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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.
101

Incorporation de chaînes longues dans des alliages nanostructurés de polymères semi-cristallins : extrusion réactive, structure et propriétés mécaniques

Gani, Léa 23 November 2010 (has links) (PDF)
Des alliages nanostructurés, co-continus et thermodynamiquement stables sont synthétisés, par extrusion réactive d'un polyéthylène fonctionnalisé (FPE) et d'un mélange bimodal de petites et longues chaînes de polyamide 6 (PA). Les petites chaînes réagissent rapidement pour former beaucoup de copolymères, garantissant ainsi la nanostructuration. Le greffage et l'incorporation des longues chaînes a pour but d'introduire des enchevêtrements et des molécules liens entre les cristallites de PA. Deux extractions sélectives successives nous ont permis de caractériser les chaînes de copolymères greffés et les chaînes non-réagies de FPE et de PA. Les propriétés macroscopiques des alliages sont optimisées en jouant sur l'ordre d'introduction des constituants, les conditions d'extrusion et la composition de la phase de PA. L'étude structurale des alliages et des copolymères greffés précise l'organisation des chaînes dans les deux nanostructures. Les deux phases de FPE et PA cristallisent de manière confinée ce qui confère aux alliages des propriétés mécaniques remarquables. Aux faibles déformations et au dessus de la fusion du FPE, les alliages de composition 64/36 FPE/PA en masse, présentent une tenue thermomécanique d'une vingtaine de mégapascals. Les longues chaînes de PA jouent le rôle de chaînes liens entre les cristallites et améliorent la ductilité des alliages nanostructurés à haute température (allongement à la rupture 250% à 150°C). Des expériences de diffusion des rayons X couplées à de la microscopie électronique en transmission avant et après traction permettent de relier les évolutions structurales et morphologiques aux comportements mécaniques de ces alliages.
102

Solid phase microextraction (SPME) applied to studies of polyamide 6.6 long-term thermo-oxidation and In-plant recycling

Gröning, Mikael January 2002 (has links)
No description available.
103

Anionic polymarisation of caprolactam : an approach to optimising thr polymerisation condition to be used in the jetting process

Khodabakhshi, Khosrow January 2011 (has links)
The main aim of this project was to investigate the possibility of manufacturing 3D parts of polyamide (nylon or PA) 6 by inkjetting its monomer caprolactam (CL). The principle of this process was similar to the other rapid prototype (RP) and rapid manufacturing (RM) processes in which a 3D part is manufactured by layer on layer deposition of material. PA6 was used as the thermoplastic polymer in this work because of its good properties and also because PA6 can be produced by heating its monomer (i.e. plus catalyst and activator) in a short time. Two polymerisation mixtures of CL-catalyst (mixture A) and CL-activator (mixture B) are intended to be jetted separately using conventional jetting heads and polymerise shortly after heating. Anionic polymerisation of CL (APCL) was investigated in the bulk and on a smaller scale. Sodium caprolactamate (CLNa and C10) and caprolactam magnesium bromide (CLMgBr) were used as catalysts and N-acetylcaprolactam (ACL) and a di-functional activator (C20) were used as activators. The influence of polymerisation conditions was investigated and optimised. These were catalyst-activator concentration, polymerisation temperature and the influence of the polymerisation atmosphere. The physical properties (monomer conversion, crystallinity, and viscosity average molecular weight) of PA6 samples produced using each catalyst-activator combinations were measured and compared. Small scale polymerisation was carried out using a hotplate, by hot stage microscopy and using differential scanning calorimetry (DSC). The influence of heating strategy on small scale polymerisation was studied using DSC. The polymerisation mixture compositions were characterised using rheometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and optical microscopy to investigate their suitability in jetting for using the available jetting heads. It was shown that the combination of CLMgBr-ACL resulted in fast polymerisation which was not sensitive to moisture. The C10-C20 combination resulted in fast polymerisation with the best properties in a protected environment (nitrogen); however, the polymerisation was affected by moisture in air and the properties of polymer produced and rate of polymerisation decreased in air. Polymers produced using CLNa-ACL had the poorest properties and polymerisation did not occur in air. Material characterisation showed that micro-crystals of CLMgBr existed in CLMgBr-CL mixture at the jetting temperature (80oC) which were too large to be jetted. However, the mixture of C10 in CL could be partially jetted. The activator mixtures had similar properties to CL and were easily jetted. Drop on drop polymerisation was carried out by dripping droplets of mixtures A and B (at 80oC) on top of each other on a hotplate at the polymerisation temperature. Small scale polymerisation in a DSC showed that the monomer conversion increased with increase in polymerisation temperature from 140oC to 180oC and decreased from 180oC to 200oC. The crystallinity of the polymer produced in the DSC decreased with increase in polymerisation temperature. Hot stage microscopy produced evidence for simultaneous polymerisation and crystallisation processes on heating. Small scale polymerisation in an oven and analysed by DSC showed that increasing catalystactivator concentration resulted in increasing monomer conversion and decrease in crystallinity. Monomer conversion also increased with increase in polymerisation temperature and polymerisation time. Comparison between small scale and bulk polymerisations shows a good agreement between the two polymerisation rates. This shows that the polymerisation mechanism did not change significantly when the quantity of materials was reduced to less than 20mg. Finally, the polymerisation was carried out in a DSC after jetting C10-CL and C20-CL mixtures into a DSC pan using a jetting system, which was made in another work.
104

Vliv uzlu na pevnostní charakteristiku ploché šité smyčky při dynamickém zatížení / The impact of selected nodes on strength of flat slings under static load

Komorous, Miroslav January 2016 (has links)
Název práce Vliv vybraných uzlů na pevnost ploché šité smyčky při statickém zatížení. Cíle práce Cílem práce je posoudit pevnost plochých šitých smyček při statickém zatížení a vliv uzlů na snížení jejich pevnosti. Metody Zpracovávaná studie je designována jako dvoufaktorový experiment, při kterém zkoumáme vliv použitých uzlů na pokles nominální pevnosti u dvou typů smyček. Měření bylo prováděno na horizontálním trhacím stroji. Byly vybrány smyčky materiálu dyneema, polyamid a nejčastěji používané uzly (vůdcovský, osmičkový a devítkový). Výsledky Větší pevnosti dosáhly smyčky materiálu Polyamid 26,0 ± 1,1 kN a pevnosti v průřezu 1,3 kN na 1 mm2 . Smyčky materiálu dyneema dosáhli pevnosti 25,1 ± 0,9 kN a pevnosti v průřezu 1,3 kN na 1 mm2 . Na smyčce materiálu polyamid nejméně snižoval pevnost vůdcovský uzel. Smyčka praskla při tažné síle 17,4 ± 0,7 kN. U dyneemy to byl uzel osmičkový s hodnotami 12,2 ± 0,8 kN. Závěr Pro použití smyček v kombinaci s uzly bychom mohli doporučit materiál polyamid, kde uzel snižuje méně nominální pevnost než u dyneemy. Klíčová slova Horolezectví, sportovní lezení, dyneema, polyamid, trhová zkouška
105

CHLORAMINATION OF POLYAMIDE-BASED REVERSE OSMOSIS MEMBRANES IN THE PRESENCE OF HALIDES

Holly M Haflich (7010435) 13 August 2019 (has links)
<div>Polyamide based reverse osmosis (PA-RO) membranes are applied for the desalination of halide-containing waters such as seawater and brackish groundwater. They are the industry standard because of their high selectivity and ability to withstand a wide range of pH. However, one of their pitfalls is their propensity to undergo biofouling, which is deterioration due to biological growth. Biofouling is known to dramatically decrease membrane performance and increase energy consumption. In order to overcome biofouling, a disinfectant, typically free chlorine, is applied; however, free chlorine is known to react with the polyamide layer and result in further membrane deterioration and performance loss.<br></div><div>One topic that has garnered less attention is the application of chloramines and their interactions with the PA-RO membrane when applied as a biofouling control. Furthermore, the role of halides (e.g. chloride, bromide, and iodide) in the presence of chloramines must be further explored because they are known to react to form secondary species which are reactive toward PA-RO membranes. In Chapter 2, the PA based monomers benzanilide (BA) and N-Methyl-N-phenylbenzamide (N-CH<sub>3</sub>-BA) were used to model the PA layer. Monomers were exposed to halide containing waters and chloraminated with pre-formed NH<sub>2</sub>Cl over a wide range of pH. The decay and by-product formation after exposure were evaluated using HPLC-DAD, LC/MS, and/or GC/MS. Results indicated that pH of the system and bromide concentration controlled parent compound decay and brominated by-product formation, where low pH and high bromide concentrations led to the highest formation of brominated by-products.</div><div>In Chapter 3, commercially made PA-RO membranes (SWC4-LD) were chloraminated or chlorinated with and without halides over a wide pH range. Their performance was evaluated after exposure through flux experiments using a dead-end flow cell. Results indicated that exposure to free chlorine led to the greatest change in flux and monochloramine resulted in the smallest change in flux. During chloramination of the membranes, the reactors containing bromide led to further change in flux than the chloramine only conditions. This was likely due to formation of secondary species that were reactive toward the PA membrane. Furthermore, Chapter 4 summarizes overall research contributions from this work and proposes future work pertaining to this topic.</div>
106

"Propriedades da pasta de cimento portland com adições do copolímero Va/VeoVa e fibras de poliamida - estudo da interface fibra-matriz" / properties of va/veova copolymer modified cement pastes reinforced by polyamide fibers - study of interface fiber-matrix

Gomes, Carlos Eduardo Marmorato 19 September 2005 (has links)
O crescente emprego de compósitos fibrosos pela indústria da construção civil, nos últimos anos, comprova a eficiência da adoção de fibras como reforço de matrizes frágeis, a exemplo das pastas, argamassas e concreto de cimento Portland. Com o desenvolvimento de novas fibras sintéticas em suas propriedades, com custo similar ao das fibras comuns, faz-se supor que os produtos reforçados por essas fibras tenham grande avanço nos próximos anos. Especificamente em relação à fibra poliamida 6.6, constata-se que a mesma possui módulo de elasticidade menor em relação às matrizes de cimento Portland convencionais e pobre interface fibra/matriz. O incremento do módulo de elasticidade dessas fibras constitui grande desafio à industria têxtil devido às características de seu processo de fabricação, especificamente no que se refere à fiação, porém, isso não bastaria, havendo também a necessidade de aumentar sua aderência com as matrizes cimenticias. Dessa maneira, o presente trabalho buscou, pela adição de um copolímero redispersável (Va/VeoVa – vinil acetato/ vinil éster do ácido versático), tornar compatível o valor do módulo de elasticidade da matriz cimentícia ao das fibras de poliamida, além de proporcionar o desenvolvimento da zona de transição interfacial (ZTI), com melhor transferência de tensões entre a matriz de cimento modificada e as fibras de poliamida. Além desses objetivos, o emprego conjunto das tecnologias do cimento/concreto modificado com polímero (CMP) e do cimento/concreto reforçado com fibras (CRF) permitiu à presente pesquisa a exploração de sinergismos em xi propriedades como tenacidade, flexibilidade, resistência à tração e resistência ao impacto. Para caracterização desses compostos, foram realizados ensaios no estado fresco (mini-slump e tempo de pega), ensaios mecânicos (compressão axial, tração na flexão e impacto) e análises microscópicas, com intuito de analisar a interface fibra-matriz e a possível interação química entre o copolímero e a pasta de cimento Portland, por meio das técnicas de Termogravimetria (TG), Difratometria de Raios-X (DRX), Infravermelho por Transformada de Fourier (FT-IR), Porosimetria por Intrusão de Mercúrio (PIM), Microscopia Eletrônica de Varredura (MEV) com sistema de Espectroscopia por Dispersão de Energias (EDS) em amostras fraturadas e Microscopia Eletrônica de Varredura (MEV) por imagem de elétrons retroespalhados (BSEI) em amostras polidas. / In the last years, the increasing employment of fiber reinforced composites by the building industry shows the efficiency of the fibers as reinforcement of brittle matrices such as the pastes, mortars and Portland cement concrete. The development of the synthetic fibers characteristics with costs that are compatible with other fibers allows us to preview the biggest improvement of the products reinforced by these fibers. In relation to polyamide 6.6 specifically, it is verified that its elasticity modulus is slower compared with the value of conventional Portland cement matrices and poor interface fiber/matrix. The increase of elasticity modulus of these fibers is the biggest challenge for the textile industry due to characteristics of their fabrication, specifically to cord production. But it is not sufficient, because the adherence between polyamide fiber and Portland cement matrices needs to be improved. In this way, the goals of this present research were to make the elasticity modulus of the Portland cement matrix compatible with the elasticity modulus of polyamide fibers and to allow the development of the interfacial transition zone (ITZ) by the addition of the redispersible copolymer Va/VeoVa (acetate-versatate). Moreover, the use of both technologies, fiber reinforcement and polymermodified cement, allowed the present work to reach synergism in several properties, such as toughness, flexibility, traction strength and impact strength. The composites characterization was realized by tests in the fresh state, mechanical tests and microscopic analyses (Thermogravimetric Analyses, X-Ray Diffraction, Fourier-Transform Infrared, Mercury Intrusion Porosity and Scanning Electronic xiii Microscopy), which also had, as goals, to verify possible chemical interaction between copolymer and Portland cement paste.
107

Nanocompósitos de poliamida 6,6 reciclada reforçados com nanofibras de celulose para aplicação em peças automotivas / Nanocomposite of recycled polyamide 6,6 reinforced with cellulose nanofibers for application in automotive parts

Benaducci, Daiane 15 January 2014 (has links)
A busca é cada vez maior por parte das indústrias para encontrar alternativas de uso para seus materiais de descarte. Considerando as vantagens da aplicação da poliamida 6,6 reciclada (PA66Rec), material de descarte da empresa Rhodia Poliamida e Especialidades Ltda, o principal objetivo do trabalho foi a obtenção e caracterização de nanocompósitos a partir desse polímero sintético. Este material possui elevada temperatura de fusão e por esse e outros motivos, como o fato de possuírem mesma polaridade, as nanofibras de celulose (NFC) tornaram-se excelentes candidatas como reforço para essa matriz de poliamida 6,6. As poliamidas 6,6 são amplamente utilizadas na indústria automobilística, porém apesar desse grande interesse tecnológico nas mesmas, poucos estudos de compósitos poliméricos poliamida 6,6/celulose foram publicados. A fim de comparar os resultados obtidos foram preparados também nanocompósitos com matriz de poliamida obtida a partir de resina virgem (PA66) reforçados com NFC. Neste trabalho as NFC foram dispersas em ácido fórmico e a essa suspensão a matriz polimérica foi solubilizada. Foi considerado um branco desse pré-processamento, sem NFC, para comparação. As amostras foram então processadas por extrusão e moldagem por injeção. As propriedades mecânicas, térmicas e morfológicas foram caracterizadas utilizando ensaio de tração, calorimetria exploratória diferencial (DSC), análise termogravimétrica (TG) e microscopia eletrônica de varredura (MEV). Os resultados de TG confirmaram a menor estabilidade térmica das amostras com NFC em relação as sem NFC. Os resultados de DSC das amostras obtidas com a PA66Rec indicaram que o pré-processamento e a adição de 1 e 2% em massa de NFC não modificaram significativamente as temperaturas de fusão e cristalização. O grau de cristalinidade da amostra com maior teor de NFC diminuiu, entretanto as imagens de MEV mostraram as NFC bem ancoradas na matriz e os resultados de ensaio mecânico revelaram que a adição de 1 e 2% de NFC levou a um aumento de 10% do módulo elástico, em média. Para as amostras obtidas com a PA66 a adição de NFC levou a um aumento do grau de cristalinidade de 16 para 23%, em média, justificando o aumento de 15% do módulo elástico encontrado no ensaio mecânico de tração. As imagens de MEV para todas as amostras revelaram a boa incorporação da NFC nas matrizes, bem como a boa dispersão das mesmas. Tanto o pré-processamento como a incorporação das NFC não prejudicou o módulo elástico e a resistência máxima à tração, podendo indicar uma alternativa de uso para poliamida 6,6 reciclada, dependendo da aplicação final do material. / The search by industry to find alternative uses for its materials disposal is increasing. Considering the advantages application of recycled polyamide 6,6 (PA66Rec), disposal material of Rhodia Polyamide and Specialities Ltd company, the main objective of the work was to obtain and characterize nanocomposites from this synthetic polymer. This material has a high melting temperature and for this and other reasons, like the fact that they have the same polarity, the cellulose nanofibers (CNF) have become excellent candidates as reinforcement to the matrix polyamide 6,6. The polyamides 6,6 are widely used in the automotive industry, but despite this great technological interest in them, few studies of polymer composite polyamide 6,6/cellulose were published. In order to compare the results obtained nanocomposites were also prepared with polyamide matrix obtained from virgin resin (PA66) reinforced with NFC. In this work the CNF were dispersed in formic acid and the polymer matrix was solubilized in this suspension. It was considered a control sample without CNF for this preprocessing for comparison. Then, the samples were processed by extrusion and injection molding. The mechanical, thermal and morphological properties were characterized using tensile test, differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and scanning electron microscopy (SEM). The TG results confirmed the lower thermal stability of the samples with CNF compared with those without CNF. The DSC results obtained from the PA66Rec samples indicated that preprocessing and the addition of 1 and 2% mass fraction of CNF not significantly changes in melt and crystallization temperatures. The degree of crystallinity of the sample with a higher content of NFC decreased, however the SEM images showed the CNF well anchored in the matrix and the results of mechanical test showed that the addition of 1 and 2% NFC led to a 10% increase in the elastic modulus. For the samples obtained with PA66 the addition of CNF led to an increase in the degree of crystallinity of 16 to 23%, on average, justifying the 15% increase in the elastic modulus found in mechanical tests. The SEM images for all the samples showed good incorporation in the matrix of CNF and the good dispersion thereof. Any preprocessing such as the incorporation of NFC did not impair the elastic modulus and maximum tensile strength, and may indicate an alternative use for recycled polyamide 6,6, depending on the final application of the material.
108

Proposta de desenvolvimento de produtos de malha para gestantes utilizando a tecnologia seamless / A proposal for developing seamless knitted clothing for pregnant women

Mentone, Daniela Antunes Nolasco 02 April 2018 (has links)
Estudos têm sido realizados sobre artigos têxteis de diferentes fibras quanto ao desempenho em relação ao conforto e à funcionalidade. Porém, são raros os que tratam das malhas sintéticas com elastano, utilizando-se da tecnologia denominada seamless com uma proposta de vestuário exterior para gestantes. O objetivo deste trabalho foi desenvolver um protótipo de roupa para gestantes, fabricado a partir de fibras sintéticas de poliamida e poliéster (convencional e microfibra), utilizando a tecnologia seamless, que atendesse às necessidades de conforto e bem-estar deste grupo especial de usuárias. A metodologia utilizada para o desenvolvimento do protótipo foi o Design Thinking, que partiu da busca de conhecimento sobre as necessidades destas usuárias e da obtenção de depoimentos de trinta gestantes. Com o material coletado, identificou-se uma centralidade na necessidade de vestimentas que privilegiassem o conforto das mamas. Em seguida, foi desenvolvido um protótipo de blusa, com malha sintética contendo elastano, utilizando-se da tecnologia denominada seamless e com uma proposta de vestuário exterior para gestantes que dispensasse o uso de sutiã. Para verificar a validade da pesquisa um protótipo foi confeccionado e posteriormente foram fabricadas trinta e duas amostras com as matérias-primas selecionadas. Com os protótipos fabricados, foram realizados os seguintes ensaios físicos: densidade linear (ASTM D3776-96), determinação da espessura (ASTM D 1777 06), tendência à formação de snagging (JIS L 1058), determinação do alongamento e da elasticidade (JIS L 1018 02), gestão da umidade (AATCC Test Method 195 01) e determinação da absorção por capilaridade (JIS 1907 02). Também foi feito um teste de usabilidade com um grupo menor de gestantes, avaliando-se a funcionalidade, o conforto, a adequação das cores e o desejo de compra das peças. A partir da análise dos resultados dos ensaios físicos e do teste de experimentação das amostras, foi possível avaliar a eficiência dos produtos desenvolvidos e a possibilidade de um aprimoramento da solução encontrada. O protótipo se mostrou bem avaliado, sobretudo, no quesito sustentação das mamas. Entre as sugestões de adequações destacaram-se adequação do manequim ao tamanho P e a oferta de cores mais escuras que não evidenciem os mamilos, mais protusos na gestação, além da não retenção de umidade, uma vez que gestantes têm maior produção de suor. A tecnologia seamless agradou as gestantes, por dispensar costuras, causadoras de desconforto e alergias. A presente investigação apresenta o potencial de inspirar o prosseguimento de mais estudos integrando tecnologia têxtil, produção de moda e saúde / There have been a number of studies of textiles made up of different yarns regarding comfort and functionality. However, few have dealt with synthetic fabrics combined with spandex, using seamless technologies to provide outer garments for pregnant women. In order to assess the properties of items of clothing manufactured from different syntetic yarns, the experimental procedure was based on Design Thinking. During the first stage of the investigation, a semi structured interview was conducted with a group of thirty pregnant women. With the collected material, the need of clothes that favor comfort in the breast region was identified as a common issue. A prototype of a blouse with synthetic (polyamide and polyester) knitted fabric containing elastane was developed using the so-called seamless technology. The product was proposed as an outdoor garment for pregnant women, that could also dispense bra use. The prototype was then created and in order to check for validity, thirty-two samples were manufactured from the selected raw materials. The next stage dealt with following physical tests of the manufactured items of clothing: assessment of linear density (ASTM D 3776-96), thickness determination (ASTM D 1777 06), tendency to the formation of snagging (JIS L 1058), stretching determination (JIS L 1018-02), management of liquid moisture (AATCC test Method 195-01) and absorption for capillarity (JIS 1907 02). After that, a smaller group of pregnant women undertook a usability test in order to assess functionality, comfort, color suitability and purchase desirability of the garment. The prototype was well evaluated, above all, in the matter of breast support. Among suggestions highlighted for adjustments are the suitability of size S and the availability of darker colors so that nipples would not show. Seamless technoloty pleased the pregnant women in this study due to dispensing seams that often cause discomfort and allergies. The present research presents the potential to inspire the continuation of further studies integrating textile technoloty, fashion production and health
109

Blendas de rejeitos pós-industriais de filmes multicamadas de polietileno de baixa densidade (PEBD) e poliamida (PA6) / Blends of post-industrial waste from low density polyethylene multilayer films (LDPE) and polyamide (PA6)

Moreno, Diego David Pinzon 11 May 2015 (has links)
A reciclagem de resíduos sólidos tem se tornado cada vez mais relevante devido a alguns fatores como os impactos ambientais ocasionados com o seu descarte inadequado, ao rigor crescente de legislação específica e ao custo elevado para o gerenciamento apropriado destes resíduos. Na área de materiais poliméricos, os resíduos poliméricos podem ser de origem pósconsumo ou pós-industrial. Alguns rejeitos industriais poliméricos possuem características estruturais ou químicas que impossibilitam o seu reaproveitamento direto no processo que o gerou, como é o caso filmes multicamadas de polietileno de baixa densidade (PEBD) com poliamida 6 (PA6), usados para a produção de embalagens. O presente trabalho teve como objetivo central o reaproveitamento de rejeitos de filmes multicamadas de PEBD com PA6 na forma de blendas recicladas destes polímeros, fazendo uso de agente compatibilizante e variação na composição das blendas com a incorporação de PA6 virgem, a fim de produzir materiais com propriedades adequadas e custo compatível para a aplicação comercial. O desenvolvimento experimental foi dividido em três etapas que consistiram na avaliação do teor mais adequado de agente compatibilizante de fases da blenda (etapa 1), na determinação do comportamento das propriedades das blendas não compatibilizadas em diferentes composições de rejeito do filme multicamada e PA6 virgem (etapa 2) e na associação do uso de compatibilizante com variação das composições das blendas (etapa 3). A partir da execução experimental das atividades das etapas 1 e 2 do trabalho foi possível determinar que o teor de 2,5% do agente compatibilizante polietileno grafitizado com anidrido maleico (PEg- AM) é o mais adequado para compatibilizar as blendas poliméricas e que a maioria das suas propriedades das blendas apresentam um comportamento próximo ao aditivo linear, que leva em consideração somente as propriedades iniciais dos componentes poliméricos PEBD e PA6 isolados. Os diversos materiais gerados no desenvolvimento desta pesquisa apresentam desempenho de propriedades e custo de produção variáveis em função do teor de PA6 nas blendas, que podem viabilizar o uso deste material reciclado em aplicações comerciais específicas. / Recycling of solid waste has been an important issue due to some factors such as environmental damage caused by inappropriate discards, increasing rigor of specific legislation and high cost to the appropriate management of these waste. Polymeric waste can be originated from post-consume or post-industrial sources. Some polymeric waste have chemical or structural characteristics that difficult their direct reuse in the same productive process such as multilayer film of low density polyethylene (LDPE) and polyamide 6 (PA6), which are used for packing. The aim of this work has been the study the mechanical recycling of multilayer films of PEBD and PA6 as PEBD/PA6 blends with adequate properties and compatible cost for commercial applications. The experimental development has been performed in 3 steps, which correspond to evaluation of more adequate content of compatibilizer agent for interface of blends (step 1), determination of behavior of the properties of blends without compatibilizer agent on different compositions of waste form multilayer films (step 2) and production of blends with compatibilizer agent graphitized polyethylene with maleic anhydride (PE-g-MA) (step 3). Has been verified that the content of 2.5% of PE-g-MA is more adequate to be used in the compatibilization of recycled PEBD/PA blends and that the performance of the blends dependents of the content of PA6 in the material. The recycled materials have potential for commercial applications.
110

Caracterização e aplicabilidade de vidro de tela de LCD em matriz de Poliamida-6. / Use of glass from LCD screen in a Polyamide-6 matrix.

Massaro, Natalia 16 October 2013 (has links)
Monitores de LCD (Liquid Crystal Display) para computador são equipamentos eletroeletrônicos que têm como destino de descarte os aterros sanitários ou a incineração. O vidro presente nas telas de LCD pode ser reaproveitado como carga em matrizes poliméricas para melhorar as propriedades mecânicas das mesmas ampliando o seu mercado de aplicação. A Poliamida-6 (PA-6) é um dos mais importantes plásticos de engenharia comercializados, devido as suas ótimas propriedades mecânicas e térmicas. Porém, a PA-6 é higroscópica e apresenta baixa estabilidade dimensional. A adição de cargas inorgânicas além de elevar o módulo de elasticidade do polímero, eleva a estabilidade dimensional devido à redução da absorção de água. Desse modo, compósitos de PA-6 reforçados com cargas particuladas provenientes de telas de LCD e microesferas de vidro, cargas usualmente empregadas pela indústria, foram processados em laboratório em extrusora dupla-rosca. Os corpos de prova foram obtidos por injeção e suas propriedades foram avaliadas por ensaio de resistência à tração, ensaio de resistência ao impacto Izod, com e sem entalhe, microscopia eletrônica de varredura (MEV), calorimetria exploratória diferencial (DSC), análise termogravimétrica (TG) e difração de raios X (DRX). Os resultados indicaram que todas as cargas estudadas provocaram redução na resistência à tração da matriz de PA-6 e em sua resistência ao impacto, embora em alguns casos não tenham causado perdas significativas nos valores dos módulos de elasticidade. Embora as microesferas de vidro tenham mostrado desempenhos melhores quanto às propriedades mecânicas dos compósitos quando comparados àqueles que continham vidro particulado proveniente das telas de monitores LCD, o material reaproveitado apresenta potencial econômico e mecânico para ser usado como carga em matriz de PA-6, respeitadas as limitações mecânicas do compósito obtido. / The current destination of end of life (or defective) computer Liquid Crystal Displays (LCDs) is incineration or to be discarded in landfills. However, the inorganic glass of the LCDs can be used as a filler in polymer matrices. In particular, Polyamide-6 (PA-6) is one of the most important engineering polymers in the market, due to its remarkably good mechanical properties, although presenting high hygroscopicity and low thermal stability. The presence of an inorganic filler in PA-6s can elevate its elastic modulus, while improving its thermal stability. Therefore, in this study, several properties of PA-6 composites reinforced with LCDs particulate glass where compared to PA-6 composites reinforced with industrial glass spheres, a widespread industrial filler. Samples were prepared in a laboratory twin-screw extruder followed by injection molding, and were submitted to tensile strength test, Izod-notched impact resistance test, scanning electron microscopy, X-ray diffraction, and thermal analyses (TG and DSC). The results indicated that all studied fillers caused reduction in the tensile strength of the PA-6 matrix and in its impact strength, although, in some cases, did not cause any significant reduction in the values of the elastic modulus. Composites containing glass microspheres showed a better performance in terms of mechanical properties when compared to the ones containing particulate glass from LCD screens. Nevertheless, the recycled glass material exhibits mechanical and economic potential to be used as filler for PA-6 matrix, once the mechanical properties limitations of the obtained composites are adequately considered.

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