Otimização do processamento para obtenção de compósitos polímero/cerâmica com propriedades piezo e piroelétricas
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Data
2012-03-23
Autores
Oliveira, Cibele Aparecida de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Materiais eletrocerâmicos possuem diversas aplicações, tais como: capacitor de multicamadas, transdutores, sensor piroelétrico e dispositivos eletro-ópticos. Nos últimos anos, tem ocorrido uma crescente demanda por eletrocerâmicas de melhor desempenho e funcionalidade acelerando o desenvolvimento de técnicas de síntese e visando a produção de pós com partículas bem definidas em tamanho, forma e cristalinidade. O método dos precursores poliméricos e a síntese hidrotérmica, tem se destacado entre as demais técnicas, pois são consideradas ideais para a preparação destas partículas. Baseado neste contexto, este projeto teve como objetivo utilizar o método dos precursores poliméricos e a síntese hidrotérmica assistida por microondas para preparar pós com estrutura perovskitas, como o titanato zirconato de chumbo Pb(Zrx,Ti1-x)O3, com tamanho de partículas controlado, boa cristalinidade e estabilidade química. A cerâmica foi associada a um polímero para formar um compósito na forma de filmes. O polímero usado foi fluoreto de polivinideno, PVDF, já conhecido na literatura. Foram controlados o tamanho das partículas cerâmicas e a espessura dos filmes compósitos visando estabelecer um ótimo para as propriedades piezoelétricas e piroelétricas. A polarização tornou-se mais efetiva com a inclusão do polímero condutor a polianilina (PAni). A condutividade foi controlada pelos processos de protonação, desprotonação e reprotonação. Os resultados mostraram que é possível obter filmes compósitos e a melhor proporção foi de 30/70 v/v (cerâmica/polímero) garantindo boas propriedades eletrocerâmicas e ainda a flexibilidade proporcionada pelo polímero. Para a formação do compósito, PZT-PAni-rp/PVDF, a melhor condição encontrada foi para os filmes...
Electroceramic materials have many applications such as multilayer capacitor, transducer, pyroelectric sensor and electro-optical devices. In recent years, there has been a growing demand for electroceramics with better performance and functionality, accelerating the development of synthesis techniques and focusing on the production of powders with well-defined particle size, shape and crystallinity. The polymeric precursor method developed by Pechini and hydrothermal synthesis have stood out among the other techniques and they are considered ideal for the preparation of these particles. Based on this context, this project aimed to use the polymeric precursor method and hydrothermal synthesis assisted by microwave to prepare powders with perovskite structure, such as lead zirconate titanate Pb (Zrx, Ti1-x) O3, with controlled particle size, good crystallinity and chemical stability. The ceramic was associated with a polymer to form a composite in the form of films. The used polymer was polyvinylidene fluoride, PVDF, already known in the literature. We controlled the size of the ceramic particles and the thickness of the composite films to establish the best for the pyroelectric and piezoelectric properties. The polarization has become more effective with the inclusion of the conducting polymer polyaniline (PAni). The conductivity was controlled by the processes of protonation, deprotonation - reprotonation. The results showed that is possible to obtain composite films and the best ratio was 30/70 v / v (ceramic / polymer) electroceramics ensuring good properties and also the flexibility offered by the polymer. To formation the composite PZT-PAni-rp/PVDF, was the best condition found for the films that the PZT was obtained by the method of the polymeric precursor to larger particle sizes and rounded morphology... (Complete abstract click electronic access below)
Electroceramic materials have many applications such as multilayer capacitor, transducer, pyroelectric sensor and electro-optical devices. In recent years, there has been a growing demand for electroceramics with better performance and functionality, accelerating the development of synthesis techniques and focusing on the production of powders with well-defined particle size, shape and crystallinity. The polymeric precursor method developed by Pechini and hydrothermal synthesis have stood out among the other techniques and they are considered ideal for the preparation of these particles. Based on this context, this project aimed to use the polymeric precursor method and hydrothermal synthesis assisted by microwave to prepare powders with perovskite structure, such as lead zirconate titanate Pb (Zrx, Ti1-x) O3, with controlled particle size, good crystallinity and chemical stability. The ceramic was associated with a polymer to form a composite in the form of films. The used polymer was polyvinylidene fluoride, PVDF, already known in the literature. We controlled the size of the ceramic particles and the thickness of the composite films to establish the best for the pyroelectric and piezoelectric properties. The polarization has become more effective with the inclusion of the conducting polymer polyaniline (PAni). The conductivity was controlled by the processes of protonation, deprotonation - reprotonation. The results showed that is possible to obtain composite films and the best ratio was 30/70 v / v (ceramic / polymer) electroceramics ensuring good properties and also the flexibility offered by the polymer. To formation the composite PZT-PAni-rp/PVDF, was the best condition found for the films that the PZT was obtained by the method of the polymeric precursor to larger particle sizes and rounded morphology... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Físico-química, Materiais, Compositos polimericos, Ceramica, Physical chemistry, Materials, Polymeric composites, Ceramics
Como citar
OLIVEIRA, Cibele Aparecida de. Otimização do processamento para obtenção de compósitos polímero/cerâmica com propriedades piezo e piroelétricas. 2012. 97 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Química, 2012.