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Tesi etd-01102011-112943


Thesis type
Tesi di dottorato di ricerca
Author
FILPI, ANTONIO
URN
etd-01102011-112943
Title
Synthesis and Physico-Chemical characterization of anion-exchange polymeric materials for electrochemical applications
Settore scientifico disciplinare
CHIM/05
Corso di studi
SCIENZE CHIMICHE
Commissione
tutor Prof. Ciardelli, Francesco
Parole chiave
  • SBS
  • PEMFC
  • ion-exchange
  • Fuel Cell
  • electrochemistry
  • AMFC
Data inizio appello
27/01/2011;
Consultabilità
completa
Riassunto analitico
In the last few years a number of new anion-exchange polymers have been developed, offering the possibility of assembling Membrane Electrode Assemblies (MEAs) to develop Anion-exchange Membrane Fuel Cells (AMFCs) and Anion-exchange Membrane-based Electrolyzers (AMEs).<br>The current technologies of Anion Exchange Materials (AMs) for electrochemical application shows several limitations relate to the possibility of obtaining a reasonable low cost membrane having: high ionic conductivity, chemical stability in strong alkaline media, low permeability, low water swelling and good mechanical properties.<br>The purpose of this study was to develop and characterize AMs based on Styrene–butadiene–styrene (SBS) copolymer, a thermoplastic material with a block structure widely employed in the rubber industry. In the present work is reported a controlled radical functionalization, initiated by benzoyl peroxide (BPO), of SBS with 4-vinylbenzyl chloride (VBC). The resulting thermoplastic polymer was converted into an anion exchange membrane via quaternization reaction with aliphatic amines, such as trimethylamine or <br>1,4-diazabicyclo[2.2.2]octane (DABCO). Electrochemical properties of these materials were measured and correlated with synthetic parameters. Correlations between transport properties and synthetic parameters were explained in terms of Cluster-Network morphological model. Performance of the synthesized SBS-based AMs were then evaluated in a working AMFC and compared with commercial materials. Diagnostics on AMFCs, by means of electrochemical impedance spectroscopy (EIS), were performed in order to evaluate measured performances.
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