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Master's Dissertation
DOI
10.11606/D.85.2008.tde-02062009-163925
Document
Author
Full name
Gilberto de Oliveira Moraes
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2008
Supervisor
Committee
Lugão, Ademar Benévolo (President)
Parra, Duclerc Fernandes
Wiebeck, Helio
Title in Portuguese
Obtenção de membranas trocadoras de prótons a base de polietileno para uso em células à combustível
Keywords in Portuguese
exertia
membranas
polietileno
Abstract in Portuguese
A enxertia induzida por radiação do polietileno (PE) e estireno (ST), via fonte de 60 Co foi conduzida usando irradiação direta (simultânea) e indireta (pré- irradiação e peroxidação) á temperatura ambiente. As doses irradiadas, em ambos os caso, foi de 0,5 kGy até 80 kGy. Pelo método da irradiação simultânea, os filmes foram imersos em mistura estireno: metanol (30:70 v/v) mais 30% de aditivo (ácido sulfúrico) em ampolas de vidro de 40 mL sob atmosfera inerte, seladas em atmosfera inerte, para então, serem irradiadas em instalações industriais (EMBRARAD / CBE). Após a irradiação, as amostras foram retiradas, lavadas e secas em estufas, por 8 horas e pesadas para cálculo de grau de enxertia. Pelo método da pré-irradiação, as amostras foram irradiadas em ampolas, seladas sob atmosfera inerte. A mistura acima mencionada era adicionada após a irradiação, A enxertia propriamente se inicia no momento de adição de mistura. Após 8 horas, as amostras eram retiradas, secas e pesadas para cálculo de grau de enxertia. No método da peroxidação, as amostras foram seladas com ar (oxigênio). Todo o procedimento do método pré-irradiação era então repetido. As amostras que apresentaram grau de enxertia (DOG na sigla em inglês) significativo eram caracterizadas (TGA, DSC) e sulfonadas para cálculo de capacidade de troca iônica (IEC na sigla em inglês). Observou-se que, pelo método indireto, as amostras não apresentaram enxertia significativa. Pelo método direto (simultânea) as amostras apresentaram modificação (aumento de massa), ou seja, houve enxertia, mas não apresentaram IEC significativo. A dose que apresentou o melhor DOG foi 80 kGy.
Title in English
POLYETHYLENE (PE) BASED PROTON EXCHANGE MEMBRANE FOR USE IN FUEL CELL
Keywords in English
enxertia
membranas
polietileno
Abstract in English
The irradiation – induced graft of styrene onto polyethylene (PE) in a Cobalt-60 source was carried out using direct (simultaneous) and indirect (preirradiation and peroxidation) methods at room temperature. The dose applied in both cases varied from 0,5 to 80 kGy; In the direct method, the films were immersed in a solution of styrene: methanol (30:70 v/v) and 30% of sulfuric acid(additive) in glass ampoules of 40 mL under inert atmosphere, and then irradiated. After irradiation process, the samples were kept in solution for 8 hours and taken off the ampoules, dried in oven at 60 0C for another 8 hour period until constant weight. In pre-irradiation method, the samples were irradiated in dry and sealed ampoules, under inert atmosphere. The solution was then added to the samples, and after 8 hours, taken off, dried, sealed and weighted. In peroxidation method, the difference was not inert atmosphere but atmosphere of air (O2).For each samples it was calculated the degree of grafting (DOG). The samples that showed some DOG were sulfonated, characterized (DSC, TGA and infrared) and the ion exchange capacity (IEC) was calculated. The samples processed by indirect method presented no DOG at all. The samples processed by direct method present grafting (best result was 80 kGy). These samples, after sulfonated, presented ion exchange properties.
 
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Publishing Date
2009-06-25
 
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