侧链结构对侧链型磺化聚砜质子交换膜性能的影响

以双酚A型聚砜(PS)为基础,与自制的1,4-二氯甲氧基丁烷反应制备氯甲基化聚砜(CPS),接着与2-萘酚-6,8-二磺酸钾(NSK)进行亲核取代反应制备萘磺酸型侧链磺化聚砜(PS-NS)。采用溶液浇注法制备相应的质子交换膜(PEMs),结合前期研究的脂肪磺酸型侧链磺化聚砜(PS-ES)和苯磺酸型侧链磺化聚砜(PS-BS) PEMs,考察侧链结构对PEMs的吸水率、吸水溶胀率和尺寸稳定性的影响关系。结果表明,与主链型芳香聚合物PEMs相比,3种侧链型磺化聚砜PEMs由于亲水基团远离疏水主链,能够形成类似于Nafion膜的相分离结构,在高吸水率下保持更好的尺寸稳定性;在相同的离子交换膜容量(IEC)下,PS-ES、PS-BS和PS-NS膜随着侧链刚性苯环数目的增加,侧链的运动能力减弱,导致PEMs的尺寸稳定性增加,相应的质子传导率减小; PS-ES膜在25℃和85℃的质子传导率分别达到0. 072和0. 141 S/cm,PS-NS在25℃和85℃的尺寸溶胀性仅为21. 8%和51. 5%,性能与商业化的Nafion115膜十分接近。     

萘磺酸型侧链磺化聚砜质子交换膜的性能

以聚砜(PS)和自制的1,4-二氯甲氧基丁烷(BCD)为氯甲基化试剂通过Fridel-Crafts烷基反应制备氯甲基化聚砜(CPS),紧接着氯甲基与2-萘酚-6,8-二磺酸钾(NSK)试剂通过亲核取代反应制备一种萘磺酸型磺化聚砜(PS-NS),在用红外和核磁氢谱充分表征的基础上制备一系列磺酸基团键合量不同的PS-NS质子交换膜(分别为PS-NS-1,PS-NS-2,PS-NS-3)重点研究温度对质子交换膜性能的影响规律。研究结果表明:由于亲水基团与疏水主链距离较远,能够形成类似于Nafion膜的微相分离结构,使得该质子交换膜在高磺化度下仍能保持高的尺寸稳定性,同时随着温度升高,质子交换膜的吸水率、溶胀性以及质子传导率增加,PS-NS-3在25℃和85℃的吸水率为21. 3%和42. 7%,但是溶胀率仅为22. 2%和50. 3%,与商业化Nafion115膜(24. 9%和55. 0%)的性能十分接近,表现出很好的尺寸稳定性。     

侧链磺化型聚砜质子交换膜的设计与制备及其性能研究

在制备氯甲基化聚砜(CMPSF)的基础上,以对羟基苯磺酸钠(HBSS)和羟基苯二磺酸钠(HBDSS)为亲核试剂,通过亲核取代反应,在聚砜(PSF)主链上分别键联了以苯磺酸根(BSS)和苯二磺酸根(BDSS)基团为末端基的侧链,制得了亲水磺酸根基团与疏水主链"微相分离"结构的2种侧链型磺化聚砜PSF-BSS和PSF-BDSS,并优化了制备条件.在对磺化聚砜产物进行充分表征(FTIR和1H-NMR谱)的基础上,采用流延成膜法制备了质子交换膜,测定了质子交换膜的基本性能,重点考察了质子交换膜"芳香性"主链和亲疏水微区"相分离"这2种结构因素对交换膜性能的影响.实验结果表明,在极性较强的溶剂中,CMPSF与羟基苯磺酸钠可顺利地发生亲核取代反应,于100℃经40 h反应可制得磺酸根键合量分别为2.07 mmol/g和2.11 mmol/g的磺化聚砜PSF-BSS和PSF-BDSS.所制备的质子交换薄膜具有较高的质子传导率(PSF-BDSS交换膜室温为4.7×10-2S/cm,80℃为8.1×10-2S/cm),优良的尺寸稳定性(室温溶胀率为8.6%,80℃溶胀率为30%),且具有良好的热稳定性与抗氧化稳定性.     

侧链型磺化聚砜质子交换膜构-效关系的研究

在制备氯乙酰基化聚砜(CAPS)和氯丁酰基化聚砜(CBPS)的基础上,以对羟基苯磺酸钠(HBS)为试剂,通过亲核取代反应制备侧链长度不同的两种侧链型磺化聚砜2PS-BS和4PS-BS (侧链碳原子数目分别是2和4),利用FT-IR和1H-NMR表征它们的化学结构后,采用溶液浇注法制备它们的质子交换膜(PEM),同时结合我们前期制备的侧链型磺化聚砜1PS-BS质子交换膜,研究柔性侧链的长度对PEM性能的影响。研究结果显示,与主链型PEM相比,1PS-BS、2PS-BS和4PS-BS由于亲水基团远离疏水主链,能够形成类似于Nafion膜的相分离结构,相应的PEM在高吸水率下仍能保持优越的尺寸稳定性和耐氧化性能。在相同的温度和IEC下,3种PEM随着柔性侧链长度的增加,PEM的相分离程度增强,进而导致PEM的尺寸稳定性、耐氧化性能和质子传导率增强,其中4PS-BS-4膜在25℃时的吸水溶胀性仅为7.1%,优于相同条件下Nafion115和Nafion117膜(室温溶胀率分别为9.5%和11%),相应的质子传导率达到了0.049S/cm,满足燃料电池的实际应用要求。     

一类含多磺酸结构侧链型聚芳醚酮质子交换膜材料的合成及性能研究

为进一步改善芳香型磺化聚合物质子交换膜材料的离子传导率、尺寸稳定性和耐化学氧化稳定性,从聚合物结构设计出发,首先利用9,9-双(3-苯基-4-羟基)苯基芴与4,4′-(六氟异亚丙基)二苯酚、1,4-二(4-氟苯甲酰基)苯经芳香亲核缩聚合成了一系列含芴和苯侧基结构新型聚芳醚酮聚合物(4-PAEK-xx),进一步通过温和的后磺化反应,制备了一系列含多磺酸结构侧链型聚芳醚酮质子交换膜(4-SPAEK-xx).对所制备的侧链型聚芳醚酮质子交换膜的结构和性能分别进行了表征分析.结果表明,该类质子交换膜具有适中的吸水率和较低的溶胀率,80°C时的吸水率和溶胀率分别在21%~51.2%和7.4%~17.2%.该类聚芳醚酮质子交换膜展现出了良好的离子传导性,80°C时的离子传导率在115~171 mS/cm,其中4-PAEK-45膜(离子交换容量为2.12 mequiv/g)的离子传导率已经超过了商品化的Nafion膜.此外,所制备的侧链型聚芳醚酮质子交换膜还表现出了良好的热稳定性、力学性能和耐化学氧化性.磺化膜优良的综合性能主要归因于侧链多磺酸结构和长尺寸含氟疏水结构单元的同时引入,其中侧链多磺酸结构的引入降低了主链磺化结构单元的比例,同时使亲水性的磺酸基团与分子主链分隔开来;而长尺寸含氟疏水性结构单元的引入进一步提高了膜材料的尺寸稳定性和耐氧化稳定性.     

侧链末端为磺酸根基团的磺化改性聚砜的制备及其阳离子交换膜的基本性能

采用两步一锅法,在聚砜(PSF)主链上键联了末端基为磺酸根基团的侧链,获得了疏水主链与磺酸根基团"微相分离"结构的磺化改性PSF。以氯乙基异氰酸酯(CEIC)为亲电试剂,使PSF主链上的苯环发生付-克烷基化反应,制得侧链含有活性基团—NCO的中间产物聚合物PSFeic;通过活性基团—NCO与对羟基苯磺酸钠(HBSAS)生成氨基甲酸酯的较快速的反应,获得了侧链末端为磺酸根基团的磺化改性聚砜PSF-sas。采用FT-IR、1 H-NMR及紫外分光光度法对目标产物聚合物PSF-sas的化学结构进行了表征。以PSF-sas为膜材,采用流延法制备了PSF阳离子交换膜,测定了交换膜的基本性能,包括离子交换容量、吸水率及质子传导率。研究结果表明,在路易斯酸催化剂作用下,CEIC与PSF主链上苯环之间的付-克烷基化反应可顺利进行,生成中间聚合物产物PSF-eic;以强极性的二甲基乙酰胺(DMAC)为溶剂,反应24h,PSF-eic分子链中乙基异氰酸酯(eic)的键合量可达2.43mmol/g。在此基础上进行第2步反应,可得到磺酸根基团含量为2.23mmol/g的目标产物PSF-sas,所制备的阳离子交换膜,具有高的离子交换容量,适当的吸水率与高的质子传导率。     

燃料电池用侧链型磺化聚砜质子交换膜的性能

在制备氯甲基化聚砜(CPS)的基础上,以1,2-二羟基苯-3,5-二磺酸钠为试剂,通过亲核取代反应制备一种侧链末端为磺酸基团的侧链型磺化聚砜(PS-BDS),并采用溶液浇注法制备相应的质子交换膜(PEM),研究温度对PEM性能的影响规律。 结果表明,由于亲水基团远离疏水聚合物主链,该PEM能够形成亲水微区远离疏水微区的相分离结构,亲水区域对主链的影响较小,该PEM在高磺化度下仍能保持较好的尺寸稳定性,随着温度的升高,PEM的吸水率(WU)、吸水溶胀率(SW)和质子传导率(PC)升高,其中PS-BDS-4(离子交换容量为1.57 mmol/g)在25和85 ℃时的SW仅为22.1%和55.0%,甲醇的渗透率(DK)仅为10.17×10^-7 cm²/s,低于商业化的Nafion115(16.8×10^-7 cm²/s)和Nafion117(23.8×10^-7 cm²/s),表现出很好的综合性能。     

具有高效长侧链的芘磺酸型磺化聚砜阳离子交换膜的性能

以双酚A型聚砜和无致癌毒性的溴甲基化试剂1,4-二溴丁烷为原料,通过烷基化反应在聚砜分子上引入可交换溴原子制备溴代聚砜(BPSF),将BPSF与8-羟基-1,3,6-芘三磺酸钠(TS)试剂通过亲核取代反应制备一种磺酸基团远离聚合物主链的芘磺酸型磺化聚砜(PS-TS).采用溶液流延法制备PS-TS阳离子交换膜,通过控制亲...     

“点击化学”离子化聚砜对磺化聚醚醚酮/聚砜共混膜性能的影响研究

为制备氢离子/二价金属离子渗透选择性优异的阳离子交换膜，探究功能基团(季铵基团、羧基)含量对膜性能的影响规律，采用“点击化学”反应，在聚砜(PSF)侧链接枝季铵基团和羧基获得离子化PSF，将其与磺化聚醚醚酮(SPEEK)共混制备阳离子交换膜，分别通过离子化PSF添加量、功能化度和侧链阴阳离子比例调控共混膜中季铵基团含量，探究其对膜性能的影响规律.膜对氢离子和亚铁离子的渗透选择性随着离子化PSF含量和功能化度的增加均呈现先升高后降低的趋势，当离子化PSF的季铵与羧基比例为1:1时，共混膜的渗透选择性最佳.季铵基团与磺酸基形成离子对有利于抑制膜溶胀，通过Donnan排斥和尺寸筛分效应提高阳离子交换膜的渗透选择性；但当季铵基团的含量超过一定值，离子簇的形成导致其在膜内分布不均，膜的渗透选择性有所降低.羧基则通过形成氢键减小膜的氢离子渗透性降低幅度.     

侧链型磺化聚砜的制备及侧链链长对质子交换膜性能影响的研究

以氯乙酰氯和氯丁酰氯为亲电试剂,通过Friedel-Crafts酰基化反应,在聚砜(PSF)主链引入了含氯的且碳原子数目不同的(分别为2和4)柔性侧链,然后以对羟基苯磺酸钠(HBSS)为试剂,通过亲核取代反应制备了侧链型磺化聚砜2PSF-BSS和4PSF-BSS。采用佛尔哈德分析法、红外光谱(FT-IR)以及核磁氢谱(1HNMR)对侧链型磺化聚砜的化学结构和性能进行了表征,重点考察主要因素对Friedel-Crafts酰基化和亲核取代反应的影响,实验结果表明:以无水Al Cl3为催化剂,CH2Cl2为反应溶剂,反应温度50℃,CAPSF和CBPSF中氯含量分别达到2.03mmol/g和2.07mmol/g,第2步亲核取代反应遵循SN1机理,在强极性溶剂DMSO中磺酸基键合量分别为1.48mmol/g和1.46mmol/g。同时初步探索侧链链长对质子交换膜的质子传导率的影响,随着侧链长度的增长,侧链的柔性增强,亲水微区与疏水微区微相分离的程度增强,导致交换膜的质子传导率增大。     

后磺化法精确可控合成主链型磺化聚苯喹喔啉及其质子交换膜性能研究

以不同摩尔比的4,4′-双(4-(2-苯基乙二酮基)苯氧基联苯、4,4′-双(2-苯基乙二酮基)二苯醚与3,3′,4,4′-四氨基联苯共聚制备聚喹喔啉,经后磺化法得到一系列磺化度可控的磺化聚苯基喹喔啉(SPPQ).模型化合物确认,磺酸基团精确接入电子云密度较高的含醚键的联苯片段的2,2′-位上,证明通过单体分子结构设计与后磺化法结合,可使磺酸基团在温和条件下,按预想接入到聚合物主链上,达到磺化度和磺化位置精确可控的目的. SPPQ的相对黏度均在3.8 dL/g以上.通过溶液涂膜法制备的主链型磺化聚苯基喹喔啉质子交换膜(SPPQ PEM)的吸水率都低于39%,尺寸变化率为2.1%~13%,且随着IEC和温度的提高而线性增加.如,80℃下,IEC高达2.21 meq/g的SPPQ-5的膜面和膜厚方向的尺寸变化率仅为11%和13%,具有良好的形状维持能力.热重分析表明,SPPQ PEM在320℃左右脱去磺酸基团,550℃左右发生聚合物主链降解,具有良好的热稳定性. Fenton试剂测试表明,SPPQ PEM开始破碎的时间随IEC的增加而缩短,在20℃时,IEC较低的SPPQ-1 (1.29 meq/g)破碎时间可达151 h,而IEC较高的SPPQ-5(2.21 meq/g)破碎时间缩短至81 h. PEM的质子传导率随温度和IEC的增加而显著提高,最高可达64 mS/cm,由于磺酸基团和喹喔啉酸碱对的形成以及吸水率偏低的原因,这一数值远低于Nafion.     

Phosphonation of polysulfones via lithiation and reaction with chlorophosphonic acid esters

A noncatalytic route for the phosphonation of polysulfones was established in which lithiated sites on polysulfones were reacted with an excess of chlorophosphonic acid esters through an S_NP(V) mechanism. Both the bisphenol A and biphenyl sulfone segments of the polysulfone main chain were modified according to whether brominated polysulfone or pristine polysulfone was used. Up to 50% of the repeating units of the polysulfones were modified by a careful selection of reaction parameters to avoid crosslinking. The phosphonated polysulfones in their acid form showed high thermal stability with decomposition temperatures of approximately 350 °C under nitrogen. Polysulfones with phosphonated bisphenol A segments showed good membrane‐forming properties and are candidates for components in ionomer composite membranes for fuel cells. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 273–286, 2005     

Crosslinking of sulphonated poly (ether ether ketone) using aromatic bis(hydroxymethyl) compound

2,6-Bis(hydroxymethyl)-4-methyl phenol and 1,4-bis(hydroxymethyl) benzene have been used as crosslinkers in sulphonated poly (ether ether ketone) (SPEEK DS 65%, IEC 1.84 mequiv./g) for the preparation of proton exchange membranes (PEMs). Crosslinking of SPEEK has been achieved by thermally activated bridging of the polymer chain with the hydroxymethyl group of crosslinker through condensation reaction with sulphonic acid group. The physico-chemical properties of uncrosslinked and crosslinked membrane were evaluated in terms of ion exchange capacity (IEC), water uptake, ionic conductivity and mechanical properties. The crosslinked membrane showed controlled swelling, ionic conductivity of 25–50 mS/cm at 80 °C and good mechanical properties. The chemical stability of the crosslinked membranes was studied by Fenton's test. The % loss in weight and changes in physico-chemical properties of the treated membranes were determined.     

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

A 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     

Sulfophenylation of Polysulfones for Proton‐Conducting Fuel Cell Membranes

Polysulfone has been sulfophenylated by lithiation and anionic reaction with 2‐sulfobenzoic acid cyclic anhydride. This provides a new convenient method to modify polysulfones by attaching pendant sulfonated phenyl groups via ketone links. Membranes of the sulfophenylated polysulfones show promise for use in proton‐exchange‐membrane fuel cells. For example, a membrane with 0.9 sulfophenyl units per repeating polysulfone unit and 30 wt.‐% water was found to have a proton conductivity of 32 mS/cm at 60°C.     

侧链结构对磺化聚芳醚性能及微观形貌的影响

比较了3种主链结构相同而侧链结构不同的磺化聚芳醚(SPAE)材料的性能. 分析了侧链结构对聚合物的吸水、 溶胀及质子传导行为的影响. 结果表明, 在相同的离子交换容量(IEC)条件下, 具有柔顺脂肪族侧链的聚芳醚材料具有较高的质子传导率. 其原因是由于柔顺的脂肪族侧链比刚性的芳香族侧链更易运动, 有利于侧链末端磺酸基团的聚集, 进而形成离子簇. 3种聚合物微观形貌的分析结果表明, 含柔顺侧链结构的聚合物薄膜具有更大的质子传输通道, 其结果与聚合物的宏观吸水和传导现象相吻合.     

Preparation and properties of ionic cross‐linked sulfonated copolyimide membranes containing pyrimidine groups

A series of sulfonated copolyimides containing pyrimidine groups (SPIs) were synthesized by random copolymerization of 1,4,5,8‐naphthalenetetracarboxylic dianhydride (NTDA), 2‐(4‐aminophenyl)‐5‐aminopyrimidine (PAPRM), and 4,4′‐diaminodiphenyl ether‐2,2′‐disulfonic acid (ODADS). Proton exchange treatment in 1.0 M sulfuric acid solution resulted in ionic cross‐linking of the sulfonated copolymers due to the acid (sulfonic acid)‐base (pyrimidine group) interactions and the membrane with more basic PAPRM moiety could absorb sulfuric acid to favor the proton transfer. The effects of the structure of the diamines on the properties of SPI membranes were evaluated by studying the membrane parameters including water uptake, proton conductivity, water stability, and methanol permeability. The basic pyrimidine groups introduced in the main chains could effectively resist membrane swelling due to the strong interchain interactions through basic pyrimidine groups and sulfonic acid groups. Compared with the corresponding uncross‐linked copolyimides (NTDA/ODADS/ODA), the acid–base copolyimides displayed excellent water stability. The SPI membranes also exhibited improved mechanical properties and decreased methanol permeability. However, the cross‐linked membranes showed lowered proton conductivities than the uncross‐linked ones because a small part of the sulfonic acid groups had been consumed during the cross‐linking process. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis and performance study of a novel sulfonated polytriazole proton exchange membrane

Sulfonated polytriazole (SPTA) proton exchange membranes (PEMs) with a series of sulfonation degrees was synthesized based on click chemistry from a rigid diazide monomer, 4,4′-bis(azidomethyl)-1,1′-biphenyl (BAMB), with 2,2-bis[(4-propargyloxy)phenyl]propane (BPBPA) and 4,4′-diazido-2,2′-stilbenedisulfonic acid disodium salt (DSDA). The structure of the copolymers was characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). As a result of the introduction of rigid biphenyl structure and the ionic interaction between triazole rings and sulfonic acid groups, the SPTA membranes exhibited higher water uptake and lower swelling ratio compared to NRE211 membrane, indicating excellent dimensional stability. AC impedance revealed that the proton conductivity of SPTA membranes ranged from 2.5 to 35 mS/cm at 30 °C and 13–105 mS/cm at 80 °C. Besides, the membranes have high thermal and oxidative stability, good mechanical property, and low methanol permeability as well.     

Polysulfone ionomers functionalized with benzoyl(difluoromethylenephosphonic acid) side chains for proton‐conducting fuel‐cell membranes

Polysulfones carrying benzoyl(difluoromethylenephosphonic acid) side chains were prepared and investigated for use as proton‐conducting fuel‐cell membranes. In the first step, polysulfones were lithiated and reacted with methyl iodobenzoates to prepare p‐ and o‐iodobenzoyl polysulfones. Next, the phosphonated polysulfones were prepared via CuBr‐mediated cross‐coupling reactions between the iodinated polymer and [(diethoxyphosphinyl)difluoromethyl]zinc bromide. Finally, dealkylation with bromotrimethylsilane afforded highly acidic ? CF₂? PO₃H₂ derivatives. The replacement of the iodine atoms by ? CF₂? PO₃Et₂ units was almost quantitative in the case of o‐iodobenzoyl polysulfone. Membranes based on ionomers having 0.90 mmol of phosphonic acid units/g of dry polymer took up 6 wt % water when immersed at room temperature, and conductivities up to 5 mS cm^?1 at 100 °C were recorded. This level of conductivity was comparable to that reached by a membrane based on a sulfonated polysulfone having 0.86 mmol of sulfonic acid/g of dry polymer. Thermogravimetry revealed that the aryl? CF₂? PO₃H₂ arrangement decomposed at approximately 230 °C via cleavage of the C? P bond. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 269–283, 2007.