ETFE-PEM

Scheme 6.33 Preparation procedures for ETFE-PEMs consisting of hydrophilic polystyrene sulfonic acid grafts. Reproduced with permission from Ref. [130].

ETFE and PVDF have also been used as base substrates by Shen et al. and Horsfall and Lovell. PEMs (30,31) made using these materials have been shown to demonstrate comparable FC performance in both PEMFC and DMFC to that of 32. It was concluded from these studies that the primary controlling... 

Examples of radiation-grafted PEMs poly(ethylene-flZf-tetrafluoroethylene)-gra/f-poly(sty-rene sulfonic acid) (ETFE-g-PSSA), 30 PVDF-g-PSSA, 31 and poly(tetrafluoroethylene-co-hexafluoropropylene)-g-PSSA (FEP-g-PSSA), 32. 

Hatanaka et al. [92] prepared and tested the performance of ETFE-g-PSSA membranes in DMFC. These membranes were prepared by preirradiation of ETFE film (120 am) from y-radiation followed by styrene grafting and subsequent sulfonation. The membranes with degrees of grafting exceeding 30% displayed better transport properties, i.e., higher ionic conductivity and lower methanol permeation, compared with Nafion membranes. However, the PEM fuel cell performance of these membranes was found to be inferior to that of Nafion. The authors attributed such behavior to the poor bonding of the electrodes to the membrane surface in the MEA. 

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