Membrane chemical degradation operating temperature effects

Membranes will chemically degrade by decarboxylation if subjected to high temperature. This effect is reinforced at higher caustic concentrations, and membrane life can be reduced significantly by prolonged operation above 35% NaOH. 

Increased temperatures have a strong correlation to some of the key degradation mechanisms. Membrane degradation due to chemical mechanisms as indicated by fluoride release rate has been shown to follow an Arrhenius relationship with temperature, with an increase of 1.8 times for a 10 °C rise. Figure 6.4 shows the relationship between temperature and the fluoride release rate as measured in the cathode and anode effluent at open-circuit voltage operation for an MEA containing DuPont Nafion 112 membrane. This trend is consistent with data reported in the Uterature, e.g. Madden et al. (2009). Sethuraman et al. (2008) showed the effect of temperature on lifetime at open-circuit voltage and found a lifetime of -500 h at 80 °C was dramatically decreased to -60 h at 100 °C and only -30 h at 120 °C (Sethuraman et al., 2008). 

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