Preparo e modificação química de látex magnético à base de nanocompósitos de ferrita de cobalto e poliestireno
Autor(a) principal: | |
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Data de Publicação: | 2009 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFG |
Texto Completo: | http://repositorio.bc.ufg.br/tede/handle/tde/1065 |
Resumo: | In this work, magnetic nanocomposites based on cobalt ferrite/polystyrene with aproximately 30 % of encapsulated ferrite and average diameter of 100 nm were prepared through miniemulsion polymerization with poly(vinyl alcohol) (PVA) as emulsifying agent. The cobalt ferrite was synthesized through coprecipitation technique followed by the formation of hydrophobic gel constituted of nanoparticles surfactated with oleic acid. Ferrite gel was separated by simple filtration and directly dispersed in styrene monomer for encapsulation, even after drying and storage for several days. After ferrite gel dispersion in styrene, it was produced a miniemulsion in water through mechanical agitation with high speed in the presence of PVA. This system was polymerized at 70 oC with sodium persulfate as initiator. The grafting of PVA on polystyrene surface was investigated. The hydroxyl groups of PVA on the surface of cobalt ferrite/polystyrene nanocomposite were esterified in aqueous medium with stearic acid and dodecylbenzene sulfonic acid as catalyst and surfactant directly in polymerization reactor. Cobalt ferrite nanoparticles in the form of powder and gel, magnetic cobalt ferrite/polystyrene nanocomposites non-esterified and esterified were characterized by thermogravimetric analysis and differential thermal analysis (TG/DTA), infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy, X-ray diffraction, transmission electron microscopy (TEM) and dynamic light scattering. Dispersions in mineral oil of CoFe2O4 gel and CoFe2O4/polystyrene nanocomposite esterified with concentrations of 0,05%; 0,1%; 0,2%; 0,5% e 1,0% (w/v) were characterizated by particle size distribution and stability. The presence of NaCl in CoFe2O4 gel and in CoFe2O4/polystyrene nanocomposite esterified induced corrosion reactions of CoFe2O4 nanoparticles at high temperatures during TG/DTA analysis. NaCl contamination also prevented the correct determination of CoFe2O4 content in the gel and in the esterified nanocomposite. The nanofluid with 1% of CoFe2O4/polystyrene nanocomposite esterified was more stable than all nanofluids of ferrite gel. The presence of agglomerates in mineral oil dispersion of CoFe2O4 gel and CoFe2O4/polystyrene nanocomposite esterified can be due the presence of NaCl and the inefficiency of mechanical dispersion process |
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RABELO, Denilsonhttp://lattes.cnpq.br/4961539278604455http://lattes.cnpq.br/0902980243470015CRUZ, Fábio Pereira da2014-07-29T15:12:49Z2010-04-132009-12-15CRUZ, Fábio Pereira da. Preparation and chemical modification of latex-based nanocomposite magnetic cobalt ferrite and polystyrene. 2009. 69 f. Dissertação (Mestrado em Educação em Química) - Universidade Federal de Goiás, Goiânia, 2009.http://repositorio.bc.ufg.br/tede/handle/tde/1065ark:/38995/00130000093jpIn this work, magnetic nanocomposites based on cobalt ferrite/polystyrene with aproximately 30 % of encapsulated ferrite and average diameter of 100 nm were prepared through miniemulsion polymerization with poly(vinyl alcohol) (PVA) as emulsifying agent. The cobalt ferrite was synthesized through coprecipitation technique followed by the formation of hydrophobic gel constituted of nanoparticles surfactated with oleic acid. Ferrite gel was separated by simple filtration and directly dispersed in styrene monomer for encapsulation, even after drying and storage for several days. After ferrite gel dispersion in styrene, it was produced a miniemulsion in water through mechanical agitation with high speed in the presence of PVA. This system was polymerized at 70 oC with sodium persulfate as initiator. The grafting of PVA on polystyrene surface was investigated. The hydroxyl groups of PVA on the surface of cobalt ferrite/polystyrene nanocomposite were esterified in aqueous medium with stearic acid and dodecylbenzene sulfonic acid as catalyst and surfactant directly in polymerization reactor. Cobalt ferrite nanoparticles in the form of powder and gel, magnetic cobalt ferrite/polystyrene nanocomposites non-esterified and esterified were characterized by thermogravimetric analysis and differential thermal analysis (TG/DTA), infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy, X-ray diffraction, transmission electron microscopy (TEM) and dynamic light scattering. Dispersions in mineral oil of CoFe2O4 gel and CoFe2O4/polystyrene nanocomposite esterified with concentrations of 0,05%; 0,1%; 0,2%; 0,5% e 1,0% (w/v) were characterizated by particle size distribution and stability. The presence of NaCl in CoFe2O4 gel and in CoFe2O4/polystyrene nanocomposite esterified induced corrosion reactions of CoFe2O4 nanoparticles at high temperatures during TG/DTA analysis. NaCl contamination also prevented the correct determination of CoFe2O4 content in the gel and in the esterified nanocomposite. The nanofluid with 1% of CoFe2O4/polystyrene nanocomposite esterified was more stable than all nanofluids of ferrite gel. The presence of agglomerates in mineral oil dispersion of CoFe2O4 gel and CoFe2O4/polystyrene nanocomposite esterified can be due the presence of NaCl and the inefficiency of mechanical dispersion processNeste trabalho, nanocompósitos magnéticos de ferrita de cobalto/poliestireno, com aproximadamente 30% de teor de ferrita de cobalto encapsulada e tamanho médio de 100nm foram preparados, a partir da técnica de polimerização em miniemulsão, com uso de poli(álcool vinílico) (PVA) como agente emulsificante. A ferrita de cobalto (CoFe2O4) foi sintetizada pela técnica de coprecipitação seguida da formação de um gel hidrofóbico constituído de nanopartículas surfactadas por ácido oléico. O gel de CoFe2O4 foi separado por filtração simples e disperso diretamente no monômero estireno para o processo de encapsulamento, mesmo após secagem e estocagem por vários dias. Após a dispersão do gel de CoFe2O4 em estireno, foi produzida uma miniemulsão através de agitação mecânica em alta velocidade na presença de PVA. O sistema foi polimerizado a 70º C com persulfato de sódio como iniciador. Foi investigada a grafitização do PVA na superfície do poliestireno. As hidroxilas do PVA na superfície do nanocompósito de ferrita de cobalto/poliestireno foram esterificadas em meio aquoso com adição de ácido esteárico e ácido dodecilbenzeno sulfônico como catalisador e surfactante diretamente no reator de polimerização. As nanopartículas de CoFe2O4 na forma de pó e gel, nanocompósitos magnéticos de CoFe2O4/poliestireno não-esterificado e esterificado foram caracterizados por análise termogravimétrica e análise térmica diferencial (TG/DTA), espectroscopia de absorção na região do infravermelho (FTIR), espectroscopia na região do ultravioleta e visível, difração de raios X, microscopia eletrônica de varredura e espalhamento dinâmico de luz. Dispersões em óleo mineral do gel de CoFe2O4 e do nanocompósito de CoFe2O4/poliestireno esterificado nas concentrações de 0,05%; 0,1%; 0,2%; 0,5% e 1,0% (m/v) foram caracterizadas quanto à distribuição de tamanho de partículas e a estabilidade. A presença de NaCl no gel de CoFe2O4, após a modificação de superfície com ácido oléico e no látex de CoFe2O4/poliestireno esterificado, contribuiu para reações de corrosão das nanopartículas de CoFe2O4 em altas temperaturas durante a análise de TG/DTA. A contaminação com NaCl, também, impediu a correta determinação da percentagem de CoFe2O4 no gel e no nanocompósito esterificado. O nanofluído com 1% (v/v) de nanocompósito CoFe2O4/poliestireno esterificado apresentou maior estabilidade que todos os nanofluidos de gel de CoFe2O4. A presença de aglomerados nas dispersões do gel de ferrita e do nanocompósito CoFe2O4/poliestireno esterificado em óleo de transformador pode ser devido à presença de NaCl e à ineficiência do processo de dispersão mecânicaMade available in DSpace on 2014-07-29T15:12:49Z (GMT). No. of bitstreams: 1 01-CAPA DA DISSERTACAO.pdf: 14537 bytes, checksum: f910ab44f1c130f6ff898cec8d01d9e7 (MD5) Previous issue date: 2009-12-15application/pdfhttp://repositorio.bc.ufg.br/TEDE/retrieve/3766/01-CAPA%20DA%20DISSERTACAO.pdf.jpgporUniversidade Federal de GoiásMestrado em QuímicaUFGBREducação em Químicananocompósitos magnéticos, de cobalto/poliestirenomagnetic nanocomposites, cobalt / polystyreneCNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICAPreparo e modificação química de látex magnético à base de nanocompósitos de ferrita de cobalto e poliestirenoPreparation and chemical modification of latex-based nanocomposite magnetic cobalt ferrite and polystyreneinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFGinstname:Universidade Federal de Goiás (UFG)instacron:UFGORIGINAL01-CAPA DA DISSERTACAO.pdfapplication/pdf14537http://repositorio.bc.ufg.br/tede/bitstreams/95b10686-f97e-49da-ad5d-1a3c259a023b/downloadf910ab44f1c130f6ff898cec8d01d9e7MD51THUMBNAIL01-CAPA DA DISSERTACAO.pdf.jpg01-CAPA DA DISSERTACAO.pdf.jpgGenerated Thumbnailimage/jpeg2225http://repositorio.bc.ufg.br/tede/bitstreams/09dcc0fc-3777-4791-b3bc-37df5a201767/download27adb1096fb4dbb6972ef9ddf1db72ecMD52tde/10652014-07-30 03:08:03.266open.accessoai:repositorio.bc.ufg.br:tde/1065http://repositorio.bc.ufg.br/tedeRepositório InstitucionalPUBhttp://repositorio.bc.ufg.br/oai/requesttasesdissertacoes.bc@ufg.bropendoar:2014-07-30T06:08:03Repositório Institucional da UFG - Universidade Federal de Goiás (UFG)false |
dc.title.por.fl_str_mv |
Preparo e modificação química de látex magnético à base de nanocompósitos de ferrita de cobalto e poliestireno |
dc.title.alternative.eng.fl_str_mv |
Preparation and chemical modification of latex-based nanocomposite magnetic cobalt ferrite and polystyrene |
title |
Preparo e modificação química de látex magnético à base de nanocompósitos de ferrita de cobalto e poliestireno |
spellingShingle |
Preparo e modificação química de látex magnético à base de nanocompósitos de ferrita de cobalto e poliestireno CRUZ, Fábio Pereira da nanocompósitos magnéticos, de cobalto/poliestireno magnetic nanocomposites, cobalt / polystyrene CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
title_short |
Preparo e modificação química de látex magnético à base de nanocompósitos de ferrita de cobalto e poliestireno |
title_full |
Preparo e modificação química de látex magnético à base de nanocompósitos de ferrita de cobalto e poliestireno |
title_fullStr |
Preparo e modificação química de látex magnético à base de nanocompósitos de ferrita de cobalto e poliestireno |
title_full_unstemmed |
Preparo e modificação química de látex magnético à base de nanocompósitos de ferrita de cobalto e poliestireno |
title_sort |
Preparo e modificação química de látex magnético à base de nanocompósitos de ferrita de cobalto e poliestireno |
author |
CRUZ, Fábio Pereira da |
author_facet |
CRUZ, Fábio Pereira da |
author_role |
author |
dc.contributor.advisor1.fl_str_mv |
RABELO, Denilson |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/4961539278604455 |
dc.contributor.authorLattes.fl_str_mv |
http://lattes.cnpq.br/0902980243470015 |
dc.contributor.author.fl_str_mv |
CRUZ, Fábio Pereira da |
contributor_str_mv |
RABELO, Denilson |
dc.subject.por.fl_str_mv |
nanocompósitos magnéticos, de cobalto/poliestireno |
topic |
nanocompósitos magnéticos, de cobalto/poliestireno magnetic nanocomposites, cobalt / polystyrene CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
dc.subject.eng.fl_str_mv |
magnetic nanocomposites, cobalt / polystyrene |
dc.subject.cnpq.fl_str_mv |
CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
description |
In this work, magnetic nanocomposites based on cobalt ferrite/polystyrene with aproximately 30 % of encapsulated ferrite and average diameter of 100 nm were prepared through miniemulsion polymerization with poly(vinyl alcohol) (PVA) as emulsifying agent. The cobalt ferrite was synthesized through coprecipitation technique followed by the formation of hydrophobic gel constituted of nanoparticles surfactated with oleic acid. Ferrite gel was separated by simple filtration and directly dispersed in styrene monomer for encapsulation, even after drying and storage for several days. After ferrite gel dispersion in styrene, it was produced a miniemulsion in water through mechanical agitation with high speed in the presence of PVA. This system was polymerized at 70 oC with sodium persulfate as initiator. The grafting of PVA on polystyrene surface was investigated. The hydroxyl groups of PVA on the surface of cobalt ferrite/polystyrene nanocomposite were esterified in aqueous medium with stearic acid and dodecylbenzene sulfonic acid as catalyst and surfactant directly in polymerization reactor. Cobalt ferrite nanoparticles in the form of powder and gel, magnetic cobalt ferrite/polystyrene nanocomposites non-esterified and esterified were characterized by thermogravimetric analysis and differential thermal analysis (TG/DTA), infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy, X-ray diffraction, transmission electron microscopy (TEM) and dynamic light scattering. Dispersions in mineral oil of CoFe2O4 gel and CoFe2O4/polystyrene nanocomposite esterified with concentrations of 0,05%; 0,1%; 0,2%; 0,5% e 1,0% (w/v) were characterizated by particle size distribution and stability. The presence of NaCl in CoFe2O4 gel and in CoFe2O4/polystyrene nanocomposite esterified induced corrosion reactions of CoFe2O4 nanoparticles at high temperatures during TG/DTA analysis. NaCl contamination also prevented the correct determination of CoFe2O4 content in the gel and in the esterified nanocomposite. The nanofluid with 1% of CoFe2O4/polystyrene nanocomposite esterified was more stable than all nanofluids of ferrite gel. The presence of agglomerates in mineral oil dispersion of CoFe2O4 gel and CoFe2O4/polystyrene nanocomposite esterified can be due the presence of NaCl and the inefficiency of mechanical dispersion process |
publishDate |
2009 |
dc.date.issued.fl_str_mv |
2009-12-15 |
dc.date.available.fl_str_mv |
2010-04-13 |
dc.date.accessioned.fl_str_mv |
2014-07-29T15:12:49Z |
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.citation.fl_str_mv |
CRUZ, Fábio Pereira da. Preparation and chemical modification of latex-based nanocomposite magnetic cobalt ferrite and polystyrene. 2009. 69 f. Dissertação (Mestrado em Educação em Química) - Universidade Federal de Goiás, Goiânia, 2009. |
dc.identifier.uri.fl_str_mv |
http://repositorio.bc.ufg.br/tede/handle/tde/1065 |
dc.identifier.dark.fl_str_mv |
ark:/38995/00130000093jp |
identifier_str_mv |
CRUZ, Fábio Pereira da. Preparation and chemical modification of latex-based nanocomposite magnetic cobalt ferrite and polystyrene. 2009. 69 f. Dissertação (Mestrado em Educação em Química) - Universidade Federal de Goiás, Goiânia, 2009. ark:/38995/00130000093jp |
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http://repositorio.bc.ufg.br/tede/handle/tde/1065 |
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por |
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Universidade Federal de Goiás |
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Mestrado em Química |
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UFG |
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BR |
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Educação em Química |
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Universidade Federal de Goiás |
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Universidade Federal de Goiás (UFG) |
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UFG |
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Repositório Institucional da UFG |
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