【作者】 刘晨光；

【导师】 吴忠文； 那辉；

【作者基本信息】 吉林大学 ， 高分子化学与物理， 2005， 博士

【摘要】 本论文是以磺化聚芳醚酮在质子交换膜中的应用为研究背景,从分子设计的角度合成了新型可控磺酸基团的单体和多种侧基不同的磺化聚芳醚酮聚合物。通过电性能,热性能,力学性能,阻醇性能的测试,可知合成的聚合物符合质子交换膜性能要求。利用它们相互间结构的相似性和可比性,对其结构和性能的关系进行了研究,研究中发现,聚合物的膜性能随磺化度增加呈明显变化,而且由于侧基体积不同,影响链段柔顺性,规整性及固定离子浓度,聚合物宏观性能有所差异。叔丁基磺化聚醚醚酮具有更好的溶解性和电性能,而叔丁基磺化聚醚醚酮酮的热性能和阻醇性能好一些。叔丁基磺化聚醚醚酮电性能上表现的最好,在室温下可以与Nafion117 膜媲美,但由于吸水率的影响,其阻醇性也是这三个系列中比较差的。为解决叔丁基磺化聚醚醚酮阻醇性差的问题,我们设计合成含双键可自交联的磺化聚醚醚酮,分别采用热和光对其进行引发交联。由于有效热引发温度要高于磺酸钠基团脱落温度,我们采用光引发交联,对交联前后性能进行了研究。通过试验发现,在一定交联条件下,聚合物的力学性能有所提高,甲醇透过性降低明显,而质子传导率下降不明显,达到了我们提高阻醇性能的要求。并且交联方法简单易行,条件可控,可在用于高磺化度聚合物阻醇改性。更多还原

【Abstract】 Fuel cells have the potential to become an important energy conversiontechnology. Research efforts directed toward the widespread commercialization offuel cells have accelerated in light of ongoing efforts to develop a hydrogen-basedenergy economy to reduce dependence on foreign oil and decrease pollution. Protonexchange membrane fuel cells (PEMFC) employing a solid polymer electrolyte toseparate the fuel from the oxidant were first deployed in the Gemini space programin the early 1960s using cells that were extremely expensive and had short lifetimesdue to the oxidative degradation of their sulfonated polystyrene-divinylbenzenecopolymer membranes. These cells were considered too costly and short-lived forreal-world applications. The commercialization of Nafion by DuPont in the late1960s helped to demonstrate the potential interest in terrestrial applications for fuelcells.PEM fuel cells are being developed for three main applications: automotive,stationary, and portable power. Each of these applications has its unique operatingconditions and material requirements. Common themes critical to all highperformance proton exchange membranes include (1) high proton conductivity, (2)low electronic conductivity, (3) low permeability to fuel and oxidant, (4) low watertransport through diffusion and electro-osmosis, (5) oxidative and hydrolyticstability, (6) good mechanical properties in both the dry and hydrated states, (7) cost Although Nafion has good chemical and physical properties for use in fuel cellfields. It has three major draw backs, including low conductivity at low humidity orhigh temperature, as well as high methanol permeability. Unreacted methanol at theanode can diffuse through the membrane and react at the cathode, lowering thevoltage efficiency of the cell and reducing the system’s fuel efficiency. Thedrawbacks limited application in the direct methanol polymer Electrolyte membranefuel cells. Besides, the perfluorinated membranes are very expensive, which is alsoregarded as a limiting factor. Thus new polymer electrolyte membranes for fuel cellare being explored. Poly (aryl ether ketone)s belong to the class of high-performancepolymers. It is desirable to modify poly (aryl ether ketone)s to some degree whilemaintaining their excellent properties for the application in PEMFC. Our work is base on the background: the application of sulfonated PEEK inPEMFC. In this thesis based on Molecular Resign Principle, novel sodiumsulfonate-functionalized poly(ether ether ketone)s contain vary side groups weresynthesized. Unitized the similar and comparability, we study the relationshipbetween structure and property. The polymers look promising for the potential useas high performance polymer electrolyte membraneTwo sulfonated fluoric monomers were designed and synthesized successfullyThe results of FTIR and HNMR were agreed with supposed structure Novel sodiumsulfonated-functionalized poly (ether ether ketone)s derived for vary side groupsdiphenol. With degree of sulfonation up to 1.0 were synthesized by nucleophibicpolycondensation. Component and structure if the polymers were confirm by IR. The test of the polymers was taken at room temperature. From the testing result,we can see that the properties of the polymers were discrepant due to the differentstructure of side groups. We compare STPEEK with SMPEEK from the molecularstructure. Tert-butyl have biggish balk, which can prevent the polymer chainsordinal arrange and compact deposit, easily form ion channels, extend the diffuse ofion in order to improve the proton conductivity. The logarithm of the protonconductivity of STPEEK changes linearly with log (H2O/SO3H), the slope of thestraight lire being about 2, this implies that the conductivity depends on the squareof the hydration number. On the other hand, the side groups imported are pliancychains, they can drive the polymer main chain move in organic solvent, so improvethe resolvability in the solvent and the SW was increase. Besides the biggish bulk,the atom distributes compactly the space clag affects the chain segments’movementthe main chain flexibility is lower, Tg and weight loss temperature are higher. Compare STPEEKK with STPEEK from molecular structure, the different ofrigid chain length influence the properties of the two series polymers. As the 1,4-fluorobenzoyl benzene processes the longer rigid clear the structure of the moleculemain chain hard to circumrotate. Rigidity of the molecule chain increases, Tg ofSTPEEKK improved. And as the increase of rigid chain length the chain orderlinessof the STPEEKK increase, the resolvability of STPEEKK was minish, and the SWwas minish. For the main chain length, the fixed ion concentration of STPEEKKwas less than STPEEK the IEC was less than that of STPEEK so that theconductivity of STPEEKK was less them that of STPEEK The IEC and SW of STPEEK were the best of the three series polymers. Theconductivity of STPEEK can reach to 5×10-2S/cm, it can compare beauty withNafion117 at room temperature. Because of the SW, the preventability of methanolosmosis was badly. It request come to a balance among SW, conductivity andmethanol permeability. The difference of conductivity can influence the cellperformance and output power. We choice STPEEK as the study object towards theFuel Cell application. In order to decrease the methanol permeability, we import theself-crosslinking allyl group in STPEEK, define the new polymer as polymerSATPEEK and APEEK. We took the model APEEK as object to study the heat-induced crosslinking.When the polymer heat to above 300℃, the Tg hoist obviously. It is prove that theAPEEK can get crosslinking when heat, but the crosslinking temperature wascomparatively high. We study the thermodecompose process of STPEEK usedTG-DTG method. Compared with two different calculate methods, the activationenergy calculated by the Kissinger method was close to that calculated by the Ozawamethod. We also gained the break temperature of sodium sulfonated at differentcalefactive speed. And compare with the TM1 (497-531K) of SPEEK, thecrosslinking temperature was too high. We compare the influence of allyl content at polymer properties. With the sameDS, the rule of the IEC, methanol permeability and conductivity is 10DABPA >50DABPA > 30DABPA. The Tg was lower as the allyl content decrease. Photochemical crosslinking experiment carried out in the presence ofbenzophenone as a photosensitizer and triethanolamine as a photoinitiator. Weinvestigated the effect of the different modify condition. As the result, we can see when the UV crosslinking of SATPEEK membraneswith different time, the methanol permeability of 50DABPA-46 was reduced withirradiated time. The Elastic and Stress increase more sharply before 5min. After5min, the Elastic enhance slowly, and the Stress tends to plateau. Therefore, theconductivity decreases mot much when irradiated time less than 10min. When contain various allyl groups content, the properties of polymer havedifference. In the course of UV-irradiation, the solicitation speed of 10DABPA islower than that of 50DABPA. The mechanical properties of 10DABPA increaseslower than that of 50DABPA, maybe can get more improvement. But decreaseextent of methanol permeability and conductivity of 10DABPA was much largerthan that of 50DABPA. When the membranes were irradiated at different temperature, the change ofproperties was also different. The mechanical properties of 50DABPA have nonotable variety irradiated at 25℃, only increase little extent. However, they increaseobviously irradiated at 60℃and 90℃. Furthermore, the latter shows more evidentheighten. Change of conductivity is not obviously, but the decrease range ofmethanol permeability was lower than that of irradiation at 90℃. In the future, we anticipate that the UV irradiation induced crosslinking can be更多还原