磺化聚醚砜质子交换膜的制备及性能研究

以浓硫酸为溶剂、氯磺酸为磺化剂对聚醚砜（PES）进行了磺化，采用氢核磁共振谱（^1H NMR）、傅立叶变换红外光谱（FTIR）及热重分析（TGA）对磺化聚醚砜（SPES）进行了表征，证实PES得到了磺化。制备了一系列不同磺化度的SPES膜，测试了膜的接触角、含水率和电导率。试验结果表明，SPES具有良好的热稳定性；随着磺化度的增加，膜的亲水性能增加，膜的电导率增加。当SPES膜的磺化度达到37．0％（摩尔分数）时，SPES膜在室温下的电导率与商业化的Nafion 112膜的电导率相当。     

一种新型的燃料电池用质子交换膜--磺化聚酰亚胺膜

综述了磺化聚酰亚胺作为质子交换膜燃料电池中膜材料的研究概况。介绍了其制备方法,总结了磺化聚酰亚胺结构对膜性能的影响。重点讨论了提高磺化聚酰亚胺质子交换膜电导率的途径和影响水解稳定性的因素,结果表明：纳米孔和相分离结构有助于提高质子电导率;磺化聚酰亚胺的水解稳定性不仅与吸水率有关,还与分子链的柔性和二胺单体的碱性有关。     

一种新型磺化聚酰亚胺质子交换膜的合成与表征

质子交换膜是质子交换膜燃料电池膜电极的核心部件之一,它的性能好坏对整个系统的运行起着至关重要的作用．目前在质子交换膜燃料电池中普遍采用的质子交换膜材料是全氟磺酸系列薄膜,这类材料具有较高的质子传导率、化学及机械稳定性,但用于直接甲醇燃料电池（DMFC）时则存在甲醇渗透、导致燃料电池输出性能大大降低的问题     

静电层层自组装改性SPPESK/PWA质子交换膜

运用直接掺杂法制备的磺化聚芳醚砜酮/磷钨酸(SPPESK/PWA)复合质子交换膜存在PWA流失严重的问题,影响了膜的正常使用。为了解决这一问题,以壳聚糖(CS)和PWA为聚阴阳离子电解质对,对复合膜进行静电层层(LBL)自组装改性研究,对膜的吸水率、溶胀度、质子传导率等性能进行了表征,并测试了膜中PWA的稳定性。经测定,SPPESK/PWA/(CS/PWA)₂的质子传导率达到154mS/cm(80℃),高于相应的SPPESK膜(118mS/cm)及SPPESK/PWA膜(147mS/cm);SPPESK/PWA/(CS/PWA)₄在80℃水中浸泡30天后,膜的质量损失率由18.45%降为11.81%,电导率损失率由32.20%降为16.77%。结果表明,该方法不仅提高了复合膜的质子传导率,并且有效抑制了PWA的流失。     

六元环型磺化聚酰亚胺类质子交换膜

磺化聚酰亚胺是一类很有希望在燃料电池中获得应用的质子交换膜材料。本文对近年来六元环型磺化聚酰亚胺的制备、磺化聚酰亚胺质子交换膜的各项性能做了一定的归纳与分析。重点介绍了耐水性、耐久性、离子交换容量、质子电导率四个方面的测试方法及影响因素,指出目前存在的问题并预测了今后重点研究的方向。     

磺化聚苯并咪唑/磺化聚醚砜酸碱复合质子交换膜的制备与表征

为提高膜的尺寸稳定性和阻醇性能,以磺化聚苯并咪唑(S-PBI)与高磺化度聚醚砜(ABPS)两种聚合物为原料,采用溶液共混的方法,制备了系列酸碱复合质子交换膜。研究了复合膜的甲醇溶胀性、吸水率、甲醇渗透系数、质子传导率随S-PBI含量的变化规律。研究表明,随着S-PBI含量的增加,膜的阻醇性能和尺寸稳定性明显提高;同时,复合膜具有较好的质子传导率,有望应用于直接甲醇燃料电池。     

DMFC用磺化聚酰亚胺质子交换膜的合成与性能

以一种磺化二胺单体2,2′-二磺酸基-4,4′-二苯醚二胺(S-ODA)与非磺化单体4,4′-二苯醚二胺(ODA),及二酐单体3,3′,4,4′-二苯甲酮四羧酸二酐(BTDA)为原料,采用高温一步法直接聚合,得到了一系列磺化聚酰亚胺(SPI)质子交换膜材料,并用红外光谱对聚合物进行了表征.通过改变聚合体系中磺化单体与非磺化单体的比例控制聚合物的磺化度,并研究了材料的组成对膜的电导率、吸水率等性能的影响。     

硫酸化SnO2/SPPESK复合质子交换膜的制备及燃料电池性能

非氟聚合物磺化聚芳醚砜酮（SPPESK）具有甲醇渗透率低、化学、热稳定性高等优点,但其高的电导率需通过提高磺化度获得,导致膜因过度溶胀而失去尺寸稳定性。添加无机纳米颗粒可以有效提高膜性能,但因其表面缺少功能化基团,导致颗粒有机相容性差,阻醇性能和质子传导率不易同时提高。硫酸化改性的纳米颗粒因其表面具有酸性位点和硫酸基团,能够有效克服这一问题。本文制备表面硫酸化改性的SnO₂（SSnO₂）纳米颗粒并引入SPPESK基质制备有机无机复合质子交换膜。当SSnO₂含量不大于7.5%时,纳米颗粒具有良好的有机相容性,可均匀分散于聚合物基质。SSnO₂含量为7.5%时,80℃下复合膜吸水率（19.6%）比SPPESK原膜提高19%,接近Nafion115。颗粒诱导膜内离子簇的聚集扩大,降低了质子的传导阻力,质子传导率分别比SPPESK原膜和Nafion115膜提高48%和30%。同时,纳米颗粒增大了甲醇传递空间位阻,甲醇渗透率较SPPESK原膜和Nafion115膜分别降低46%和71%。直接甲醇燃料电池0.5V处功率密度分别比SPPESK原膜和Nafion115膜高205%和50%。     

车用燃料电池质子交换膜的制备及性能

合成了一系列具有不同支化度的磺化聚芳醚砜材料,并对其结构和性能进行了表征。所制备的磺化的支化聚芳醚砜材料的分子量可达7.00×105以上,并且分子量分布在1.17左右,拉伸强度可达20.55~28.81 MPa。随着聚合物支化度的增加,聚合物的热稳定性得到改善,在550℃下的热失重可降低至39%~45%。高支化的磺化聚芳醚砜薄膜的氧化稳定性也得到改善,80℃下的使用寿命可提高至7.25 h。支化的磺化聚芳醚砜薄膜的吸水率和质子传导率都较高。80℃下高支化度的聚芳醚砜薄膜的质子传导率可达0.33 S/cm。对其微观形貌进行观测发现,支化聚芳醚砜中的支化结构可对周围的亲水磺酸基团起支撑作用,促使其发生团聚而形成连续的质子通道。     

磺化聚芳烃质子交换膜的研究进展

质子交换膜燃料电池是21世纪最清洁的能源之一,质子交换膜是其核心组件,目前商业化的质子交换膜存在着成本高、无法高温操作、甲醇渗透率高等缺点,因此开发新型低成本,高性能的聚芳香烃质子交换膜的研究热点之一。本文介绍了聚芳烃质子交换膜的改性方法及产生的效果。     

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     

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     

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

Novel 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     

Preparation and characterization of poly(vinylidene fluoride)/sulfonated poly(phthalazinone ether sulfone ketone) blends for proton exchange membrane

Poly(vinylidene fluoride)/sulfonated poly(phthalazinone ether sulfone ketone) (PVdF/SPPESK) blend membranes are successfully prepared by solution blending method for novel proton exchange membrane (PEM). PVdF crystallinity, FTIR‐ATR spectroscopy, thermal stability, morphology, water uptake, dimension stability, and proton conductivity are investigated on PVdF/SPPESK blends with different PVdF contents. XRD and DSC analysis reveal that the PVdF crystallinity in the blends depends on PVdF content. The FTIR‐ATR spectra indicate that SPPESK remains proton‐conducting function in the blends due to the intactness of ? SO₃H group. Thermal analysis results show a very high thermal stability (T_d1 = 246–261°C) of the blends. PVdF crystallinity and morphology study demonstrate that with lower PVdF content, PVdF are very compatible with SPPESK. Also, with lower PVdF content, PVdF/SPPESK blends possess high water uptake, e.g., P/S 10/90 and P/S 15/85 have water uptake of 135 and 99% at 95°C, respectively. The blend membranes also have good dimension stability because the swelling ratios are at a fairly low level (e.g., 8–22%, 80°C). PVdF/SPPESK blends with low PVdF content exhibit very high proton conductivity, e.g., at 80°C, P/S 15/85 and P/S 10/90 reach 2.6 × 10^?2 and 3.6 × 10^?2 S cm^?1, respectively, which are close to or even higher than that (3.4 × 10^?2 S cm^?1) of Nafion115 under the same test condition. All above properties indicate that the PVdF/SPPESK blend membranes (particularly, with 10–20% of PVdF content) are very promising for use in PEM field. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Viscometric behavior of disulfonated poly(arylene ether sulfone) random copolymers used as proton exchange membranes

tert-Butylphenyl-terminated disulfonated poly(arylene ether sulfone) random copolymers with a sulfonation degree of 35 mol% (BPS35) and controlled molecular weights (M_n), 20-50 kg mol⁻¹, were successfully prepared by direct copolymerization of the two activated halides, 4,4′-dichlorodiphenyl sulfone (DCDPS) and 3,3′-disulfonate-4,4′-dichlorodiphenyl sulfone (SDCDPS) with 4,4′-biphenol and the endcapper, 4-tert-butylphenol. Dilute viscosity measurements of the BPS35 random copolymers were successfully conducted in NMP containing various concentrations of LiBr from 0.01 to 0.2 M and mostly at 0.05 M according to the measured theory. The effects of salt concentration and molecular weights of the copolymers on the viscometric behavior were studied and compared with published data for sulfonated polystyrene. The charge density parameter (ξ) for the BPS35 copolymers was determined to be smaller than 1, suggesting that no counterion condensation occurs. Studies of the effect of ionic strength (I) on the intrinsic viscosities ([η]) under theta condition were obtained by plotting [η] vs. I^−1/2 and extrapolating to infinite ionic strength. For salt-free BPS35 solutions, the viscometric behavior was shown to fit well with the Liberti-Stivala equation, providing a way to determining intrinsic viscosity when the copolymer charge is fully screened. Intrinsic viscosity and molecular weight characterization of BPS35 copolymers by SEC and static light scattering are also presented. The results are very useful for characterizing polymeric electrolyte membrane (PEM) for fuel cells, reverse osmosis and ionic transducer membranes.     

Synthesis and characterization of hexafluoroisopropylidene bisphenol poly(arylene ether sulfone) and polydimethylsiloxane segmented block copolymers

A series of hexafluoroisopropylidene bisphenol poly(arylene ether sulfone) (BAF PAES) segmented block copolymers with varying fractions of polydimethylsiloxane (PDMS) were synthesized by a condensation reaction of hydroxyl-terminated BAF PAES and dimethylamino endcapped PDMS. The segmented block copolymers have high thermal stability. The BAF PAES homopolymer exhibits a tensile modulus of 1700 MPa and an elongation at break of 16%. Copolymerizing BAF PAES with increasing molecular weight amounts of PDMS results in tensile properties ranging from plastic to elastomeric where the elongation is 417% for a segmented block copolymer with 64 wt% PDMS incorporated. The morphological properties of these segmented block copolymers were characterized by atomic force microscopy (AFM), small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM). AFM and TEM images show the segmented block copolymers were microphase separated, and comparison with bisphenol A (BA) PAES-b-PDMS segmented block copolymers revealed complex differences between the morphological behavior of the two systems. SAXS data of the segmented block copolymers supports AFM and TEM images, indicating microphase separation but little long-range order.     

Synthesis and characterization of controlled molecular weight disulfonated poly(arylene ether sulfone) copolymers and their applications to proton exchange membranes

tert-Butylphenyl terminated disulfonated poly(arylene ether sulfone) copolymers with controlled molecular weights (M_n), 20-50 kg mol⁻¹, were successfully prepared by direct copolymerization of the two activated halides, biphenol and the endcapper, 4-tert-butylphenol. The high molecular weight copolymer (molecular weight over 80 kg mol⁻¹) was also synthesized with 1:1 stoichiometry without an endcapping reagent. The chemical compositions and the molecular weights of the endcapped copolymers were characterized by their ¹H NMR spectra utilizing the 18 unique protons at the chain ends. Modified intrinsic viscosity measurements in 0.05 M LiBr/NMP solution further correlated well with NMR results. Combining the endcapping chemistry with proton NMR end group analysis and intrinsic viscosity measurements, one can demonstrate a powerful tool for characterizing molecular weight of sulfonated poly(arylene ether sulfone) random copolymers. This enables one to further investigate the influence of molecular weight on several critical parameters important for proton exchange membranes, including water uptake, in-plane protonic conductivity and selected mechanical properties. These are briefly discussed herein and will be more fully described in subsequent publications.     

Synthesis and characterization of poly(arylene ether sulfone)-b-polybenzimidazole copolymers for high temperature low humidity proton exchange membrane fuel cells

Multiblock copolymers based on poly(arylene ether sulfone) and polybenzimidazole (PBI) with different block lengths were synthesized by coupling carboxyl functional aromatic poly(arylene ethers) with ortho diamino functional PBI oligomers in NMP, selectively doped with phosphoric acid, and evaluated as a high temperature proton exchange membrane (PEM). Transparent and ductile membranes were produced by solvent casting from DMAc. From dynamic mechanical analysis (DMA), the neat copolymer membranes showed two distinct glass transition temperatures which implies the existence of a nanostructured morphology in the membranes. These two nanophases became more distinct with increasing block length. The membranes were immersed in various concentrations of phosphoric acid solution to produce the proton conductivity. The doping level increased with increasing concentration of the acid solution and a maximum doping level of 12 was achieved when 14.6 M phosphoric acid solution was used. The acid doped membranes showed significantly reduced swelling behavior compared to a control conventional phosphoric acid doped PBI homopolymer system which appears to be related to the selective sorption into the PBI phase. The ionic conductivity of the doped samples at 200 °C afforded up to 47 mS/cm without external humidification. The protonic conductivity was found to increase with block length at a given doping level, reflecting the sharpness of the nanophase separation and the effect was even more prominent at a low doping level of 6-7. It is suggested that the phosphoric acid doped multiblock copolymer system would be a strong candidate for high temperature and low relative humidity PEM applications such as those required for stationary power.     

Sulfonated poly(ether ether sulfone) copolymers for proton exchange membrane fuel cells

Novel aromatic sulfonated poly(ether ether sulfone)s (SPEESs) with tert‐butyl groups were synthesized by aromatic nucleophilic polycondensation of disodium 3,3′‐disulfonate‐4,4′‐dichlorodiphenylsulfone (SDCDPS), 4,4′‐dichlorodiphenylsulfone (DCDPS), and tert‐butylhydroquinone (TBHQ). The resulting copolymers showed very good thermal stability and could be cast into tough membranes. The morphology of the membranes was investigated with atomic force microscopy. The proton conductivity of SPEES‐40 membranes increased from 0.062 S/cm at 25°C to 0.083 S/cm at 80°C, which was higher than the 0.077 S/cm of Nafion 117 under the same testing conditions. These copolymers are good candidates to be new polymeric electrolyte materials for proton exchange membrane fuel cells. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1443–1450, 2007     

Hydrophilic-hydrophobic multiblock copolymers based on poly(arylene ether sulfone) via low-temperature coupling reactions for proton exchange membrane fuel cells

Two series of multiblock copolymers based on poly(arylene ether sulfone)s were developed and evaluated for use as proton exchange membranes (PEMs). The multiblock copolymers were synthesized by a coupling reaction between phenoxide terminated fully disulfonated poly(arylene ether sulfone) (BPSH100) and decafluorobiphenyl (DFBP) or hexafluorobenzene (HFB) end-capped unsulfonated poly(arylene ether sulfone) (BPS0) as hydrophilic and hydrophobic blocks, respectively. The highly reactive nature of DFBP and HFB allowed the coupling reactions to be accomplished under mild reaction conditions (e.g., <105 °C). The low coupling temperatures prevented possible ether-ether exchange reactions which can cause a loss of order due to randomization of the hydrophilic-hydrophobic sequences. The multiblock copolymers produced tough and ductile membranes and their fundamental properties as PEMs were explored. They showed enhanced conductivities under fully hydrated conditions when compared with a random BPSH copolymer with a similar IEC. These copolymers also showed anisotropic swelling behavior, whereas the random copolymers were isotropic. The synthesis and fundamental properties of the multiblock copolymers are reported here and the systematic fuel cell properties and more detailed morphology characterization will be provided elsewhere.