Poly(arylene ether sulfone) Statistical Copolymers Bearing Perfluoroalkylsulfonic Acid Moieties
Polymers and High Performance Materials
The perfluoroalkylsulfonate monomer, N,N-diisopropylethylammonium 2,2-bis(p-hydroxyphenyl)pentafluoropropanesulfonate (H PPS), was synthesized in three steps. Using triethyl phosphite, hexafluoroacetone was first converted to ethyl pentafluoroisopropenyl ether. Reaction of the ether with sulfur trioxide produced 2-ketopentafluoropropanesulfonic acid. The acid was condensed with 2 equiv of phenol, and the product was isolated as the N,N-diisopropylethylammonium salt. The structure of the final product was confirmed by X-ray crystallography. Poly(arylene ether sulfone)s (PAES) were prepared by homopolymerization of HPPS with bis(4-fluorophenyl) sulfone (FPS) and copolymerization of varying molar ratios of HPPS/biphenol (BP) with FPS. Copolymer number-average molecular weights were in the range 27 000-34 000 g/mol (GPC). Copolymer compositions ranged from 20 to 61 mol % HPPS (HPPS/BP molar ratio 0.25-1.56) as determined by (19)F NMR spectroscopy. Ion exchange capacity of the copolymers (by titration) ranged from 0.36 to 1.25 mequiv/g. Equilibrium water uptake of the copolymers at 80 degrees C and 90% relative humidity increased from 7.2 to 14.3 mol H(2)O/mol H(+), and proton conductivity increased from 1.6 to 23 mS/cm, as the HPPS/PB ratio increased from 0.25 to 1.56.
Jackson, A. B.,
Kirk, N. J.,
Mauritz, K. A.,
Storey, R. F.
(2011). Poly(arylene ether sulfone) Statistical Copolymers Bearing Perfluoroalkylsulfonic Acid Moieties. Macromolecules, 44(4), 694-702.
Available at: http://aquila.usm.edu/fac_pubs/476