Novel grafted nafion membranes for proton-exchange membrane fuel cell applications

Authors

  • M. S. Mohy Eldin,

    Corresponding author
    1. Polymer Materials Research Department Advanced Technologies and New Materials Research Institute, Mubarak City for Scientific Research and Technology Applications, New Borg El-Arab City, Alexandria 21934, Egypt
    • Polymer Materials Research Department Advanced Technologies and New Materials Research Institute, Mubarak City for Scientific Research and Technology Applications, New Borg El-Arab City, Alexandria 21934, Egypt
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  • A. A. Elzatahry,

    1. Polymer Materials Research Department Advanced Technologies and New Materials Research Institute, Mubarak City for Scientific Research and Technology Applications, New Borg El-Arab City, Alexandria 21934, Egypt
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  • K. M. El-Khatib,

    1. Pilot Plant Department, Engineering Division, National Research Center, Dokki, Giza, Egypt
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  • E. A. Hassan,

    1. Department of Chemistry, Faculty of Science, Al-Azhar University, Cairo, Egypt
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  • M. M. El-Sabbah,

    1. Department of Chemistry, Faculty of Science, Al-Azhar University, Cairo, Egypt
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  • M. A. Abu-Saied

    1. Polymer Materials Research Department Advanced Technologies and New Materials Research Institute, Mubarak City for Scientific Research and Technology Applications, New Borg El-Arab City, Alexandria 21934, Egypt
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Abstract

Novel poly(glycidyl methacrylate)-grafted Nafion–phosphoric acid membranes for direct-oxidation methanol fuel cells were prepared with a potassium persulfate chemical initiation system for the first time. The introduced epoxy groups were converted to amine groups through a reaction with ethylenediamine, which consequently doped with phosphoric acid ([BOND]PO3H) groups. The latter significantly contributed to enhancing the ion-exchange capacity, mechanical properties, and thermal stability. Factors affecting the modification steps were studied. Changes in the chemical and morphological structure were verified through Fourier transform infrared spectroscopy, TGA, and scanning electron microscopy characterization. Various grafting percentages (GP%'s) up to 32.31% were obtained. As a result, the thickness of the grafted membranes increased. Furthermore, the methanol permeability of the modified membranes was reduced with increasing grafted polymer content compared with that of the Nafion membrane. An 83.64% reduction in the methanol permeability was obtained with a polymer grafted content of 18.27%. Finally, the efficiency factor for all of the modified Nafion membranes was enhanced compared with that of Nafion. A fourfold improvement was obtained with membranes with a GP% of 18.27% as a maximum value. Such promising results nominate the used technique as a one for the improvement of Nafion membrane efficiency. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

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