全钒液流电池用SPEEK／PES共混膜的制备

通过将PES掺入高磺化度的SPEEK进行共混改性,采用流延法制备了一系列不同PES含量的SPEEK／PES共混膜,获得了SPEEK／PES共混膜的离子交换容、含水率、质子电导率等参数,特别测定了在全钒液流电池工作条件下钒（IV）离子渗透率。综合考察发现,当磺化温度为45℃,磺化时间控制为4h,得到SPEEK的DS为55％,掺入10％的PES,此时共混膜的电导率为0．08S／cm,钒（IV）离子渗透率为0．38×10^-6cm2／min,对钒（IV）离子选择性为Nation膜的5倍,含水率为35％,共混膜综合性能最好,基本满足全钒液流电池（VRB）的使用需求。     

聚醚砜/磺化聚醚醚酮共混膜的制备和性能

采用流延法制备了聚醚砜(PES)含量不同的PES/磺化聚醚醚酮(SPEEK)共混膜。PES与SPEEK具有良好的相容性。所制备PES/SPEEK共混膜的含水率、溶胀度和甲醇透过系数均随PES含量的增加而降低。虽然共混膜的质子传导性能有所降低.但阻醇性能和溶胀性能提高,这说明PES/SPEEK共混膜是一种很好的直接甲醇燃料电池用固体高分子电解质膜材料。     

SPEEK/B-SPEEK共混质子交换膜的制备及其性能

聚醚醚酮进行磺化,得到了磺化聚醚醚酮(SPEEK),再先后与氯化亚砜和对甲苯磺酰胺反应,制备侧链含磺酰亚胺基的聚醚醚酮(B-SPEEK)。将SPEEK和B-SPEEK以不同的比例共混制备质子交换膜,研究了共混膜的结构、质子交换容量、吸水率、电导率、力学性能和热性能等。结果表明:SPEEK与B-SPEEK按质量比为1.0∶1.0制备的共混膜具有较好的力学性能(拉伸强度25.3 MPa,断裂伸长率45.1%)和最高的电导率(在80℃的条件下,电导率为0.227 S/cm),是一类非常有潜力的质子交换膜。     

直接甲醇燃料电池用新型质子交换膜的研究

以聚醚醚酮(PEEK)为原料,浓硫酸为磺化剂制备了不同磺化度的磺化聚醚醚酮(SPEEK)膜,以及磺化聚醚醚酮与聚乙烯醇(PVA)、正硅酸乙酯(TEOS)、磷钨酸的复合膜.分别对膜的电导率、阻醇性能和吸水率进行了研究.随着SPEEK膜磺化度的增大,膜的电导率有所提高,然而甲醇渗透系数也增大,膜的机械强度明显降低.SPEEK膜的吸水率低于Nafion 115膜,而PVA膜的吸水率则过高.     

高通量PES/PAN超滤膜的制备及性能研究

为了制备高通量、高截留PES超滤膜,将不同质量的PES和聚丙烯腈(PAN)进行共混,通过非溶剂致相分离法(NIPS)制备PES/PAN超滤膜。详细探讨了PES与PAN共混比例对PES/PAN超滤膜的结构和性能的影响,结果表明,当PES/PAN的共混质量比例为8∶2时,PES/PAN膜的分离性能最佳,通量为509 L/(m2·h),是纯PES膜的5倍,BSA的截留率达到98.75%。     

SPEEK/改性MWCNT复合质子交换膜的制备与性能

制备了带有柔性有机侧链的改性碳纳米管(MWCNT-G),并与磺化聚醚醚酮(SPEEK)共混制得复合膜。扫描电镜(SEM)分析结果表明,MWCNT-G比原始MWCNT在SPEEK中分散更均匀。在1%的掺杂比例下对比分析了SPEEK/MWCNT膜及SPEEK/MWCNT-G膜的质子传导率、吸水率、溶胀度、机械性能、化学稳定性、热稳定性等。SPEEK/MWCNT-G膜未降低吸水率却降低了溶胀度,在机械强度及稳定性上均有所提高。SPEEK/MWCNT-G膜质子传递阻力更低,60℃时其质子传导率达0. 086 S/cm,是SPEEK/MWCNT膜的1. 46倍、SPEEK膜的1. 72倍。该方案使MWCNT与SPEEK相容性差的状况得以改善。     

新型聚醚砜-磺化聚醚砜共混膜的性能研究

以浓硫酸为聚醚砜(PES)的溶剂和磺化剂,制备磺化聚醚砜(SPES)。选取磺化度(DS)为14%的SPES溶液,制备PES-SPES共混膜,考察了共混膜的脱盐效果和抗污染性能。结果表明,共混膜的基质材料中,随SPES、PES的质量比的增加,共混膜表面膜孔径增大,断面结构由指状孔向海绵状孔转化,共混膜水通量增加,截留率降低,当SPES的DS为14%、SPES、PES的质量比0.75时,制得共混膜水通量为253.7 L/(m~2·h),对PEG6000、PEG10000和PEG20000的截留率分别为56.8%、74.5%和90.6%;共混膜在相同测试条件下对Na_2SO_4截留效果大于NaCl,经亲水改性的PES-SPES共混膜亲水性提高,抗污染性能明显增强。     

磺化聚砜/聚醚砜纳滤膜的制备及性能表征

采用相转化法制备了磺化聚砜(SPSF)/聚醚砜(PES)共混新型纳滤膜,并研究了SPSF/PES共混质量比、水解的苯乙烯–马来酸酐共聚物(H–PSMA)的添加量、铸膜液预蒸发时间和温度对膜的脱盐率及水通量的影响。结果表明,当SPSF/PES共混质量比为4∶6,添加剂H–PSMA的质量分数为2%,铸膜液预蒸发时间为3 min,预蒸发温度为70℃时,在操作压力为0.5 MPa,料液温度为25℃下,SPSF/PES共混膜对2 g/L的Na_2SO_4盐溶液脱盐率为56.77%,水通量为24.45 L/(m~2·h)。     

聚醚砜质量分数对聚偏氟乙烯/聚醚砜共混膜性能和结构的影响

用与聚醚砜共混的方法来改善聚偏氟乙烯膜的抗收缩性能,以二甲基乙酰胺作溶剂,聚乙烯吡咯烷酮为添加剂,研究了聚醚砜(PES)质量分数对聚偏氟乙烯/聚醚砜共混膜的收缩率、水通量、截留率及形态结构的影响。聚醚砜的加入可以有效地降低共混膜的收缩率,在w(PES)=1.5%时,共混膜的水通量取得极大值,截留率取得极小值。     

两亲性聚合物的合成及其共混改性聚醚砜超滤膜的研究

针对聚醚砜(PES)高分子膜材料的分子结构特点进行分子设计,合成了一系列既具有聚醚砜结构单元又有聚乙二醇(PEG)亲水链段的两亲性聚合物PES-co-PEG,与PES共混用相转化法制备超滤膜,对PES-co-PEG进行了表征,考察了反应条件对聚合产物的影响,测试了PES-co-PEG膜的性能。结果表明,使用相对分子质量为2 000的PEG、以环丁砜做溶剂、在230℃下聚合8 h以上反应效果为佳;共混改性的超滤膜纯水通量由99.5 L/(m2.h)最高上升到277.7 L/(m2.h),截留率与纯PES膜相比差别很小,均保持在90%以上;经过纯水清洗后的共混膜的通量基本恢复到原来水平。共混改性成功改善了PES超滤膜的亲水性和抗污染性能。     

Preparation and characterization of blend anion-exchange membrane from quarternized hydroxyethylcellulose/quaternized poly(vinyl alcohol)

阴离子交换膜是碱性直接甲醇燃料电池（ADMFC）的核心。本文将季铵化羟乙基纤维素（QHEC）和季铵化聚乙烯醇（QPVA）共混制备了一系列不同配比的QPVA/QHEC阴离子交换膜并对其进行热交联,对膜进行测试和分析,结果表明：膜表面均匀致密,低于300 ℃膜基本稳定;QPVA/QHEC共混膜的导电率随着QPVA量的增大而增大,在（2.0～7.8）×10－2 s/cm范围内,随着使用温度的升高逐渐升高;QHEC膜对甲醇有很好的阻隔效果,在20 ℃时,甲醇渗透率最低为2.49×10－6 cm2/s;随QPVA量的增加,共混膜的甲醇渗透率会略有增加。     

Partially Sulfonated Poly(1,4‐phenylene ether‐ether‐sulfone) and Poly(vinylidene fluoride) Blend Membranes for Fuel Cells

Blend membranes based on high conductive sulfonated poly(1,4‐phenylene ether‐ether‐sulfone) (SPEES) and poly(vinylidene fluoride) (PVDF) having excellent chemical stability were prepared and characterized for direct methanol fuel cells. The effects of PVDF content on the proton conductivity, water uptake, and chemical stability of SPEES/PVDF blend membranes were investigated. The morphology, miscibility, thermal, and mechanical properties of blend membranes were also studied by means of scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) measurements. The blend membrane containing 90 wt.% SPEES (degree of sulfonation – DS = 72%) and 10 wt.% PVDF (M_w = 180,000) exhibits optimum properties among various SPEES72/PVDF membranes. Addition of PVDF enhanced resistance of the SPEES membrane against peroxide radicals and methanol significantly without deterioration of its proton conductivity. It's proton conductivity at 80 °C and 100% relative humidity is higher than Nafion 115 while it's methanol permeability is only half of that of Nafion 115 at 80 °C. The direct methanol fuel cell performance of the SPEES membranes was better than that of Nafion 115 membrane at 80 °C.     

Proton exchange membranes based on poly(vinylidene fluoride) and sulfonated poly(ether ether ketone)

Blend membranes were obtained by solution casting from poly(vinylidene fluoride) (PVDF) and sulfonated poly(ether ether ketone) (SPEEK) in N,N-dimethylacetamide (DMAc). DSC and XRD were used to characterize the structure of the blend membranes. The effect of PVDF content on the membrane properties was investigated. The methanol permeability, water uptake and the swelling ratio of blend membranes decreased with the increase of PVDF content. Though the proton conductivity decreased upon the addition of PVDF, they were still comparable to that of Nafion^® 117 membrane. Higher selectivities were also found for most blend membranes in comparison with Nafion^® 117 membrane. The effect of methanol concentration on solution uptake, swelling ratio and methanol permeability of the blend membranes was also studied.     

DMFCs用磺化聚醚醚酮/磺化酚酞型聚醚砜共混质子交换膜

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 SPEEK/SPES-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 70ºC, whereas the swelling degree of the SPEEK (DS 61.7%)/SPES-C (40%, by mass) membrane is 29.7% at 80ºC. From room temperature to 80ºC, 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 150ºC. 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 140ºC and 100% RH, while pure SPEEK (DS 55.1%) membrane dissolves at 90ºC. 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.     

Preparation and characterizations of direct methanol fuel cell membrane from sulfonated polystyrene/poly(vinylidene fluoride) blend compatibilized with poly(styrene)‐b‐poly(methyl methacrytlate) block copolymer

This work concerned a development of sulfonated polystyrene (SPS)/poly(vinylidene fluoride) (PVDF) blend membrane for use as an electrolyte in a direct methanol fuel cell. The aim of this work was to investigate effects of the blend ratio on properties of the blend membranes. The partially SPS with various degrees of substitution were prepared by using propionyl sulfate as a sulfonating agent. After that, the optimum SPS was selected for further blending with PVDF, at various blend ratios. Poly(styrene)–poly(methyl methacrytlate) block copolymer (PS‐b‐PMMA), used as a compatibilizer, was synthesized via a controlled radical polymerization through the use of an iniferter. Thermal behaviors, water uptake, proton conductivity, and methanol permeability of various blend membranes were determine by using TGA, gravimetry, impedance analyzer, and gas chromatography, respectively. From the results, it was found that, water uptake and methanol permeability of the blend membranes tended to increase with the weight ratio of SPS. It was also found that the blend membranes were incompatible, especially those containing more than 40 wt % of the SPS. However, by adding 5 wt % of the block copolymer, the blend became more compatible. Mechanical strength, proton conductivity, and resistance to methanol crossover of the blend membrane remarkably increased after the compatibilization. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Sulfonated poly(ether ether ketone)/epoxy/phenol novolac blend proton‐exchange membranes with low methanol permeability

A crosslinked epoxy [4,4′‐diglycidyl‐(3,3′,5,5′‐tetramethylbiphenyl) epoxy resin (TMBP)], cured by phenol novolac (PN), was introduced into a sulfonated poly(ether ether ketone) (SPEEK) membrane (ion‐exchange capacity = 2.0 mequiv/g) with a casting‐solution, evaporation, and heating crosslinking method to improve the mechanical properties, dimensional stability, water retention, and methanol resistance. By Fourier transform infrared analysis, the interactions between the sulfonic acid groups and hydroxyl groups in the blend membranes were confirmed. The microstructure and morphology of the blend membranes were investigated with atomic force microscopy. As expected, the blend membranes showed excellent mechanical properties, good thermal properties (thermal stability above 200°C), lower swelling ratios (1.4% at 25°C and 7.0% at 80°C), higher water retention (water diffusion coefficient = 9.8 × 10^?6 cm²/s), and a lower methanol permeability coefficient (3.6 × 10^?8 cm²/s) than the pristine SPEEK membrane. Although the proton conductivity of the blend membranes decreased, a higher selectivity (ratio of the proton conductivity to the methanol permeability) was obtained than that of the pristine SPEEK membrane. The results showed that the SPEEK/TMBP/PN blend membranes could have potential use as proton‐exchange membranes in direct methanol fuel cells. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

季铵化羟乙基纤维素/季铵化聚乙烯醇共混阴离子交换膜的制备与表征

阴离子交换膜是碱性直接甲醇燃料电池(ADMFC)的核心。本文将季铵化羟乙基纤维素(QHEC)和季铵化聚乙烯醇(QPVA)共混制备了一系列不同配比的QPVA/QHEC阴离子交换膜并对其进行热交联,对膜进行测试和分析,结果表明:膜表面均匀致密,低于300℃膜基本稳定;QPVA/QHEC共混膜的导电率随着QPVA量的增大而增大,在(2.0～7.8)×10-2 s/cm范围内,随着使用温度的升高逐渐升高;QHEC膜对甲醇有很好的阻隔效果,在20℃时,甲醇渗透率最低为2.49×10-6 cm2/s;随QPVA量的增加,共混膜的甲醇渗透率会略有增加。     

PEO–PPO–PEO triblock copolymer/Nafion blend as membrane material for intermediate temperature DMFCs

This paper describes homogeneous triblock copolymer/Nafion blend membranes, which facilitate proton conduction in direct methanol fuel cells (DMFCs) at intermediate temperatures. The interaction between the two polymer components is investigated by FT-IR spectroscopy. The blend membranes show higher proton conductivity than recast Nafion under partially anhydrous conditions. Protons can be transported with the assistance of ether chain under such conditions at elevated temperature. In addition, the membranes exhibit more favourable methanol permeability and selectivity. This kind of blend membrane shows somewhat better performance in DMFC compared to bare recast Nafion at intermediate temperature (≥120 °C). This work is a first attempt in our group to design membrane materials with enhanced proton conductivity under conditions typical of intermediate temperature DMFCs.     

Preparation and characterization of PSSA/PVA catalytic membrane for biodiesel production

Poly(styrene sulfonic acid) (PSSA)/Poly(vinyl alcohol) (PVA) blend membranes prepared by the solution casting were employed as heterogeneous acid catalysts for biodiesel production from acidic oil obtained from waste cooking oil (WCO). The membranes were annealed at different temperature in order to enhance their stability. The structure and properties of the membranes were investigated by means of Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), X-ray diffraction (XRD). It is found that the crosslinking structure among PVA and PSSA chains formed when the thermal treatment temperature was higher than 80 °C. The retention of PSSA in the blend membranes in the methanol/water solvent was markedly increased from 50% to 85% with the increase of the annealing temperature from room temperature (for the untreated membrane) to 150 °C due to the formation of the crosslinking structure. The results of esterification of acidic oil show that the conversion was slightly improve with the PVA content in the membrane at a fixed PSSA content. The thickness of the catalytic membrane had no significant effect on the conversion in the end. The membrane annealed at 120 °C exhibited the best catalytic performance among the membranes, with a stable conversion of 80% with the runs.     

Methanol permeability and properties of DMFC membranes based on sulfonated PEEK/PVDF blends

Proton exchange membranes for a direct methanol fuel cell were prepared by blending poly(vinylidene fluoride) [PVDF] with sulfonated poly(etheretherketone) [SPEEK]. The effects of PVDF content on methanol permeability in the blend membranes were investigated by using a diffusion cell and gas chromatography technique. The thermal resistance and proton conductivity of the membranes were also determined by using a thermal gravimetric analysis (TGA) and an impedance analysis technique, respectively. It was found that methanol permeability in the blend membranes decreased with PVDF content at the expense of proton conductivity. The methanol permeability values of the blend membranes are much lower than that of Nafion 115, whereas proton conductivities of the membranes are comparable to that of Nafion. The thermal stability of these blend membranes are above 250°C which is sufficiently high for use in DMFC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5941–5947, 2006