Synthesis and characterization of rigid-rod sulfonated polyimides bearing sulfobenzoyl side groups as proton exchange membranes

A novel wholly aromatic diamine, 2,2 '-bis(3-sulfobenzoyl)benzidine (2,2 '-BSBB), was successfully prepared by the reaction of 2,2 '-dibenzoylbenzidine (2,2 '-DBB) with fuming sulfuric acid. Copolymerization of 1,4,5,8-naphathlenetetracarboxylic dianhydride with 2,2 '-BSBB and 2,2 '-DBB generated a series of rigid-rod sulfonated polyimides. The synthesized copolymers with the -SO3H group on the side chain of polymers possessed high molecular weights revealed by their high viscosity and the formation of tough and flexible membranes. The copolymer membranes exhibited excellent oxidative stability and mechanical properties due to their fully aromatic structure extending through the backbone and pendent groups. They displayed clear anisotropic membrane swelling in water with negligibly small dimensional changes in the plane direction of the membrane. The proton conductivities of copolymer membranes increased with increasing IEC and temperature, reaching value above 1.25 x 10(-1) S/cm at 20 degrees C, which is higher than that of Nafion (R) 117 at the same measurement condition. They displayed reasonably high proton conductivity due to the higher acidity of benzoyl sulfonic acid group, the larger interchain spacing, which is available for water to occupy, taking their lower water uptake (WU) into account. Consequently, these materials proved to be promising as proton exchange membrane.

Preparation and evaluation of a proton exchange membrane based on oxidation and water stable sulfonated polyimides

A series of novel oxidation and water stable sulfonated polyimides (SPIs) were synthesized from 4,4'-binaphthyl-1,1',8,8'-tetracarboxylic dianhydride (BTDA), and wholly aromatic diamine 2,2'-bis(3-sulfobenzoyl) benzidine (2,2'-BSBB) for proton exchange membrane fuel cells. These polyimides could be cast into flexible and tough membranes from m-cresol solutions. The copolymer membranes exhibited excellent oxidative stability and mechanical properties due to their fully aromatic structure extending through the backbone and pendant groups. Moreover, all BTDA-based SPI membranes exhibited much better water stability than those based on the conventional 1,4,5,8-naphthalenecarboxylic dianhydride. The improved water stability of BTDA-based polyimides was attributed to its unique binaphthalimide structure. The SPI membranes with ion exchange capacity (IEC) of 1.36-1.90 mequiv g(-1) had proton conductivity in the range of 0.41 x 10(-1) to 1. 12 x 10(-1) S cm(-1) at 20 degrees C. The membrane with IEC value of 1.90 mequiv g(-1) displayed reasonably higher proton conductivity than Nafion((R)) 117 (0.9 x 10(-1) S cm(-1)) under the same test condition and the high conductivity of 0.184 S cm(-1) was obtained at 80 degrees C. Microscopic analyses revealed that well-dispersed hydrophilic domains contribute to better proton conducting properties. These results showed that the synthesized materials might have the potential to be applied as the proton exchange membranes for PEMFCs.

Sulfonated polyimides bearing benzimidazole groups for proton exchange membranes

A series of sulfonated polymides containing benzimidazole groups were synthesized using 4,4'-binaphthyl-1,1',8,8'-tetracarboxylic dianhydride (BTDA), 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid (ODADS) as the sulfonated diamine, and 2-(3',5-diaminophenyl)benzimidazole (a) or 6,4'-diamino-2-phenylbenzimidazole (b) as the nonsulfortated diamine. The electrolyte properties of the synthesized polyimides Ia-x, Ib-x, x refers to molar percentage of the sulfonated diamine) were investigated and compared with those of polyimides (Ic-x) from BTDA, ODADS, and m-phenylenediamine (c). All synthesized polyimides possessed high molecular weights revealed by their high viscosity, and formation of tough and flexible membranes. Polyintides with benzimidazole groups exhibited much better swelling capacity than those without benzimiclazole groups. This was attributed to the strong interchain interaction through basic benzimidazole functions and sulfonic acid groups. The sulfortated polyimides that are incorporated with 1, 1',8,8'-binaphthalimide exhibited better hydrolytic stability than that with 1,4,5,8-naphthalimide. Polyimide membranes with good water stability as well as high proton conductivity were developed. Polyimide membrane (Ia - 90), for example, did not lose mechanical properties after being soaked in boiling water for tOOO h, while its proton conductivity was still at a high level (compared to that of Nafion 117).

高分子科学实验中异常数据的判别与剔除

简单介绍了对测量值中异常数据进行判别与剔除的三种统计判别方法——3σ准则、格鲁布斯准则和Q检验方法的基本原理,并以高分子科学实验中的两个实例为代表,应用Visual Basic for Applica-tions(VBA)编写的程序模块,对测量值中异常数据的判别与剔除进行了详细讨论。

Synthesis and characterization of novel sulfonated polyimides from 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid

A novel sulfonated diamine monomer, 1,4-bis(4-aminophenoxy)-naphthyl-2,7-disulfonic acid (BAPNDS), was synthesized. A series of sulfonated polyimide copolymers were prepared from BAPNDS, 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) and nonsulfonated diamine 4,4'-diaminodiphenyl ether (ODA). Flexible, transparent, and mechanically strong membranes were obtained. The membranes displayed slightly anisotropic membrane swelling. The dimensional change in thickness direction was larger than that in planar. The novel SPI membranes showed higher conductivity, which was comparable or even higher than Nafion 117. Membranes exhibited methanol permeability from 0.24 x 10(-6) to 0.80 X 10(-6) cm(2)/s at room temperature, which was much lower than that of Nafion (2 x 10-6 CM2/s). The copolymers were thermally stable up to 340 degrees C. These preliminary results have proved its potential availability as proton-exchange membrane for PEMFCs or DMFCs.

Sulfonated poly(arylene-co-naphthalimide)s synthesized by copolymerization of primarily sulfonated monomer and fluorinated naphthalimide dichlorides as novel polymers for proton exchange membranes

A novel sulfonated aromatic dichloride monomer was successfully prepared by the reaction of 2, 5-dichlorobenzophenone with fuming sulfuric acid. Copolymerization of this monomer in the form of sodium salt (1) with N-(4-chloro-2-trifluoromethylphenyl)-5-chloro-1,8-naphthalimide (2) or bis(N-(4-chloro-2-trifluoromethylphenyl)1,4,5,8-naphthalimide (3) generated two series of novel poly(arylene-co-naphthalimide) s I-x and II-x where x represents the content of the sulfonated monomer. The synthesized copolymers with the -SO3H group in the side chains possessed high molecular weights revealed by their high viscosity and the formation of tough and flexible membranes. The copolymers exhibited excellent stability toward water and oxidation due to the introduction of the hydrophobic CF3 groups. The sulfonated copolyimides that incorporated with 1,8-naphthalimide (I-x) exhibited better hydrolytic and oxidative stabilities than those with 1,4,5,8-naphthalimide. Copolymer I-50 membrane endured for more than 83 h in Fenton's reagent at room temperature. The mechanical properties of I-50 membrane kept almost unchanged after immersing membrane in boiling water for 196 h. The proton conductivities of copolymer films increased with increasing IEC and temperature, reaching values above 6.8 x 10(-1) S/cm at 80 degrees C.

苯肾上腺素诱导乳鼠心肌细胞蛋白质表达变化的蛋白质组分析

α1-肾上腺素受体(α1-Adrenergic receptor,α1-AR)是G蛋白偶联受体(G-protein coupled receptor,GPCR),也是内源性儿茶酚胺、去甲肾上腺素和肾上腺素最重要的靶受体之一.α1-AR广泛分布于机体的各种器官、组织和细胞中,并介导多种生理效应,如血管收缩、蛋白质合成及心脏变力变时作用等[1,2].很多研究已经证实,α1-AR及其信号转导通路与许多心血管疾病存在密切关系[3,4].蛋白质组学可提供一种发现在疾病情况下异常表达蛋白质的方法,为疾病的早期诊断和愈后判断提供指南,并为针对性疾病治疗提供科学依据.本研究以乳鼠心肌细胞为实验模型,利用双向凝胶电泳和飞行时间质谱分析苯肾上腺素诱导乳鼠心肌细胞表达变化的蛋白质.1实验部分1.1试剂苯肾上腺素(Phenylephine,PE)购自Sigma公司;胰蛋白酶和DMEM购自Hyclone公司;IPG预制胶条(pH=5~8,胶条长17 cm),载体两性电解质(B io-Lyte5-8)购于B io-Rad公司;TPCK修饰的测序级胰酶购自Promega公司;其它试剂均为国产分析纯.1.2实验过程(1)乳鼠心肌细胞培养及样...

铀原子多色三光子共振电离谱研究

利用Nd∶YAG二倍频激光同步泵浦的脉冲染料激光系统、原子束装置、飞行时间质谱和Boxcar技术测量了2 38U的多色三光子共振电离谱。研究了电场对铀原子第一激发态的影响。解决了如何确定三色三光子共振电离谱图中所含的单色、双色和三色共振电离峰的问题。

Study on surface acid-base property of carboxylic acid-terminated self-assembled monolayers by cyclic voltammetry and electrochemical impedance spectroscopy

Cyclic voltammetry and electrochemical impedance spectroscopy were used to study the surface acid-base property of carboxylic acid-terminated self-assembled monolayers (SAMs). A carboxylic acid-terminated thiol, such as thioctic acid (1,2-dithiolane-3-pentanoic add), was self-assembled on gold electrodes. Electron transfer between the bulk solution and the SAM modified electrode was studied at different pH using Fe(CN)(6)(3-) as a probe. The surface pK(a) of thioctic acid was determined by cyclic voltammetry and electrochemical impedance spectroscopy to be 5.6 +/- 0.1 and 5.8 +/- 0.1, respectively. The method is compared with other methods of monolayer pK(a) measurement.

Synthesis and crystal structure of a new supermolecular compound: [C12H24O6][H3PMo12O40]center dot 22H(2)O (C12H24O6=18-crown-6)

The title compound, [C12H24O6][H3PMo12O40]. 22H(2)O, was synthesized by the self-assembly of 18-crown-6 (abbreviated as C12H24O6 or 18C6) and H3PMo12O40 in the mixed solvent of CH3OH and CH3CN, and was characterized by IR, H-1 NMR and Xray diffraction for the first time. Crystal data: Triclinic, P (1) over bar, a = 13.428(3) Angstrom, b = 13.557(3)A, c = 14.642(3) Angstrom, a = 105.39(3)degrees, beta = 90.06(3)degrees, gamma = 119.56(5)degrees, V = 2207.5(8) Angstrom(3), Z = 1, R1 = 0.0719, wR2 = 0.1990. It has a disordered alpha-Keggin PMo12O403- anion, which contains the strong alternating short (mean 1.844 Angstrom) and long (mean 1.958 Angstrom) Mo-O-Mo bonds. In the unit cell, crown ethers and molybdophosphates are alternatively arranged in good order along c-axis. An oxonium ion is located at the center of a crown ether molecule., Oxonium ion interacts with 18C6 by the means of hydrogen bonds (mean 2.7771 Angstrom), which are electrostatic or resonant. The observations show the existence of [H3O(C12H24O6)](+) (C) 2000 Elsevier Science B.V. All rights reserved.

The multicolour three-photon resonant ionization spectrum studies in uranium atom

The multicolour three-photon resonant ionization spectra of U-238 were measured by using the pulsed dye lasers system synchronously pumped by a frequency doubled Nd:YAG-laser 532 nm output(operated at 10 Hz),a device for atomic beam of U, time-of-flight mass spectrometer and boxcar integrator. The dye laser pulses have a 6 ns duration. Beams from the dye lasers, which have the same polarization direction and are focused by lenses, entered an interaction chamber through opposite windows on a common axis and spatialy overlapped the U atomic beam. The optical pulse from dye laser DL2 was delayed to arrive at the interaction region 8 ns after the pulse from dye laser DL1; in the same way,the pulse from DL3 was delayed 8 ns after from DL2. The atomic beam device was made from stainless steel. We generated the U vapor by heating solid U in a graphite crucible by e-type electron -field on first excited states were studied in uranium atom. The question how to determine single-colour, two-colour and three-colour three-photon resonant ionization peak in the three-colour three-photon resonant ionization spectra diagram were solved.

环戊二烯—12-钼硅杂多四丁基铵电荷转移盐的合成、表征与晶体结构

以环戊二烯与 1 2 钼硅杂多四丁基铵为原料 ,采用光化学法合成了一种新型电荷转移盐 (Bu4N) 4(C5 H6 ) [HSiMoVI11MoVO40 ]。用元素分析、IR、CV、固体漫反射电子光谱、ESR进行了表征。X 射线晶体结构测定其晶体属三斜晶系 ,空间群P1 ,晶胞参数a =1 4.347(3) ,b =1 4.42 3(3) ,c =2 7.1 5 8(5 ) ,α =96 .90 (3) ,β =1 0 4.1 8(3) ,γ =98.2 0 (3)° ,V =5 32 2 (2 ) 3,Z =2 ,Mr=2 85 5 .30 ,Dc=1 .782 g·cm-3,F(0 0 0 ) =2 86 0 ,R =0 .0 71 9,wR =0 .1 983。标题化合物由 1个环戊二烯、4个Bu4N+阳离子和 1个 [SiMoVI11MoVO40 ]4 -阴离子构成。

长白山白眉蝮蛇蛇毒精氨酸酯酶1的研究Ⅱ.酶学性质和荧光光谱研究(续Ⅰ)

测得了长白山白眉蝮蛇毒精氨酸酯酶 1的最适反应的pH范围为 7.0～ 8.0 ,且与酶反应底物对甲苯磺酰-L -精氨酸甲酯 (TAME)的反应无明显的最适应反应温度 .荧光光谱的研究结果表明 :该酶的酪氨酸残基的荧光被色氨酸残基的荧光所掩盖 ;同步荧光光谱结果表明 :当发射波长与激发波长差Δλ分别为 2 0nm和 75nm时 ,精氨酸酯酶 1的荧光光谱分别由酪氨酸 (Tyr)和色氨酸 (Trp)残基所贡献 ,且处于亲水性环境中 ;精氨酸酯酶 1的荧光发射强度受溶液酸度变化的影响 .I- ,Acr和NBS对精氨酸酯酶 1的荧光淬灭结果表明这种酶中含有多个色氨酸残基 ,且处于不同的微环境中。

环化氯丁橡胶的表征

在氯丁橡胶中加入环化试剂AlEt2 Cl-C6H5CH2 Cl,在 12 0℃× 2 0min条件下 ,可制备环化氯丁橡胶。借助IR ,1H -NMR ,DSC ,GPC和裂解色谱测试方法对产物进行了表征。结果表明 ,二甲苯溶剂参与了环化反应 ,且随环化度增加 ,参与反应的溶剂二甲苯的数目也逐渐增加 ,并确定了环结构的形成

Reaction and formation of crystalline silicon oxynitride in Si-O-N systems under solid high pressure

Oxidized amorphous Si3N4 and SiO2 powders were pressed alone or as a mixture under high pressure (1.0-5.0 GPa) at high temperatures (800-1700 degreesC). Formation of crystalline silicon oxynitride (Si(2ON)2) was observed from amorphous silicon nitride (Si3N4) powders containing 5.8 wt% oxygen at 1.0 GPa and 1400 degreesC, The Si2ON2 coexisted with beta -Si3N4 with a weight fraction of 40 wt%, suggesting that all oxygen in the powders participated in the reaction to form Si2ON2. Pressing a mixture of amorphous Si3N4 of lower oxygen (1.5 wt%) and SiO2 under 1.0-5.0 GPa between 1000 degrees and 1350 degreesC did not give Si2ON2 phase, but yielded a mixture of alpha,beta -Si3N4, quartz, and coesite (a high-pressure form of SiO2). The formation of Si2ON2, from oxidized amorphous Si3N4 seemed to be assisted by formation of a Si-O-N melt in the system that was enhanced under the high pressure.