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Preparation, Proton Conductivity and Mechanical Properties of Nafion 117–Zirconium Phosphate Sulphophenylphosphonate Composite Membranes
Author(s) -
Casciola M.,
Capitani D.,
Donnadio A.,
Frittella V.,
Pica M.,
Sganappa M.
Publication year - 2009
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.200800128
Subject(s) - nafion , membrane , zirconium phosphate , conductivity , materials science , aqueous solution , chemical engineering , composite number , polymer , polymer chemistry , phosphate , chemistry , composite material , organic chemistry , electrochemistry , biochemistry , electrode , engineering
Nafion–zirconium phosphate (ZrP) composite membranes, containing 20 to 40 wt.‐% ZrP were treated with aqueous solutions of meta‐sulphophenylphosphonic acid (H 2 SPP) in order to functionalise the filler particles with strongly acidic sulphonic groups. The functionalised samples (Nafion/ZrSPP) were characterised by 31 P MAS NMR, water uptake determinations, stress–strain mechanical tests and conductivity measurements. The Nafion/ZrSPP membranes are more hydrophilic than Nafion 117 and stiffer than the parent Nafion/ZrP membranes: at room temperature, the elastic modulus of the membranes with 20 and 40 wt.‐% ZrP increases from 191 and 329 N mm –2 to 342 and 470 N mm –2 , respectively, after functionalisation. At 100 °C and in the RH range of 30–90% the conductivity of the Nafion/ZrSPP membranes decreases with the increase in the filler loading, being however always higher than that of the parent Nafion/ZrP membranes and nearly coincident with that of Nafion 117. Conductivity measurements as a function of temperature in the range of 80–150 °C showed that, at 90% RH, the conductivity of the Nafion/ZrSPP membranes is stable up to 140 °C thus indicating a better dimensional stability of the composite membrane in comparison with neat Nafion 117.