Novel Sulfonated Copolyimides as a Candidate for Proton Exchange Membrane Fuel Cell

Proton exchange membrane (PEM) fuel cells (polymer electrolyte membrane) are one of the most important types of fuel cells that employ a solid polymer electrolyte to separate the fuel from the oxidant. During last decades different polymers with various structures have been reported for application as membrane in stationary or mobile fuel cell systems. Sulfonated polyimides, polysulfones, polystyrenes, polybenzimidazoles, poly(ether ether ketone)s are some of the main types of membranes have been used recently [1,2]. Polyimides with appropriate ionconducting sites are one of the best candidates for fuel cell membrane [3,4]. Here we intend to describe the preparation of some new sulfonated copolyimides as fuel cell membranes. Polyimide membranes with various degrees of sulfonation were prepared from a new sulfonated diamine (3,3'-Disulfonic acid-bis[4-(5-amino-1- naphthoxy)phenyl]sulfone or DANPS), two new unsulfonated diamines (4,4'-(5- amino-1-naphthoxy) diphenylsulfone or ANDS, and 4,4'-(4-Aminophenoxy) diphenylsulfone or APDS), and a six-membered ring dianhydride (NDA).