Comparative effect of phthalazinone units in sulfonated poly(arylene ether ether ketone ketone) copolymers as proton exchange membrane materials

Abstract

A new series of aromatic poly(arylene ether ether ketone ketone) copolymers containing pendant sulfonic acid groups (SPAEEKK-D) were synthesized from commercially available monomers 1,3-bis(4-fluorobenzoyl)-benzene, sodium 6,7-dihydroxy-2-naphthalenesulfonate, and 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one (DHPZ). Structure-property relationships of the phthalazinone SPAEEKK-D series poly(arylene ether ether ketone ketone) copolymer were compared with copolymers SPAEEKK-B and SPAEEKK-H containing different diols such as 4,4 0 -biphenol and hydroquinone, respectively, prepared in our earlier work. Ion exchange capacity (IEC w , weight-based; IEC v , volume-based), thermal stabilities, swelling, proton and methanol transport properties of the membranes were investigated in relation to their structures and compared with those of perfluorinated ionomer (Nafion 117). The SPAEEKK-D membrane incorporating the phthalazinone monomer DHPZ showed relatively lower water uptake and methanol permeability compared with earlier SPAEEKK-B and SPAEEKK-H membranes incorporating biphenol and hydroquinone monomers, respectively. Inclusion of phthalazinone in the SPAEEKK-D copolymers led to lower water absorption, enabling increased proton exchange concentrations in the hydrated polymer matrix that resulted in more desirable membrane properties for future direct methanol fuel cell applications. The SPAEEKK-D membranes also showed improved mechanical and thermal properties and oxidative stability compared with the earlier SPAEEKK-B and -H membranes.

Synthesis and properties of sulfonated poly(ether ketone)s containing 3,5-dimethyl phthalazinone moieties as proton exchange membrane materials

“…All the membranes were not broken into pieces before 3 h treatment. The SPPEK-DMs membranes exhibited better oxidative stability than previously reported sulfonated poly(phthalazinone ether ketone) and other sulfonated poly(aryl ether ketone)s [20,25,42,43] . It has been known that the oxidative attack by HO· and HOO· radicals occurs mainly on the main chain of aromatic rings bound with electron-donating ether groups.…”

Preparation and properties of sulfonated poly(phthalazinone ether sulfone ketone)/tungsten oxide composite membranes

“…This behavior can be attributed to the presence of water content in the membranes. The hydrated WO 3 can transfer protons to the form of H x WO 3 23, 24. The conductivity of SPPESK/WO 3 (30 wt%) composite membrane was measured at 100 °C under different RH values.…”

Durability of Sulfonated Aromatic Polymers for Proton‐Exchange‐Membrane Fuel Cells

“…For the same reason, Kim and Guiver synthesized sulfonated poly(etheretherketoneketone) SPEEKK molecules with sulfonated naphthyl rings as side chains: the obtained membrane exhibited improved mechanical and thermal properties and oxidation stability. [57] In another example, Chen et al designed and synthesized a novel sidechain-sulfonated aromatic polyimide, and the highlight was a desulfonation temperature as high as 350 8C. [58] In addition, Xing and Kerres compared the effect of the location of SO 3 H in the main chain on the stability of sulfonated poly(arylene ether)s, and the results suggested that sulfonic acid groups at the meta position to the ether or sulfone groups have higher thermal and chemical stability and higher proton conductivity than those at the ortho position to ether and sulfone.…”