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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.
11

Desenvolvimento e caracteriza??o de comp?sitos poli(tereftalato de etileno) reciclado (PET reciclado) com flocos de vidro.

Moura, M?rcio Cleto Soares de 29 July 2011 (has links)
Made available in DSpace on 2014-12-17T14:07:07Z (GMT). No. of bitstreams: 1 MarcioCSM_TESE.pdf: 957118 bytes, checksum: 7c10d815ada900ecb0efde8936a6064e (MD5) Previous issue date: 2011-07-29 / The growing concern with the solid residues management, observed in the last decade, due to its huge amount and impact, has motivated the search for recycling processes, where these residues can be reprocessed to generate new products, enlarging the cycle of materials and energy which are present. Among the polymeric residues, there is poly (ethylene terephthalate) (PET). PET is used in food packaging, preferably in the bottling of carbonated beverages. The reintegration of post-consumer PET in half can be considered a productive action mitigation of environmental impacts caused by these wastes and it is done through the preparation of several different products at the origin, i.e. food packaging, with recycling rates increasing to each year. This work focused on the development and characterization mechanical, thermal, thermo-mechanical, dynamic mechanical thermal and morphology of the pure recycled PET and recycled PET composites with glass flakes in the weight fraction of 5%, 10% and 20% processed in a single screw extruder, using the following analytical techniques: thermogravimetry (TG), differential scanning calorimetry (DSC), tensile, Izod impact, Rockwell hardness, Vicat softening temperature, melt flow rate, burn rate, dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM). The results of thermal analysis and mechanical properties leading to a positive evaluation, because in the thermograms the addition of glass flakes showed increasing behavior in the initial temperatures of thermal decomposition and melting crystalline, Furthermore was observed growing behavior in the mechanical performance of polymer composites, whose morphological structure was observed by SEM, verifying a good distribution of glass flakes, showing difference orientation in the center and in the surface layer of test body of composites with 10 and 20% of glass flakes. The results of DMTA Tg values of the composites obtained from the peak of tan ? showed little reductions due to poor interfacial adhesion between PET and recycled glass flakes. / A crescente preocupa??o com a gest?o de res?duos s?lidos, observada na ?ltima d?cada, em virtude de sua enorme quantidade e impacto ambiental, tem motivado a busca por processos de reciclagem, onde estes res?duos podem ser reprocessados de modo a gerarem novos produtos, ampliando o ciclo dos materiais e energia neles contidos. Dentre os res?duos polim?ricos, destaca-se o poli(tereftalato de etileno) (PET). O PET ? utilizado em embalagens de alimentos, preferencialmente, no envase de bebidas carbonatadas. A reintegra??o do PET p?s-consumo ao meio produtivo pode ser considerada uma a??o mitigat?ria dos impactos ambientais causados por estes res?duos e j? ? realizada por meio da obten??o de diversos produtos diferentes ao da origem, ou seja, embalagens para alimento, com taxas de reciclagem crescente a cada ano. Este trabalho focou o desenvolvimento e a caracteriza??o mec?nica, t?rmica, termo-mec?nica, termo-din?mico-mec?nica e morfol?gica do PET reciclado processado e dos comp?sitos de PET reciclado com flocos de vidro na fra??o em peso de 5%, 10% e 20% processados em uma extrusora rosca simples, utilizando as seguintes t?cnicas de an?lise: termogravimetria (TG), calorimetria explorat?ria diferencial (DSC), tra??o uniaxial, impacto Izod, dureza Rockwel, temperatura de amolecimento Vicat, ?ndice de fluidez, taxa de queima, an?lise termo-din?mico-mec?nica (DMTA) e microscopia eletr?nica de varredura (MEV). Os resultados das an?lises t?rmicas e das propriedades mec?nicas conduziram a uma avalia??o positiva, pois nos termogramas as adi??es dos flocos de vidro mostraram comportamento crescente nas temperaturas inicial de decomposi??o t?rmica e de fus?o cristalina, al?m disso, observou-se comportamento crescente no desempenho mec?nico dos comp?sitos polim?ricos, cuja estrutura morfol?gica foi observada por MEV, verificando uma boa distribui??o dos flocos de vidro, apresentando diferen?a na orienta??o no centro e na camada superficial do corpo de prova dos comp?sitos com 10 e 20% de flocos de vidro. Nos resultados de DMTA os valores de Tg dos comp?sitos obtidos a partir do pico de tan ?, apresentaram pequenas redu??es, devido a pobre ades?o interfacial entre o PET reciclado e os flocos de vidro.
12

Processamento de compósitos de poli (tereftalato de etileno) reciclado reforçado com fibras de vidro

Mondadori, Nilcéa Mares da Luz 28 August 2007 (has links)
Neste trabalho, compósitos de PET sob a forma de flake e pós-condensado foram preparados com teores diferenciados de fibra de vidro (0, 20, 30 e 40%). Dois tipos de fibra foram utilizados: uma fibra com tratamento superficial a base de amino-silano e outra com tratamento a base de epóxi-silano. Os compósitos foram extrusados em extrusora mono-rosca, utilizando uma rosca de filete duplo com barreira, e em extrusora dupla-rosca interpenetrante co-rotacional. Após extrusão, os compósitos foram injetados a 120 ºC que, após várias temperaturas testadas, foi a temperatura que conferiu maior grau de cristalinidade do artefato final (acima de 30%). Os compósitos foram caracterizados quanto às propriedades mecânicas, térmicas e morfológicas. Os resultados mostraram que com a utilização de uma mono-rosca apropriada ao processamento de PET com fibra de vidro foi possível produzir compósitos com boas propriedades, comparáveis aos obtidos em extrusora dupla-rosca. Em relação aos tipos de PET utilizados, verificou-se que a massa molar da matriz polimérica, maior para o PET pós-condensado, teve uma pequena influência no desempenho das propriedades analisadas. Porém foi observado que os resultados foram indiferentes ao tratamento superficial das fibras testadas. Através da determinação do comprimento das fibras por análise óptica, e dos resultados experimentais do módulo de tração dos compósitos, pode-se constatar que nos compósitos injetados as fibras estão orientadas no sentido longitudinal à deformação. Com a microscopia eletrônica de varredura verificou-se que há sempre uma melhor distribuição e dispersão das fibras, com menores vazios à medida que aumenta o teor de fibras, corroborando os resultados mecânicos, sempre crescentes com o teor incorporado. A cristalinidade obtida nos corpos de prova moldados por injeção com o molde a uma temperatura de 120 ºC, aliada à presença da fibra de vidro, leva a um aumento na temperatura de distorção térmica (HDT). As análises de raios-X mostraram que com o aumento da quantidade da fibra, os picos cristalinos característicos do PET perdem definição, o que está associado à característica amorfa da fibra. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-15T17:17:43Z No. of bitstreams: 1 Dissertacao Nilcea Mondadori.pdf: 5475607 bytes, checksum: 3b5580025f75099d47502055cd80fde5 (MD5) / Made available in DSpace on 2014-05-15T17:17:43Z (GMT). No. of bitstreams: 1 Dissertacao Nilcea Mondadori.pdf: 5475607 bytes, checksum: 3b5580025f75099d47502055cd80fde5 (MD5) / In this work, flake and post-condensed PET composites of different glass fiber contents (0, 20, 30 and 40%) were prepared. Tow kinds of fibers were employed: one fiber having an amino silane-based surface treatment and another one having an epoxi silane-based surface treatment. The composites were extruded in a single-screw extruder with a barrier double-flight screw, and in a co-rotating interpenetrating twin-screw extruder. After extrusion the composites were injected at 120°C, this temperature being chosen after several tests indicating that it could promote the highest possible degree of crystallinity of the final product (higher than 30%). The composites were characterized as for mechanical, thermal and morphological features. Data indicate that by using a single-screw extruder proper to the processing of PET and fiber glass the properties of the obtained composites are fairly good, being comparable to those obtained from a twin-screw extruder. As for the types of PET utilized, it could be found that the molar mass of the polymeric matrix, larger for the post-condensed PET had some influence on the performance of the tested properties. On the other hand it could be observed that the surface treatment of the fibers does not influence the obtained data. Based on the optical analysis of the fiber length and the elastic modulus data it is possible to determine that the fibers of the injected composites are oriented longitudinally to the strain direction. With the aid of scanning electron microscopy (SEM), improvements in the distribution and dispersion of the fibers were always observed, with smaller voids as the fiber content increases, backing higher mechanical data as the incorporated fiber content is increased. Crystallinity resulting from injection-molded test specimens processed at 120°C, together with the presence of the glass fiber leads to a synergism in the heat distortion temperature (HDT). X-rays analyses indicate that at higher fiber content the composites show lower definition of the crystalline peaks, this being associated to the amorphous feature of the fiber.
13

Processamento de compósitos de poli (tereftalato de etileno) reciclado reforçado com fibras de vidro

Mondadori, Nilcéa Mares da Luz 28 August 2007 (has links)
Neste trabalho, compósitos de PET sob a forma de flake e pós-condensado foram preparados com teores diferenciados de fibra de vidro (0, 20, 30 e 40%). Dois tipos de fibra foram utilizados: uma fibra com tratamento superficial a base de amino-silano e outra com tratamento a base de epóxi-silano. Os compósitos foram extrusados em extrusora mono-rosca, utilizando uma rosca de filete duplo com barreira, e em extrusora dupla-rosca interpenetrante co-rotacional. Após extrusão, os compósitos foram injetados a 120 ºC que, após várias temperaturas testadas, foi a temperatura que conferiu maior grau de cristalinidade do artefato final (acima de 30%). Os compósitos foram caracterizados quanto às propriedades mecânicas, térmicas e morfológicas. Os resultados mostraram que com a utilização de uma mono-rosca apropriada ao processamento de PET com fibra de vidro foi possível produzir compósitos com boas propriedades, comparáveis aos obtidos em extrusora dupla-rosca. Em relação aos tipos de PET utilizados, verificou-se que a massa molar da matriz polimérica, maior para o PET pós-condensado, teve uma pequena influência no desempenho das propriedades analisadas. Porém foi observado que os resultados foram indiferentes ao tratamento superficial das fibras testadas. Através da determinação do comprimento das fibras por análise óptica, e dos resultados experimentais do módulo de tração dos compósitos, pode-se constatar que nos compósitos injetados as fibras estão orientadas no sentido longitudinal à deformação. Com a microscopia eletrônica de varredura verificou-se que há sempre uma melhor distribuição e dispersão das fibras, com menores vazios à medida que aumenta o teor de fibras, corroborando os resultados mecânicos, sempre crescentes com o teor incorporado. A cristalinidade obtida nos corpos de prova moldados por injeção com o molde a uma temperatura de 120 ºC, aliada à presença da fibra de vidro, leva a um aumento na temperatura de distorção térmica (HDT). As análises de raios-X mostraram que com o aumento da quantidade da fibra, os picos cristalinos característicos do PET perdem definição, o que está associado à característica amorfa da fibra. / In this work, flake and post-condensed PET composites of different glass fiber contents (0, 20, 30 and 40%) were prepared. Tow kinds of fibers were employed: one fiber having an amino silane-based surface treatment and another one having an epoxi silane-based surface treatment. The composites were extruded in a single-screw extruder with a barrier double-flight screw, and in a co-rotating interpenetrating twin-screw extruder. After extrusion the composites were injected at 120°C, this temperature being chosen after several tests indicating that it could promote the highest possible degree of crystallinity of the final product (higher than 30%). The composites were characterized as for mechanical, thermal and morphological features. Data indicate that by using a single-screw extruder proper to the processing of PET and fiber glass the properties of the obtained composites are fairly good, being comparable to those obtained from a twin-screw extruder. As for the types of PET utilized, it could be found that the molar mass of the polymeric matrix, larger for the post-condensed PET had some influence on the performance of the tested properties. On the other hand it could be observed that the surface treatment of the fibers does not influence the obtained data. Based on the optical analysis of the fiber length and the elastic modulus data it is possible to determine that the fibers of the injected composites are oriented longitudinally to the strain direction. With the aid of scanning electron microscopy (SEM), improvements in the distribution and dispersion of the fibers were always observed, with smaller voids as the fiber content increases, backing higher mechanical data as the incorporated fiber content is increased. Crystallinity resulting from injection-molded test specimens processed at 120°C, together with the presence of the glass fiber leads to a synergism in the heat distortion temperature (HDT). X-rays analyses indicate that at higher fiber content the composites show lower definition of the crystalline peaks, this being associated to the amorphous feature of the fiber.
14

Jämförelse av mekaniska egenskaper vid nötning samt miljöpåverkan av ren ny ull och återvunnen : En studie om fiberalternativ inom mattindustrin / Comparison of Mechanical Properties in Abrasion and Environmental Impact of Pure New Wool and Recycled PET : A Study on Fiber Alternatives in the Carpet Industry

Fredriksson, Sofia, Sandberg, Klara January 2024 (has links)
Användningen av ren ny ull i mattor medför både önskvärda mekaniska egenskaper och miljömässiga utmaningar. Ullproduktionen påverkar lokala ekosystem och det globala klimatet på grund av faktorer som överanvändning av kemikalier och otillräcklig djurvård. Dessutom står ullindustrin inför utmaningar relaterade till energi, vatten och kemikalieanvändning under framställningen av ren ny ull. Mattsektorn inom hemtextil är idag den största användaren av ren ny ull, och står för cirka 45 procent av den globala produktionen. FN:s globala mål nr 12.5 är en del av Agenda 2030 och syftar till att främja hållbar konsumtion och produktion. Specifikt handlar målet om att öka återvinningen och minska avfallet inom olika industrier, inklusive textilindustrin. Med FN:s mål samt miljöpåverkan från ren ny ull i åtanke, står mattindustrin inför ökad uppmärksamhet och efterfrågan på återvunna materiella alternativ. Även den omfattande produktionen och konsumtionen av ny plast utgör, likt ren ny ull, betydande miljömässiga hot, med miljontals ton plastavfall som genereras årligen. Hanteringen av plastavfall är en global oro och ett stort utvecklingsområde kopplat till FN:s globala mål. En typ av plastfiber som, även i återvunnet tillstånd, har goda förutsättningar inom hemtextilindustrin tack vare dess mekaniska egenskaper är återvunnen polyetentereftalat, rPET. Denna studie utforskar möjligheten att ersätta ren ny ull med rPET som huvudmaterial i vävda mattor för inomhusbruk, baserat på en balans mellan mekaniska egenskaper och miljöpåverkan. Genom att analysera både de mekaniska egenskaperna och miljöpåverkan av de två materialen, syftar studien till att ge insikt i vilket materialval som kan leda till minsta negativa miljökonsekvenser utan att kompromissa med produktkvalitet. Med hjälp av en kvantitativ ansats undersöker denna studie mekaniska egenskaper och miljöpåverkan av mattor tillverkade med huvudmaterial ren ny ull respektive rPET. Mekaniska tester, inklusive nötningshärdighet och färghärdighet vid nötning, genomförs enligt standardiserade metoder. Bedömningen av miljöpåverkan utförs med enligt Higg Index, ett verktyg med syftet att utvärdera miljöprestanda inom textilindustrin. Resultaten visar att mattor med rPET som huvudmaterial uppvisar överlägsen nötningshärdighet jämfört med de av ren ny ull. Samtidigt visar mattor med ren ny ull något högre färghärdighet vid nötning. Miljöanalysen visar att mattor med huvudmaterial rPET har en lägre total miljöpåverkan jämfört med mattor med huvudmaterial ren ny ull, under förutsättning att övriga parametrar kopplade till produktion och produkt förblir identiska. Slutligen understryker studien vikten av ett informerat materialval vid tillverkning av mattor. Även om rPET erbjuder förbättrade mekaniska egenskaper och minskad miljöpåverkan, beror valet mellan ull och rPET på specifika applikationskrav och hållbarhetsmål. Att modifiera övriga parametrar i mattans näringskedja kan minska miljöpåverkan i samma utsträckning utan att nödvändigtvis ändra det primära materialet. / The use of virgin wool in carpets presents both desirable mechanical properties and at the same time environmental challenges. Wool production affects local ecosystems and the global climate due to factors such as chemical overuse and inadequate animal care. Additionally, the wool industry faces challenges related to energy, water, and chemical usage during manufacture of virgin wool. UN Sustainable Development Goal 12.5, part of Agenda 2030, aims to promote sustainable consumption and production, specifically targeting increased recycling and waste reduction across industries, including textiles. With consideration for these goals and the environmental impact of virgin wool, the carpet industry faces growing attention and demand for recycled material alternatives. Similarly, the extensive production and consumption of new plastics pose significant environmental threats, with millions of tons of plastic waste generated annually. Plastic waste management is a global concern and a major development area linked to UN Sustainable Development Goals. One type of plastic fiber that maintains favorable mechanical properties even in recycled form, suitable for the home textile industry, is recycled polyethylene terephthalate (rPET). This study explores the possibility of replacing virgin wool with rPET as the primary material in woven indoor carpets, based on a balance between mechanical properties and environmental impact. By analyzing the mechanical properties and environmental impact of both materials, the study aims to provide insight into material choices that minimize negative environmental consequences without compromising product quality. Using a quantitative approach, this study examines the mechanical properties and environmental impact of carpets made with virgin wool and rPET as the main materials. Mechanical tests, including abrasion resistance and color fastness to abrasion, are conducted using standardized methods. Environmental impact assessment utilizes the Higg Index, a tool for evaluating environmental performance in the textile industry. The results indicate that carpets with rPET as the main material exhibit superior abrasion resistance compared to those with virgin wool. However, carpets with virgin wool demonstrate slightly higher color fastness to abrasion. The environmental analysis reveals that carpets with rPET as the main material have a lower overall environmental impact compared to those with virgin wool, assuming all other production and product parameters remain constant. In conclusion, this study emphasizes the importance of informed material selection in carpet manufacturing. While rPET offers improved mechanical properties and reduced environmental impact, the choice between wool and rPET depends on specific application requirements and sustainability goals. Modifying other parameters in the carpet's lifecycle can also reduce environmental impact to the same extent without necessarily changing the primary material.

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