Sulfonated polyimide membrane for fuel cell application; Prepaartion, Characterization and evaluation of filmability of membrane

Sulfonated polymer is a member of widely used polymers and investigated intensively because of their current and potential applications in many areas. In the past decade, sulfonatedpolyimide (SPI) have been considered as promising alternative for commercial perfluorosulfonic acid (PFSA) membranessuch as Nafion for polymer electrolyte membrane fuel cells (PEMFCs) application.[1] The polymer is converted to a sulfonated form by either (1) post sulfonation by sulfuric acidfunction agents (2) direct sulfonation by sulfonated monomers onto the polymer backbone. Post sulfonation has been shownthat this reaction produces some defects on the polymer backbone such as polymer chain scissions, which limit thelifetime in PEMFCs.[2] Deligoz and coworker, used 3,3,4,4- benzophenonetetracarboxylic dianhydride (BTDA), 4,4- oxydianiline (ODA) and post sulfonation process forpreparing sulfonated polyimide membrane. But They can’t carried out all kind of test for this polyimide structure due to the most of synthesized membranes were brittle after thermal imidization.[3] In this study, we considered effect of polyimide synthesis condition such as solution concentrationand reaction time on final filmability sulfonated polyimide and discussed about reason of low filmability of Deligoz’s membrane