Effect of the Molecular Weight of Poly(vinyl alcohol) Blended with Sulfonated Polysulfone Membranes for Fuel Cell Applications

  • Published : 2003.12.01

Abstract

In order to improve the mechanical properties of the sulfonated polysulfone (SPSf) membranes previously synthesized in our laboratory, poly(vinyl alcohol) (PVA) was blended which is well known as the excellent physical and chemical properties. The resulting membranes blended with several molecular weight of PVA varying from 13,000 to 124,000 have been characterized to investigate the effect of PVA molecular weight in terms of ion conductivities, methanol permeabilities, water contents and ion exchange capacities for both heat treated and untreated membranes at 150$^{\circ}C$. The proton conductivity is decreased as the molecular weight of PVA increases. The plain SPSf-6.0 showed the proton conductivity of 0.078 S/cm whereas the blended membrane with M.W. 31,000 PVA indicated 0.04 S/cm. For methanol permeabilities, when PVA is added to SPAf-6.0, methanol crossover is increased because of the gain of the hydrophilicity from 3.4 to 6.5${\times}$10$\^$-6/ $\textrm{cm}^2$/s. For the annealed blended membranes (with M.W. 31,000 PVA), both the methanol corssover and proton conductivity showed very consistent values, about 2.3${\times}$10$\^$-6/ $\textrm{cm}^2$/s and 0.036 S/cm, respectively.

Keywords

References

  1. B. C. H. Steele and A. Heinzel, 'Materials for fuel-cell technologies', Nature, 414, 345 (2001)
  2. J. A. Kerres, 'Development of ionomer membranes for fuel cells', J Membr. Sci., 185, 3 (2001)
  3. M. Rikukawa and K. Sanui, 'Proton-conducting polymer electrolyte membranes based on hydrocarbon polymers', Prog. Polym. Sci., 25, 1463 (2000) https://doi.org/10.1016/S0079-6700(00)00032-0
  4. G. Inzrlt, M. Pineri, J. W. Schultze, and M. A. Vorotyntsev, 'Electron and proton conducting polymers: recent developments and prospects', Electrochim Acta, 45, 2403 (2000)
  5. T. Norby, 'The promise of protonics', Nature, 410, 877 (2001)
  6. T. Schultz, S. Zhou, and K. Sundmacher, 'Current status of and recent developments in the direct methanol fuel cell', Chem. Eng. Technol., 24, 1223(2001)
  7. J. Fang, X. Guo, S. Harada, T. Watari, K. Tanaka, H. Kita, and K. -I. Okamoto, 'Novel sulfonated polyimides as polymer electrolytes for fuel cell application.1. synthesis, proton conductivity, and water stability of polyimides from 4,4'-diamino diphenylether-2,2'-disulfonic acid', Macromolecules, 35, 9022 (2002)
  8. C. Genies, R. Mercier, B. Sillion, N. Corent, G. Gebel, and M. Pineri, 'Soluble sulfonated naphthalenic polyimides as materials for proton exchange membranes', Polymer, 42, 359 (2001)
  9. M. B. Gieselman and J. R. Reynolds, 'Water-soluble polybenzimidazole-based polyelectrolytes', Macromolecules, 25, 4832 (1992)
  10. Q. Guo, P. N. Pintauro, H. Tang, and S. O'Connor, 'Sulfonated and cross-linked polyphosphazene-based proton-exchange membranes', J. Membr. Sci., 154, 175 (1999)
  11. S. M. J. Zaidi, S. D. Mikhailenko, G. P. Robertson, M. D. Guiver, and S. Kaliaguine, 'Proton conducting composite membranes from polyether ketone and heteropolyacids for fuel cell applications', J. Membr. Sci., 173, 17 (2000)
  12. A. Noshayand L. M. Robeson, 'Sulfonated polysulfone', J. Appl. Polym. Sci., 20, 1885 (1976)
  13. M. Drzewinski, W. J. Macknight, 'Structure and properties of sulfonated polysulfone ionomers', J. Appl. Polym. Sci., 30, 4753 (1985)
  14. N. Sivashinsky, G. B. Tanny, 'Ionic heterogeneities in sulfonated polysulfone films', J. Appl. Polym. Sci., 28, 3235 (1983)
  15. M.-H. Chen, T.-C. Chiao, T.-W. Tseng, 'Preparation of sulfonated polysulfone/polysulfone and aminated polysulfone/polysulfone membranes', J. Appl. Polym. Sci., 61, 1205 (1996)
  16. R. Malaisamy, R. Mahendran, D. Mohan, M. Rajendran, and V. Mohan, 'Cellulose acetate and sulfonated polysulfone blend ultrafiltration membranes. I. preparation and characterization', J. Appl. Polym. Sci., 86, 1749 (2002)
  17. H. B. Park, S. Y. Nam, J. W. Rhim, J. M. Lee, S. E. Kim, J. R. Kim, and Y. M. Lee, 'Gastransport properties through cation-exchanged sulfonated polysulfone membranes', J. Appl. Polym. Sci., 86, 2611 (2002)
  18. F. Lufrano, I. Gatto, P. Staiti, V. Antonucci, and E. Passalacqua, 'Sulfonated polysulfone ionomer membranes for fuel cells', Solid State Ionics, 145, 47 (2001)
  19. F. Lufrano, G. Squadrito, A Patti, and E. Passalacqua,'Sulfonated polysulfone as promising membranes for polymer electrolyte fuel cells', J Appl. Polym. Sci., 77, 1250 (2000)
  20. Ho Bum Park, Young Moo Lee, Hyun Soo Shin, and Ji Won Rhim, 'Annealing effect of sulfonated polysulfone ionomer membranes on proton conductivity and methanol transport', submitted to J. Membr. Sci. for publication (2003)
  21. A. F. Ismail and W. Lorna, 'Suppression of plasticization in polysulfone membranes for gas separations by heat-treatment technique', Sep. Pure.Tech., 30, 37 (2003)
  22. B. S. Pivovar, Y. Wang, and E. L. Cussler, 'Pervaporation membranes in direct methanol fuel cell', J. Membr. Sci., 154, 155 (1999)