Preparation And Characterization Of Anion Exchange Membrane Based On Quaternary Ammonium Functionalized Poly(Arylene Ether)s

AEMFCs have attracted enormous attention with advantages as follows:(1) faster oxygenreaction kinetics,(2) extended selective range of catalysts and (3) low fuel permeability.Anion exchange membrane (AEM) is one of the key components in AEMFCs. The presentstudy of AEM focuses on the synthesis of novel monomers, the expansion of modifiedtechnology and the exploration of new cation group. While the investigation on structure andproperties of AEM based on poly(arylene ether)s gains littler attention. In this thesis, twoseries of AEMs derived from quarternized poly(arylene ether)s were successfully prepared,and their fundamental properties were evaluated in details.(1) Quaternary ammonium functionalized poly(arylene ether)s (QPAEs) containing2,2’,6,6’-tetramethylbiphenol moieties were designed and successfully synthesized vianucleophilic substitution polycondensation, bromination, quaternization and alkalization. Thestructure, water uptake, ion exchange capacities (IEC), hydroxide ion conductivities, andmechanical properties, as well as thermal and chemical stabilities of the obtained QPAEsmembranes were investigated. The QPAEs membranes were tough and thermally stable up to150°C. The QPAE-a membrane with IEC value of0.98meq·g1demonstrated the highest ionconductivity (47.4mS·cm1) at80°C. The transport activation energy (Ea) of QPAEsmembranes varied from8.57~19.95kJ·mol-1. After chemical stability test conditioned in1mol·L-1NaOH at60°C for7days, the QPAEs membranes except QPAE-c (IEC=0.88meq·g1) still exhibited high hydroxide ion conductivities (over15mS·cm1) and acceptabletensile strength (approximate10MPa).(2) Block copolymers containing quaternary ammonium basic groups functionedtetramethylbiphenol moieties with sequential hydrophobic/hydrophilic sturcture weresynthesized via prepolycondensation, block copolycondensatio, bromination, quaternizationand alkalization. The QPAEs membranes were thermally stable up to200°C with IEC valuesof0.86~1.24meq·g1. The highest ion conductivity was obtained by QPAE-X14Y21with thevalue of50.4mS·cm1at60°C. After chemical stability test conditioned in1mol·L-1NaOHat60°C for28days, the ion conductivities of QPAE-X8Y9and QPAE-X8Y15were29.4mS·cm-1and40.5mS·cm-1, respectively, without significant attenuation.