Durability of Fluoropolymers for Proton Exchange Membranes

28 Synthesis of PVDF-g-PVBC-g-PS by ATRP of styrene initiated by PVDF- -PVBC copolymers [137]. 

Given the importance of fuel cell durability to the ongoing drive toward commercialization, it would be reasonable to assume that failure modes for PEMs would be a well-studied topic. Surprisingly, relatively little has been published on this topic, and in 

mass spectroscopy, and various chromatographic techniques. Among the accelerated life tests used in fuel cell systems, Fenton s reagent, a combination of ferrous ions and aqueous hydrogen peroxide, is a well-known method for generating peroxide radicals at temperatures that mimic fuel cell operation (Fig. 2.30) [157], 

In support of the mechanism shown in Fig. 2.31, fluoride emissions in operating fuel cells are essentially linear over hundreds (sometimes thousands) of hours, and in highly accelerated life tests over several days. DuPont reports that these linear behaviors hold for both as-produced membranes and those wherein approximately 

32 Relative rates of degradation (Fenton s 400 1) of model compounds of DuPont 

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