标题: 利用点击反应与原位聚合法制备磺酸化聚三唑/黏土奈米复合材料之燃料电池质子传导膜与性质探讨
Preparation and Characterization of Sulfonated Polytriazole (SPTA)-Clay Nanocomposites Proton Exchange Membranes of Fuel Cell by In Situ Polymerization and Click Chemistry Processes
作者: 徐郁娟
Hsu Yu-Chuan
张丰志
Chang, Feng-Chih
应用化学系硕博士班
关键字: 燃料电池;质子交换膜;黏土;fuel cell;proton exchang membrane;clay
公开日期: 2009
摘要: 第一部分研究,利用修饰炔丙基官能基(Propargyl groups)的黏土(Clay)经由点击化学(Click chemistry),以原位聚合(In situ polymerization)的方式制备出脱层型态Polytriazole (PTA) /Clay奈米复合材料。本篇研究中,蒙脱土已成功的以脱层型态分散在高分子Polytriazole基材中,并且改善了复材的热性质与机械性质。利用此方式也可应用在其他具炔丙基改质土与具叠氮(azide-)和炔烃基(alkyne-)的高分子聚合反应中。

近年有许多不同种類的质子交换膜(Proton exchange membrane)应用于燃料电池(Fuel cells),其中以非含氟的高分子材料为基材之质子交换膜最被广泛研究。经由导入高含量磺酸根于高分子,非含氟材料的质子交换膜可以达到高的质子导电度(Proton conductivity),但此方式也同时损耗交换膜的机械性质,并且引起了甲醇穿透(Methanol crossover)的问题。此外这些聚集的磺酸根離子也将会造成质子交换膜有过度澎润甚至溶在甲醇水溶液中。研究如何改善质子导电度且降低甲醇穿透的问题时,同时也不牺牲交换膜的机械性质和化学稳定性目前仍然具有相当大的挑战。

第二部份研究,介绍如何利用点击反应(Click reaction)并以原位聚合法 (In situ polymerization)制备出Sulfonated Polytriazole (SPTA) / Clay燃料电池质子传导膜。有鉴于第一部份PTA/Clay奈米复材制备的成功,在此我们将单体1,4-bis(azidomethyl)benzene(BAB)换成具磺酸根官能基的sodium (E)-6,6'-(ethene-1,2-diyl) bis(3-azidobenzenesulfonate) (SEBA),使复材可更多元的应用在燃料电池质子传导膜。本篇研究中,蒙脱土也成功的以脱层型态分散在高分子基材中,不仅热性质与机械性质提升,复材的保水性更佳、离子通道变小及离子团簇均匀分散,以上特性也使甲醇穿透度大幅下降与质子传导度提升。只要加少量的的黏土(1-3wt%)即可有大幅性能提升。对于无机材料黏土导入的新手法,使未来在直接甲醇燃料电池(DMFC)质子传导膜(PEM)的部分,又增加了一个很好的制备路径。
(Part 1) This manuscript describes the preparation of polytriazole/clay nanocomposites through in situ polymerization of PTA, using click chemistry, in the presence of a propargyl-modified clay. The clay layers became exfoliated and dispersed well in the PTA matrix, thereby improving the thermal and mechanical properties of the clay. This approach can be extended to combine propargyl-modified clays with other azide- and alkyne-containing polymers.

Among various types of proton exchange membranes(PEMs) for fuel cells, several nonfluorinated polymeric materials are attracting more attention as alternatives to perfluorinated polymer membranes.The nonfluorinated PEMs can achieve high proton conductivities by introducing high extent of sulfonic acid groups, but tend to deteriorate the mechanical strength and permeability of PEMs simultaneously. The aggregation of conductive sites will cause these PEMs highly swollen or dissolved in aqueous/alcoholic solutions. The development of more efficient membranes with improved proton conductivity and reduced methanol crossover without detrimentally mechanical and chemical stabilities remains an important challenge.

(Part 2) Sulfonated polytriazole-clay (SPTA-clay) nanocomposites have been successfully prepared by in situ polymerization of SPTA using click chemistry in the presence of propargyl-functionality modified clay. The clay layers were found to be exfoliated and well dispersed in the SPTA matrix which resulted in improvement of thermal stability, echanical strength, methanol permeatbility, water retention, ion channel size, and ionic cluster distribution by the incorporation of a small amount of clay (SPTA 1 and 3). The SPTA-clay nanocomposite membranes by incorporating a small amount of clay in SPTA matrix possess higher selectivity defined as ratio of proton conductivity to methanol permeability, therefore, it had potential usage of a proton exchange membrane (PEM) for direct methanol fuel cells (DMFCs).
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT079725502
http://hdl.handle.net/11536/45149
显示于类别:Thesis