【作者】 吴永会；

【导师】 徐铜文；

【作者基本信息】 中国科学技术大学 ， 应用化学， 2009， 博士

【摘要】 与有机或无机膜相比,有机—无机杂化膜具有优良的强度和柔韧性、成膜性能、热和化学稳定性等,并且能发展单一膜材料原先所没有的综合性能,因此具有广阔的应用前景。杂化离子交换膜可以将无机材料的优点引入有机离子交换膜中,应用于多种领域。其中,杂化阴离子交换膜在一些重要的应用领域具有不可替代的作用,所以进一步的发展很有潜力。杂化阴离子交换膜可以应用于多价离子的截留和贵重金属的回收、压力驱动液相分离、蛋白质分离、气体分离膜等领域,特别是应用于碱性膜燃料电池（AMFC）上。在AMFC领域,杂化阴离子交换膜的性能可以与相应的氟化聚合物膜相比,显示出优异的机械强度、化学和热稳定性、以及良好的电学性能。杂化阴离子交换膜的制备方法包括原位聚合法、掺杂法、聚合物改性法、接枝法,其中最重要的方法之一是共聚法,它可以避免有机—无机相分离或降低相分离的程度、兼顾膜的强度和柔韧性、使有机-无机相之间的相对比例更容易调节、使离子交换基团更容易引入且更加稳定。因此,共聚法是本论文所采用的主要制备方法。本论文共包括七章。第一章是绪论,先对有机—无机杂化材料和杂化膜作简要的介绍,然后对杂化离子交换膜的发展、应用和制备进行了概括,再过渡到杂化阴离子交换膜的应用和发展,并重点介绍了它们的制备方法。最后提出本论文的设计思想和论文的主要工作。由于共聚法具有特出的优点,第二章先制备了共聚物（甲基丙烯酸缩水甘油酯/甲基丙烯酸-三甲氧基硅丙酯）(poly（GMA-co-KH-570）。共聚物涂覆在陶瓷片上,随后进行开环反应和sol-gel反应;得到以陶瓷为支撑体的杂化阴离子交换膜。考察了聚合物成分对膜的亲水性、水通量、电学性能、热稳定性和形貌的影响,结果表明膜可以应用于压力驱动过程,如超滤和纳滤。为了制备可以应用于电驱动过程的杂化膜,第三章选用了柔韧性良好的聚乙二醇（PEO）作为改性材料。PEO经过封端和季铵化后,得到前驱体PEO-[Si（OCH₃）₃]（+）。前驱体与荷电、不荷电的小分子烷氧基硅烷一同进行sol-gel反应,得到无支撑体的杂化阴离子交换膜。膜均匀致密,具有较高的热稳定性、合适的电导率和优异的机械性能,有可能应用于AMFC上。第四章采用了共聚法,先制备了共聚物（氯甲基苯乙烯/甲基丙烯酸-三甲氧基硅丙酯）（poly（VBC-co-KH-570））,共聚物进行季铵化,同时和小分子烷氧基硅烷进行sol-gel反应后,得到杂化阴离子交换膜。膜平整致密、具有优异的化学稳定性和热稳定性、以及较高的离子交换容量（IEC）,但电导率偏低。膜有可能应用于AMFC上第五章以聚（2,6-二甲基-1,4-苯撑氧）（PPO）为原料,进行溴化、羟基化、季铵化,随后和烷氧基硅烷一同进行sol-gel反应,热处理后得到杂化阴离子交换膜。调节以上制备过程,得到两种不同系列杂化膜:（1）变化热处理时间和温度,可以对膜的亲水性、柔韧性、电学性能和热稳定性进行有效调节。合适的热处理条件（130℃4-6h）得到的膜具有较高的耐碱能力和热稳定性,以及可接受的电导率。总体上,杂化膜可以有可能应用于AMFC上;（2）选定一个优化的热处理条件（130℃5h）,变化烷氧基硅烷的用量,探索无机相的含量对膜性能的影响。结果表明适当的氧化硅含量可以提高膜的性能,相对于系列（1）,膜的抗溶涨能力和电学性能得到了显著的改善,更加适合应用于AMFC上。以上膜制备过程中均涉及到sol-gel反应,为了探索sol-gel反应与膜性质之间的关系,在第六章中,选用了poly（GMA-co-KH-570）进行了材料-制备过程-膜性能关系的研究。poly（GMA-co-KH-570）和荷电、不荷电小分子烷氧基硅烷一同进行sol-gel反应,制备了杂化阴离子交换膜。初步的研究表明,高分子量的共聚物不利于sol-gel反应的充分进行,制得的膜常不均匀。低分子量的共聚物可以制备出具有较高交联程度的膜、高度均相和柔韧的膜;膜的热稳定性受交联程度的影响,膜的电学性能主要受到荷电小分子烷氧基硅烷用量的影响。更多还原

【Abstract】 Compared with organic or inorganic membranes,organic-inorganic hybrid membranes have favorable strength and flexibility,membrane formation ability, thermal and chemical stabilities,and also new synergetic properties.Hence,hybrid membranes can be potentially widely used.Ion-exchange hybrid membranes can introduce the merits of inorganic material into the organic polymers,thus is widely applied to various fileds.As the anion-exchange hybrid membranes have irreplaceable effects in some important applications,further development is quite necessary and meaningful.Anion-exchange hybrid membranes are widely needed on some important occasions such as retention of multi-valent ions,recovery of valuable metals, pressure-driven liquid separation,protein separation and gas separation,etc, eapecially on alkaline membrane fuel cells（AMFCs）.In the filed of AMFCs,the performances of anion-exchange hybrid membranes are comparable with those of fluorinated polymer membranes.The hybrid membranes show excellent mechanical properties,chemical and thermal stabilities,as well as favorable electrical properties. The hybrid membranes can be prepared by various methods,including in-situ polymerization,adulteration,polymer modification and grafting.One of the most important methods is the copolymerization.This method can overcome organic-inorganic phase separation or reduce the degree of phase separation,obtain membranes with both favorable strength and flexibility,adjust the ratios between organic and inorganic phases more easily,introduce ion-exchange groups more conveniently,and make the ion-exchange groups more stable.Hence, copolymerization route is the main adopted method in this dissertation.This dissertation includes seven chapters.ChapterⅠgives an overview on the research background through the introduction of organic-inorganic hybrid materials and membranes.Subsequently,chapterⅠgeneralizes the development,application and preparation of ion-exchange hybrid membranes.Then the chapter focuses on the application and development,especially preparation of anion-exchange hybrid membranes.Finally,the research ideas and outline of the dissertation are proposed.As the method of copolymerization has excellent merits,In chapterⅡ,the copolymer of glycidylmethacrylate andγ-methacryloxypropyl trimethoxy silane （poly（GMA-co-KH-570）） is prepared firstly.The copolymer is dip-coated on ceramic plate,and then undergos the ring-opening and sol-gel reaction,respectively. Finally,ceramic supported anion-exchange hybrid membranes are obtained. Effects of the copolymer composition are fully discussed on membrane hydrophilicity,water flux,electrical properties,thermal stability and membrane morphology.Results show that the membranes are suitable for potential application in pressure driven process,such as UF and NF.In order to develop hybrid membranes that can be used in electro-driven process, chapterⅢselects flexible polyethylene oxide（PEO） as the starting material.PEO is endcapped and quaternized to obtain precursor PEO-[Si（OCH₃）₃]（+）.The precursor undergoes the sol-gel reaction together with charged and non-charged alkoxysilanes of small molecular weight.Finally,free-standing anion-exchange hybrid membranes are obtained.The membranes are compact and homogenous.They have relatively high thermal stability,proper conductivity and excellent mechanical properties,thus can be potentially applied to AMFCs.ChapterⅣadopts the method of copolymerization.The copolymer of vinylbenzyl chloride and KH-570（poly（VBC-co-KH-570）） undergoes the quaternization,and sol-gel reaction with alkoxysilanes of small molecular weight.The obtained anion-exchange hybrid membranes are compact and dense,with relatively high ion-exchange capacities（IECs） but low conductivity.The membranes have excellent chemical and thermal stabilities.They are intended for application in AMFCs.ChapterⅤutilize the polymer of poly（2,6-dimethyl-l,4-phenylene oxide）（PPO）. PPO is modified by bromination,hydroxylation and quaternization in sequence, subsequent sol-gel reaction with alkoxysilanes,followed by heat treatment,yields two series of anion-exchange hybrid membranes.（1） Through varying the conditions of heat treatment,the hydrophilicity,flexibility,electrical properties and thermal stabilities of the hybrid membranes can be adiusted effectively.Membranes endured proper heat treatment（130℃4-6 h） can have relatively high alkaline resistance, thermal stability and acceptable conductivity.Generally speaking,the hybrid membranes can be potentially applied to AMFCs;（2） An optimized condition of heat treatment is selected（130℃5 h）.The dosages of alkoxysilanes are varied,and the impacts of inorganic content on the membrane properties are investigated.Results show that proper silica content can improve the membrane performances.Compared with the membranes of part（1）,the membranes here have significantly improved swelling resistance and electrical properties.Hence,they are more suitable for application in AMFCs.The above membrane formation processes all involve sol-gel reactions.To investigate the relations between sol-gel reaction and membrane properties,chapterⅥselects poly（GMA-co-KH-570）.The copolymer is used to investigate the relations among materials,membrane formation process and membrane properties. Poly（GMA-co-KH-570） undergoes the sol-gel reaction together with charged and non-charged alkoxysilanes of small molecular weight.After the sol-gel process, anion-exchange hybrid membranes are obtained.Primary studies indicate that,the copolymer of high molecular weight is disadvantage to the sol-gel reaction,and the obtained membranes are always inhomogenous.The membranes prepared from the copolymer of low molecular weight have relatively high crosslinking degree,and are highly homogenous and flexible.The crosslinking degree affects their thermal stability significantly,while the dosage of charged alkoxysilane controls their electrical properties.更多还原