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Keywords:

  • polystyrene-butadiene rubber;
  • degree of sulphonation;
  • proton conductivity;
  • kinetic and activation energy

Abstract

Proton exchange membrane for fuel cell application was synthesized from a hydrophobic polystyrene-butadiene rubber (PSBR) via sulphonation at different temperatures (22, 35, 55, 65, and 75°C) and varying time with chlorosulphonic acid. Infra-red spectroscopy (IR) and proton nuclear magnetic resonance (1H-NMR) were used to confirm the occurrence of sulphonation. Sulphonation occurred only on the phenyl ring with a maximum degree of sulphonation of 70.96 mole percent. Consequently, 10−3–10−2 S/cm proton conductivity was achieved. Two models for the reaction kinetics were investigated: first-order reversible and first-order irreversible, respectively. However, the reaction kinetic was found to obey the first-order reversible model. The activation energy (Ea) of the reaction was calculated to be 41.56 kJ/mol of PSBR repeat unit, which is an indication that the reaction is nonspontaneous. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010