No abstract

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=1884314&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=1884314&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1149/1.3040242 Society, 156, 2, pp. B258-B263, 2009 Blend Low-cost blend membranes consisting of sulfonated poly͑ether ether ketone͒͑ SPEEK͒͑ an acidic polymer͒ and polysulfone-4-nitrobenzimidazole ͑PSf-NBIm͒͑ a basic polymer͒ have been prepared with various PSf-NBIm contents ͑0-5.0 wt %͒ and characterized by ion-exchange capacity, proton conductivity, and water uptake measurements. The blend membranes with PSf-NBIm contents of 2.5 and 5.0 wt % show higher proton conductivity and lower water uptake in water and methanol/water solutions at a given temperature than plain SPEEK. The blend membranes also exhibit better electrochemical performance and lower methanol crossover in a direct methanol fuel cell than plain SPEEK and Nafion 115 membranes due to an enhancement in proton conductivity through acid-base interactions and an insertion of the benzimidazole side groups into the ionic clusters of SPEEK, as indicated by small-angle X-ray scattering. The maximum power density of the blend membrane with a PSf-NBIm content of 2.5 wt % is 1.5 times higher than that of the Nafion 115 in 1 M methanol solution at 80°C. Journal of te Electrochemical

The stress-strain characteristics of PTFE under uniaxial tension and compression have been measured at various temperatures. A new nite element analysis procedure using MARC is presented, which can simulate the diVerent properties of PTFE from tension and compression data. This method is based on using the maximum principal stress value at the integration point of each element to de ne whether the element is under tension or compression at each increment, then using subroutines to specify the material properties. A positive value indicates a state of tension and a negative value indicates compression. It has been found that the nite element analysis results are in good agreement with those from experiment. Finally, a PTFE rotary seal was modelled using this new method, and results were obtained incorporating stress and lip loads of the rotary seal, with diVerent temperature eVects.