.79 meq g^?1, respectively. The copolymer membranes reached proton conductivities as high as 142 mS cm^?1 under 100% relative humidity, with relatively low water uptake values (8–32 wt%). Copyright © 2012 Society of Chemical Industry     

Novel hollow‐fiber anion‐exchange hybrid membranes: Preparation and characterization

To develop ion‐exchange membranes for application in severe conditions, such as those with high temperatures, strongly oxidizing environments, or organic solvents, new hollow‐fiber anion‐exchange hybrid membranes were prepared by the immersion of brominated poly(2,6‐dimethyl‐1,4‐phenylene oxide) base hollow fibers in a tetraethoxysilane–ethanol solution followed by sol–gel and quaternary amination. Compared to conventional polymeric charged membranes, the prepared hybrid membranes were higher in both thermal and dimensional stabilities. The results suggest that tetraethoxysilane concentration was an important factor affecting the membrane's intrinsic properties. When the tetraethoxysilane concentration was in the range 15–45%, the final hollow‐fiber anion‐exchange hybrid membranes had an ion‐exchange capacity of 1.9–2.0 mmol/g, a water uptake of.83–1.23 g of water/g of dry weight, and a dimensional change ratio of 13–18%. An evaluation on the membranes' separation performances is underway. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

In situ crosslinkable sulfonated polyaromatic ionomers for the polyelectrolyte used in proton exchange membrane fuel cell

Two series of sulfonated poly(arylene ether nitrile ketone) ionomers containing potential crosslinkable nitrile groups were synthesized in high yield by direct aromatic nucleophilic polycondensation of 1,4‐bis‐(4‐hydroxyphenyl)‐2,3‐dicyano ‐naphthalene ( 3 ) with different molar ratio of disodium 5,5′‐carbonyl‐bis‐(2‐fluorobenzene‐sulfonate) ( 4 ) to 5,5′‐carbonyl‐bis‐(2‐fluorobenzene) ( 5 ) or 4,4‐biphenol ( 7 ). Subsequently, the sulfonated polymeric ionomers were in situ crosslinked when cast into membranes from solution at 180°C under nitrogen protection. The structure of the synthesized polymers was characterized by ¹H‐nuclear magnetic resonance (NMR), Fourier‐transform infrared spectra, and elemental analysis. Comparing with the original polymeric membranes, the crosslinked membranes showed much better thermal and hydrolytic stabilities and superior mechanical properties as well as much lower swelling behavior, which were even better than Nafion 117 membrane. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Microporous membranes prepared from blends of polysulfone and sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Membranes were prepared from solutions containing Udel‐type polysulfone (PSf) and sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SPPO). Polymer solutions in 1‐methyl‐2‐pyrrolidone were cast on a nonwoven textile and precipitated in a water bath. The permeabilities and selectivities of the prepared membranes depended on the concentrations of both polymers in the casting solution. The higher the concentration of PSf, the lower were the permeabilities to water and average pore sizes of the membranes. On the other hand, a very small amount of SPPO in the casting solution (about 1–4 wt % relative to the casting solution weight) brought about a considerable increase in water permeabilities and had a small influence on the average pore sizes. The effects were most pronounced if SPPO with a degree of sulfonation of 20–40% was used. The considerable increase in water permeabilities was explained by separation of the PSf and SPPO phases during precipitation in water and by the concentration of hydrophilic SPPO on the surface of the membrane and its pores. The determinations of the oriented concentration potentials proved the presence of a negative surface charge in the membranes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 134–142, 2001     

Characterization of molecular interaionic and intraionic crosslinkable sulfonated poly(ether ether ketone‐alt‐benzimidazole) membrane

Lysozyme-loaded polymeric composite microparticles were successfully coprecipitated by solution-enhanced dispersion by supercritical CO₂ (SEDS), starting with a homogeneous organic solvent solution of lysozyme/poly(L -lactide)/poly(ethylene glycol) (lysozyme/PLLA/PEG). The effects of different drug loads (5, 8, and 12% w/w), PLLA Mw (10, 50, 100, and 200 kDa), PEG contents (0, 10, 30, and 50% PEG/(PLLA+PEG) w/w), and PEG Mw (400, 1000, and 4000 kDa) on the surface morphology, particle size, and drug release profile of the resulting composite microparticles were investigated. The results indicate that the size of the microparticles decreased and the rate of drug release increased with an increase in drug load, PEG content, or PEG Mw; the particle size first increased and then decreased with an increase in PLLA Mw, and the drug release was controlled by both particle size and PLLA Mw. The Fourier transform infrared spectrometer analysis and circular dichroism spectra measurement reveal that no significant changes occurred in the molecular structures during the SEDS processing, which is favorable to the production of protein–polymer composite microparticles for a protein drug delivery system. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Influence of chemical compositions on the properties of random and multiblock sulfonated poly(arylene ether sulfone)‐based proton‐exchange membranes

The influence of chemical compositions on the properties of sulfonated poly(arylene ether sulfone)‐based proton‐exchange membranes was studied. First, we synthesized three different series of random SPAES copolymers using three kinds of hydrophobic monomers, including 4,4′‐dihydroxyldiphenylether, 2,6‐dihydroxynaphthalene (DHN), and 4,4′‐hexafluoroisopropylidenediphenol (6F‐BPA) to investigate effects of hydrophobic components on the properties of SPAES membranes as proton‐exchange membranes. Random SPAES copolymers with 6F‐BPA showed the highest proton conductivity while random SPAES copolymers with DHN displayed the lowest methanol permeability among the three random copolymers. Subsequently, we synthesized multiblock SPAES using the DHN as a hydrophobic monomer and studied the effect of the length of hydrophilic segments in the multiblock SPAES copolymers on membrane performance. The results indicated that longer hydrophilic segments in the copolymers led to higher water uptake, proton conductivity, and proton/methanol selectivity of membranes even at low humidity. In addition, the morphology studies (AFM and SAXS measurements) of membranes suggested that multiblock copolymers with long hydrophilic segments resulted in developed phase separation in membranes, and ionic clusters formed more easily, thus improving the membrane performance. Therefore, both the kinds of hydrophobic monomers and the length of hydrophilic segments in SPAES copolymers would influence the membranes performance as proton‐exchange membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Characterization of random and multiblock copolymers of highly sulfonated poly(arylene ether sulfone) for a proton‐exchange membrane

Random and multiblock copolymers of sulfonated poly(arylene ether sulfone) (SPAES) were synthesized and characterized to compare the differences in the properties of proton‐exchange membranes made with random and multiblock SPAES copolymers. Atomic force microscopy observations and small‐angle X‐ray scattering measurements suggested the presence of nanoscale, clusterlike structures in the multiblock SPAES copolymers but not in the random SPAES copolymers. Proton‐exchange membranes were prepared from random and multiblock copolymers with various ion‐exchange capacities (IECs). The water uptake, proton conductivity, and methanol permeability of the SPAES membranes depended on the IECs of the random and multiblock SPAES copolymers. At the same IEC, the multiblock SPAES copolymers exhibited higher performances with respect to proton conductivity and proton/methanol permeation selectivity than the random SPAES copolymers. The higher performances of the multiblock SPAES copolymers were thought to be due to their clusterlike structure, which was similar to the ionic cluster of a Nafion membrane. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Proton exchange membranes prepared by simultaneous radiation grafting of styrene onto poly(tetrafluoroethylene‐co‐hexafluoropropylene) films. II. Properties of sulfonated membranes

Proton exchange membranes were prepared by radiation‐induced grafting of styrene onto commercial poly(tetrafluoroethylene‐co‐hexafluoropropylene) films using a simultaneous irradiation technique followed by a sulfonation reaction. The resulting membranes were characterized by measuring their physicochemical properties such as water uptake, ion exchange capacity, hydration number, and proton conductivity as a function of the degree of grafting. The thermal properties (melting and glass transition temperatures) and thermal stability of the membrane were also investigated using differential scanning calorimetry and thermal gravimetric analysis, respectively. Membranes having degrees of grafting of 16% and above showed proton conductivity of the magnitude of 10⁻² Ω⁻¹ cm⁻¹ at room temperature, as well as thermal stability at up to 290°C under an oxygen atmosphere. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2443–2453, 2000     

Synthesis and properties of novel sulfonated poly(phenylquinoxaline)s as proton exchange membranes

Two series of sulfonated poly(phenylquinoxaline)s (SPPQ-x and SPPQ(O)-x, x refers to molar percentage of sulfonated tetraamine monomer) were first synthesized from a sulfonated tetraamine (4,4′-bis(3,4-diaminophenoxy)biphenyl-3.3′-disulfonic acid) and two aromatic bisbenzils (4-phenylglyoxalylbenzil and p,p′-oxydibenzil) in a mild condition. The structures of SPPQ-x and SPPQ(O)-x were characterized by IR and ¹H NMR spectra. The properties of these polymer films, such as water uptake, water swelling ratio, proton conductivity, thermal properties, methanol permeability, hydrolytic and oxidative stability were also investigated. The resulting polymers generally showed good solubility in DMAc and DMSO. Flexible and tough membranes with high mechanical strength were prepared. They show very high thermal, thermooxidative, hydrolytic stabilities and low methanol permeability. SPPQ-100 with the IEC value (2.41 mmol/g) displays the conductivity of 0.1 S/cm and a swelling ratio of 7.3% at 100 °C. The low swelling was attributed to the high rigid of polymer backbones and the strong intermolecular interaction between the basic nitrogen atoms of quinoxaline units and sulfonic acid groups. Moreover, we found that the conductivities of SPPQ(O)-x membranes were higher than SPPQ-x membranes at the similar IEC value. The highest conductivity of 0.2 S/cm was obtained for SPPQ(O)-100 at 140 °C. A combination of excellent dimensional and hydrolytic stabilities indicated that the SPPQ ionomers were good candidate materials for proton exchange membrane in fuel cell applications.     

磺化聚苯醚质子交换膜的制备与性能研究

以氯磺酸为磺化剂制备了一系列不同磺化度的磺化聚苯醚(SPPO)膜,通过热重-红外联用分析、差示扫描量热分析、含水率测试、力学性能和电导率测试,探讨了SPPO膜作为质子交换膜用于燃料电池的可能性。结果表明,SPPO存在3个阶段的失重,分别归属于吸收的水分、磺酸基团及主链的降解,磺化之后热稳定性虽有所下降,但主链的降解温度基本保持不变,玻璃化转变温度明显升高;SPPO的含水率随着磺化度和温度的增加而增加;膜的拉伸强度则随着磺化度的增加而降低,且膜在湿态时的强度较干态时的要低,但与商业化的Nafion 112膜相比仍具有较高的强度;磺化度为40.1%的SPPO膜在室温下的电导率为1.16×10-2S/cm,与Nafion 112膜为同一数量级。     

全钒液流电池用磺化聚芴醚酮质子交换膜的制备及性能

质子交换膜(PEM)作为全钒液流电池(VRFB)的核心组件之一,应当解决成本高昂、合成过程复杂等问题,并具备高质子传导率、低钒离子渗透率、高机械强度和优异化学稳定性等关键性能。本文基于四甲基双酚芴单体通过缩聚反应合成了一系列聚芴醚酮化合物PFEKs,再利用溴代反应将苯甲基功能化为溴甲基,接着通过4-羟基苯磺酸钠的SN₂亲核取代制得了一系列不同离子交换容量的磺化聚芴醚酮聚合物(SPFEKs)。通过溶液浇铸法成膜并酸化,得到一系列新型低成本PEMs。该合成路线的原料来源广泛,价格低廉,不涉及危险的磺化反应,易于工业放大。所得膜都具有良好的机械性能和氧化稳定性,其中SPFEK-40膜具有较高的质子传导率及离子选择性、较低的钒离子渗透率及面电阻,综合性能优异。以SPFEK-40膜组装的VRFB在电流密度为80 mA/cm₂^{时的能量效率}(EE)为88.2%,高于以Nafion 212膜组装的VRFB的84.8%。此外,以SPFEK-40膜组装的VRFB在30次循环后放电容量仅衰减至84.3%,远高于以Nafion 212膜组装的VRFB的66.1%。     

Effect of polymers blend ratio binder on electrochemical and morphological properties of PC/S‐PVC‐based heterogeneous cation‐exchange membranes

In this research, heterogeneous cation exchange membranes were prepared by the casting‐solution technique using polycarbonate (PC) and S‐polyvinylchloride (S‐PVC) as binders along with cation exchange resin as functional group agent. The effect of blend ratio (PC to S‐PVC) of polymer binder on structure and electrochemical properties of the prepared membranes were elucidated. The morphology of the prepared membranes was investigated by scanning electron microscopy (SEM) and scanning optical microscopy (SOM). The images show that the addition of PC ratio in the casting solution results in formation of a membrane with more inner cavities and micro voids. The electrochemical properties and mechanical strength tests were conducted. Water content, ion exchange capacity, ion permeability, flux, current efficiency, and oxidative stability of the prepared membranes initially were decreased by increasing the PC ratio in the casting solution and then it began to increase. The blending of S‐PVC and PC polymers results in membranes with lower mechanical strength. Membrane potential, surface charge density, perm‐selectivity, cationic transport number, electrical resistance, and energy consumption were initially improved by the increment of PC ratio in the casting solution and then it decreased. The membrane with 70% PC exhibited the highest flux, maximum current efficiency, and minimum energy consumption. However, the selectivity of this membrane was low compared with the other prepared membranes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Ion‐exchange membranes prepared by blending sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide) with polybenzimidazole

New ion‐exchange acid/base‐blend (SPPO/PBI) membranes were prepared by mixing N,N‐dimethylacetamide (DMA) solutions of sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SPPO) in the ammonium form and of polybenzimidazole (PBI), casting the solution as a thin film, evaporating the solvent, and treating the membrane with aqueous hydrochloric acid. The resulting membranes were found insoluble in DMA. The preliminary tests of the membranes were carried out in an H₂/O₂ fuel cell at room temperature. Their performance in the fuel cell increased with the increase in the concentration of SPPO sulfonic acid groups in the blend, but the membranes formed with the highly sulfonated SPPO alone or predominanting, which swelled excessively in water, did not give reproducible results, and their performance was usually inferior to that of the membranes having an optimum ratio of both components. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1118–1127, 2002     

聚丙烯腈/磺化聚苯醚质子交换膜的制备和性能

采用溶液共混浇铸法制备了一系列的聚丙烯腈/磺化聚苯醚(PAN/SPPO)共混质子交换膜.结果表明,磺酸基团成功引入交换膜,共混膜有较好的相容性,没产生相分离,PAN/SPPO共混膜的吸水率和溶胀率明显降低,其热性能稳定.与纯SPPO膜相比,虽然英质子传导率有所下降,但都在10-2～ 10-3S/cm数量级范围内,究全可...     

Influence of casting conditions on the properties of sulfonated poly(ether ether ketone ketone)/phosphotungstic acid composite proton exchange membranes

The sulfonated poly(ether ether ketone ketone)/phosphotungstic acid (SPEEKK/PWA) composite membranes were researched for proton exchange membranes. The effect of casting condition on the properties of membranes was studied in detail. The study showed that the casting condition has great influence on the membrane properties because of the hydrogen bond between the SPEEK and PWA and the interaction between the SPEEKK and dimethylformamide (DMF). The PWA particles are well crystallized on the surface when the velocity of the solvent volatilization is very slow under the SEM. The study will favor further research on excellent composite membranes for proton exchange membrane fuel cells. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4020–4026, 2007