Preparation of nanocomposite membranes of propylsulfonated Poly[2,2'-(m-pyrazolidene)-5,5'-bibenzimidazole] / surface modified nanopartices as Proton Exchange Membrane for Fuel Cell Application

Propylsulfonated Poly 2,2'-(m-pyrazolidene)-5,5'-bibenzimidazole] (PSPPBI) was ynthesized from Poly[2,2'-(m-pyrazolidene)-5,5'-bibenzimidazole] (PPBI) and propansultone in DMSO using anionically reaction. PPBI was prepared from pyrazole-3,5-dicarboxylic acid and 3,3',4,4'-tetraaminobiphenyle (TAB) through polycondensation reaction in polyphosphoric acid (PPA) with suitable viscosity. The modification of silica nanoparticles were confirmed by free radical polymerization of vinylimidazole and sulfonated vinylbenzene to surface bonded initiator. The proton conductivity of nanocomposite membranes prepared with modified nanoparticles was higher than pure propylsulfonated polymer membrane. While, The nanocomposite membrane obtained from PSPPBI and unmodified silica nanoparticles was lower than pure PSPPBI and PPBI membtanes. The proton conductivity of membranes was measured by Electrochemical Impedance Spectroscopy (EIS) method. The structure of synthesized polymer was characterized by using FT-IR and 1H-NMR spectroscopy. Inherent viscosity was measured in order to determine the polymer molecular weight. Thermogravimmetery analysis (TGA) was carried out to investigate the thermal stability characteristics. The morphological study of modified nanoparticles was investigated with AFM method.

Keywords:

PSPPBI/modified SiO2 nanocomposite , Proton exchange membrane , propylsulfonated polybenzimidazole , Sulfonated vinylbenzene ,