Fully Aromatic Copolyethers for High Temperature Polymer Electrolyte Membrane Fuel Cells

New aromatic polyethers containing diphenylpyridine, phosphinoxide and tetramethyl-biphenyl units have been synthesised employing various comonomers' ratios affording a complete series of soluble high molecular weight copolymers. Their properties in respect to their potential as electrolytes for high temperature PEM fuel cells were thoroughly investigated. All materials exhibit excellent film forming properties and mechanical integrity, high thermal and oxidative stability in combination with the ability to absorb phosphoric acid resulting in conductivities in the range of 10(-2) S cm(-1). A discussion on the effect of the chemical structure on the properties is also depicted herein.