Silk fibroin-based polymeric membranes for fuel cells
Autor(a) principal: | |
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Data de Publicação: | 2018 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10773/24459 |
Resumo: | Polymer electrolyte fuel cells (PEFCs) have been widely used for their ability to generate electricity in a sustainable way. However, the materials used in PEFCs present themselves with clear negative environmental impacts. Thus, the search for alternative materials is a critical aspect in order to improve the sustainability of such technologies. This dissertation aimed at the development of polymeric membranes of silk fibroin, a protein produced by the domestic silkworm, not thoroughly explored for fuel cell related applications. In an initial phase of this work, two methods for fibroin extraction and purification were tested and the one that proved to be more reproductive was chosen. After that, the membrane preparation conditions were studied and optimized, using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM), and a significant impact on the structure of fibroin by the evaporation process of water was verified. Considering the application in PEFCs, the ion-exchange capacity (IEC), dynamic water vapor sorption (DVS), thermal and mechanical properties were also studied. The obtained results demonstrated that when the -sheet fraction is higher in the membrane structure, water sorption is up to 28% of its mass, at 25 °C. Finally, the ionic conductivity of the membranes was evaluated by impedance spectroscopy, at different temperature (T) and relative humidity (RH) conditions. Silk fibroin membranes present ionic conductivity values ranging from 5.7 107 S.cm1, at lower temperatures and relative humidities, to 1.8 103 S.cm1 at RH = 98% and T = 94°C. The obtained values for conductivity are lower when compared with commercial membranes based on Nafion®, however, the silk fibroin membranes still demonstrate promising results regarding thermal and mechanical properties, with degradation temperatures up to 260 °C. As a biopolymer with such promising properties, silk fibroin is a material with potential application in PEFCs |
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Silk fibroin-based polymeric membranes for fuel cellsFuel cellConductivityPolymer electrolyte membraneSilk fibroinPolymer electrolyte fuel cells (PEFCs) have been widely used for their ability to generate electricity in a sustainable way. However, the materials used in PEFCs present themselves with clear negative environmental impacts. Thus, the search for alternative materials is a critical aspect in order to improve the sustainability of such technologies. This dissertation aimed at the development of polymeric membranes of silk fibroin, a protein produced by the domestic silkworm, not thoroughly explored for fuel cell related applications. In an initial phase of this work, two methods for fibroin extraction and purification were tested and the one that proved to be more reproductive was chosen. After that, the membrane preparation conditions were studied and optimized, using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM), and a significant impact on the structure of fibroin by the evaporation process of water was verified. Considering the application in PEFCs, the ion-exchange capacity (IEC), dynamic water vapor sorption (DVS), thermal and mechanical properties were also studied. The obtained results demonstrated that when the -sheet fraction is higher in the membrane structure, water sorption is up to 28% of its mass, at 25 °C. Finally, the ionic conductivity of the membranes was evaluated by impedance spectroscopy, at different temperature (T) and relative humidity (RH) conditions. Silk fibroin membranes present ionic conductivity values ranging from 5.7 107 S.cm1, at lower temperatures and relative humidities, to 1.8 103 S.cm1 at RH = 98% and T = 94°C. The obtained values for conductivity are lower when compared with commercial membranes based on Nafion®, however, the silk fibroin membranes still demonstrate promising results regarding thermal and mechanical properties, with degradation temperatures up to 260 °C. As a biopolymer with such promising properties, silk fibroin is a material with potential application in PEFCsAs pilhas de combustível de electrólito polimérico (PCEPs) têm sido amplamente estudadas devido à sua capacidade de produzir energia eléctrica de uma forma sustentável. No entanto, os materiais utilizados como electrólitos nas PCEPs apresentam impactos ambientais negativos. Assim, a procura de materiais alternativos é um aspeto crítico para melhorar a sustentabilidade deste tipo de tecnologias. Esta dissertação visou o desenvolvimento de membranas poliméricas a partir de fibroína, uma proteína fabricada pelo bicho da seda, pouco explorada em aplicações relacionadas com células de combustível. Numa fase inicial do trabalho foram testados dois métodos de extração e purificação da fibroina tendo-se selecionado aquele que se revelou mais reprodutível. Seguidamente estudouse e otimizou-se as condições de preparação de membranas recorrendo a uma caracterização sistemática através de espectroscopia de infravermelho com transformada de Fourier (FTIR), difração de raios-X (XRD) e microscopia eletrónica de varrimento (SEM) tendo-se verificado que o processo de evaporação da água tem um impacto significativo na estrutura da fibroina. Com vista à aplicação em PCEPs, estudou-se ainda a capacidade de troca iónica (IEC), a adsorção dinâmica de vapor de água (DVS), assim como as propriedades térmicas e mecânicas. Os resultados obtidos confirmaram o efeito que o modo de preparação das membranas tem no seu desempenho, sendo de realçar os resultados de DVS. Estes resultados demonstram que nas membranas em que a conformação do tipo folhas- é mais abundante, a adsorção de água chega a ser de 28% da sua massa, a 25 °C. Por fim, avaliou-se a condutividade iónica recorrendo à espectroscopia de impedância variando a temperatura (T) e a humidade relativa (RH). As membranas de fibroína apresentam valores de condutividade de 5.7 107 S.cm1, a valores mais baixos de T e RH e de 1.8 103 S.cm1 para T = 94°C e RH = 98 %. Os valores obtidos são mais baixos quando comparados com membranas comerciais baseadas em Nafion®, no entanto, as membranas de fibroína apresentam resultados promissores no que diz respeito a propriedades térmicas e mecânicas, com temperaturas de degradação superiores a 260 °C. Sendo um biopolímero com propriedades de base promissoras, a fibroína apresenta-se assim como um material com potencial aplicação em PCEPs2020-07-16T00:00:00Z2018-07-12T00:00:00Z2018-07-12info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10773/24459TID:202234754engAlmeida, Tomás Coelhoinfo:eu-repo/semantics/embargoedAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-02-22T11:47:53Zoai:ria.ua.pt:10773/24459Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T02:58:04.598768Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Silk fibroin-based polymeric membranes for fuel cells |
title |
Silk fibroin-based polymeric membranes for fuel cells |
spellingShingle |
Silk fibroin-based polymeric membranes for fuel cells Almeida, Tomás Coelho Fuel cell Conductivity Polymer electrolyte membrane Silk fibroin |
title_short |
Silk fibroin-based polymeric membranes for fuel cells |
title_full |
Silk fibroin-based polymeric membranes for fuel cells |
title_fullStr |
Silk fibroin-based polymeric membranes for fuel cells |
title_full_unstemmed |
Silk fibroin-based polymeric membranes for fuel cells |
title_sort |
Silk fibroin-based polymeric membranes for fuel cells |
author |
Almeida, Tomás Coelho |
author_facet |
Almeida, Tomás Coelho |
author_role |
author |
dc.contributor.author.fl_str_mv |
Almeida, Tomás Coelho |
dc.subject.por.fl_str_mv |
Fuel cell Conductivity Polymer electrolyte membrane Silk fibroin |
topic |
Fuel cell Conductivity Polymer electrolyte membrane Silk fibroin |
description |
Polymer electrolyte fuel cells (PEFCs) have been widely used for their ability to generate electricity in a sustainable way. However, the materials used in PEFCs present themselves with clear negative environmental impacts. Thus, the search for alternative materials is a critical aspect in order to improve the sustainability of such technologies. This dissertation aimed at the development of polymeric membranes of silk fibroin, a protein produced by the domestic silkworm, not thoroughly explored for fuel cell related applications. In an initial phase of this work, two methods for fibroin extraction and purification were tested and the one that proved to be more reproductive was chosen. After that, the membrane preparation conditions were studied and optimized, using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM), and a significant impact on the structure of fibroin by the evaporation process of water was verified. Considering the application in PEFCs, the ion-exchange capacity (IEC), dynamic water vapor sorption (DVS), thermal and mechanical properties were also studied. The obtained results demonstrated that when the -sheet fraction is higher in the membrane structure, water sorption is up to 28% of its mass, at 25 °C. Finally, the ionic conductivity of the membranes was evaluated by impedance spectroscopy, at different temperature (T) and relative humidity (RH) conditions. Silk fibroin membranes present ionic conductivity values ranging from 5.7 107 S.cm1, at lower temperatures and relative humidities, to 1.8 103 S.cm1 at RH = 98% and T = 94°C. The obtained values for conductivity are lower when compared with commercial membranes based on Nafion®, however, the silk fibroin membranes still demonstrate promising results regarding thermal and mechanical properties, with degradation temperatures up to 260 °C. As a biopolymer with such promising properties, silk fibroin is a material with potential application in PEFCs |
publishDate |
2018 |
dc.date.none.fl_str_mv |
2018-07-12T00:00:00Z 2018-07-12 2020-07-16T00:00:00Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10773/24459 TID:202234754 |
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http://hdl.handle.net/10773/24459 |
identifier_str_mv |
TID:202234754 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/embargoedAccess |
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embargoedAccess |
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application/pdf |
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reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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1799137635381280768 |