Synthesis and proton conductivity studies of doped azole functional polymer electrolyte membranes

The development of anhydrous proton-conducting membranes is important for the operation of polymer electrolyte membrane fuel cell (PEMFC) at intermediate temperature (100-200 degrees C) In this work poly(vinylbenzylchloride) PVBC was produced by free radical polymerization of 4-vinylbenzylchloride and then it was modified with 5-aminotetrazole (ATET) to obtain poly(vinylbenzylaminotetrazole) PVBC-ATET The composition of the polymer was verified by elemental analysis (EA) and the structure was characterized by FT-IR and C-13 NMR spectra According to the elemental analysis result PVBC was modified by ATET with 80% yield The polymer was doped with trifluoromethanesulfonic acid (TA) at various molar ratios x 1 25 2 5 3 75 with respect to tetrazole unit The proton transfer from TA to the tetrazole rings was proved with FT-IR spectroscopy Thermogravimetry (TG) analysis showed that the samples are thermally stable up to approximately 200 degrees C Differential scanning calorimetry (DSC) results illustrated the homogeneity of the materials Cyclic voltammetry (CV) study illustrated that the electrochemical stability domain for PVBC-ATET-TA(2 5) extends over 3 0 V The proton conductivity of these materials increased with dopant concentration and the temperature Maximum proton conductivity of PVBC-ATET-TA(2 5) was found to be 001 S/cm at 150 C in the anhydrous state (C) 2010 Elsevier Ltd All rights reserved