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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

Aproveitamento de Carepa e E-cat no desenvolvimento de comp?sitos de polietileno reciclado e modificado com agentes oxidantes / Use of Scale e E-cat on the development of composites of recycled and modified polietilen with oxidizing agents.

Fraga, Isabel Matos 08 December 2010 (has links)
Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-08-18T17:45:44Z No. of bitstreams: 1 2010 - Isabel Matos de Fraga.pdf: 5201934 bytes, checksum: 6bbaeba09901aea4cbaa9f69dbb0402e (MD5) / Made available in DSpace on 2017-08-18T17:45:44Z (GMT). No. of bitstreams: 1 2010 - Isabel Matos de Fraga.pdf: 5201934 bytes, checksum: 6bbaeba09901aea4cbaa9f69dbb0402e (MD5) Previous issue date: 2010-12-08 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES, Brasil. / The researches on recycling of industrial wastes has been stepped up around the world to enhance the quality of the recycled product and provide greater efficiency of the productive system. The recycling of plastic materials has also grown in recent years, with Brazil improving its market position. In this way, this work aimed the development of composite materials using as a matrix, the low density polyethylene recycled (PEBDrec), chemical treated with oxidizing agents and, as fillers, E-cat and waste of scale. The PEBDrec was treated with oxidizing agent in order to cause modifications over its chemical structure and to improve compatibility with the residues of scale and E-cat. Were produced composites of PEBDrec treated with hydrogen peroxide (H2O2) and scale; PEBDrec treated with hydrogen peroxide and E-cat; PEBDrec treated with potassium permanganate (KmnO4) and scale and PEBDrec treated with potassium permanganate and E-cat. Were also obtained composites of PEBDrec untreated and mixed with scale or E-cat, to evaluate the action of the oxidizing agent in the compatibility between fillers that were used and the polymer matrix. The results obtained by the analysis of FTIR, XDR, TGA, SEM and mechanicals tests presented that the composites of PEBDrec treated with oxidizing agents showed a good interaction between the dispersed phase and the polymer matrix in comparison to composites PEBDrec without chemical treatment, and this compatibility was better for the lowest proportions. But this good interaction resulted in a decrease of thermal stability of composites in relation to the polymer matrix. It was also observed that the oxidizing agent KMnO4 was more effective in increasing the compatibility between the polymer and the E-cat, while the oxidizing agent H2O2 acted more strongly on increasing the compatibility between the polymer and scale. The composites of PEBDrec untreated, compared to the composites of PEBDrec treated with H2O2 and treated with KMnO4 , had a lower water absorption, indicating that chemical treatment was effective to modify the structure of the polymer, inducing the surface to a greater polarity, giving the chemical treated composites of PEBDrec a higher affinity to water. However a material more mechanical resistant was obtained just with the untreated polymer. The incorporation of the charges in the polymer matrix did not change the density of the material composites, indicating that despite of these materials be crystalline, they present low density, being possible to be used in civil construction. / As pesquisas sobre a reciclagem de res?duos industriais v?m sendo intensificadas em todo o mundo a fim de aumentar a qualidade do produto reciclado e propiciar maior efici?ncia do sistema produtivo. O reaproveitamento de materiais pl?sticos tamb?m tem crescido nos ?ltimos anos, com o Brasil melhorando seu posicionamento no mercado. Nesse sentido, essa disserta??o objetivou o desenvolvimento de materiais comp?sitos utilizando como matriz, o polietileno de baixa densidade reciclado (PEBDrec), tratado quimicamente com agentes oxidantes e como cargas, res?duos de Carepa e E-cat. O PEBDrec foi submetido a tratamento com agentes oxidantes com o objetivo de causar modifica??es na sua estrutura qu?mica e, propiciar uma melhoria na compatibilidade com os res?duos de carepa e E-cat. Foram produzidos comp?sitos de PEBDrec tratado com per?xido de hidrog?nio (H2O2) e carepa; PEBDrec tratado com per?xido de hidrog?nio e E-cat; PEBDrec tratado com permanganato de pot?ssio (KMnO4) e carepa e PEBDrec tratado com permanganato de pot?ssio e E-cat. Tamb?m foram obtidos comp?sitos de PEBDrec n?o tratado misturado a carepa ou E-cat, para avaliar a a??o do agente oxidante na compatibilidade entre a matriz polim?rica e as cargas utilizadas. Os resultados obtidos pelas an?lises de FTIR, DRX, TGA, MEV e ensaios mec?nicos mostraram que os comp?sitos de PEBDrec tratado com os agentes oxidantes apresentaram uma boa intera??o entre a fase dispersa e a matriz polim?rica em compara??o aos comp?sitos de PEBDrec sem o tratamento qu?mico, e essa compatibilidade foi melhor para as menores propor??es. Por?m, essa boa intera??o acarretou em uma diminui??o da estabilidade t?rmica dos comp?sitos, em rela??o a matriz polim?rica. Tamb?m foi poss?vel observar que o agente oxidante KMnO4 foi mais eficaz no aumento da compatibilidade entre o pol?mero e o E-cat, enquanto que o agente oxidante H2O2 atuou mais fortemente no aumento da compatibilidade entre o pol?mero e a carepa. Os comp?sitos de PEBDrec n?o tratado, em compara??o aos comp?sitos de PEBDrec tratados com H2O2 e tratados com KMnO4, apresentaram uma menor absor??o de ?gua, indicando que o tratamento qu?mico foi eficaz para modificar a estrutura do pol?mero deixando sua superf?cie com maior polaridade e conferindo aos comp?sitos de PEBDrec tratado quimicamente uma maior afinidade pela ?gua. Por?m um material mais resistente mecanicamente s? foi obtido com o pol?mero n?o tratado. A incorpora??o das cargas na matriz polim?rica praticamente n?o alterou a densidade desses materiais comp?sitos, indicando que apesar de eles serem materiais cristalinos, eles apresentam baixa densidade, sendo poss?vel suas aplica??es no ramo da constru??o civil.
2

O efeito do tratamento da atapulgita no desenvolvimento de comp?sito com o polietileno reciclado

Domingos, Luanda Gomes 24 August 2012 (has links)
Made available in DSpace on 2014-12-17T14:07:03Z (GMT). No. of bitstreams: 1 LuandaGD_DISSERT.pdf: 2374976 bytes, checksum: 5b49cc11854aa2427f22f38d6ff109c2 (MD5) Previous issue date: 2012-08-24 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The study aimed at the treatment of attapulgite for the development and characterization of composite recycled low density polyethylene - PEBD_rec embedded with natural attapulgite - ATP_NAT, sifted - ATP_PN and attapulgite treated with sulfuric acid - ATP_TR in different compositions (1, 3 and 5%) and compared with the PEBD_rec. The atapulgitas, natural, screened and treated, were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and determining the area specific surface (BET). The composites were characterized by thermogravimetry (TG), differential scanning calorimetry (DSC), Xray diffraction (XRD), torque rheometry, scanning electron microscopy (SEM) and traction. The composite PEBD_rec / ATP (natural, sieved and treated) were produced by mixing in the molten state in a single screw extruder matrix wire with subsequent reprocessing matrix tape. It was found that the screening of attapulgite not reduce the quantity of quartz and the acid treatment completely extracted dolomite aggregate impurities of the channels attapulgite, and increase their surface area. The addition of attapulgite in PEBD_rec acts as a catalyst, reducing the thermal stability of the polymer. The increased concentration of attapulgite, increases resistance and reduces the elongation at break and modulus of elasticity of the composite PEBD_rec / attapulgite / O trabalho teve como objetivo o tratamento da atapulgita para o desenvolvimento e a caracteriza??o de comp?sito de polietileno de baixa densidade reciclado PEBD_rec incorporado com atapulgita natural ATP_NAT, peneirada ATP_PN e com atapulgita tratada com ?cido sulf?rico ATP_TR, em diferentes composi??es (1, 3 e 5%) e comparado com o PEBD_rec. As atapulgitas, natural, peneirada e tratada, foram caracterizadas por difra??o de raios X (DRX), fluoresc?ncia de raios X (FRX), an?lise granulom?trica, microscopia eletr?nica de varredura (MEV), espectroscopia de energia dispersiva (EDS) e determina??o da ?rea superficial espec?fica (BET). Os comp?sitos foram caracterizados por an?lise termogravim?trica (TG), calorimetria diferencial explorat?ria (DSC), difra??o de raios X (DRX), reometria de torque, microscopia eletr?nica de varredura (MEV) e tra??o. Os comp?sitos de PEBD_rec /ATP (natural, peneirada e tratada) foram produzidos por meio de mistura no estado fundido em uma extrusora monorosca com matriz de fio com posterior reprocessamento com matriz de fita. Verificou-se que o peneiramento da atapulgita n?o reduziu o teor de quartzo e que o tratamento ?cido extraiu completamente a dolomita, impureza agregada nos canais da atapulgita, al?m de aumentar sua ?rea superficial. A adi??o da atapulgita no PEBD_rec atua como catalisador, reduzindo a estabilidade t?rmica do pol?mero. O aumento da concentra??o de atapulgita aumenta a resist?ncia e reduz o alongamento na ruptura e o m?dulo de elasticidade do comp?sito PEBD_rec / atapulgita
3

Obten??o de blendas polim?ricas a partir da reciclagem de sucatas de aparelhos celulares e polietileno de baixa densidade reciclado / Obtaining polymer blends from the recycling of scrap from cell phones and low density recycled polyethylene

Santos, C?ssia Thais Silva 20 July 2016 (has links)
Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-06-06T11:42:39Z No. of bitstreams: 1 2016 - C?ssia Thais Silva Santos.pdf: 4767415 bytes, checksum: 7078f4a6b3c6455dd65b9fa432b3a6ff (MD5) / Made available in DSpace on 2017-06-06T11:42:39Z (GMT). No. of bitstreams: 1 2016 - C?ssia Thais Silva Santos.pdf: 4767415 bytes, checksum: 7078f4a6b3c6455dd65b9fa432b3a6ff (MD5) Previous issue date: 2016-07-20 / It is crescent the research by new materials and methods for creating and same market insertion. Currently, among the various types of waste, electronic waste is considered obsolete in a very short time and require proper disposal. In Brazil, the last year, the reuse of plastic materials has increased. This study aimed to research the importance of mobile phones waste recycling, which have short pace of useful life used as reinforcements, no development of new materials containing recycled thermoplastic polymer (Low Density Polyethylene LDPE) and from the analyzes mechanical and dangerousness of these new materials, so justify the replacement of the importance of some materials with longer life time and easy recyclability, that form provides a reduction of environmental impacts caused by the generated waste were developed six blends of (Low Density Polyethylene recycled and PCABS carcasses - LDPErec/PC-ABS), with composition and grain size variation of cell granulometry housing and also an analysis of pure materials. The results obtained for analysis of diffraction X-ray, density, water absorption, hardness, scanning electronic microscopy and mechanical testing showed one low interaction between polymers, beyond the performance of the amorphous polymer morphology and hence the crystallinity mix, directly affected at the thermal and mechanical properties. As for the hazard analysis of the materials developed, they were not found excess levels of metal toxicants, the limits established by ABNT NBR 10004 / ? crescente a pesquisa por novos materiais e metodologias para a cria??o e inser??o dos mesmos no mercado. Atualmente, dentre os diversos tipos de res?duos, os res?duos eletroeletr?nicos tem aumentado exponencialmente, pois estes tem sido considerados obsoletos em um intervalo de tempo muito curto e necessitam de descarte adequado. No Brasil, nos ?ltimos anos, o reaproveitamento de materiais pl?sticos tamb?m tem aumentado. Neste contexto, este trabalho teve como objetivo pesquisar a import?ncia da reciclagem de res?duos de telefones celulares (carca?as), que possuem curto tempo de vida ?til, utilizados como refor?os, no desenvolvimento de novos materiais, contendo pol?mero termopl?stico reciclado (polietileno de baixa densidade ? PEBD) e, a partir das an?lises mec?nicas e da periculosidade destes novos materiais, justificar a import?ncia da substitui??o de alguns materiais por outros com maior tempo de vida ?til e de f?cil reciclabilidade, de forma que proporcione a redu??o dos impactos ambientais provocados com os res?duos gerados. Para tal, foram desenvolvidas 6 blendas de (Polietileno de baixa densidade reciclado e carca?as de PC-ABS - PEBDrec/PC-ABS), com varia??o da composi??o e granulometria das carca?as de aparelhos celular, e tamb?m a an?lise dos mat?rias puros. Os resultados obtidos pelas an?lises de difra??o de raios-X, densidade, absor??o de ?gua, dureza, microscopia eletr?nica de varredura e ensaios mec?nicos mostraram que a baixa intera??o entre os pol?meros, al?m da atua??o do pol?mero amorfo na morfologia e, consequentemente, na cristalinidade da mistura, afetou diretamente nas propriedades t?rmicas e mec?nicas. Quanto ? an?lise de periculosidade dos materiais desenvolvidos, n?o foram encontrados n?veis excedentes de metais t?xicos, conforme limites estabelecidos pela NBR ABNT 10004.

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