Novel method for the preparation of ionically crosslinked sulfonated poly(arylene ether sulfone)/polybenzimidazole composite membranes via in situ polymerization

A series of ionically crosslinked composite membranes were prepared from sulfonated poly(arylene ether sulfone) (SPAES) and polybenzimidazole (PBI) via in situ polymerization method. The structure of the pristine polymer and the composite membranes were characterized by FT-IR. The performance of the composite membranes was characterized. The study showed that the introduction of PBI led to the reduction of methanol swelling ratio and the increase of mechanical properties due to the acid–base interaction between the sulfonic acid groups and benzimidazole groups. Moreover, the oxidative stability and thermal stability of the composite membranes were improved greatly. With the increase of PBI content, the methanol permeability coefficient of the composite membranes gradually decreased from 1.59 × 10⁻⁶ cm²/s to 1.28 × 10⁻⁸ cm²/s at 30 °C. Despite the fact that the proton conductivity decreased to some extent as a result of the addition of PBI, the composite membrane with PBI content of 5 wt.% still showed a proton conductivity of 0.201 S/cm at 80 °C which could actually meet the requirement of proton exchange fuel cell application. Furthermore, the composite membranes with PBI content of 2.5–7.5 wt.% showed better selectivity than Nafion117 taking into consideration the methanol swelling ratio and proton conductivity comprehensively.     

Novel thin-film composite membranes with improved water flux from sulfonated cardo poly(arylene ether sulfone) bearing pendant amino groups

A new class of polymeric amine, namely, sulfonated cardo poly(arylene ether sulfone) (SPES-NH₂) was synthesized and used for the preparation of thin-film composite membrane. The TFC membranes were prepared on a polysulfone supporting film through interfacial polymerization with trimesoyl chloride (TMC) solutions and amine solutions containing SPES-NH₂ and m-phenylenediamine (MPDA). The resultant membranes were characterized with water permeation performance, chemical structure, hydrophilicity of active layer and membrane morphology including top surface and cross-section. The membrane prepared under the optimum condition showed the salt rejection and water flux reached 97.3% and 51.2 L/m² h, respectively. The high salt rejection and water flux was attributed to the rigid polymer backbone and the presence of strong hydrophilic sulfonic groups.     

Sulfonated poly(aryl ether ether ketone ketone)s containing fluorinated moieties as proton exchange membrane materials

A series of sulfonated poly(aryl ether ether ketone ketone)s statistical copolymers with high molecular weights were synthesized via an aromatic nucleophilic substitution polymerization. The sulfonation content (SC), defined as the number of sulfonic acid groups contained in an average repeat unit, could be controlled by the feed ratios of monomers. Flexible and strong membranes in sodium sulfonate form could be prepared by the solution casting method, and readily transformed to their proton forms by treating them in 2 N sulfuric acid. The polymers showed high T_gs, which increased with an increase in SC. Membranes prepared from the present sulfonated poly(ether ether ketone ketone) copolymers containing the hexafluoroisopropylidene moiety (SPEEKK‐6F) and copolymers containing the pendant 3,5‐ditrifluoromethylphenyl moiety (SPEEKK‐6FP) had lower water uptakes and lower swelling ratios in comparison with previously prepared copolymers containing 6F units. All of the polymers possessed proton conductivities higher than 1 × 10^?2 S/cm at room temperature, and proton conductivity values of several polymers were comparable to that of Nafion at high relative humidity. Their thermal stability, oxidative stability, and mechanical properties were also evaluated. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2299–2310, 2006     

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     

Controlled sulfonation of poly(arylene ether sulfone)s and poly(arylene ether ketone)s with different molecular structures for polymer electrolyte membranes

Poly(arylene ether sulfone) copolymers derived from 9,9-bis(4-hydroxyphenyl)fluorene, bisphenol S and 4,4′-difluorodiphenylsulfone and poly(arylene ether ketone) copolymers derived from 4-phenoxybiphenyl, diphenyl ether and isophthaloyl chloride were prepared as precursor polymers for sulfonation reaction in which sulfonic groups are introduced quantitatively into specified positions. Sulfonation reaction for these two series of copolymers by concentrated sulfuric acid was successfully carried out to give sulfonated polymers with controlled positions and degree of sulfonation. Thermal stability, moisture absorption and proton conductivity for these two series of copolymers were measured and the results were compared to those of perfluorosulfonic acid polymers.     

序列式含芴季铵化聚芳醚砜阴离子交换膜的制备及交联改性

为得到具有高电导率和稳定性的阴离子交换膜,采用两步聚合法合成了含芴的序列式聚芳醚砜,经付克氯甲基化、季铵化及碱化制备了季铵化聚芳醚砜,并以脂肪族二胺(N,N,N′,N′-四甲基丙二胺(TMPDA)及N,N,N′,N′-四甲基己二胺(TMHDA))为交联剂,通过直接交联及后交联法分别制备了2类序列交联型阴离子交换膜.制得的膜材料离子交换容量为1.59~2.12 mmol/g,柔韧结实.与具有相似离子交换容量的非交联膜相比,交联膜的抗溶剂性能、尺寸稳定性、离子电导率等性能均得到了提高.交联膜在高温水中的水解稳定性、强碱性条件下的化学稳定性显著增强.探讨了直接浇铸交联处理及成膜后交联处理2种交联方式对膜性能的影响,结果表明,后交联处理可以有效避免浇膜过程凝胶的形成,而且膜的稳定性相对于未交联膜有大幅度提高.尤其以TMHDA为交联剂的后交联膜的各项性能均优于相应非交联膜,IEC为2.17 mmol/g的PCL-M(H)膜,在30°C时吸水率为99%,膜径向尺寸变化率为15%,电导率为23.8 mS/cm,90°C时电导率达到82 mS/cm,经过4 mol/L的NaOH溶液室温处理240 h后,离子电导率损失为7.6%,100°C水处理24 h后重量损失为5.1%,表现出较好的稳定性.     

Sulfonated poly(ether sulfone)s with binaphthyl units as proton exchange membranes for fuel cell application

Sulfonated poly(ether sulfone)s containing binaphthyl units (BNSHs) were successfully prepared for fuel cell application. BNSHs, which have very simple structures, were easily synthesized by postsulfonation of poly(1,1′‐dinaphthyl ether phenyl sulfone)s and gave tough, flexible, and transparent membranes by solvent casting. The BNSH membranes showed low water uptake compared to a typical sulfonated poly(ether ether sulfone) (BPSH‐40) membrane with a similar ion exchange capacity (IEC) value and water insolubility, even with a high IEC values of 3.19 mequiv/g because of their rigid and bulky structures. The BNSH‐100 membrane (IEC = 3.19 mequiv/g) exhibited excellent proton conductivity, which was comparable to or even higher than that of Nafion 117, over a range of 30–95% relative humidity (RH). The excellent proton conductivity, especially under low RH conditions, suggests that the BNSH‐100 membrane has excellent proton paths because of its high IEC value, and water insolubility due to the high hydrophobicity of the binaphthyl structure. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5827–5834, 2009     

交联型季铵聚芳醚砜阴离子交换膜的制备

采用简便环保的方法制备了具有低溶胀、高离子交换容量(IEC)的交联型季铵聚芳醚砜阴离子交换膜.随着交联度的提高,膜的吸水率和溶胀率降低,说明交联可以抑制膜的溶胀.20℃时所有交联膜的离子传导率均达0.045 S/cm以上,拉伸强度在50.1 MPa以上,表明在高IEC值下,交联膜仍具有良好的力学性能和较高的离子传导能力.同时,交联度提高会加强膜的甲醇阻隔性能.     

Synthesis and characterization of poly(arylene ether sulfone) copolymers with sulfonimide side groups for a proton‐exchange membrane

A sulfonimide‐containing comonomer derived from 4,4′‐dichlorodiphenylsulfone was synthesized and copolymerized with 4,4′‐dichlorodiphenylsulfone and 4,4′‐biphenol to prepare sulfonimide‐containing poly(arylene ether sulfone) random copolymers (BPSIs). These copolymers showed slightly higher water uptake than disulfonated poly(arylene ether sulfone) copolymer (BPSH) controls, but their proton‐conductivity values were very comparable to those of the BPSH series with similar ion contents. The proton conductivity increased with the temperature for both systems. For samples with 30 mol % ionic groups, BPSI showed less temperature dependence in proton conductivity and slightly higher methanol permeability in comparison with BPSH. The thermal characterization of the sulfonimide copolymers showed that both the acid and salt forms were stable up to 250 °C under a nitrogen atmosphere. The results suggested that the presumed enhanced stability of the sulfonimide systems did not translate into higher protonic conductivity in liquid water. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6007–6014, 2006     

磺化聚醚酰亚胺/聚醚砜共混型质子交换膜的制备及其性能

以磺化聚醚酰亚胺(SPEI)和聚醚砜(PES)为原料, 采用溶液共混法成功制备出了SPEI/PES共混型质子交换膜,并经热重分析、AFM、SEM等对膜的结构和性能进行了表征. 结果表明, 共混膜较纯SPEI膜具有更高的热稳定性和较低的溶胀性; 在室温环境下, 共混膜在干态和湿态时均具有优异的机械性能; 与纯SPEI膜相比, 共混膜的形态结构更为致密, 这将有利于降低甲醇的渗透性. 采用交流阻抗法和隔膜扩散法分别考察了膜的质子传导性和阻醇性能, 对于共混质量比为50/50的膜来说, 其质子传导率达到了5.5 mS·cm-1的水平, 能满足质子交换膜的需求, 但其甲醇渗透系数明显降低, 仅为市用Nafion 112膜的5%, 这表明该共混膜有望作为一种新型的直接甲醇燃料电池用质子交换膜.     

Preparation and properties of UV irradiation-induced crosslinked sulfonated poly(ether ether ketone) proton exchange membranes

The crosslinkable sulfonated poly(ether ether ketone)s (SPEEKs) were synthesized by nucleophilic substitution reaction of diallyl bisphenol A, tert-butylhydroquinone, 4,4′-difluorobenzophenone and sodium 5,5′-carbonylbis(2-fluorobenzene-sulfonate). The SPEEKs with high intrinsic viscosity showed good solubility and could be cast into flexible and transparent membranes. The SPEEK membranes containing benzophenone (BP) and triethylamine (TEA) photo-initiator system were treated by UV light to promote crosslinking. The experimental results revealed that the crosslinked membrane with 10 min irradiation time showed the most potential as proton exchange membrane for direct methanol fuel cell applications. When the irradiation time increased from 0 to 10 min, the water uptake decreased from 29.1 to 26.1%, and the tensile modulus and the tensile strength enhanced sharply from 0.80 to 1.44 GPa and from 40.3 to 63.4 MPa, respectively. In addition, the methanol diffusion coefficient reduced sharply from 1.70 × 10⁻⁶ to 7.42 × 10⁻⁷ cm²/s with only slight sacrifice in the proton conductivity, which made the crosslinked membrane with 10 min irradiation time possess the highest selectivity.     

复合型季铵化聚醚砜碱性聚合物电解质膜的制备及性能

利用4,4?-二氟二苯砜(DFDPS)、9,9?-双(4-羟苯基)芴(BHPF)、2,2?-二(4-羟基苯基)丙烷(双酚A)及4,4?-(六氟异丙叉)双酚(双酚AF)为原料,制备了2类具有不同主链刚性的聚醚砜材料.以聚醚砜及其氯甲基化产物按一定质量比采用溶液浇铸法,制备了2类新型共混阴离子交换膜,并避免了成膜过程中的相分离现象.在高分子主链上通过引入双酚芴(BQPAES系列)及双酚A(BQPES系列)结构调整主链的刚性,探讨了主链刚性对性能的影响;表征了共混膜的离子交换容量(IEC)、吸水及溶胀特性与离子电导率,并考察了它们的耐水解和耐碱稳定性.结果表明:2种聚合物相容性良好,共混膜质地均一,柔韧透明,吸水率和溶胀率适中,均随着温度的升高逐渐增加、随着聚醚砜含量增加逐渐减小;在90?C时,离子电导率最高达到89 m S/cm.经过沸水处理24 h后,均保持高机械强度,失重率低于5%;经2 mol/L的Na OH溶液30?C处理168~240 h后离子电导率仍可保持65%~80%.由于含双酚芴结构的高分子主链具有更高的刚性,在类似IEC条件下,BQPAES膜显示了比BQPES膜更好的尺寸稳定性和化学稳定性,同时维持了较高的电导率水平.由此表明,复合处理及适度提高高分子主链的刚性,有利于提高膜的性能.     

Blend membranes of Nafion/sulfonated poly(aryl ether ketone) for direct methanol fuel cell

Sulfonated poly(aryl ether ketone) (sPAEK) synthesized by LG Chem. was confirmed by FT-IR. To estimate the thermal stability, glass transition temperature and decomposition temperature were investigated. They showed that sPAEK had good thermal properties. The proton conductivity, methanol permeability and water uptake of sPAEK were also measured. Nafion/sulfonated poly(aryl ether ketone) composite membranes were prepared by blending two materials. The blend ratios of sPAEK and Nafion were 2:1, 3:1, 5:1, and 7:1. The blend membranes showed phase separated morphology since they became immiscible during the solvent evaporation process. Due to the differences in specific gravity and solvent concentration profile during the solvent evaporation process, the upper region had lower Nafion volume fraction with smaller domains and the lower region had higher Nafion volume fraction with larger domains. Mechanical properties such as the stress at break, yield stress, Young's modulus, and elongation at break were measured. The sPAEK had better mechanical properties than Nafion. The mechanical properties increased with increasing sPAEK content. Proton conductivity and methanol permeability of the blend membranes were lower than those of Nafion. Both decreased with decreasing Nafion content. Since the methanol permeability of sPAEK was lower than that of Nafion, sPAEK acted as the methanol barrier. Water uptake of sPAEK was higher than that of Nafion.     

Synthesis and properties of highly branched sulfonated poly(arylene ether)s as proton exchange membranes

A series of branched sulfonated poly(arylene ether)s were successfully synthesized using 1,3,5-tris[4-(4-fluorobenzoyl)phenoxy]benzene (B₃) as branching agent. The synthesized branched copolymers were soluble in polar organic solvents, such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc) and dimethylsulfoxide (DMSO), and could be cast to form tough and smooth films. The effect of degree of branching (DB) on the proton conductivity, swelling ratio and oxidative stability of the membranes was investigated. With increasing DB value, the proton conductivity and oxidative stability of the membranes increased. A maximum oxidative stability of the branched membrane with 4% of DB value was determined to be 3.4 times larger than that of the linear membrane. In addition, as the DB value increased, the swelling ratio of the membranes decreased from 13.51% to 9.09% at 80 °C. The results indicated that increasing DB value might be an effective way to improve the properties of proton exchange membranes.     

Preparation and characterization of branched and linear sulfonated poly(ether ketone sulfone) proton exchange membranes for fuel cell applications

Branched sulfonated poly(ether ketone sulfone)s (Br‐SPEKS) were prepared with bisphenol A, bis(4‐fluorophenyl)sulfone, 3,3′‐disodiumsulfonyl‐4,4′‐difluorobenzophenone, and THPE (1,1,1‐tris‐p‐hydroxyphenylethane), respectively, at 180 °C using potassium carbonate in NMP (N‐methylpyrrolidinone). THPE, as a branching agent, was used with 0.4 mol % of bisphenol A to synthesize branched copolymers. Copolymers containing 10–50 mol % disulfonated units were cast from dimethylsulfoxide solutions to form films. Linear sulfonated poly(ether ketone sulfone)s (SPEKS) were also synthesized without THPE. The films were converted from the salt to acid forms with dilute hydrochloric acid. A series of copolymers were studied by Fourier transform infrared, ¹H‐NMR spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of sulfonated polymers with water and methanol. The ion‐exchange capacity (IEC), a measure of proton conductivity, was evaluated. The synthesized Br‐SPEKS and SPEKS membranes exhibit conductivities (25 °C) from 1.04 × 10^?3 to 4.32 × 10^?3 S/cm, water swell from 20.18 to 62.35%, IEC from 0.24 to 0.83 mequiv/g, and methanol diffusion coefficients from 3.2 × 10^?7 to 4.7 × 10^?7 cm²/S at 25 °C. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1792–1799, 2008     

含氨基磺化聚芳醚酮砜质子交换膜的制备与性能

通过四元缩聚的方法合成了带有氨基的磺化度可控的磺化聚芳醚酮砜共聚物(Am-SPAEKS). 采用红外光谱和核磁共振谱表征了Am-SPAEKS共聚物的结构. 该共聚物膜具有较好的热性能、尺寸稳定性、较高的质子传导率和阻醇能力. 在80℃时Am-SPAEKS-1膜的质子传导率达到0.0894 S/cm, 而其甲醇渗透系数在25℃时为0.24×10^-6 cm²/s, 低于相同温度下SPAEKS膜(0.87×10^-6 cm²/s)和Nafion膜(2×10^-6 cm²/s). 结果表明, Am-SPAEKS膜能够满足质子交换膜燃料电池(PEMFC)的使用要求.     

Sequence analysis of poly (ether sulfone) copolymers by 13C NMR

Random and block copolymers of poly (ether sulfone) (PES) and poly (ether ether sulfone) (PEES) were synthesized by the nucleophilic polycondensation of 4,4′‐dichlorodiphenyl sulfone (DCDPS) with 4,4′‐dihydroxydiphenyl sulfone (DHDPS) and hydroquinone (HQ). Chemical structures of these copolymers were characterized by ¹³C NMR. The monomer molar fraction, sequential distribution, and degree of randomness of the copolymers were determined through analyses of the resonances of quaternary carbons in the DCDPS unit. Experimental results show that the molar fractions of the comonomer determined by ¹³C NMR analyses are close to the charged values in the synthetic step. Moreover, these copolymers, which were prepared by different polymerization methods, revealed different number‐average sequential length and degree of randomness. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1624–1630, 2005     

含咪唑酮结构聚芳醚砜共聚物的制备与表征

通过共聚的方法在酚酞聚芳醚砜(PES-C)的主链上引入苯并咪唑酮和5,6-二甲基苯并咪唑酮结构,制备了一系列苯并咪唑酮和5,6-二甲基苯并咪唑酮结构含量不同的高玻璃化转变温度(T_g)聚芳醚砜共聚物。利用核磁共振谱(NMR)、傅里叶变换红外光谱仪(FTIR)、热重分析仪(TGA)等技术手段表征了三元共聚物的结构和性能。结果表明,聚芳醚砜共聚物为无定型结构。聚合物具有优异的热性能,并且均呈现出单一的T_g(T_g271℃);随着苯并咪唑酮和5,6-二甲基苯并咪唑酮的摩尔分数的增加,聚合物T_g呈现规律性升高,分别从270℃升高到340和344℃。两种共聚物均能够溶于极性非质子N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAc)、二甲基亚砜(DMSO)、N-甲基吡咯烷酮(NMP)及氯仿(CHCl_3)等溶剂中。具有很好的溶解加工性和成膜性,可以进行溶液加工制备韧性的薄膜。     

Allyl-containing Poly(aryl ether sulfone): Synthesis and Crosslinking

A novel type of crosslinkable poly(aryl ether sulfone)(PAES) bearing an allyl pendant(PES-OAllyl) was synthesized by a grafting reaction of hydrophenyl-containing PAES(PES-OH) and allyl bromide. PES-OH was prepared by a demethylation reaction of a methoxyphenylated PAES(PES-OCH3) in the presence of pyridine/hydrochlo- ride. The PES-OCH3 was synthesized by an aromatic nucleophilic substitution of bis(4-chlorophenyl)sulfone and (p-methoxy)phenylhydroquinone. Both DSC and solubility investigation were used to ...     

侧链型磺化聚芳醚酮质子交换膜材料的制备

本文通过对聚合物的结构设计, 采用均聚的途径将柔顺的大侧基(甲氧基苯基)引入聚芳醚酮侧链, 然后通过室温后磺化的方法成功制备出侧链型磺化聚芳醚酮材料. 此类材料表现出较好的热稳定性; 力学性能优异; 聚合物的质子传导率比报道过的类似材料有较大程度的提高; 于80 ℃时的质子传导率在0.190 S/cm以上, 超过了Nafion 117 薄膜的传导率(0.175 S/cm). 因此这类材料有望在质子交换膜领域得到应用.