Guillermo M. González Guerra
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Alejandro Alatorre-Ordaz
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Gerardo González Garcia
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Jesus S. Jaime-Ferrer
ABSTRACTThis work presents the synthesis and characterization of a pearylated polysiloxane material (PAP) from a polycondensation reaction, followed by functionalization with HClSO3 by an electrophilic substitution reaction. According to the characterization techniques applied, a sulfonated pearylated polysiloxane was also obtained, (SPAP). The purpose of this sulfonated material is to obtain an ionomer able to be applied in hydrogen fuel cells of the proton exchange membrane kind (PEMFC). The reaction to produce the polysiloxane precursor was carried out with the commercial reagents: PhSiCl3, Ph2SiCl2 and Ph3SiCl in anhydrous THF at 75 °C and the SPAP material was obtained by sulfonation of the precursor with chlorosulfonic acid. PAP and SPAP were characterized by 1H, NMR for liquids, 29Si NMR for solids, IR-ATR, SEM, and cyclic voltammetry. The NMR 29Si spectra show that PAP and PAPS contain crosslinking regions due to PhSiCl3, growing chain zones due to Ph2SiCl2 and polymer termination zones due to Ph3SiCl, obtaining a mixture of siloxanes. The analysis by cyclic voltammetry indicates that by integrating the area under the curve of the adsorption peaks of H2, a value of 0.062 mC/cm2 is obtained, a value close to the commercial ionomer of Nafion®.
