A series of block ionomers containing sulfonated poly(phthalazinone ether ketone) hydrophilic segments and poly(fluorene ether sulfone) hydrophobic segments were synthesized via two-pot two-step nucleophilic polycondensation.Bis(4-chlorophenyl) sulfone and 9

9-bis(4-hydroxyphenyl) fluorene (BHF) were used as comonomers for hydrophobic blocks.Bisphthalazinone and sulfonated 4

4-difluorobenzophenone (SDFBP) were used to synthsize hydrophilic blocks.Ionomers with different segment sizes were synthesized by adjusting the molar ratios and prepolymerization and polycondensation.The structure of the ionomers was characterized by 1H-NMR and FTIR.The spectra and data indicated that these ploymers were in accordance with the designed backbone structure well.The TGA measurements of the ploymers were performed under a nitrogen atmosphere from 50℃ to 600℃

and results demonstrated that the so-made polymers exhibited good thermal stabilities with 5% weight loss temperature over 250℃.The polymers were soluble in common aprotic solvents

such as DMSO

DMAc

dimethylformamide (DMF)

N-methylpyrroridone (NMP) and tetramethylene sulfone.The inherent viscosity of the synthesized polymers ranged from 0.40 dL/g to 0.71 dL/g

demonstrating high molecular weight of the resulted polymers.The water uptakes of the copolymers with blocks of varying size were moderate.Moreover

these copolymers demonstrated greatly improved oxidative stabilities and hydrolysis resistance.Polymers 8c ~ 8e with block size bigger than eighteen repeat units were undegradable after 720 h and unhydrolyzable after 480 h.The hydrolysis resistance of the resulted membrances were much better than that of Nafion 117.The copolymers had strong alcohol resistance at refluxing temperature.The methanol penetrabilities of the prepared membranes varied from 0.2310-6 cm2/s to 0.2810-6 cm2/s

while that of Nafion 117 was 1.3210-6 cm2/s under the identical conditions.Especially

polymer 8e gave the proton conductivity of 1.8310-3 S/cm at 80℃.It is a promising proton exchange membrane material for proton exchange membrane fuel cell using methanol or ethanol as fuel.