JOURNAL OF POLYMER MATERIALS, vol.36, no.4, pp.337-349, 2019 (SCI-Expanded)
In the present study, polybenzimidazole (PBI) polymer which has a great importance in polymer electrolyte membrane (PEM) research was synthesized via the solution polycondensation method, under various synthesis conditions to put forward the effect of the synthesis parameters on the properties of the synthesized polymer and consequently to the quality of the prepared polymer electrolyte membrane. The synthesized polymers were characterized in terms of their chemical structure, thermal degradation behaviour, and molecular weight by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (H-1 NMR), thermogravimetric analysis (TGA). The Mechanical properties, acid-doping level capacity, proton conductivity, and fuel cell performances of the produced phosphoric acid doped PBI were investigated. The Thermogravimetric analyses showed that the synthesized polymers have an excellent thermal stability up to 580 degrees C. Mechanical analyses revealed that the mechanical strength of the PBI membranes increases with increasing molecular weight of the polymer and reaches the maximum value of 17.65 MPa. The maximum power density was observed to be 48.6 mW/cm(2) of the fuel cell test at 120 degrees C.