Síntesis y caracterización de membranas protónicas híbridas para su aplicación en pilas de combustible poliméricas

Mención Internacional en el título de doctorEsta tesis contiene artículos de investigación en anexoEn la actualidad, se están realizando grandes esfuerzos en la búsqueda y desarrollo de nuevos electrolitos poliméricos para pilas de combustible tipo PEM. La membrana polimérica más utilizada como electrolito es el Nafion, cuyas ventajas son una buena estabilidad térmica, es químicamente inerte y presenta una elevada acidez proporcionada por el grupo ácido sulfónico (-CF₂SO₃H). Las desventajas que presenta este material son una baja conductividad a temperaturas superiores a 100 °C, alto coste, baja conductividad a bajo grado de humedad, escasa durabilidad, problemas de crossover o paso de combustible a través de la membrana, cuando el combustible es metanol. Por estas razones, todas las investigaciones que actualmente se realizan están encaminadas a sustituir el Nafion por otros polímeros de bajo coste y alta conductividad protónica. Esta Tesis Doctoral se centra en la preparación de diferentes materiales poliméricos protónicos para su eventual utilización como electrolitos en pilas de combustible tipo PEM. Para ello y en primer lugar, se eligió como polímero base la polisulfona Udel (PSU) debido a sus buenas propiedades: bajo coste, alta temperatura de transición vítrea, alta estabilidad térmica, alta resistencia química, excelentes propiedades mecánicas y alta resistencia frente a la oxidación. La PSU se modificó mediante una reacción de sulfonación, utilizando dos reactivos sulfonantes para obtener polisulfonas sulfonadas (SPSU) con distintos grados de sulfonación. Estas membranas sulfonadas se caracterizaron estructural, térmica y eléctricamente. A partir de las SPSU obtenidas, se prepararon y se caracterizaron membranas híbridas cargadas con diferentes compuestos inorgánicos ( Zn₂Al ̶ Mo₇O₂₄, (NH₄)₆Mo₇O₂₄, [Zn₁₋ₓAlₓ(OH)₂](NO₃)ₓ.∙0,8H₂O (x=0.33), y H₃PMo₁₂O₄₀). Las distintas cargas provocan comportamientos similares. En general, al aumentar la cantidad de carga la conductividad protónica aumenta ligeramente. La membrana con mejores propiedades tanto en conductividad como en durabilidad en el test de la pila de combustible fue la membrana cargada con un 5 % de Zn₂Al ̶ Mo₇O₂₄ y con mayor grado de sulfonación de SPSU. En segundo lugar, se eligieron los polímeros PEEK y PES para formar copolímeros porque presentan alta resistencia mecánica, química y térmica. Sin embargo, en estado húmedo pueden tener una alta absorción de agua, haciendo que disminuyan las propiedades mecánicas. Estos copolímeros se sintetizaron a partir de los monómeros que forman los polímeros PEEK y PES, y cuyo monómero puente fue la fenolftaleína. Los copolímeros se prepararon con diferentes relaciones molares, variando las cantidades de los monómeros PEEK, PES y manteniendo fija la cantidad de fenolftaleína. Una vez preparados, se modificaron químicamente mediante una reacción de sulfonación para proporcionar conductividad protónica al material. Todas las membranas preparadas se caracterizaron estructural, térmica y eléctricamente. A pesar de que la resistencia mecánica y la conductividad de los copolímeros preparados fueron similares a los del Nafion y de la polisulfona, el rendimiento en la MEA fue inferior.Nowadays, great efforts are been made in the research and development of polymer electrolytes PEM for fuel cells. Nafion is the most used membrane as electrolyte in the market. This membrane is the reference in all studies due to its properties: good thermal stability, chemically inert, and high acidity provided by the sulfonic acid group (-CF₂SO₃H). However, this membrane also exhibits some drawbacks, mainly the low conductivity at temperatures above 100◦C, high cost, low conductivity at low humidity, poor durability and crossover, when the fuel is methanol. For this reason, the current researches are conducted to replace the Nafion by other polymers with less cost and high proton conductivity. This PhD Thesis is focused on the study and development of different polymeric materials for their use as electrolytes in proton exchange membrane fuel cells (PEMFC). The first studied was the sulfonation of polysulfone (SPSU). This material was chosen due to its excellent properties: low cost, high glass transition temperature, high thermal stability, high chemical resistance, excellent mechanical properties and high resistance to oxidation. The PSU was modified by a sulfonation reaction using two sulfonating reagents, to obtain sulfonated polysulfone (SPSU) with different degrees of sulfonation. The SPSU was characterized from the structural, thermal and electrical points of view. In the second studied, we prepared and characterized SPSU/inorganic composite membranes with different inorganic materials ( Zn₂Al ̶ Mo₇O₂₄, (NH₄)₆Mo₇O₂₄, [Zn₁₋ₓAlₓ(OH)₂](NO₃)ₓ.∙0,8H₂O (x=0.33), and H₃PMo₁₂O₄₀). All the chosen inorganic particles produced similar behaviours. The study showed that the proton conductivity increases with the amount of inorganic compounds. The membrane with highest conductivity and better durability in the fuel cell test was SPSU3T+ 5 % Zn₂Al ̶ Mo₇O₂₄. The last study was focused on the synthesis and characterization of copolymers base on PEEK, PES and phenolphthalein monomers. These copolymers were prepared with different molar ratios, varying amounts of PEEK, PES monomers and keeping fixed the quantity of phenolphthalein. After, the copolymers were chemically modified by a sulfonation reaction to provide proton conductivity. All the membranes were characterized from the structural, thermal and electrical points of view. The mechanical properties and proton conductivity of the different copolymers were similar to that of Nafion, and polysulfone, however the MEA’s performance are slightly lower.Esta Tesis Doctoral ha sido realizada en el Departamento de Ciencia e Ingeniería de Materiales e Ingeniería Química de la Universidad Carlos III de Madrid y ha sido financiada por los proyectos de investigación MAT2010-19837-C06-05 Síntesis, caracterización y procesado de materiales para baterías y pilas de combustible y MAT2013-46452-C4-3-R Electrodos y electrolitos para almacenamiento y producción eficientes de energía: baterías y pilas de combustible del Ministerio de Economía y Competitividad, P2009/PPQ-1626 Materiales para la energía y relacionados y MATERYENER3CM S2013/MIT-2753 Materiales para la energía: eléctricos, magnéticos y superconductores de la Comunidad de Madrid y por una beca de Personal Investigador en Formación (PIF) de la Universidad Carlos III de Madrid.Programa Oficial de Doctorado en Ciencia e Ingeniería de MaterialesPresidente: Carmen del Río Bueno.- Secretario: María Teresa Pérez Prior.- Vocal: Francesco Trott

Synthesis and characterization of new membranes based on sulfonated polysulfone/Zn,Al-heptamolibdate LDH

New proton conducting organic/inorganic nano-hybrid polymer electrolyte membranes were synthesized by solving casting method. Inorganic nanopowders were a layered double hydroxides (LDH) with Zn,Al cations in which heptamolybdate were inserted. These nanopowders were prepared by anion exchange method from hydrotalcite (LDH) with interlayer anions (NO₃). The sulfonated polymers were prepared by an electrophilic aromatic substitution reaction between the polymer and trimethylsylil cholorosulfonate (TMSCS). The composites membranes were characterized by FTIR and TGA and water uptake was determined. Electrochemical impedance spectroscopy (EIS) was used to study the proton conductivity of the membranes. EIS measurements were performed facing the membrane to different HCl concentrations (103 ≤ c ≤101 M). It was concluded that these new composite membranes present good thermal properties and proton conductivity slightly higher than SPSU.This work has been supported by the Projects from the regional government (Comunidad de Madrid through MATERYENER3CM S2013/MIT2753) and Spanish Government, MINECO (MAT2013 46452C43R)

Electrochemical and structural characterization of sulfonated polysulfone

We describe the synthesis, as well as the electrochemical and structural characterization, of sulfonated polysulfone intended for use in PEM fuel cells. Starting from a commercial polysulfone, we assessed the performance of these prepared ionomers using synthesis protocols compatible with industrial production. The efficiency of the trimethylsilyl chlorosulfonate and chlorosulfonic acid reagents in the sulfonation process was confirmed by H-1 NMR, FTIR, elemental analysis, chemical titration and thermal analysis (DSC and TGA). Chlorosulfonic acid was the most effective sulfonation reagent. However, based on SEC-MALLS, this reagent induced degradation of the backbone that is detrimental to the thermomechanical stability and lifespan of the membranes. The electrical characterization of the membranes was undertaken using impedance spectroscopy in contact with different HCl aqueous solutions at various temperatures. The activation energies, which ranged from 8.2 to 11 kJ/mol, were in agreement with the prevailing proton vehicular mechanism. (C) 2015 Elsevier Ltd. All rights reserved.This study was supported by the Ministry of Science and lnnovation with a project MAT2013 46452 C4 3 R and the Regional Program MATERYENER3CM S2013/MIT 2753 of the Community of Madrid. J Y Sanchez also wishes to thank "Catedras de Excelencia" of Universidad Carlos III de Madrid for providing a grant. A.M. Martos wishes to thank the mobility grant of Universidad Carlos III de Madrid

Synthesis and characterization of polysulfone/layered double hydroxides nanocomposite membranes for fuel cell application

In the present study, sulfonated polysulfone (SPSU)/layered double hydroxide (LDH) composite membranes for use in proton exchange membrane fuel cells (PEMFCs) were investigated. Polysulfone (PSU) was sulfonated with trimethylsilyl chlorosulfonate in 1,2 dichloroethane at room temperature. Composite membranes were prepared by blending different amount (0, 1, 2, and 5%) of LDH nanoparticles with SPSU in dimethylacetamide (DMAc). The membranes were prepared by the casting method and the samples obtained were characterized by XRD, FTIR spectroscopy. The thermal behavior for all samples was evaluated by thermogravimetrical analysis (TGA). Finally electrochemical impedance spectroscopy (EIS) was used to study the membranes electrical properties. The EIS measurements were carried out with the membranes in contact with HCl solutions at different concentrations (103 ≤ c ≤101). Results show a clear dependence of the membrane electrical resistance with the sulfonation degree and the amount of the LDH addedAuthors thanks financial support received from the regional government (Comunidad de Madrid through MATERYENER S2009 PPQ-1626), and Spanish Government,MICINN (MAT2010-19837-CO6)

Synthesis and characterization of novel hybrid polysulfone/silica membranes doped with phosphomolybdic acid for fuel cell applications

Novel proton conducting composite membranes based on sulfonated polysulfone (sPSU)/SiO₂ doped with phosphomolybdic acid (PMoA) were synthesized, and their proton conductivity in acid solutions was evaluated. The hybrid membranes were prepared by casting and the characterization by scanning electron microscopy (SEM), Fourier transform infrared (FIR) and X-ray diffraction (XRD) confirmed the presence of the inorganic charges into the polymer. Thermal properties and proton conductivity were also studied by means of thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS), respectively. The incorporation of the inorganic particles modified the thermal and mechanical properties of the sPSU as well as its proton conductivity. Taking into account that a compromise between these properties is necessary, the hybrid membrane with 2%SiO₂ and 20%PMoA seems to be a promising candidate for its application in proton-exchange membrane in fuel cells (PEMECs) operated at high temperatures.This work has been supported by the Projects from the Regional government (Comunidad de Madrid through MATERYENER3CM S2013/MIT 2753) and MINECO (MAT2013 46452 C4 3R) from Spanish Government

Educar en patrimonio con perspectiva de género desde la educación no formal: El proyecto “Soleando en el río de la vida”

Introduction: This article presents the research project entitled "Sunning in the river of life". Carried out by a group of women belonging to Matria Association of women for a culture also in feminine*, linked to the field of formal and non-formal education, with the aim of valuing the maintenance activities carried out by women in their daily life called "domestic".  Method: The methodology used has been narrative biographical, which as a branch of interpretive research, shares some general principles of qualitative research. Method that focuses on the experience of the subject whose story allows us to know her experience centered on a topic and in a specific time and context. Using standardized and in-depth interviews, systematic and participant observation, discussion groups with the participation of researchers, to obtain data.  Results: The results of the investigation have shown numerous variables related to the daily work of women and water, relevant to deepen the analysis of the history of the daily life of women and to value the so-called "domestic" jobs that They are guarantors of the well-being of the community.  Conclusions: This research opens the way to continue with the investigation of the history of the daily life of women in a specific time and context and to reflect on it from a critical and constructive perspective both in formal and non-formal and informal education with the goal of achieving a more just and egalitarian society and favor culture also in feminine.Introducción: En este artículo se presenta el proyecto de investigación titulado “Soleando en el río de la vida”. Llevado a cabo por un grupo de mujeres pertenecientes a Matria Asociación de mujeres por una cultura también en femenino*, vinculadas al ámbito de la educación formal y no formal, con el objetivo de poner en valor las actividades de mantenimiento realizadas por las mujeres en su vida cotidiana denominadas “domésticas“. Método: La metodología utilizada ha sido la biográfica narrativa, la cual como rama de la investigación interpretativa, comparte algunos principios generales de la investigación cualitativa. Método que se focaliza en la experiencia del sujeto cuyo relato permite conocer su experiencia centrada en un tema y en un tiempo y contexto geográfico concreto. Utilizando para la obtención de datos las entrevistas estandarizadas y en profundidad, la observación sistemática y participante y los grupos de discusión con la participación de las personas que componen el equipo de investigación  Resultados: Los resultados de la investigación han mostrado numerosas variables relacionadas con el trabajo cotidiano de las mujeres y el agua, relevantes para profundizar en el análisis de la historia de la vida cotidiana de la mujeres y poner el valor los trabajos denominados “domésticos” que son garantes del bienestar de la comunidad. Conclusiones: Esta investigación abre camino para continuar con la investigación de la historia de la vida cotidiana de la mujeres en un tiempo y un espacio concretos y reflexionar sobre ello desde una perspectiva critica y constructiva tanto en la educación formal como no formal con el objetivo de lograr un sociedad más justa e igualitaria y favorecer la cultura también en femenino.&nbsp

Anàlisi epidemiològica i patològica dels tumors germinals testiculars durant el període 1996-2004

Els tumors germinals testiculars són neoplàssies poc freqüents, representant un 1-2% dels tumors que afecten al varó jove. No obstant sembla que en els últims anys estem assistint a un augment de la seva incidència tal i com ho reflexen algunes dades de la literatura mèdica. La cirurgia juntament amb els protocols de quimioteràpia actuals permeten assolir alts nivells de curaci