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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Blendas condutoras elétricas obtidas a partir do látex de seringueira Hevea Brasiliensis com polianilina / Electrical conductive blends obtained using the rubber tree Hevea brasiliensis latex with polyaniline

Teruya, Marcia Yumi 28 March 2003 (has links)
É grande o interesse em combinar as propriedades mecânicas e elétricas de diferentes materiais poliméricos. Neste trabalho, filmes de Borracha Natural com camadas superficiais condutoras de polianilina (PANI) são preparados e caracterizados por diferentes técnicas. A PANI dopada foi depositada em ambos os lados do filme de borracha por polimerização química \"in situ\" da anilina a temperatura ambiente. O processo da polimerização da PANI \"in situ\" foi otimizado variando a concentração dos reagentes químicos com o objetivo de se obter uma camada de PANI com espessura desejada, boa adesão na borracha e que produzisse também aumento da condutividade elétrica na superfície. As amostras obtidas são caracterizadas usando-se Microscopia Eletrônica de Varredura, Microscopia Óptica, Difratometria de raios-X, análise por Calorimetria Diferencial de Varredura, análise Termo-Dinâmico-Mecânica, análise Termogravimétrica, Espectroscopia no FT-IR, Ensaio Mecânico e condutividade elétrica na superfície e no volume dos filmes preparados. Os resultados mostram que os filmes produzidos são do tipo multicamadas, pois não há uma interpenetração da PANI na borracha. A melhor condutividade e uniformidade é obtida com filmes preparados com três deposições, atingindo a ordem de 10-7 S/cm / The combination of properties of different polymeric materials in one sample is of great interest. In this work natural rubber films covered with a layer of conductive polyaniline (PANI) were prepared and studied by means of several experimental techniques. The doped PANI layer was deposited onto both rubber films surfaces by the \"in situ\" polymerization technique. The polymerization of PANI was performed at room temperature and the deposition process was optimized in order to obtain a PANI layer with an adequate thickness, good adhesion to the rubber and to promote the increase of its surface electric conductivity. Samples were characterized employing the scanning electron microscopy, optical microscopy, X-ray diffractometry, differential scanning calorimetry, thermo gravimetric analysis, dynamic mechanical thermal analysis, mechanical analysis and surface/volume electric conductivity. Results showed that the formed films consisted of a PANI layer that did not penetrated in the rubber. The better uniformity of deposition and maximum electric conductivity of the order of 10-7 S/cm was obtained on films that were prepared by deposition of three PANl layers
2

Blendas condutoras elétricas obtidas a partir do látex de seringueira Hevea Brasiliensis com polianilina / Electrical conductive blends obtained using the rubber tree Hevea brasiliensis latex with polyaniline

Marcia Yumi Teruya 28 March 2003 (has links)
É grande o interesse em combinar as propriedades mecânicas e elétricas de diferentes materiais poliméricos. Neste trabalho, filmes de Borracha Natural com camadas superficiais condutoras de polianilina (PANI) são preparados e caracterizados por diferentes técnicas. A PANI dopada foi depositada em ambos os lados do filme de borracha por polimerização química \"in situ\" da anilina a temperatura ambiente. O processo da polimerização da PANI \"in situ\" foi otimizado variando a concentração dos reagentes químicos com o objetivo de se obter uma camada de PANI com espessura desejada, boa adesão na borracha e que produzisse também aumento da condutividade elétrica na superfície. As amostras obtidas são caracterizadas usando-se Microscopia Eletrônica de Varredura, Microscopia Óptica, Difratometria de raios-X, análise por Calorimetria Diferencial de Varredura, análise Termo-Dinâmico-Mecânica, análise Termogravimétrica, Espectroscopia no FT-IR, Ensaio Mecânico e condutividade elétrica na superfície e no volume dos filmes preparados. Os resultados mostram que os filmes produzidos são do tipo multicamadas, pois não há uma interpenetração da PANI na borracha. A melhor condutividade e uniformidade é obtida com filmes preparados com três deposições, atingindo a ordem de 10-7 S/cm / The combination of properties of different polymeric materials in one sample is of great interest. In this work natural rubber films covered with a layer of conductive polyaniline (PANI) were prepared and studied by means of several experimental techniques. The doped PANI layer was deposited onto both rubber films surfaces by the \"in situ\" polymerization technique. The polymerization of PANI was performed at room temperature and the deposition process was optimized in order to obtain a PANI layer with an adequate thickness, good adhesion to the rubber and to promote the increase of its surface electric conductivity. Samples were characterized employing the scanning electron microscopy, optical microscopy, X-ray diffractometry, differential scanning calorimetry, thermo gravimetric analysis, dynamic mechanical thermal analysis, mechanical analysis and surface/volume electric conductivity. Results showed that the formed films consisted of a PANI layer that did not penetrated in the rubber. The better uniformity of deposition and maximum electric conductivity of the order of 10-7 S/cm was obtained on films that were prepared by deposition of three PANl layers
3

NOVEL ON-LINE TRUE STRESS-STRAIN-ELECTRICAL CONDUCTIVITYUNIAXIAL TENSILE STRETCHING SYSTEM AND ITS UTILITY ON ELECTRICALLYCONDUCTIVE POLYLACTIC ACID (PLA) NANOCOMPOSITES

Kwa, Teik Lim 18 May 2006 (has links)
No description available.
4

Optimisation de la conductivité électrique transverse de composites structuraux PAEK-fils submicroniques d'argent/fibres de carbone continues avec ensimage conducteur / Optimization of transverse electrical conductivity for structural composites PAEK–Silver nanowires / carbon fiber with electrically conductive sizing

Audoit, Jérémie 17 January 2017 (has links)
Ce travail propose une optimisation de la conductivité électrique transverse des composites structuraux matrice/fibres de carbone. L'influence de la fonctionnalisation électrique de l'ensimage sur la conductivité des composites est particulièrement étudiée. Des feuillets submicroniques d'argent (AgNpts) ont été élaborés en présence de citrate de sodium (TSC). Leur morphologie plane est particulièrement adaptée à une dispersion dans un ensimage. Les feuillets ont été dispersés dans une matrice modèle. Le seuil de percolation électrique des feuillets est déterminé à 5,9 %. Cette valeur est cohérente avec un facteur de forme modéré, compris entre 12 et 28. L'ensimage fonctionnalisé a ensuite été déposé sur une mèche de fibres de carbone, elle-même imprégnée par une matrice PAEK hautes performances. Avant imprégnation des fibres de carbone, des fils submicroniques d'argent ont été introduits dans la matrice PAEK. Des composites matrice-fils submicroniques d'argent/fibres de carbone avec ensimage conducteur ont été mis en œuvre. Leur conductivité électrique est élevée (7 S.m-1), alors que la fraction volumique en particules d'argent (fils et feuillets) est inférieure à 1 % en volume. / This PhD thesis deals with the optimization of transverse electrical conductivity of Thermoplastic Carbon Fiber Reinforced Polymer. The influence of an electrically conductive sizing has been investigated. Silver nanoplates (AgNpts) have been successfully synthesized by a soft chemical reduction, with trisodiumcitrate (TSC) as surfactant. Silver nanoplates have been dispersed into a model matrix, percolation threshold has been determined near 5.9 % in volume fraction. This value is consistent with their moderate aspect ratio (between 12 and 28). Size and morphology of silver nanoplates are suitable for their dispersion in the sizing. Carbon fiber has been coated with conductive sizing. Carbon fiber will be further impregnated by a PAEK thermoplastic matrix. A higher conductivity level has been achieved by introducing silver nanowires in the PAEK matrix. Structural composites consisting of matrix-silver nanowires / continuous carbon fiber sized with conductive sizing have been elaborated. Their electrical conductivity reached 7 S.m-1 for a total silver volume fraction of 1 %.vol.
5

Kan livscykelanalyser bistå riskvärderingen vid val av åtgärdsmetod? : En fallstudie vid ett område förorenat med klorerade lösningsmedel / Is it possible for life cycle analyzes to assist the risk assessment when choosing a remediation method? : A case study at a site contaminated with chlorinated solvents

Björnsdotter, Regina January 2021 (has links)
Hur kan livscykelanalyser bistå riskvärderingen vid val av åtgärdsmetod? I det här examensarbetet undersöktes hur resultaten från livscykelanalyser kan användas i beslutstödsverktyget SAMLA för förorenade områden för att bistå val av åtgärdsmetod vid Finspångs centraltvätt. Examensarbetet har genomförts i samarbete med Structor Miljö Öst AB. Livscykelanalyser har utförts för två olika typer av åtgärdsmetoder in situ, stimulerad anaerob reduktiv deklorering samt elektrisk konduktiv uppvärmning. Tidigare studier har visat att olika livscykelanalysmetoder ger olika resultat. Även den här studien bekräftar det. Därför bör inte resultat från olika metoder jämföras. Livscykelanalyser kompletterar SAMLA för förorenade områden väl. De procentuella förhållandena beräknades mellan åtgärdsmetodernas miljö- och klimatpåverkan. I värderingssteget i SAMLA bedöms åtgärdsalternativens påverkan i jämförelse med nollalternativet. En bedömning gjordes av respektive åtgärdsalternativ och korrigering av förhållandet mellan metoderna utfördes genom att samma procentuella förhållande som beräknats fram för miljöbelastningen respektive klimatpåverkan beräknades för värderingspoängen. Med stöd av livscykelanalyser samt riskvärdering bör efterbehandlingsmetoden stimulerad anaerob reduktiv deklorering väljas för Finspångs centraltvätt. / How can life cycle analyzes assist the risk assessment when choosing a remediation method? In this thesis, it was investigated how the results from life cycle analyzes can be used in the decision support tool SAMLA for contaminated sites to assist in the choice of remediation method at Finspång's Centraltvätt. The thesis has been carried out in collaboration with Structor Miljö Öst AB. Life cycle analyzes have been performed for two different types of in situ remediation methods, Enhanced Reductive Dechlorination and Electrical Conductive Heating. Previous studies have shown that different life cycle analysis methods lead to different results. This study also confirms this. Therefore, results from different methods should not be compared. Life cycle analyzes complement SAMLA for contaminated sites. The percentage ratios were calculated between the remediation methods' environmental and climate impact. In the valuation step in SAMLA, the impact of the remediation alternatives is assessed in comparison with the no action alternative. An assessment was made of the respectively remediation alternatives and a correction of the relationship between the methods was performed by calculating the same percentage ratio that was calculated for the valuation points of the environmental and climate impact. With the support of the life cycle analysis and the risk assessment the remediation method Enhanced Reductive Dechlorination should be chosen for Finspång's Centraltvätt.

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