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A selective conductive polymer-based sensor for volatile halogenated organic compounds (VHOC)

LI, Rosamaria W. C.; VENTURA, Leonardo; GRUBER, Jonas; KAWANO, Yoshio; CARVALHO, Lilian R. F.
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
ENG
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A novel poly(p-xylylene), PPX, derivative bearing alkoxyphenyl side groups was electrochemically synthesized in 87% yield. The polymer, poly(4`-hexyloxy-2,5-biphenyleneethylene) (PHBPE), presented a fraction (92%) soluble in common organic solvents. It showed to be thermally resistant up to 185 degrees C. UV-vis analysis revealed an E-gap of 3.5 eV Gas sensors made from thin films of 10-camphorsulfonic acid-doped PHBPE deposited on interdigitated electrodes exhibited significant changes in electrical conductance upon exposure to five VHOCs: 1,2-dichloroethane, bromochloromethane, trichloromethane, dichloromethane and tetrachloromethane. The conductance decreased after exposure to tetrachloromethane and increased after exposure to all the other VHOCs. Three-dimensional plots of relative response versus time of half response versus time of half recovery showed good discrimination between the five VHOCs tested. (c) 2008 Elsevier B.V. All rights reserved.

Síntese de polímeros condutores e sua aplicação em narizes eletrônicos; Synthesis of conducting polymers and their application in electronic noses

Szulc, Ricardo Leme
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/10/2007 PT
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O trabalho desenvolvido consistiu na síntese eletroquíca de 4 polímeros conjugados da família dos PPVs, substituídos por cadeias laterais formadas por unidades - CORS (tioéster) com grupos R de comprimentos distintos. A caracterização desses polímeros foi feita por métodos espectroscópicos, análises térmicas e cromatografia por exclusão de tamanho. Os polímeros foram dopados com ácido canforsulfônico. Sensores foram construídos pela deposição de filmes poliméricos finos sobre eletrodos interdigitados. Suas respostas resistivas, frente à exposição aos vapores de substâncias voláteis, foram estudadas. Um equipamento foi desenvolvido para testar os sensores. Através dessa ferramenta, os sensores foram conectados a condutivímetros, cujas saídas foram lidas e digitalizadas por um microcontrolador, qeu enviou esses dados a um computador (PC). O conjunto de dados colhidos permitiu gerar gráficos de resposta vs. tempo e de PCA (análise das componentes principais), utilizados na avaliação da seletividade dos sensores. Os sensores foram expostos a ar saturado com vapores de compostos orgânicos voláteis. Os resultados mostraram que esses são capazes de distinguir os compostos testados. O arranjo de alguns sensores diferentes gerou padrões distintos de resposta para cada substância analisada...

Desenvolvimento de membranas íon-seletivas com poliestireno sulfonado e polianilina dopada para a aplicação em eletrodiálise

Proença, Marcela Pinheiro
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
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Atualmente, a preocupação com a redução da poluição industrial tem motivado os pesquisadores na busca de novas tecnologias para o tratamento de resíduos industriais. Tecnologias limpas, como a eletrodiálise, são capazes de tratar alguns destes resíduos, como por exemplo o efluente da indústria de galvanoplastia, minimizando os impactos que ocorreriam caso eles fossem descartados diretamente no meio ambiente. O componente principal desta técnica é a membrana na qual ocorre a etapa de retirada dos íons da solução. Atualmente estas membranas são importadas e caras, o que justifica o desenvolvimento de membranas eficientes e acessíveis. Neste sentido, no presente trabalho membranas de poliestireno sulfonado/ poliestireno de alto impacto (SPS/HIPS), polianilina dopada com ácido canforsulfônico/ poliestireno sulfonado/ poliestireno de alto impacto (PAniCSA/SPS/HIPS), polianilina sulfonada/ poliestireno sulfonado/ poliestireno de alto impacto (SPAN/SPS/HIPS), e polianilina dopada com ácido p-tolueno sulfônico/ poliestireno sulfonado/ poliestireno de alto impacto (PAniTSA/SPS/HIPS) foram desenvolvidas usando o método de mistura química. As membranas foram caracterizadas utilizando as técnicas Análise termogravimétrica (TGA)...

Membranas poliméricas íon seletivas aniônicas e catiônicas para uso em eletrodiálise

Müller, Franciélli
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
POR
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O objetivo principal da presente Tese de Doutorado é o desenvolvimento de membranas poliméricas aniônicas e catiônicas para tratamento de soluções que contenham íons metálicos utilizando o processo de eletrodiálise. Foram sintetizadas membranas catiônicas a partir de poliestireno cristal (PS) ou poliestireno de alto impacto (HIPS) com copolímero em bloco de estireno-etileno/butileno-estireno (SEBS) e polianilina (PAni) dopada com ácido canforsulfônico (CSA). Após sulfonação, as combinações dos polímeros foram usadas para produzir membranas íon seletivas por evaporação do solvente com subsequente tratamento térmico. As membranas aniônicas foram sintetizadas a partir de poli(álcool vinílico) (PVA), com inserção de grupos quaternários de amônio na matriz polimérica e posterior reticulação com glutaraldeído e anidrido maleico. Diferentes membranas foram sintetizadas com o propósito de avaliar a combinação de propriedades mecânicas, químicas, eletroquímicas e de transporte iônico. A morfologia e a estrutura das membranas foram analisadas por microscopia eletrônica de varredura, microscopia de força atômica e espectroscopia de infravermelho. As transições térmicas e estabilidade de todas as membranas foram caracterizadas usando técnicas calorimétricas e comparadas com todos os polímeros individuais. Análises das propriedades físicas (ex. condutividade iônica...

Development of an amperometric enzyme electrode based on poly(o-phenylenediamine) for the determination of total cholesterol in serum

Zeybek,Derya Koyuncu; Zeybek,Bülent; Pekmez,Nuran Özçiçek; Pekyardımcı,Şule; Kılıç,Esma
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2012 EN
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A polymer-based amperometric enzyme electrode (Pt/PoPD/ChOx) was prepared for the amperometric detection of free cholesterol. Firstly, poly(o-phenylenediamine) (PoPD) polymer film was prepared in acetonitrile-water medium containing o-phenylenediamine (oPD) monomer and (±)-10-camphorsulfonic acid (HCSA) on Pt electrode by the use of cyclic voltammetry technique. Cholesterol oxidase (ChOx) enzyme was immobilized onto Pt/PoPD electrode surface. The determination of cholesterol was performed via monitoring of the oxidation current of enzymatically produced H2O2 at +0.7 V vs. Ag/AgCl. Optimum buffer concentration, pH and working temperature were found as 0.05 mol L-1, 7.5 and 40 ºC, respectively. The working range of enzyme electrode to cholesterol was 9.8 × 10-3-11 µmol L-1 and response time 150 s. The effects of possible interferences present in serum samples on response of enzyme electrode were examined. The determination of total cholesterol in serum samples was performed by using proposed Pt/PoPD/ChOx enzyme electrode and results were in good agreement with those obtained by spectrophotometric method.

Polyaniline synthesized with functionalized sulfonic acids for blends manufacture

Cardoso,Mara Joelma Raupp; Lima,Martha Fogliato Santos; Lenz,Denise Maria
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2007 EN
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Polyaniline (PAni), an electronic conductive polymer, has poor mechanical properties, such as low tensile, compressive and flexural strength that render PAni a non-ideal material to be processed for practical applications. Desired properties of polyaniline can be enhanced by mixing it with a polymer that has good mechanical properties. In this work, PAni was synthesised using functionalized sulfonic acids like camphorsulfonic acid (CSA) and dodecilbenzene sulfonic acid (DBSA) in order to promote PAni doping and improve its solubility, making possible conductive blends manufacture. The different forms of PAni were characterized by infra-red spectroscopy, thermal analysis, scanning electron microscopy and conductivity measurements. A conductive blend composed of PAni/DBSA and lower density polyethylene (LDPE) was obtained via solubilization method and its thermal, morphological and electrical properties were investigated. Concentrations as low as 5 wt. (%) of PAni was able to lead to electrical conductivities of PAni/LDPE blends in the range of 10-3 S.cm-1, showing great potential to be used in antistatic packing, electromagnetic shielding, anti-corrosion shielding or as a semiconductor.

An Atom-Economic and Selective Ruthenium-Catalyzed Redox Isomerization of Propargylic Alcohols. An Efficient Strategy for the Synthesis of Leukotrienes

Trost, Barry M.; Livingston, Robert C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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Catalytic ruthenium complexes in conjunction with an indium cocatalyst and Bronsted acid isomerize primary and secondary propargylic alcohols in good yields to provide trans enals and enones exclusively. Readily available indenylbis(triphenylphosphine)ruthenium chloride in the presence of indium triflate and camphorsulfonic acid give the best turnover numbers and reactivity with the broadest range of substrates. Deuterium labeling experiments suggest that the process occurs through propargylic hydride migration followed by protic cleavage of the resultant vinylruthenium intermediate. Application of this method to the synthesis of leukotriene B4 demonstrates its utility and extraordinary selectivity.

Low-Cost Gas Sensors Produced by the Graphite Line-Patterning Technique Applied to Monitoring Banana Ripeness

Manzoli, Alexandra; Steffens, Clarice; Paschoalin, Rafaella T.; Correa, Alessandra A.; Alves, William F.; Leite, Fábio L.; Herrmann, Paulo S. P.
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 17/06/2011 EN
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A low-cost sensor array system for banana ripeness monitoring is presented. The sensors are constructed by employing a graphite line-patterning technique (LPT) to print interdigitated graphite electrodes on tracing paper and then coating the printed area with a thin film of polyaniline (PANI) by in-situ polymerization as the gas-sensitive layer. The PANI layers were used for the detection of volatile organic compounds (VOCs), including ethylene, emitted during ripening. The influence of the various acid dopants, hydrochloric acid (HCl), methanesulfonic acid (MSA), p-toluenesulfonic acid (TSA) and camphorsulfonic acid (CSA), on the electrical properties of the thin film of PANI adsorbed on the electrodes was also studied. The extent of doping of the films was investigated by UV-Vis absorption spectroscopy and tests showed that the type of dopant plays an important role in the performance of these low-cost sensors. The array of three sensors, without the PANI-HCl sensor, was able to produce a distinct pattern of signals, taken as a signature (fingerprint) that can be used to characterize bananas ripeness.

Synthesis and photooxidation of styrene copolymer bearing camphorquinone pendant groups

Husár, Branislav; Moszner, Norbert; Lukáč, Ivan
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 06/03/2012 EN
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(±)-10-Methacryloyloxycamphorquinone (MCQ) was synthesized from (±)-10-camphorsulfonic acid either by a known seven-step synthetic route or by a novel, shorter five-step synthetic route. MCQ was copolymerized with styrene (S) and the photochemical behavior of the copolymer MCQ/S was compared with that of a formerly studied copolymer of styrene with monomers containing the benzil (BZ) moiety (another 1,2-dicarbonyl). Irradiation (λ > 380 nm) of aerated films of styrene copolymers with monomers containing the BZ moiety leads to the insertion of two oxygen atoms between the carbonyl groups of BZ and to the formation of benzoyl peroxide (BP) as pendant groups on the polymer backbone. An equivalent irradiation of MCQ/S led mainly to the insertion of only one oxygen atom between the carbonyl groups of camphorquinone (CQ) and to the formation of camphoric anhydride (11) covalently bound to the polymer backbone. While the decomposition of pendant BP groups formed in irradiated films of styrene copolymers with pendant BZ groups leads to crosslinking, only small molecular-weight changes in irradiated MCQ/S were observed.

The total synthesis of D-chalcose and its C-3 epimer

Sun, Jun; Fan, Song; Wang, Zhan; Zhang, Guoning; Bao, Kai; Zhang, Weige
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 22/11/2013 EN
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We completed a new and efficient synthesis of D-chalcose (I) and the first synthesis of its C-3 epimer (I′) in nine steps with overall yields of 23% and 24%, respectively. The key steps in the sequence were the formation of the stereocenter on C3 via Grignard reaction, the introduction of the stereogenic center on C2 by Sharpless asymmetric dihydroxylation, the protection of the C1 and C2 hydroxy groups with tert-butyldimethylsilyl trifluoromethanesulfonate (TBSOTf), and the selective cleavage of the primary OTBS ether using catalytic DL-10-camphorsulfonic acid (CSA) in MeOH.

CSA Doped Poly(aniline-co-o-toluidine) and Dispersed Zinc Oxide Nanoparticles: a Promising Material for Photovoltaics

Mahudeswaran,Arunachalam; Manoharan,Devarajan; Chandrasekaran,Joseph; Vivekanandan,Janakiraman; Vijayanand,Pachanoor Subbaian
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
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Copolymerization of aniline and o-toluidine is achieved by chemical oxidative polymerization with equal molar ratio of monomers in the presence of hydrochloric acid and ammonium persulphate as an oxidant. The copolymer found to be more soluble in polar solvents such as NMP, DMF and DMSO. FTIR spectroscopy confirms the copolymer chemical structure. UV spectroscopy shows π to π* transition and excitonic transition of the copolymer film. The copolymer is doped with camphorsulfonic acid (CSA) in m-cresol and then zinc oxide nanoparticles are dispersed into the copolymer and spin coated on to a glass plate. The scanning electron microscope image shows the morphology of the copolymer matrix. X-ray Diffraction shows the characteristic peaks of CSA and zinc oxide. EDAX analysis confirms the presence of CSA and zinc oxide. The dispersion of zinc oxide nanoparticles show quenching property of photoluminescence indicating that the copolymer can be used in the opto-electronics.

Carbon Nanotube Mediated Reduction in Optical Activity in Polyaniline Composite Materials

In het Panhuis, Marc; Doherty, Kathie D; Sainz, Raquel; Benito, Ana M.; Maser, Wolfgang K.
Fonte: Conselho Superior de Investigações Científicas Publicador: Conselho Superior de Investigações Científicas
Tipo: Artículo Formato: 114511 bytes; application/pdf
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Optically active composite materials were prepared by in situ polymerization of aniline in the presence of multiwalled carbon nanotubes, followed by doping with (R)-(-)-10-camphorsulfonic acid. The reduction in circular dichroism intensity with increasing nanotube loading fraction is attributed to changes in the ratio of “free” polymer versus polymer interacting with carbon nanotubes. These changes are shown to correspond to a decreasing polyaniline stereoselectivity with increasing nanotube loading fraction; University of Wollongong internal funding. Australian Research Council. MEC: MAT2006-13167-C02-02 DGA-PIP021/2005; Peer reviewed

NSC4167; d-10-Camphorsulfonic acid

US National Cancer Institute
Fonte: Unilever Center for Molecular Informatics, Cambridge University Publicador: Unilever Center for Molecular Informatics, Cambridge University
Tipo: Outros Formato: 4981 bytes; 4821 bytes; chemical/x-cml; chemical/x-cml
EN_GB
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Submicrometric Fibrillar Structures of Codoped Polyaniline Obtained by Co-oxidation Using the NaClO/Ammonium Peroxydisulfate System: Synthesis and Characterization

Osorio-Fuente,Jorge Enrique; Gómez-Yáñez,Carlos; Hernández-Pérez,María de los Ángeles; Corea-Téllez,Mónica de la Luz
Fonte: Sociedad Química de México A.C. Publicador: Sociedad Química de México A.C.
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2013 EN
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Abstract A mixture of ammonium peroxydisulfate and sodium hypochlorite (NaClO) (co-oxidating system) were used to obtain polyaniline (PANi) doped with HCl and camphorsulfonic acid (CSA) (co-doping). The effect of HCl/CSA ratio added during polymerization on structure, morphology and electrical conductivity of the conducting polymer was investigated. When NaClO is used, the polymerization rate is substantially increased and the morphology changes from micrometric granular to nanometric fibrillar. CSA was used as complementary dopant but also to improve the solubility of PANi in common solvents. However, results suggest that quinone-like heterocycles containing carbonyl radicals as well as phenazine-type aromatic rings might be impeding an efficient doping in detriment of the conductivity.

Camphor Sulfonic Acid-hydrochloric Acid Codoped Polyaniline/polyvinyl Alcohol Composite: Synthesis and Characterization

Osorio-Fuente,Jorge Enrique; Gómez-Yáñez,Carlos; Hernández-Pérez,María de los Ángeles; Pérez-Moreno,Fidel
Fonte: Sociedad Química de México A.C. Publicador: Sociedad Química de México A.C.
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 EN
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A complementary dopant system formed by hydrochloric and camphor sulfonic (CSA) acids was used in the in-situ synthesis of a polyaniline (PANi)/polyvinyl alcohol (PVA) composite. The conductivity measurements showed that the use of CSA either as single dopant or codopant caused a decrement up to 2 orders of magnitude on the overall conductivity as well as an improvement on thermal stability. The PANi/PVA composites were characterized by spectro-scopic and thermal analysis. Conducting emeraldine salt formation was confirmed by UV-VIS and FTIR spectroscopy. Microstructure analysis was performed by SEM imaging.