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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.
261

Synthèse de nouveaux polyesters "verts" issus de ressources oléagineuses : application au renfort au choc du poly(L-lactide)

Lebarbe, Thomas 06 December 2013 (has links) (PDF)
Dans cette étude, plusieurs voies ont été explorées dans l'objectif d'utiliser des polyesters aliphatiques issus de ressources oléagineuses comme additifs pour le renfort au choc du poly(L-lactide) (PLLA). Dans un premier temps, des poly(ester-amide)s (PEAs) ont été synthétisés à partir de dérivés de l'huile de ricin. La relation structure-propriétés des PEAs obtenus a été clairement établie. La dispersion des PEAs (à différents taux) par extrusion à l'état fondu dans une matrice de PLLA a ensuite été effectuée, démontrant un accroissement de la résilience de ces mélanges en comparaison au PLLA seul. Une étude systématique reliant la structure d'une large gamme de polyesters aux propriétés des mélanges polyesters/PLLA, a ensuite été réalisée. Une forte dépendance de la résilience des mélanges polyesters/PLLA avec la cristallinité de l'additif polyester a été observée et quantifiée.Une amélioration des propriétés mécaniques du PLLA a également été obtenue par polymérisation par ouverture de cycle du lactide amorcée par un poly(acide ricinoléique) di-hydroxy téléchélique. Les copolymères triblocs ainsi formés ont été caractérisés d'un point de vue morphologique et mécanique.Enfin, un travail exploratoire utilisant l'ADMET comme méthode de polymérisation a été conduit, permettant la synthèse de nouveaux polymères prometteurs pour le renfort au choc du PLLA. Notamment, la copolymérisation de α,ω-diènes bio-sourcés a permis de mimer le polyéthylène basse densité linéaire, couramment employé pour le renfort au choc du PLLA.
262

Concreto celular polim?rico: influ?ncia na adi??o de res?duo de poli?ster insaturado termofixo

Melo, Guilherme F?bio de 23 March 2009 (has links)
Made available in DSpace on 2014-12-17T14:07:00Z (GMT). No. of bitstreams: 1 GuilhermeFM.pdf: 1361832 bytes, checksum: 90befe7961c07f2510ca8f988b71da6b (MD5) Previous issue date: 2009-03-23 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This work addresses the production of lightweight concrete building elements, such as plates, prefabricated slabs for pre-molded and panels of fencing, presenting a singular concrete: the Lightweight Concrete, with special properties such low density and good strength, by means of the joint use of industrial waste of thermosetting unsaturated polyesters and biodegradable foaming agent, named Polymeric Lightweight Concrete. This study covered various features of the materials used in the composition of the Polymeric Lightweight Concrete, using a planning of factorial design 23, aiming at studying of the strength, production, dosage processes, characterization of mechanical properties and microstructural analysis of the transition zone between the light artificial aggregate and the matrix of cement. The results of the mechanical strength tests were analyzed using a computational statistics tool (Statistica software) to understand the behavior and obtain the ideal quantity of each material used in the formula of the Polymeric Lightweight Concrete. The definition of the ideal formula has the purpose of obtaining a material with the lowest possible dry density and resistance to compression in accordance with NBR 12.646/92 (≥ 2.5 MPa after 28 days). In the microstructural characterization by scanning electron microscopy it was observed an influence of the materials in the process of cement hydration, showing good interaction between the wrinkled face of the residue of unsaturated polyesters thermosetting and putty and, consequently, the final strength. The attaining of an ideal formula, given the Brazilian standards, the experimental results obtained in the characterization and comparison of these results with conventional materials, confirmed that the developed Polymeric Lightweight Concrete is suitable for the production of building elements that are advantageous for construction / Neste trabalho ? abordada a aplica??o da tecnologia dos concretos leves ? produ??o de elementos construtivos, tais como placas pr?-fabricadas para lajes pr?-moldadas, pain?is de veda??o e pe?as pr?-moldadas, e ao desenvolvimento de um concreto celular com propriedades especiais de baixa densidade e boa resist?ncia mec?nica, em fun??o da utiliza??o conjunta de res?duo industrial de poli?ster insaturado termofixo (PIT) e espuma biodegrad?vel incorporadora de ar, denominado de Concreto Celular Polim?rico (CCP) . O estudo abrangeu diferentes tra?os dos materiais empregados na composi??o do CCP, sendo utilizado um planejamento fatorial 23, para an?lises dos processos de dosagem e produ??o, caracteriza??o das propriedades mec?nicas, bem como an?lises microestruturais da zona de transi??o entre o agregado artificial leve (PIT) e a matriz de cimento. Os resultados dos testes de resist?ncia mec?nica foram analisados utilizando-se uma ferramenta computacional de estat?stica (Statistica Software) para compreens?o do comportamento e obten??o da concentra??o ideal de cada material utilizado na formula??o do CCP. A defini??o da f?rmula ideal teve como finalidade a obten??o de um material com a menor densidade a seco poss?vel e resist?ncia ? compress?o que atendesse ? norma NBR 12.646/92 (≥ 2,5 MPa aos 28 dias). Na caracteriza??o microestrutural por microscopia eletr?nica de varredura, observou-se a influ?ncia dos materiais no processo de hidrata??o do cimento, onde constatou-se boa intera??o entre o res?duo de PIT, cuja face ? enrugada, e a pasta de cimento. A obten??o da formula??o de um novo material que atende ? norma brasileira, os resultados experimentais obtidos nas caracteriza??es e compara??o desses resultados com materiais convencionais, comprovaram que o Concreto Celular Polim?rico desenvolvido ? adequado ? produ??o de elementos construtivos que apresentam vantagens quando aplicados ? constru??o civil
263

Homogeneous catalysts for the synthesis of oxygenated polymers

Thevenon, Arnaud January 2017 (has links)
This thesis describes the synthesis and characterisation of novel mono and dinuclear homogenous [Zn(II)] and [In(III)] metal complexes. Their applications as catalysts for CO<sub>2</sub>/epoxide or epoxide/anhydride ring opening copolymerisation and lactide ring opening polymerisation to generate polycarbonates and polyesters, respectively, are also reported. Chapter 3 reports the first indium phosphasalen catalysts for CO<sub>2</sub>/cyclohexene oxide ring opening copolymerization. The catalysts are active at 1 bar pressure of CO<sub>2</sub> and are most effective without any co-catalyst. It is also possible to use the complexes to isolate and characterise the key intermediates in the catalytic cycle. Kinetic and spectroscopic analyses show that polymerisation proceeds via a rare cis-mononuclear coordination- insertion mechanism. Chapter 4 describes a series of mono and dinuclear zinc macrocycle catalysts with very high activities for the racemic lactide ring opening polymerisation. In most cases, the dinuclear zinc catalysts significantly out-perform the mono-zinc homologue. In addition, kinetic and spectroscopic investigations suggest a role for the ligand conformation in mediating rate. The catalysts perform very well under immortal conditions and operate at low catalyst loading, whilst conserving high activities. Chapter 5 presents four dinuclear zinc acetate salen catalysts for the ring opening copolymerisation of CO<sub>2</sub>/cyclohexene oxide and phthalic anhydride/cyclohexene oxide. The catalysts show moderate activities for CO<sub>2</sub>/epoxide copolymerisation but are highly active for epoxide/anhydride copolymerisation. Structure/activity relationship studies reveal that the more flexible and electron donating ligand displays the highest activity. Poly(ester-b-carbonate)s are also afforded using the most active catalyst in terpolymerisations of anhydride/epoxide/CO<sub>2</sub>.
264

Design and characterization of thermally-induced shape memory polymers

Wang, Kaojin 01 1900 (has links)
No description available.
265

Chemical and physical changes in PET fibres due to exhaust dyeing : Issues in thermo-mechanical recycling of dyed PET textiles

Lindström, Frida January 2018 (has links)
Polyethylene terephthalate (PET) is the most used fibre in the textile industry. PET is also used in other products, e.g. soft-drink bottles and food packaging. Approximately 60% of the globally produced PET is intended for production of textile fibres and the demand for polyester fibres have steadily increased over the last decade. Yet, most of the recycled PET fibres are produced from discarded bottles and not discarded textiles even though the generation of textile waste is increasing year by year. The importance of finding efficient recycling routes for discarded PET textiles is obvious. In thermo-mechanical recycling the thermoplastic characteristic of PET is utilized to re-melt and re-form PET waste into new valuable products. Today, this is used for bottle-to-fibre recycling but not for fibre-to-fibre recycling. The main research question asked in this Master thesis is if the process of exhaust dyeing compromise the possibility to recycle PET textiles through remelt spinning. It is believed that PET degradation through hydrolysis may occur during dyeing. The degradation behaviour of PET has been widely studied. However, degradation during exhaust dyeing has not been investigated.   The process parameters temperature, time and number of dyeing cycles have been investigated. Also, possible effects of different auxiliary chemicals have been studied. Dyeing and characterisation of two PET fabrics with filaments of different titer was performed in order to investigate if the filament titer is also a parameter to consider.   Tensile testing and surface characterisation through demand absorbency test showed that the filament titer seems to affect how the tensile and moisture related properties change due to dyeing. Differential scanning calorimetry showed that the crystallisation rate is affected by the dyeing process. This can be an effect of formation of shorter PET chains during dyeing. The auxiliary chemicals have been shown to be the most critical factor in changes of the crystallisation behaviour. Fourier-Transform infrared spectroscopy indicated that chain scission has occurred during dyeing.   The results have shown that the exhaust dyeing process causes changes in tensile properties, moisture related properties, degree of crystallinity as well as crystallisation behaviour. DSC and FTIR results indicate chain scission. Based on the results it cannot be concluded if the changes are large enough to compromise the possibility to recycle PET textiles thermo-mechanically. Further research is required in order to correlate the observed changes with possible problems in thermomechanical recycling of dyed PET textiles.
266

Desenvolvimento e an?lise de material comp?sito a base de penas de frango (fibras de queratina-KF) e matriz de poli?ster insaturado

Galv?o, Alcione Olinto 26 August 2011 (has links)
Made available in DSpace on 2014-12-17T14:58:13Z (GMT). No. of bitstreams: 1 AlcioneOG_DISSERT.pdf: 4986234 bytes, checksum: d81c2eeeb91a55690b1f5b9671a9a5e3 (MD5) Previous issue date: 2011-08-26 / Use of natural fibres as a reinforcement material in the manufacture of composites show a series of advantages: availability, biodegradability, low weight and regeneration in relation to synthetic fibres, thus justifying its utilization. In the present research work, composites were developed with chicken feathers (KF), using unsaturated polyester resin as matrix, for diversified applications, mainly in the furniture/timber industry.At present, in Brazil the chicken feathers are used as part of the animal feed, even though this material possesses low aggregated value. The chicken feathers are hollow, light and resistant. After washing with water at room temperature, a part of the chicken feathers were treated with 2% NaOH. Composites were manufactured using treated and untreated chicken feathers with unsaturated orthothalic polyester resin and 1% peroxide as catalyser, obtained in the commerce. Samples with size 150x25x3 mm for mechanical tests were cut by laser in the composite plate. Mechanical analyses were carried out in the Laborat?rio de Metais e Ensaios Mec?nicos UFRN. All the analyses were in accordance with ASTM standards. SEM analyses were also carried out on the samples.In the analyses of the results obtained, it was observed that the composites made with untreated chicken feathers showed better results (Traction 11.406 MPa and 9.107 MPa Bending 34.947 and 20.918 MPa for samples with and without treatment respectively) compared to the composite with treated feathers. Very low values of the water absorption results, evidenced the impermeability characteristic of the feathers. From the SEM images, the structure, fracture and the fibre/matrix adsorption can be evidenced. In the flammability test, it was observed that despite the feathers having sulfur as a constituent, natural inhibitor of flame, no burning support of the composites, because the manufacturing process of the composite / O uso de fibras naturais como refor?o em comp?sitos apresenta uma s?rie de vantagens: abund?ncia, biodegradabilidade, baixo peso e regenerabilidade em rela??o ?s fibras sint?ticas, justificando sua utiliza??o. Na presente pesquisa foram desenvolvidos comp?sitos com penas de frango (KF), utilizando resina de poli?ster n?o-saturado como matriz. Atualmente, no Brasil, as penas de frango s?o utilizadas como parte de ra??o animal, por?m este produto possui um baixo valor agregado. As penas s?o um material oco, leve e resistente. Ap?s a lavagem com ?gua em temperatura ambiente uma parte das penas foi tratada com 2% de NaOH. Foram fabricados dois comp?sitos, um com as penas tratadas e outro sem tratamento, usando o processo de molde fechado por compress?o, utilizando a resina de poli?ster ortoft?lica e 1% de per?xido MEK (per?xido de metil etil cetona) como iniciador, adquiridos no com?rcio local. As amostras com 150x25x3 mm de tamanho para os ensaios mec?nicos foram cortadas a laser na placa do comp?sito. Os ensaios de tra??o e flex?o em tr?s pontos foram realizados no Laborat?rio de Metais e Ensaios Mec?nicos - UFRN. Todas as an?lises estavam de acordo com as normas da ASTM. As amostras resultantes dos ensaios mec?nicas foram avaliadas no MEV. Com base nas observa??es dos resultados nos ensaios mec?nicos, (Tra??o 11,2 Mpa e 8,3 Mpa; Flex?o 34,9 Mpa e 22,9 MPa para as amostras sem e com tratamento respectivamente) observou-se que os comp?sitos refor?ados com as penas sem tratamento apresentaram um melhor comportamento quando foram expostos a carregamentos tanto de tra??o quanto de flex?o. O ensaio de absor??o evidenciou nos valores de absor??o de ?gua, uma das caracter?sticas da prote?na existente nas penas, a queratina, a sua capaciade de impermiabiliza??o a ?gua. Nas imagens do MEV foi poss?vel verificar a estrutura da pena, as regi?es de ruptura do comp?sito e a ades?o fibra/matriz. No ensaio de inflamabilidade, observou-se que apesar das penas terem como constituinte o enxofre, inibidor natural de chama, n?o houve a susten??o da queima nos comp?sitos, devido o processo de fabrica??o do comp?sito
267

Estudo comparativo das propriedades mec?nicas em comp?sitos da fibra modal e poliester

Silva, Jo?o Paulo Melo da 14 March 2012 (has links)
Made available in DSpace on 2014-12-17T14:58:14Z (GMT). No. of bitstreams: 1 JoaoPMS_DISSERT.pdf: 2368005 bytes, checksum: d7875a294c5267dc99db89f3b20a7106 (MD5) Previous issue date: 2012-03-14 / In the present work, three composites with distinct reinforcements (polyester, modal e polyester + modal), all if a unsaturated orthophthalic polyester resin as matrix were used, in order to conduct a comparative study by mechanical tests and water absorption. The fibre mats were prepared in a mat preparatory by immersion developed in the Textile Engineering Laboratory. The composites were manufactured using a closed mould process by compression using an unsaturated orthophthalic polyester resin as matrix and 1% MEK (methyl ethyl ketone peroxide) as an initiator. In each composite twelve samples with the dimensions of 150x25x3 mm were cut randomly for the mechanical analysis (tension x extension, three points bending and water absorption and Scanning Electron Micsroscopy). The mechanical tests were carried out in the Laborat?rio de Metais e Ensaios Mec?nicos UFRN . All the analyses were carried out according to the ASTM norms. The resultant samples from the mechanical analysis were subjected for the Scanning Electron Microscopy analysis. Based on the results obtained, it was observed that the reinforced composite with two fibres (modal + polyester) presented better results in comparison to the other two composites both in the tension/extension as well on the three point bending tests. In the water absorption test, it was possible to observe an equilibrium in the water absorption by the modal and polyester composite, due to the union of the two fibres. In the SEM images, the regions of rupture in the composites as well as the adsorption between the fiber and the matrix could be observed / No presente trabalho foram fabricados tr?s comp?sitos com refor?os distintos (poli?ster, modal e poli?ster + modal), todos com uma matriz de resina de poli?ster ortofit?lico n?o saturado, com o objetivo de realizar um estudo comparativo atrav?s de ensaios mec?nicos e absor??o d ?gua. As mantas de fibras foram preparadas num preparador de manta por imers?o desenvolvido no Laborat?rio de Engenharia T?xtil da UFRN. Os comp?sitos foram fabricados usando o processo de molde fechado por compress?o, utilizando a resina de poli?ster ortoft?lica e 1% de per?xido MEK (per?xido de metil etil cetona) como iniciador. Em cada comp?sito foram cortadas doze amostras aleatoriamente, com as dimens?es 150x25x3 mm, para avalia??o atrav?s de ensaios mec?nicos (resist?ncia ? tra??o e ? flex?o, absor??o d agua e microscopia eletr?nica de varredura). Os ensaios de tra??o e flex?o em tr?s pontos foram realizados no Laborat?rio de Metais e Ensaios Mec?nicos - UFRN. Todas as an?lises estavam de acordo com as normas da ASTM. As amostras resultantes dos ensaios mec?nicas foram avaliadas no MEV. Com base nos resultados dos ensaios mec?nicos, observou-se que o comp?sito refor?ado com as duas fibras em conjunto (poli?ster+modal) apresentou um melhor comportamento quando foram expostos a carregamentos tanto de tra??o quanto de flex?o. No ensaio de absor??o d agua foi poss?vel observar um equilibribio na absor??o de umidade do comp?sito com modal e poli?ster, devido a uni?o das duas fibras. Nas imagens do MEV foi poss?vel ver as regi?es de ruptura do comp?sito e a ades?o entre a fibra e a matriz
268

Desenvolvimento de t?xteis t?cnicos para refor?o de comp?sitos polim?ricos

Lima, Jos? Henrique Batista 02 May 2012 (has links)
Made available in DSpace on 2014-12-17T14:58:15Z (GMT). No. of bitstreams: 1 JoseHBL_DISSERT_PARCIAL.pdf: 2505963 bytes, checksum: 1b82ec8a8147b2b7e13d0af6880855f0 (MD5) Previous issue date: 2012-05-02 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Materials denominated technical textiles can be defined as structures designed and developed with function to fulfill specific functional requirements of various industrial sectors as are the cases of the automotive and aerospace industries. In this aspect the technical textiles are distinguished from conventional textile materials, in which the aesthetic and of comfort needs are of primordial importance. Based on these considerations, the subject of this dissertation was established having as its main focus the study of development of textile structures from aramid and glass fibers and acting in order to develop the manufacture of composite materials that combine properties of two different structures, manufactured in an identical operation, where each structure contributes to improving the properties of the resulting composite material. Therefore were created in laboratory scale, textile structures with low weight and different composition: aramid (100%), glass (100%) and aramid /glass (65/35%), in order to use them as a reinforcing element in composite materials with polyester matrix. These composites were tested in tension and its fracture surface, evaluated by MEV. Based on the analysis of mechanical properties of the developed composites, the efficiency of the structures prepared as reinforcing element were testified by reason of that the resistance values of the composites are far superior to the polyester matrix. It was also observed that hybridization in tissue structure was efficient, since the best results obtained were for hybrid composites, where strength to the rupture was similar to the steel 1020, reaching values on the order of 340 MPa / Os materiais denominados t?xteis t?cnicos podem ser definidos como estruturas projetadas e desenvolvidas com a fun??o de atender a requisitos funcionais espec?ficos de diversos setores da ind?stria, caso da ind?stria automotiva e aeroespacial. Nesse aspecto, distinguem-se dos materiais t?xteis convencionais, nos quais as necessidades est?ticas e de conforto t?m import?ncia primordial. Com base nessas considera??es, o tema dessa disserta??o foi estabelecido tendo como enfoque principal o estudo do desenvolvimento de estruturas t?xteis a partir de fibras de aramida e de vidro, atuando no sentido de elaborar a fabrica??o de materiais comp?sitos que combinem propriedades de duas estruturas diferentes, fabricadas em uma mesma opera??o, onde cada estrutura contribui para melhoria das propriedades do material comp?sito resultante. Para tanto foram desenvolvidas em escala laboratorial estruturas t?xteis de baixa gramatura e composi??o diferenciada de aramida (100%), vidro (100%) e aramida/vidro (65/35%) para utiliza??o como elemento refor?ante em comp?sitos com matriz de poli?ster. Os comp?sitos produzidos foram ensaiados em tra??o e sua superf?cie de fratura avaliada por MEV. Com base nas analises das propriedades mec?nicas dos comp?sitos desenvolvidos, observou-se a efici?ncia das estruturas ou elaboradas como elemento refor?ante tendo em vista que os valores de resist?ncia dos comp?sitos foram muito superiores ? matriz de poli?ster. Tamb?m foi observado que a hibridiza??o na estrutura dos tecidos foi eficiente, uma vez que os melhores resultados obtidos foram para os comp?sitos h?bridos, onde a resist?ncia na ruptura foi semelhante ? do a?o 1020, atingindo valores na ordem de 340 MPa
269

Fabricação de microcanais por moldagem em poliéster a partir de matriz de silício e pela utilização de toner como resiste para corrosão de vidro / Manufacture microchannel polyester molding from silicon matrix and by the use of toner as resistant to glass corrosion

Heron Dominguez Torres da Silva 10 August 2001 (has links)
A área de microfabricação de dispositivos de interesse em química analítica tem se expandido muito ao longo dos últimos anos. Uma série de produtos e processos tem sido proposta, tendo como base as tecnologias da área de microeletrônica. Muito destes processos são bastante sofisticados, estando além das necessidades para produção de alguns dispositivos relativamente simples e que são bastante úteis para a química analítica. Este é o caso, por exemplo, dos microcanais para implementação de sistemas eletroforéticos ou micro sistemas em fluxo. Neste contexto, surge a proposta deste trabalho, qual seja desenvolver processos e produtos de interesse nesta área. Esse objetivo foi alcançado pelo desenvolvimento de dois processos: um para produção de microcanais em resina de poliéster através de moldagem e outro de corrosão de vidro utilizando toner de impressora laser como resiste. O primeiro partiu de fotolito para produção de molde em silício através de processo de corrosão por plasma de SF6. Peças de resina de poliéster isoftálica são produzidas por polimerização sobre este molde. Para garantir a desmoldagem não traumática e boa reprodução de detalhes, foi incorporado óleo de silicone durante a preparação da resina. Com este procedimento, foi possível obter canais com 14,0 &#181;m de profundidade e irregularidades superficiais de 1,4 &#181;m para um molde com 15,3 &#181;m de elevação e 0,5 &#181;m de irregularidades superficiais. Com o uso de uma manta flexível de silicone como contraparte, foi possível gerar microcanais cuja altura foi avaliada como sendo da ordem de 5 a 7 &#181;m. Esta avaliação foi conseguida através de medida de condutância após o preenchimento do microcanal com solução de KCl. No segundo processo, toner de impressora laser foi utilizado como resiste para corrosão de vidrO. O layout era diretamente impresso sobre papel aditivado com maltodextrina ou papel utilizado como suporte para etiquetas autocolantes através de uma impressora HP LaserJet 6L com resolução de 600 dpi. Após a transferência térmica da imagem para lâminas de vidro alcalino de 1,0 mm de espessura, a corrosão em ácido fluorídrico permitiu obter canais com 7,1 &#181;m de profundidade e irregularidades de 1,0 &#181;m. Embora este segundo processo apresente desvantagens com relação à resolução tanto no plano da lâmina como na profundidade do canal, quando comparado ao primeiro, deve-se ressaltar a extrema simplicidade, rapidez e baixo custo do processo que deve ser interessante para a produção de protótipos. Já para o primeiro processo, destaca-se a adequação à produção em pequena escala de dispositivos microcanais de baixo custo. / Several processes and products have been proposed to build and use microstructures for chemical purposes. Most of these processes were adapted from microelectronic technologies, which resulted in products with excellent resolution and quality. However, there are some devices that could be generated by simpler and rougher processes. In this work, two processes were developed in order to allow producing simple devices based on microchannels. The first process is a method to produce polyester based devices. A conventional microelectronic process was used to produce a silicon matrix. This matrix was used to produce blocks of isophthalic resin by in situ polymerization. The best results were obtained by adding 1 % (w/w) silicone oil during the polyester resin preparation. This additive improves the mold relief and the smoothness of the device surface. Channels 14.0-&#181;m depth and roughness of 1.4 &#181;m were obtained with a mold with structure height of 15.3 &#181;m and roughness of 0.5 &#181;m. A flexible sheet of silicone allows forming enclosed microchannels with depth of 5-7 &#181;m. This dimension was evaluated by conductance measurement after filling the channel with KCl solution. A process for glass corrosion, using laser printer toner as resist, was proposed. In this method, the layout is printed over a special sheet of paper using a HP LaserJet 6L laser printer. The paper is used to transfer the toner to a soda-lime glass lamina by a thermic process. Hydrofluoric acid solution was used to promote the selective glass corrosion. Channels 7.1-&#181;m depth and roughness of 1.0 &#181;m were obtained. Although this second method does not give the saroe resolution and aspect ratio as the first one, it is suitable to easy and fast prototyping. Gn the other hand, the first method is suitable for low-cost production of devices in small scale.
270

Antimony diffusion from polyester textiles upon exhaust dyeing

Patwary, Shah Miran January 2017 (has links)
In recent years, environmental authorities in Sweden are reporting about high content of antimony in waste water that is discharging from polyester textile dyeing industries. It is known from available scientific publications that, antimony and its compound is harmful for both human and environment. While dyeing of polyester textiles have a commercial importance and in regards to the environmental issues, the industries are looking for the factors those results in high concentrations of antimony in their dyeing waste water. Dyeing of polyester textile requires high-temperature application in association with dyes and process aid chemicals. The waste water that is being produced after dyeing contains a complex mixture of chemicals, where antimony is one of that mixture. To comply with the industries interest, this master thesis work involved the exhaust dyeing of polyester fabrics/yarns and analyzing the dyeing waste water, to determine the amount of antimony diffusion. According to literature studies, the antimony compounds are widely used as catalyst for polyethylene terepthalate (PET) polymerization and hence antimony is present in polyester textiles. The entire experimental work intended to understand the variation of antimony concentration and the factors that are causing high antimony diffusion from polyester textiles during dyeing. The materials which are polyester yarn and fabrics were collected from 3 different dyeing industries of Sweden and the materials were in 9 different types. From material analysis (before dyeing) it has been found there were variations in antimony concentration among the materials. The process parameters that have varied during exhaust dyeing were dyeing temperature, cycle time and process aid chemical (leveling agent) adding options. With the variation in process parameters, the dyeing has performed and the dyeing waste waters have analyzed through inductively coupled plasma sector field mass spectroscopy (ICP-SFMS). The expectations from the experiments were, under specific dyeing process and with same antimony concentration, the materials varying in filament/fiber diameter; big diameter filament/fiber will diffuse less antimony compared to the small diameter filaments. Also, process-wise the antimony diffusion ratio among the materials will accordingly follow the Fick’s diffusion model. To face the environmental issues with sustainability, entire thesis work could provide concentrated knowledge’s with literature evidence for the dyeing industries. As literature study indicates, the dyeing temperature, temperature ramp set and cycle time play major factor while comparing for the expected diffusion ratio. As a gentle process parameter, comparatively lower temperature and cycle time results lower antimony diffusion. The use of levelling agent could be reduced to a level with the appropriateness while added for dyeing. Also, a strong follow-up is needed in the supply chain, for lowering the initial antimony content in the materials. Overall, the findings of this thesis work also keep an importance to do further research on the polyester textile, as during the experiments most of the materials haven’t reacted accordingly as they were expected to react with the Fick’s diffusion model.

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