Abstract

DIAZ-ORTIZ, Jolman Stiven; DELGADO-ROSERO, Miguel Iban; JURADO-MENESES, Nori Magali  and  APARICIO-ROJAS, Gladis Miriam. Thermal analysis and mass spectrometry in protonic conductors (PVDF/H ₃ PO ₂ ) for implementation in fuel cells. Dyna rev.fac.nac.minas [online]. 2018, vol.85, n.204, pp.143-149. ISSN 0012-7353.  https://doi.org/10.15446/dyna.v85n204.66968.

Polyvinyl Difluoride and Hypophosphorous Acid (PVDF/H3PO2) membranes were prepared with different concentrations of acid. The differential scanning calorimetry (DSC) results showed a typical step of the glass transition around 250 K. Two endothermic anomalies were observed: one closed to 357.6 K due to the evaporation of water, and another closed to 422 K attributed to the melting of the crystalline phase of PVDF. The mass spectrometry (MS) coupled with thermogravimetry analysis (TGA) reveal the possible presence of (C2H2O) and hydrofluoric acid (HF) molecules, thereby raises the possibility that H3PO2 lost a hydrogen atom and bonded to the polymer chain of the PVDF by displacing an atom of fluorine. The presence of water molecules at different temperatures suggests the formation of superficial, internal and structural water in the polymer-acid system. This feature makes the PVDF/H3PO2 system to be proposed as solid electrolyte in fuel cells.

Keywords : fuel cell; solid electrolyte; polymer; calorimetry DSC; thermogravimetry; spectrometry MS.

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