TY - JOUR
T1 - Poly(arylene ether) ionomers containing sulfofluorenyl groups
T2 - Effect of electron-withdrawing groups on the properties
AU - Shimura, Takuya
AU - Miyatake, Kenji
AU - Watanabe, Masahiro
N1 - Funding Information:
This work was partly supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan through a grant-in-aid for Scientific Research (20350086) and by the New Energy and Industrial Technology Development Organization (NEDO) through HiPer-FC project.
PY - 2008/12
Y1 - 2008/12
N2 - For polymer electrolyte membrane fuel membrane cell (PEMFC) applications, the effect of electron-withdrawing groups on the properties of sulfonated poly(arylene ether) (SPE) ionomer membranes was investigated. A series of poly(arylene ether)s containing fluorenyl groups and electron-withdrawing groups (sulfone, nitrile, or fluorine) was synthesized, which were sulfonated with chlorosulfonic acid using a flow reactor to obtain the title ionomers. The ionomers had high molecular weight (Mn > 77 kDa, Mw > 238 kDa) and gave tough, ductile membranes by solution casting. The ion exchange capacity (IEC) of the membranes ranged from 1.6 to 3.5 mequiv/g as determined by titration. The electron-withdrawing groups did not appear to affect the thermal properties (decomposition temperature higher than 200 °C). The presence of nitrile groups, especially at positions meta to the ether linkages, improved the oxidative stability of the SPE membranes, while it led to a deterioration of the hydrolytic stability. The perfluorinated biphenylene groups were effective in providing high mechanical strength with reasonable dimensional change, probably due to a somewhat decreased water absorbability. The SPE membrane containing sulfone groups showed the highest proton conductivity (10-3-10-1 S/cm) at 20-93% RH (relative humidity) and 80 °C. The nitrile-containing SPE membrane showed smaller apparent activation energies for oxygen and hydrogen permeability and is thus considered to be a possible candidate for applications in PEMFCs.
AB - For polymer electrolyte membrane fuel membrane cell (PEMFC) applications, the effect of electron-withdrawing groups on the properties of sulfonated poly(arylene ether) (SPE) ionomer membranes was investigated. A series of poly(arylene ether)s containing fluorenyl groups and electron-withdrawing groups (sulfone, nitrile, or fluorine) was synthesized, which were sulfonated with chlorosulfonic acid using a flow reactor to obtain the title ionomers. The ionomers had high molecular weight (Mn > 77 kDa, Mw > 238 kDa) and gave tough, ductile membranes by solution casting. The ion exchange capacity (IEC) of the membranes ranged from 1.6 to 3.5 mequiv/g as determined by titration. The electron-withdrawing groups did not appear to affect the thermal properties (decomposition temperature higher than 200 °C). The presence of nitrile groups, especially at positions meta to the ether linkages, improved the oxidative stability of the SPE membranes, while it led to a deterioration of the hydrolytic stability. The perfluorinated biphenylene groups were effective in providing high mechanical strength with reasonable dimensional change, probably due to a somewhat decreased water absorbability. The SPE membrane containing sulfone groups showed the highest proton conductivity (10-3-10-1 S/cm) at 20-93% RH (relative humidity) and 80 °C. The nitrile-containing SPE membrane showed smaller apparent activation energies for oxygen and hydrogen permeability and is thus considered to be a possible candidate for applications in PEMFCs.
KW - Electron-withdrawing groups
KW - Fuel cells
KW - Ionomers
KW - Poly(arylene ether)s
KW - Proton conduction
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U2 - 10.1016/j.eurpolymj.2008.09.017
DO - 10.1016/j.eurpolymj.2008.09.017
M3 - Article
AN - SCOPUS:56649085094
VL - 44
SP - 4054
EP - 4062
JO - European Polymer Journal
JF - European Polymer Journal
SN - 0014-3057
IS - 12
ER -