Hydrocarbon polymers temperature PEMFC

Altematiye Hydrocarbon Polymers for High Temperature PEMFC Applications... 

Because of good thermal and hydrolytic stability, excellent mechanical and chemical stability, low cost, and commercial availability of sulfonated aromatic hydrocarbon polymers, recent research has focused on the synthesis and development of sulfonated aromatic hydrocarbon polymers specifically for high-temperature PEMFCs. Typical examples include sulfonated poly(ether ether ketone) (SPEEK) or poly(ether ketone ketone) (SPEKK) [1,2], sulfonated poly(ether sulfone) (SPSE) [3], alkyl sulfonated polybenzimidazole (PBI), sulfonated naphthalenic polyinrides (sNPl) [4-6], sulfonated polyCphenylene sulfide) [7,8]. Both post- and pre-sulfona-tion methods have been used in the past. Other than the post-sulfonation modification of aromatic polymers, recently, efforts have been dedicated to direct polycondensation from sulfonic acid containing monomers to synthesize sulfonated polymers [9]. The latter approach, namely pre-sulfonation, is widely applied because of the ease of controlling sulfonation degree and deactivated sites in the arylene backbones, which further avoid side reactions such as decomposition and hydrolysis of polymers resulted from the post-sulfonation method. 

In the development of polymer electrolyte membrane fuel cells (PEMFC), the durability of the membrane is one of the most important issues. For automotive utilization of PEMFCs, high-temperature operations between 110 and 120°C and low-humidity conditions are required. Fot the membranes of PEMFCs, perfluOTOsulfonic acid (PFSA) polymers are extensively used owing to their considerably higher chemical stability over hydrocarbon polymers. However, conventional PFSA polymers have glass-transition temperatures around 80°C, and are subject to critical breakdown of the membrane at high tanperatures. Additionally, conventional PFSA polymers suffer from degradation under low-humidity conditions even at 80°C. 

C.H. Park, C.H. Lee, M.D. Guiver, Y.M. Lee, Sulfonated hydrocarbon membranes for medium-temperature and low-humidity proton exchange membrane fuel cells (PEMFCs). Progress in Polymer Science 2011, 36(11), 1443-1498. 

---