Compósito piezoelétrico trifásico baseado em poliuretano de óleo de mamona com partículas de PZT e nanotubos de carbono de paredes múltiplas
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Data
2021-08-04
Autores
Freire Filho, Fernando Célio Monte
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Materiais capazes de modificar ou alterar suas propriedades sobre a ação de um estímulo externo são classificados como inteligentes. Dentre esses materiais, confeccionados para atender exigências específicas para a finalidade que foi projetado, destacam-se os compósitos. O presente trabalho tem como objetivo realizar um estudo das propriedades dielétricas, elétricas e piezoelétricas do compósito piezoelétrico trifásico, formado por uma matriz polimérica de poliuretano à base do óleo mamona (PUR), com partículas da cerâmica ferroelétrica de titanato zirconato de chumbo (PZT) e nanotubo de carbono de múltiplas camadas (MWCNT). Para isso, as amostras foram preparadas por meio da mistura mecânica de PUR com os materiais dispersantes e obtidas pelo método de casting. Três diferentes grupos de amostras foram obtidas e analisadas a fim de avaliar a sinergia de cada componente. Compõem o primeiro grupo as amostras do nanocompósito bifásico de PUR/MWCNT, variando a proporção mássica de MWCNT de 0 a 9%. O segundo grupo corresponde a amostras do compósito piezoelétrico bifásico de PUR/PZT com variação de PZT de 10 a 50% e por último, formam o terceiro grupo as amostras sintetizadas do compósito trifásico PUR-MWCNT1/PZT (1% de MWCNT) e PUR-MWCNT3/PZT (3% de MWCNT) variando proporção volumétrica de PZT de 10% a 50%. As respostas elétricas e dielétricas de todas as amostras dos compósitos piezoelétricos mostraram dependência a três fatores principais: (i) variação da frequência; (ii) variação da temperatura; (iii) concentração dos materiais dispersantes. Quanto à avaliação da propriedade piezoelétrica por meio do coeficiente d33, os resultados demostraram que as amostras do compósito piezoelétrico trifásico PUR-MWCNT/PZT apresentaram maiores valores quando comparados com as amostras bifásicas PUR/PZT. Esse resultado é destacado, principalmente, quando se analisa a amostra com 30% de PZT, em que o compósito trifásico com 3% de MWCNT teve como resultado um 𝑑�����������������������33 de 68% superior em relação ao compósito bifásico. Esses resultados demonstram que dispersão de nanopartículas de MWCNT exercem boa sinergia nos compósitos, atuando de forma a proporcionar maior efetividade da polarização das partículas cerâmica, melhorando o coeficiente d33.
Materials capable of modifying or changing their properties upon the action of an external stimulus are classified as intelligent. These materials are made to meet the requirements during their use and for what they were designed for, among these materials, composites stand out. The present work aims to perform a study of the dielectric, electrical and piezoelectric properties of the three-phase piezoelectric composite, formed by a polymeric matrix of castor oil-based polyurethane (PU), with particles of the ferroelectric ceramic of lead zirconate titanate (PZT) and multi-walled carbon nanotube (MWCNT). For this, the samples were prepared by mechanically mixing PU with dispersing materials; and the samples in film form were obtained by casting. Three groups of samples were obtained to assess the synergy of each component. In the first group, the samples of the PU/MWCNT biphasic nanocomposite were obtained, varying the MWCNT mass proportion from 0 to 9%. In addition, samples of the two-phase PU/PZT piezoelectric composite were obtained with PZT variation from 10 to 50%, and finally samples of the three-phase composite PU-MWCNT1/PZT (1% MWCNT) and PU-MWCNT3/PZT (3% MWCNT) varying the volumetric proportion of PZT from 10% to 50% were made. The electrical and dielectric responses of all samples of piezoelectric composites were shown to be dependent on three main factors: (i) frequency variation; (ii) temperature variation; (iii) concentration of the dispersant materials. As for the evaluation of the piezoelectric property through the d33 coefficient, the results showed that the samples of the three-phase piezoelectric composite PU-MWCNT/PZT presented higher values of d33 when compared with the two-phase PU/PZT samples. especially when analyzing the sample with 30% of PZT, in which the three-phase composite with 3% MWCNT resulted in a d33 of 68% higher than the two-phase composite. These results demonstrate that dispersion of MWCNT nanoparticles exerts good synergy in the composites acting in a higher polarization effectiveness of the ceramic particles, improving the d33 coefficient. These results demonstrate that dispersion of MWCNT nanoparticles exerts good synergy in the composites acting in a higher polarization effectiveness of the ceramic particles, improving the d33 coefficient.
Materials capable of modifying or changing their properties upon the action of an external stimulus are classified as intelligent. These materials are made to meet the requirements during their use and for what they were designed for, among these materials, composites stand out. The present work aims to perform a study of the dielectric, electrical and piezoelectric properties of the three-phase piezoelectric composite, formed by a polymeric matrix of castor oil-based polyurethane (PU), with particles of the ferroelectric ceramic of lead zirconate titanate (PZT) and multi-walled carbon nanotube (MWCNT). For this, the samples were prepared by mechanically mixing PU with dispersing materials; and the samples in film form were obtained by casting. Three groups of samples were obtained to assess the synergy of each component. In the first group, the samples of the PU/MWCNT biphasic nanocomposite were obtained, varying the MWCNT mass proportion from 0 to 9%. In addition, samples of the two-phase PU/PZT piezoelectric composite were obtained with PZT variation from 10 to 50%, and finally samples of the three-phase composite PU-MWCNT1/PZT (1% MWCNT) and PU-MWCNT3/PZT (3% MWCNT) varying the volumetric proportion of PZT from 10% to 50% were made. The electrical and dielectric responses of all samples of piezoelectric composites were shown to be dependent on three main factors: (i) frequency variation; (ii) temperature variation; (iii) concentration of the dispersant materials. As for the evaluation of the piezoelectric property through the d33 coefficient, the results showed that the samples of the three-phase piezoelectric composite PU-MWCNT/PZT presented higher values of d33 when compared with the two-phase PU/PZT samples. especially when analyzing the sample with 30% of PZT, in which the three-phase composite with 3% MWCNT resulted in a d33 of 68% higher than the two-phase composite. These results demonstrate that dispersion of MWCNT nanoparticles exerts good synergy in the composites acting in a higher polarization effectiveness of the ceramic particles, improving the d33 coefficient. These results demonstrate that dispersion of MWCNT nanoparticles exerts good synergy in the composites acting in a higher polarization effectiveness of the ceramic particles, improving the d33 coefficient.
Descrição
Palavras-chave
Poliuretano, Nanotubo carbono, PZT, Compósito, Polyurethane, Carbon nanotube, PZT, Composite