Synthesis and characterization of sulfonated poly(arylene ether sulfone) ionomers incorporating perfluorohexylene units for DMFC membranes

Abstract

A new, sulfonated poly(arylene ether sulfone) ionomer with partially fluorinated groups (F-SPAES) was synthesized by the direct polymerization of 1,6-bis(4-fluororphenyl)-perfluorohexane (FPPFH) and 6F-bisphenol A (6F-BPA) with 3,3'-disulfonated 4,4'-difluorodiphenyl sulfone (SDFDPS). The effect of fluorination on the membrane properties and membrane-electrode assembly (MEA) performance for DMFC applications were investigated comprehensively and compared with the pristine SPAES sample. Deliberate control of the hydrophobicity as well as the degree of sulfonation in the F-SPAES membranes allows the effective suppression of water uptake and methanol permeability, while barely affecting the proton conductivity and IEC value. Such an improvement in the membrane properties contributes to the superior single cell performance of the F-SPAES compared to pristine SPAES and Nafion ® .

Preparation and characterization of SPEEK membranes crosslinked by electron beam irradiation

“…Many promising polymers are based on aromatic thermoplastics, such as sulfonated polyimide (SPI), 6 sulfonated poly(aryl ether ketone) (SPAEK), 7,8 sulfonated poly(aryl ether sulfone) (SPAES) 9 and sulfonated poly(ether ether ketone) (SPEEK), 10,11 etc.. These sulfonated polymers have shown excellent chemical and thermal stability, as well as good mechanical properties, and can be produced at low cost.…”

SiO2 nanoparticles-coated poly(paraphenylene terephthalamide) nonwovens as reinforcing porous substrates for proton-conducting, sulfonated poly(arylene ether sulfone)-impregnated composite membranes

“…The detailed synthesis and characterization of the SPAES have been described in previous publications [22][23][24]. The chemical structure of the SPAES is shown below.…”

“…The SPAES solution-impregnated membrane was then dried at 80°C for 4 h. The impregnation and drying steps were repeated more than four times in order to eliminate voids and pinholes in the SPAES composite membranes. Finally, the SPAES composite membranes were acidified in a 1 N boiling sulfuric acid solution for 2 h and subsequently rinsed with distilled water for 2 h [23,24]. The final thickness of the SPAES composite membranes was measured to be around 50 μm and also their weight-based composition ratio (PPTA nonwoven/(SiO 2 particles + TEOS binder)/SPAES) was 11/9/80.…”

Polymer electrolyte membranes prepared by EB‐crosslinking of sulfonated poly(ether ether ketone) with 1,4‐butanediol

“…However, the membrane also has many disadvantages, for example, high production costs, high methanol crossover, and decreased proton conductivity at temperatures above 80°C . Therefore, as an alternative to Nafion, many research groups have focused on aromatic hydrocarbon based ion‐exchange membranes, such as sulfonated polyimide, sulfonated polyphosphazene, sulfonated poly(arylene ether), and sulfonated poly(ether ether ketone), which have high‐temperature stability, low methanol permeability, environmental compatibility, and low cost. In particular, sulfonated poly(ether ether ketone) (SPEEK) has been considered a good candidate because it has excellent thermal, chemical, and mechanical properties and the proton conductivity can be easily controlled by the sulfonation conditions, such as the reaction time, temperature, and sulfonic acid content.…”