Abstract

nd s thi ETFE base film was investigated. Styrene/MAN co-grafted membranes were compared to a styrene based membrane in durability tests in single H2/O2 fuel cells. It is shown that the incorporation of MAN consid-erably improves the chemical stability, yielding fuel cell lifetimes exceeding 1000 h. The membrane prep-aration based on the co-grafting of styrene and MAN offers the prospect of tuning the MAN content and proto sues to water uptake, in a wide range to obtain desired properties. Our working group is devoted to the development of low cost polymer electrolyte membranes prepared by radiation grafting, and extensive work to improve the mechanical and chemical sta-bility has been carried out. Lifetimes exceeding 4000 h at a temper-on the influence of grafting parameters and reaction kinetics was performed for the grafting of styrene onto ETFE [8]. Moreover, the influence of crosslinker concentration was investigated and correlations between the content of DVB and the ex situ and in situ relevant properties for fuel cells were established [9,10]. It is well known that the styrene sulfonic acid group in the grafted membrane suffers from the weakness of the a-hydrogen position, which is prone to radical attack under fuel cell conditions [11]. Substantial work is devoted to improve the stability of radia-tion grafted membranes by the use of new monomer combinations