Dissertations / Theses on the topic 'Ceramics and Clay Materials'
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Terner, Mark Robert. "The production of low-cost α-sialons via carbothermal reduction-nitridation of slag-based mixtures." Monash University, School of Physics and Materials Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/9577.
Full textCalvo, Carrascal Miguel Angel. "Sustainable manufacturing of next generation building materials using microwave energy." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/55508/.
Full textHarrison, Steve. "An examination of the geological resources of the Southern Highlands of NSW as raw materials for studio ceramics." View thesis, 2007. http://handle.uws.edu.au:8081/1959.7/31721.
Full text"A thesis submitted in partial fulfilment of the requirements for the award of the degree of Doctor of Philosophy from University of Western Sydney, College of Arts, Centre for Cultural Research." Includes bibliography.
Neukamm, Ashley Marie. "Material Imperfection: Mapping Form Through Memory." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397662164.
Full textAramide, FO, KK Alaneme, PA Olubambi, and JO Borode. "In-Situ Synthesis of Mullite Fibers Reinforced Zircon-Zirconia Refractory Ceramic Composite from Clay Based Materials." International Journal of Materials and Chemistry, 2015. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001844.
Full textKirabira, John Baptist. "Properties of Ugandan minerals and fireclay refractories." Doctoral thesis, KTH, Materials Science and Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-225.
Full textDevelopment of products which can be produced from a country’s natural resources is very important as far as the industrialization of a nation and saving foreign exchange is concerned. Presently, industries in Uganda and the other states in the Lake Victoria region import all refractory-related-consumables, as the demand cannot be met locally. Based on the abundance of ceramic raw materials for high temperature applications in the region and the demand for refractories by industries it is pertinent to develop and manufacture firebricks by exploiting the locally available raw materials.
This thesis thus, concerns the characterisation of ceramic raw mineral powders from the Lake Victoria region, more particularly, Uganda, with the aim of developing firebrick refractories from the minerals. Two main deposits of kaolin and a ball clay deposit were investigated to assess their potential in the manufacture of refractory bricks. Raw- and processed sample powders were investigated by means of X-ray diffraction (XRD), thermal analysis (DTA-TG) and Scanning Electron Microscopy (SEM). In addition, the chemical composition, particle size distribution, density, and surface area of the powders were determined.
A comprehensive study on beneficiation of Mutaka kaolin was carried out using mechanical segregation of particles. The aim of the study was to explore other potential applications like in paper filling and coating. The beneficiation process improves the chemical composition of kaolin to almost pure, the major impurity being iron oxide.
A general production process scheme for manufacturing fireclay bricks starting with raw powder minerals (Mutaka kaolin and Mukono ball clay) was used to make six groups of sample fireclay brick. Experimental results from the characterization of formulated sample bricks indeed revealed the viability of manufacturing fireclay bricks from the raw minerals. Based on these results, industrial samples were formulated and manufactured at Höganäs Bjuf AB, Sweden. Kaolin from the Mutaka deposit was used as the main source of alumina while ball clay from Mukono was the main plasticizer and binder material. The formulated green body was consolidated by wet pressing and fired at 1350°C in a tunnel kiln. Characterization of the sintered articles was done by X-ray diffraction, scanning electron microscopy, and chemical composition (ICP-AES). In addition, technological properties related to thermal conductivity, thermal shock, alkali resistance, water absorption, porosity, shrinkage, permanent linear change (PLC), linear thermal expansion, refractoriness under load (RUL), and cold crushing strength were determined. The properties of the articles manufactured from the selected naturally occurring raw minerals reveal that the produced articles compare favourably with those of parallel types. Thus, the raw materials can be exploited for industrial production.
Perold, Jacques. "Ceramic parameters in the financial evaluation of brick clay deposits, with reference to two South African examples." Diss., Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-08212007-121848.
Full textWilson, Conor J. R. "Writing_making : object as body, language and material." Thesis, Royal College of Art, 2016. http://researchonline.rca.ac.uk/1764/.
Full textFriček, Jakub. "Sledování vlivu keramické vazby na vlastnosti izolačních žáromateriálů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225890.
Full textCraver, Allison Rose. "Safe | Passage: A Story About Material and Labor." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492169761621626.
Full textRoveri, Carolina Del [UNESP]. "Petrologia aplicada da formação Corumbataí (região de Rio Claro - SP) e produtos cerâmicos." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/102977.
Full textConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
As indústrias cerâmicas do Pólo de Santa Gertrudes (São Paulo, Brasil) são responsáveis por cerca de 50% da produção nacional de pisos e revestimentos e utilizam, em sua grande maioria, materiais da Formação Corumbataí como base para as massas de revestimentos cerâmicos produzidos na região. Com o objetivo de caracterizar a unidade quanto à petrologia e propriedades tecnológicas na região da atividade mineira, foram realizados levantamentos das frentes de lavras e afloramentos, distribuídas desde a porção basal até o topo da Formação. Para isso, além das atividades cartográficas normais, foram executadas atividades de compilação bibliográfica, caracterização das fácies sedimentares e cerâmicas nas frentes de lavras e afloramentos e correlação entre estas, além de análises mineralógicas, químicas e petrográficas e ensaios tecnológicos. As atividades demonstraram que, praticamente, toda a coluna estratigráfica dessa unidade pode ser utilizada na fabricação de produtos cerâmicos, sendo que a mineralogia e as propriedades tecnológicas apresentam significativa variação tanto na vertical como na horizontal, decorrentes de aspectos sedimentares, diagenéticos e alteração supérgena. A distribuição dos litotipos associada à composição mineralógica, estrutural e textural sugere que o sítio deposicional tratava-se de um extenso mar raso, com indícios de exposições aéreas já nos estratos basais com provável deposição química de carbonatos, sulfatos e outros sais. Os processos de diagênese e circulação de fluídos, principalmente relacionados à colocação e resfriamento dos corpos de diabásio, levaram à geração de illitas, interestratificados, feldspatos, zeólitas, mobilização de carbonato e ferro e o surgimento de fraturamento hidráulico, nos mais diversos litotipos. Do ponto de vista tecnológico, concluiu-se que...
The industries of Santa Gertrudes’ Pole (São Paulo, Brazil) are responsible for about 50% of internal production of ceramic tiles and use rocks from Corumbataí Formation as raw materials in the product fabrication in this region. To realize the characterization of the petrology and technological properties of the unit in the mining’ area, were made field works in mines and outcrops, distributed from the base to the top of Corumbataí Formation. For that, beyond the normal cartographic activities were carried out activities bibliographic compilation, characterization of sedimentary facies and ceramics on the fronts of mines and outcrops and correlation between them, and mineralogical analysis, chemical and petrographic and technological tests. The activities demonstrated that virtually the entire stratigraphic column of this unit can be used in the manufacture of ceramic products, and the mineralogy and technological properties show significant variation both vertically and horizontally due to aspects of sedimentary, diagenetic and supergene alteration. The distribution of rock types associated with the mineral composition, structural and textural suggests that the depositional site it was an extensive shallow sea, with evidence of exposure companies had basal strata with probable chemical deposition of carbonates, sulfates and other salts. The processes of diagenesis and fluid movement, especially regarding the placement and cooling of bodies of diabase, led to the generation of illite, mixed layer clays, feldspars, zeolites, mobilization of carbonate and iron and the appearance of hydraulic fracturing in many different rock types. From the technological point of view, it was concluded that the properties vary depending on whether the sample (top or bottom of the unit), degree of change, physical and chemical characteristics and influence of hydrothermalism, causing the ... (Complete abstract click electronic access below)
Las industrias cerámicas del Polo de Santa Gertrudes (São Paulo, Brasil) son responsables por cerca de 50% de la producción nacional de pavimentos y revestimientos y utilizan, en su gran mayoría, materiales de la Formación Corumbataí como base para las baldosas. Con el objetivo de caracterizar la unidad cuanto a la petrología y propiedades tecnológicas en la región de la actividad minera, fueron realizados trabajos de campo en las canteras y afloramientos, distribuidos desde la base hasta el topo de la Formación. Para esto, fueron realizadas actividades cartográficas usuales y actividades de compilación bibliográfica, caracterización de las facciones sedimentares (descripción de campo, petrografía y litoquímica), cerámicas (ensayos tecnológicos) y correlación entre ellas. Los resultados demostraran que, prácticamente, toda la columna estratigráfica puede ser utilizada en la fabricación de productos cerámicos, siendo que la mineralogía y las propiedades tecnológicas presentan significativa variación tanto en la vertical como en la horizontal, decurrentes de aspectos sedimentares, diagenéticos y alteración supérgena. La distribución de litotipos asociada a la composición mineralógica, estructural y textural sugiere que el sitio deposicional se trataba de un extenso mar raso, con indicios de exposiciones aéreas ya en los estratos basales con probable deposición química de carbonatos, sulfatos e otras sales de sodio, potasio y magnesio. Los procesos de diagénesis y circulación de fluidos, principalmente relacionados a la inyección y resfriamiento de los cuerpos de diabasa, llevaran a la ocurrencia de reacciones químicas que resultaron en la generación de illitas, interestratificados, feldespatos, zeolitas, movimiento de carbonato y hierro en los más diversos litotipos, más allá del fraturamento hidráulico en algunos sitios ... (Resumen completo clicar acceso electrónico abajo)
BRITO, Igor Pinheiro de. "Caracterização de novos depósitos de argilas do estado da Paraíba visando seu uso como matérias primas cerâmicas." Universidade Federal de Campina Grande, 2015. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/994.
Full textMade available in DSpace on 2018-06-15T17:35:43Z (GMT). No. of bitstreams: 1 IGOR PINHEIRO DE BRITO – DISSERTAÇÃO (PPG-CEMat) 2015.pdf: 1768632 bytes, checksum: 11cd82aad3da13be877e15e53ad3eae1 (MD5) Previous issue date: 2015-08-31
Capes
Nos últimos anos, novos depósitos de argilas foram descobertos no Estado da Paraíba, a caracterização destes depósitos é de fundamental importância para estabelecer o melhor uso industrial dos mesmos. Neste contexto, o presente trabalho teve como objetivo caracterizar argilas provenientes de jazidas do município de Cubati-PB, visando estabelecer seus usos adequados como matérias-primas cerâmicas. Para tanto, as matérias-primas foram submetidas às seguintes técnicas de caracterizações: física, química, mineralógica e térmica. Posteriormente, foram preparados corpos de prova por prensagem uniaxial a 19 MPa, estes foram secos em estufa a 110°C, e submetidos a queima nas temperaturas de 750°C, 850°C, 950°C e 1150°C. Em seguida determinadas as propriedades físico-mecânicas: retração linear de queima (RLq), absorção de água (AA), densidade aparente (DAp), porosidade aparente (PA) e módulo de ruptura à flexão (MRF). As argilas A, B e C são adequadas para uso em cerâmica branca e a argila D para cerâmica vermelha. E todas as argilas contém composição mineralógica adequada para uso em cerâmica vermelha.
In recent years, new clays deposits have been discovered in the state of Paraiba, the characterization of these deposits is of fundamental importance to establish the best industrial usage. In this context, the aim of this study was characterized clays in the municipality of Cubati-PB, to establish their appropriate uses as ceramic raw materials. Therefore, the raw materials were subjected to the following characterization techniques: physical, chemical, mineralogical and thermal. Later, specimens were prepared by uniaxial pressing at 19 MPa, before dry at 110°C, and submitted to firing at temperatures of 750°C, 850°C, 950°C and 1150°C. It were determined the physical and mechanical properties: linear firing shrinkage (LFS), water absorption (WA), apparent density (DAp), apparent porosity (PA) and flexural modulus of rupture (MRF). The clays A, B and C are suitable for use in white ceramic and D to red ceramic. And all the clays contain adequate mineralogical composition for use in red ceramic.
Roveri, Carolina Del. "Petrologia aplicada da formação Corumbataí (região de Rio Claro - SP) e produtos cerâmicos /." Rio Claro : [s.n.], 2010. http://hdl.handle.net/11449/102977.
Full textAbstract: The industries of Santa Gertrudes' Pole (São Paulo, Brazil) are responsible for about 50% of internal production of ceramic tiles and use rocks from Corumbataí Formation as raw materials in the product fabrication in this region. To realize the characterization of the petrology and technological properties of the unit in the mining' area, were made field works in mines and outcrops, distributed from the base to the top of Corumbataí Formation. For that, beyond the normal cartographic activities were carried out activities bibliographic compilation, characterization of sedimentary facies and ceramics on the fronts of mines and outcrops and correlation between them, and mineralogical analysis, chemical and petrographic and technological tests. The activities demonstrated that virtually the entire stratigraphic column of this unit can be used in the manufacture of ceramic products, and the mineralogy and technological properties show significant variation both vertically and horizontally due to aspects of sedimentary, diagenetic and supergene alteration. The distribution of rock types associated with the mineral composition, structural and textural suggests that the depositional site it was an extensive shallow sea, with evidence of exposure companies had basal strata with probable chemical deposition of carbonates, sulfates and other salts. The processes of diagenesis and fluid movement, especially regarding the placement and cooling of bodies of diabase, led to the generation of illite, mixed layer clays, feldspars, zeolites, mobilization of carbonate and iron and the appearance of hydraulic fracturing in many different rock types. From the technological point of view, it was concluded that the properties vary depending on whether the sample (top or bottom of the unit), degree of change, physical and chemical characteristics and influence of hydrothermalism, causing the ... (Complete abstract click electronic access below)
Resumen: Las industrias cerámicas del Polo de Santa Gertrudes (São Paulo, Brasil) son responsables por cerca de 50% de la producción nacional de pavimentos y revestimientos y utilizan, en su gran mayoría, materiales de la Formación Corumbataí como base para las baldosas. Con el objetivo de caracterizar la unidad cuanto a la petrología y propiedades tecnológicas en la región de la actividad minera, fueron realizados trabajos de campo en las canteras y afloramientos, distribuidos desde la base hasta el topo de la Formación. Para esto, fueron realizadas actividades cartográficas usuales y actividades de compilación bibliográfica, caracterización de las facciones sedimentares (descripción de campo, petrografía y litoquímica), cerámicas (ensayos tecnológicos) y correlación entre ellas. Los resultados demostraran que, prácticamente, toda la columna estratigráfica puede ser utilizada en la fabricación de productos cerámicos, siendo que la mineralogía y las propiedades tecnológicas presentan significativa variación tanto en la vertical como en la horizontal, decurrentes de aspectos sedimentares, diagenéticos y alteración supérgena. La distribución de litotipos asociada a la composición mineralógica, estructural y textural sugiere que el sitio deposicional se trataba de un extenso mar raso, con indicios de exposiciones aéreas ya en los estratos basales con probable deposición química de carbonatos, sulfatos e otras sales de sodio, potasio y magnesio. Los procesos de diagénesis y circulación de fluidos, principalmente relacionados a la inyección y resfriamiento de los cuerpos de diabasa, llevaran a la ocurrencia de reacciones químicas que resultaron en la generación de illitas, interestratificados, feldespatos, zeolitas, movimiento de carbonato y hierro en los más diversos litotipos, más allá del fraturamento hidráulico en algunos sitios ... (Resumen completo clicar acceso electrónico abajo)
Orientador: Antenor Zanardo
Coorientador: Anselmo Ortega Boschi
Banca: Maria Margarita Torres Moreno
Banca: Fábio Ramos Dias de Andrade
Banca: Angélica Fortes Drummond Chicarino Varajão
Banca: Emilia García Romero
Doutor
Lima, Raimundo Humberto Cavalcante [UNESP]. "Estudo de formulação de massas através do controle da mistura: argilas aluvionares do pólo cerâmico de Russas-Ceará." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/103000.
Full textConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O pólo cerâmico de Russas está localizado no estado do Ceará e representa uma das bases da economia do município, voltada para produção de telhas e tijolos estruturais. A maioria dos ceramistas do Pólo faz uso de métodos empíricos para formulação de massa cerâmica, tendo como consequência uma desuniformização dos produtos acabados. O objetivo desta pesquisa foi identificar um parâmetro de controle funcional, a ser usado na preparação de misturas, para obtenção de uma massa homogênea e consequentemente uma melhor uniformização das peças fabricadas. O método aplicado baseia-se nos valores de: absorção de água dos componentes individuais e pré-determinados para as misturas além da temperatura de queima. A preparação das massas foi realizada com componentes plásticos (granulometria fina) e não-plásticos (partículas mais grossas) utilizados em quatro cerâmicas, determinando absorção de água em corpos-de-prova prensados com 8% de umidade e densidade de prensagem de 2.0 g.cm-3. A partir desses valores foram calculadas as proporções dos componentes, visando absorção d´água de 14%. Os resultados determinaram a distribuição granulométrica padrão adequada para uso como parâmetro de controle na preparação da mistura do material plástico e não plástico e permitiram obter, através de um método gráfico complementado por um algoritmo de otimização, a proporção necessária para adquirir uma massa cerâmica homogênea nas condições em que as amostras foram processadas.
The Ceramic center of Russas has been located in Ceará State and represents one of the county economy base, aimed to produce structural bricks and roofing tiles. Most of the Pole potters make use of empirical methods for the formulation of ceramic body resulting in disuniform finished products. The objective of this research was to identify a functional control parameter, to be used in the preparation of mixtures, to obtain a homogeneous mass and therefore a better uniformity of the manufactured pieces. The method applied is based on the water values absorption of the individual components, pre-determined values for the water values absorption from the mixture and burning temperature. The preparation of the mass had been made with plastic components (thin granularity) and non-plastics (thicker particles) used in four ceramics, determining water values absorption in sample bodies pressed with 8% moisture and density of pressing of 2.0 g.cm-3. From these values the water components proportions were calculated to water absorption of 14%. The results determined the granulometric distribution pattern suitable for using as a parameter control in the preparation of the plastic and non-plastic material mixture and they allowed to get, through a graphical method supplemented by an algorithm of optimization, the proportion required to obtain a homogeneous ceramic body, under conditions where the samples had been processed.
Bezerra, CÃndido Henrique de Aguiar. "AnÃlise comparativa das propriedades fÃsicas e mineralÃgicas dos depÃsitos de argila dos municÃpios de Crato e JucÃs-CE." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9480.
Full textThis work report a comparative physical and chemical analysis of clays properties between two areas with different environmental characteristics. For determination of the Physical properties of the specimens granulometric assays were performed with the use of five (5) weight granulometric sieves previously known in the meshes 140, 200, 325, 400, 500 and ground, yielding six (6) granulometric classes were identified limits of plasticity, liquidity and plasticity indexes, as well as the levels were set temperature firing ideal for both areas of study based on the test results obtained from mass loss to fire, and linear shrinkage water absorption. To complete the physical tests were defined compression resistance of the materials of the areas in this study. Chemical analysis of samples was performed based on the results of the analysis of X-ray diffraction (XRD) and X-ray fluorescence (XRF) that indicated the presence of illite, montmorillonite and kaolinite in sample B2 and B1 in the sample located in the municipality of Crato . In samples A1 and A2 located in the municipality of JucÃs kaolinite and illite were identified in both samples. Analyzing the results of physical and chemical properties can be stated that for the production of ceramic tiles the material that best suits the requirements of the market is coming from the area 2 (Crato), as well as material from one area of the municipality is more JucÃs suitable for production of bricks sealing without structural function.
Lima, Raimundo Humberto Cavalcante. "Estudo de formulação de massas através do controle da mistura : argilas aluvionares do pólo cerâmico de Russas-Ceará /." Rio Claro : [s.n.], 2009. http://hdl.handle.net/11449/103000.
Full textBanca: Tamar Milca Bortolozzo Galembeck
Banca: Antenor Zanardo
Banca: José Francisco Marciano Motta
Banca: Shirley Cosin
Resumo: O pólo cerâmico de Russas está localizado no estado do Ceará e representa uma das bases da economia do município, voltada para produção de telhas e tijolos estruturais. A maioria dos ceramistas do Pólo faz uso de métodos empíricos para formulação de massa cerâmica, tendo como consequência uma desuniformização dos produtos acabados. O objetivo desta pesquisa foi identificar um parâmetro de controle funcional, a ser usado na preparação de misturas, para obtenção de uma massa homogênea e consequentemente uma melhor uniformização das peças fabricadas. O método aplicado baseia-se nos valores de: absorção de água dos componentes individuais e pré-determinados para as misturas além da temperatura de queima. A preparação das massas foi realizada com componentes plásticos (granulometria fina) e não-plásticos (partículas mais grossas) utilizados em quatro cerâmicas, determinando absorção de água em corpos-de-prova prensados com 8% de umidade e densidade de prensagem de 2.0 g.cm-3. A partir desses valores foram calculadas as proporções dos componentes, visando absorção d'água de 14%. Os resultados determinaram a distribuição granulométrica padrão adequada para uso como parâmetro de controle na preparação da mistura do material plástico e não plástico e permitiram obter, através de um método gráfico complementado por um algoritmo de otimização, a proporção necessária para adquirir uma massa cerâmica homogênea nas condições em que as amostras foram processadas.
Abstract: The Ceramic center of Russas has been located in Ceará State and represents one of the county economy base, aimed to produce structural bricks and roofing tiles. Most of the Pole potters make use of empirical methods for the formulation of ceramic body resulting in disuniform finished products. The objective of this research was to identify a functional control parameter, to be used in the preparation of mixtures, to obtain a homogeneous mass and therefore a better uniformity of the manufactured pieces. The method applied is based on the water values absorption of the individual components, pre-determined values for the water values absorption from the mixture and burning temperature. The preparation of the mass had been made with plastic components (thin granularity) and non-plastics (thicker particles) used in four ceramics, determining water values absorption in sample bodies pressed with 8% moisture and density of pressing of 2.0 g.cm-3. From these values the water components proportions were calculated to water absorption of 14%. The results determined the granulometric distribution pattern suitable for using as a parameter control in the preparation of the plastic and non-plastic material mixture and they allowed to get, through a graphical method supplemented by an algorithm of optimization, the proportion required to obtain a homogeneous ceramic body, under conditions where the samples had been processed.
Doutor
Jordens, Kurt. "Hybrid Inorganic-Organic Materials: Novel Poly(Propylene Oxide) Based Ceramers, Abrasion Resistant Sol-Gel Coatings for Metals, and Epoxy-Clay Nanocomposites. With an Additional Chapter On: Metallocene Catalyzed Linear Polyethylene." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/30194.
Full textPh. D.
R?go, Vilson Ribamar. "Estudo do efeito da adi??o da esc?ria de aciaria no processamento e propriedades finais de telhas cer?micas." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12772.
Full textThis research presents an overview of the addition steelwork dust of ceramic shingles in order to contribute to the utilization use of such residue. The ceramic industry perspective in the Brazilian State of Piau? is quite promising. Unlike other productive sectors, the ceramic industry uses basically natural raw materials. Its final products are, in short, the result of transforming clay compounds. These raw materials are composed primarily of aluminum oxide, silicon, iron, sodium, magnesium, end calcium, among others. It was verified that steelwork dust is composed primarily of these same oxides, so that its incorporation in to structural ceramics is a very reasonable idea. Both clay and steelwork powder were characterized by AG, XRF, XRD, TGA and DTA. In addition, steelwork dust samples containing (0%, 5%, 10%, 15%, 20% and 25%) were extruded and burned at 800?C, 850?C, 900?C and 950?C. Then t echnological tests of linear shrinkage, water uptake, apparent porosity, apparent density and flexural strengthwere carried at. The results showed the possibility of using steelwork powder in ceramic shingles until 15% significant improvement in physical and mechanical properties. This behavior shows the possibility of burning at temperatures lower than 850?C, thus promoting a product final cost reduction
Neste trabalho ? estudado o efeito da adi??o da esc?ria de aciaria em massas cer?micas para ind?strias de cer?mica vermelha, visando contribuir com o aproveitamento desses rejeitos. Foi feito uma avalia??o da sua adi??o ? massa cer?mica para produ??o de telhas. O panorama da ind?stria cer?mica no estado do Piau? ? bastante promissor. Diferente de outros setores produtivos, o setor cer?mico utiliza, basicamente, mat?rias-primas naturais. O seu produto final ?, em suma, o resultado da transforma??o de compostos argilominerais. Essas mat?rias-primas s?o compostas, basicamente, de ?xidos de alum?nio, sil?cio, ferro, s?dio, magn?sio, c?lcio, dentre outros. Verificou-se que a esc?ria de aciaria ? composta principalmente por esses mesmos ?xidos, de forma que sua incorpora??o ? massa de cer?mica estrutural ? uma ideia absolutamente razo?vel. Foram caracterizadas as mat?rias-primas argila e esc?ria de aciaria por AG, FRX, DRX, TGA e DTA. Tamb?m foram conformados por extrus?o e queimados nas temperaturas de 800?C, 850 ?C, 900?C e 950?C corpos-deprova com 0%, 5%, 10%, 15%, 20% e 25% de teor de esc?ria de aciaria. Em seguida, foram realizados ensaios tecnol?gicos de retra??o linear, absor??o de ?gua, porosidade aparente, massa espec?fica aparente e resist?ncia mec?nica ? flex?o. Os resultados mostraram a possibilidade de se utilizar at? 15% de esc?ria de aciaria na massa cer?mica para telhas. At? essa dosagem, melhorias consider?veis nas caracter?sticas f?sicas e mec?nicas avaliadas foram observadas. O estudo tamb?m mostrou a possibilidade de queima em temperaturas mais baixas que 850?C, promovendo, assim, uma redu??o dos custos finais do produto
Arbelaez, Natalia. ""Insignificant Grandeur"." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1435530944.
Full textPapargyris, Athanasios D. "Mechanical properties of clay and fibre reinforced clay-based ceramics." Thesis, University of Bath, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240685.
Full textCombs, Jasen Paul-Robert. "Altered clay vessels." Virtual Press, 2002. http://liblink.bsu.edu/uhtbin/catkey/1233190.
Full textDepartment of Art
Prado, Ana Candida de Almeida [UNESP]. "Argilas da formação Corumbataí como base para obtenção de grés porcelanato por via seca." Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/92930.
Full textEste trabalho apresenta os resultados, acompanhado das discussões apropriadas, referentes à pesquisa que objetivou viabilizar a utilização das argilas da Formação Corumbataí da região de Rio Claro (São Paulo - Brasil) como principal matéria-prima em formulações de massa cerâmica, para obtenção de um produto com as principais características do grés porcelanato. As matérias-primas utilizadas nas misturas são argilas da Formação Corumbataí provenientes das minas Sartori e Cruzeiro, um material de granulometria mais grossa rejeito de exploração de diabásio, basalto padrão do laboratório de Geoquímica e minério de manganês. Foram estudadas as possíveis adequações do processo, a fim de se obter produtos com propriedades do grés porcelanato, usando argilas de queima vermelha. Os corpos-de-prova foram produzidos em escala laboratorial, utilizando metodologia de produção de grés porcelanato tradicional, combinada com a usada em placas de revestimento cerâmico da classe BIIb, sendo a principal inovação a utilização da moagem via seca no preparo da massa cerâmica. Os ensaios laboratoriais visam a classificação das matérias-primas e caracterização física e química dos corpos-de-prova. A avaliação consiste em verificar a adequação dos resultados às exigências da norma NBR 13818/1997 da Associação Brasileira de Normas Técnicas (ABNT) para produtos da classe BIa. O objetivo foi alcançado em algumas destas misturas, gerando produtos com baixa absorção de água, alta resistência mecânica, grande estabilidade química e agradável efeito estético.
For this research, clays from Corumbataí Formation were used as the main raw material in the formulation of various mixtures, with the objective of obtaining a ceramic tile with porcelain stoneware characteristics. These mixtures were formulated using clays from the Sartori (Rio Claro-SP) and Cruzeiro (Limeira -SP) deposits, along with diabase waste, basalt and manganese ore. Different process modifications were studied in order to obtain tiles with porcelain stoneware properties, using clays with a high content of Fe2O3. Test samples were produced in laboratorial scale using traditional porcelain stoneware production methodology combined with the method used in BIIb class ceramic floor tiles. Dry milling was the main innovation used to prepare the different mixtures for this study. The laboratorial tests were designed to characterize the raw materials, and to evaluate the physical and chemical properties of the fired test samples. The evaluation consisted of verifying the final results in respect to the requirements of Brazilian Technique Norm (ABNT - NBR 13818/1997) for BIa class ceramic tiles. The objective of this research was realized in that some experimental mixtures produced tiles with low water absorption, high mechanical strength and chemical stability, while being aesthetically pleasing at the same time.
SILVA, Veralúcia Severina da. "Transferência de calor e massa em materiais com forma complexa via método da análise concentrada. Estudo de caso: secagem de materiais cerâmicos." Universidade Federal de Campina Grande, 2016. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/930.
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A secagem é um processo termodinâmico, em que há transferência simultânea de calor e a remoção da umidade de um material poroso. Os produtos argilosos quando expostos a uma secagem sem controle pode sofrer fissuras e deformações, reduzindo sua qualidade póssecagem. Este trabalho tem como objetivo estudar teórico e experimentalmente a transferência de calor e massa em sólidos com forma complexa com, com ênfase a secagem de materiais cerâmicos argilosos. Neste trabalho desenvolveu-se um modelo matemático para descrever as trocas de calor e massa durante o processo de secagem, utilizando o método da capacitância global em corpos vazados. A solução analítica das equações governantes foi feita usando o método de separação de variáveis. Foram realizados experimentos de caracterização química e terrmo-hídrica da argila, e secagem de materiais cerâmicos argilosos vazados e com formas não-convencionais, em diferentes temperaturas (60, 70, 80, 90 e 100ºC). Resultados da composição química e granulometria da argila, e cinéticos de perda de massa e aquecimento das peças cerâmicas são apresentados e analisados. Verificou-se que o processo de perda de umidade ocorre a uma velocidade mais baixa do que o aquecimento do material cerâmico, que a temperatura e forma do corpo afetam fortemente os fenômenos de transporte de calor e massa, que a secagem a baixa temperatura favorece a redução de problemas no material pós secagem e melhoramento na qualidade final, e que os números de Biot de transferência de calor e de massa influenciam diretamente no tempo que o produto atinge sua condição de equilíbrio. A comparação entre o teor de umidade e temperatura preditos pelo modelo matemático proposto e os dados experimentais permitiu a estimativa dos coeficientes de transferência de massa e calor na superfície do material, com boa precisão.
Drying is a thermodynamic process, in which there is simultaneous heat transfer and moisture removal of a porous material. Clay products exposed to drying without control may suffer cracks and deformations, reducing its quality post-drying. This work aims to study theoretical and experimental the drying of solids with complex shape. It was developed a mathematical model to describe heat and mass transfer during the drying process, using the global capacitance method of hollow bodies. The analytical solution of the governing equations was made using the variable separation method. It were realized experiments of chemical and thermo-hydric characterization of clay, and drying of hollow and non-conventional clay ceramic materials at different emperatures (60, 70, 80, 90 and 100ºC). Results of the chemical composition and granulometry, and mass loss and heating of ceramic parts are presented and analyzed. It was verified that the moisture loss process occurs at a lower velocity than the heating of the ceramic material, the temperature and body shape strongly affect heat and mass transport phenomena, drying at low temperature favors the reduction of the problems in the material post-drying and improvement in the final quality, and that Biot numbers of heat and mass transfer directly affect the time to the product to reach its equilibrium condition. Comparison between predicted and experimental moisture content and temperature permitted estimative of the convective heat and mass transfer coefficients at the surface of the material, with good precision.
Dugan, Moi. "Narratives on clay /." Online version of thesis, 1993. http://hdl.handle.net/1850/11769.
Full textŠafaříková, Hana. "Vliv obsahu kalcitu v cihlářských zeminách na vlastnosti vypáleného střepu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225878.
Full textCalaresi, Anna Carolina Marques Ayres. "Argila: matéria-prima para cerâmica popular - três casos - Rio Real (BA), Apiaí (SP) e Taubaté (SP)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3134/tde-23122014-160214/.
Full textThe present work has as its main objective to relate the use of clay, artistic expression and cultural material technical aspects often ignored by the executors (artisans artists), from the traditional techniques of analysis modeling. Search, therefore, understand how the raw material (clay), available for certain artisan community, influenced the spontaneous development of a modeling technique employed in a particular region of Brazil, resulting in a peculiar form of artistic expression, because the availability of a kind of raw material is a commonly neglected aspect in the analysis of a form of artistic expression. Often, depending on the limitations of both the material and the lack of technical knowledge, \"failures\" of the material are resolved with the use of techniques developed as a result of experimentation and observation. Thus, aims to investigate how the properties of clay are important in defining the characteristics of a work, in choosing the method of execution in its different phases. As performers can \"overcome\" certain problems presented by the material with the use of experimental solutions. The survey results proved that the raw material used by each community influences the type of work performed, promoting the choice of aesthetic solutions and appropriate modeling the properties of clays. This somehow makes the execution of work with their particular characteristics and authentic in another region, with use of a clay that not available on site. Hence the documentary also character of the study, because registers both the existence of a story press and their specific particularities finite but also the technique and the voice of these people, that of singular form to use as a means of expression and livelihood.
Harrad, Lucy. "The production and trade of prehistoric ceramics in Cornwall." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289013.
Full textAkpan, Edem T. Gogot︠s︡i I︠U︡ G. "Viscoelastic toughening of refractory ceramics /." Philadelphia, Pa. : Drexel University, 2004. http://dspace.library.drexel.edu/handle/1860/284.
Full textChen, Biqiong. "Polymer-clay nanocomposites." Thesis, Queen Mary, University of London, 2004. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1854.
Full textLao, Hongbai. "Novel microporous organo-clay materials and organo-clay polymeric composite membranes." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6830.
Full textOmonmhenle, Selina Ilunakan. "Clay derived materials for environmental management." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5332/.
Full textMalikiossis, Ariane A. A. "Experiences through clay, therapeutic modelling and ceramics in two anthroposophic communities." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ43628.pdf.
Full textAlbertson, Constant Kathryn. "Because clay has a memory, conversations about dyslexia, ceramics and success." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63994.pdf.
Full textDong, Chun. "Binder removal in ceramics." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/14101.
Full textBrito, Jorge Ferreira. "Produ??o de gr?s porcelanato a partir de mat?rias-primas do estado da Bahia." Universidade Federal do Rio Grande do Norte, 2009. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15587.
Full textCoordena??o de Aperfei?oamento de Pessoal de N?vel Superior
The State Bahia, Brazil, presents different geological sites it with a very expressive variety minerals. It is situated among the very important States which produces minerals for industries, such as pointed aggregate, ornamentals stones and ceramics raw materials. Nowadays only four companies producting ceramics tiles. Porcelainized stoneware tiles is one of the noblest ceramics, depicting low water absorption (typically below of 0,5%), in addition to excellent staining resistance and mechanical strength. The present work aims at investigating the potential of local raw materials for the production of porcelainized stoneware tiles. For this purpose, these materials were characterized by X-ray fluorescence, X-ray diffraction, particle size analysis, thermal gravimetric analysis, thermal differential analysis and dilatometric analysis. Admixtures containing different compositions were prepared and fired at four temperatures, 1100 ?C, 1150 ?C, 1200 ?C and 1250 ?C with isotherm for 60 minute and heathing rate of 5 oC/min. After firing the samples, they were characterized by water absorption tests, linear retraction, analysis, apparent porosity, apparent specific mass, flexural strength, and microstructural analysis by X-ray diffraction and scanning electron microscopy . The results revealed three ceramics with porcelainized stoneware tiles characteristics and porcelain tile will be produce from raw materials originated in the State of Bahia
O Estado da Bahia apresenta uma diversidade de terrenos geol?gicos que encerra uma expressiva dota??o mineral e est? situado entre os mais importantes Estados produtores de minerais industriais, ressaltando-se agregados, rochas ornamentais e mat?rias-primas cer?micas. Atualmente somente quatro empresas produzem placas cer?micas. O gr?s porcelanato ? uma das mais nobres cer?micas de revestimento devido a sua baixa absor??o d ?gua (tipicamente abaixo de 0,5%), al?m de apresentar excelentes caracter?sticas t?cnicas, destacando-se pelas elevadas resist?ncias mec?nica, ao risco e ao manchamento. O presente trabalho tem a finalidade de avaliar o potencial das mat?rias-primas, feldspato, argila e caulim, utilizado na produ??o de gr?s porcelanato no estado da Bahia. Para isso, foi feita a caracteriza??o das mat?rias-primas por fluoresc?ncia de raios X (FRX), difra??o de raios X (DRX), an?lise granulom?trica (AG), an?lise t?rmica gravim?trica (TG), an?lise t?rmica diferencial (DTA) e an?lise dilatom?trica, elaborando-se sete formula??es que foram queimadas nas temperaturas: 1100 ?C, 1150 ?C, 1200 ?C e 1250 ?C, com isoterma de 60 minutos e taxa de aquecimento de 5 oC/ min. Ap?s a queima, os corpos-de-prova foram submetidos a ensaios de absor??o de ?gua, retra??o linear, an?lise dilatom?trica, porosidade aparente, massa espec?fica aparente, resist?ncia ? flex?o, difra??o de raios X e microscopia eletr?nica de varredura. Em tr?s formula??es foram obtidas, propriedades compat?veis com as exigidas para a produ??o do gr?s porcelanato com mat?rias-primas oriundas do Estado da Bahia
Newton, John Michael. "The tensile strength and fracture toughness of heavy clay bodies." Thesis, University of Sheffield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296976.
Full textWellman, R. G. "Solid particle erosion of ceramics." Master's thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/18219.
Full textIserhard, José Luís Rodrigues de Freitas. "Estimativa do tempo de secagem de meios porosos inertes à base de argila em um modelo experimental." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/26541.
Full textThis study investigated the prediction of the drying time of a ceramic-based red clay, from an industry located in the region of Gravataí-RS .. The material was mixed in the compositions of 0% 5% 8% and 10% by weight in relation to its chamotte clay (firing at 950 ° C), and characterize d for chemical composition, mineralogical and particle size. In the ceramic body water was added to the plastic limit plus 3% (dry basis), and then homogenized, formed by extrusion (vacuum) and subjected to convective drying in a controlled environment psychrometric conditions applied are the typical industrial drying processes: temperatures of 40 º C, 50 º C and 60 º C, relative humidity of 40% and air velocity of 1.5 m / s. To this end, we developed an experimental apparatus who managed, monitored and recorded losses of mass (water) in real time. They have been drawn curves of mass loss over time and determined the critical moisture through the differential mass loss by the time in the Bigot curves and calculated the speed of instant weight loss. We determined linear regression curves and the estimation of drying time, depending on the temperature of the drying air and the amount of chamotte. The samples were further characterized according to their strength, whose variation was quantized by the statistical Weibull. 30 tests were performed for each conformation, and for each batch were used three bodies of test by drying cycle. The results showed that as increasing the proportion of chamotte and the drying temperature increases the drying rate, resulting in the decrease of drying time. These phenomena were equated according to each formulation serving of base for a model to estimate the drying time of clay under the same conditions depicted here, with an estimated optimally, the time that the material is subjected to drying before the beginning of the burning process of firing process, resulting in savings and time when its use in industrial process.
Williams, Kaylea N. "Archetypes in Clay." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/honors/400.
Full textPalomino, Angelica Maria. "Fabric formation and control in fine-grained materials." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-06072004-131309/unrestricted/palomino%5Fangelica%5Fm%5F200405%5Fphd.pdf.
Full textVita. Includes bibliographical references (leaves 183-192).
Nel, Jacqueline Margot. "Processing and properties of silicon nitride ceramics." Master's thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/21682.
Full textSilicon nitride, Si₃N₄, ceramics were produced using either silicon or silicon nitride powder. The silicon was reaction bonded in nitrogen atmosphere to form reaction bonded Si₃N₄,which was then sintered between 1700°C and 1800°C to form a dense Si₃N₄ ceramic. The silicon nitride powder compacts were also sintered between 1700°C and 1800°C. In order to achieve densification Y₂O₃-A1₂O₃ additive combination was used in both processing routes. The physical and mechanical properties of the Si₃N₄ materials was found to be dependent on the processing conditions. The post sintered reaction bonded Si₃N₄ materials had the highest densities and hardness values, while the sintered Si3N4 materials had the highest strength and toughness values. The microstructure was also influenced to a great extent by the processing conditions, and this in tum influenced the mechanical properties of the ceramics.
Wang, Jia. "Synthesis and properties of polyimide/organo clay and polyimide/polyaniline-modified clay nanocomposites." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282055379.
Full textLai, Alan Ph D. Massachusetts Institute of Technology. "Shape memory ceramics in small volumes." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104111.
Full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 133-139).
Shape memory ceramics rely on martensitic transformations which are similar to those found in metallic shape memory materials, but ceramics offer several advantages over metals such as higher operating temperatures and larger transformation stresses. However, polycrystalline shape memory ceramics have shown poor cycling performance which limits their use in practical applications. This is due to the inherent physical constraints of the grains that create stress concentrations and eventually leads to intergranular fracture. Here it is proposed that single crystalline and oligocrystalline ceramics-made with a single grain or very few grains-will avoid the physical constraints found in polycrystalline materials that lead to intergranular fracture and result in shape memory ceramics with enhanced cycling performance. Zirconia was chosen for study because it has the necessary martensitic transformations and has shown limited shape memory properties when in the bulk polycrystalline form. Focused ion beam milling was used to make single crystal and oligocrystal pillars of varying diameter that were compression tested using a nanomechanical testing platform to determine the mechanical properties. This work showed that removing grain constraints in micron-scale shape memory zirconia prevented cracking and fracture. It also enhanced the number of achievable repeatable cycles from five in bulk materials to at least hundreds in small structures. The transition from single- to oligo- to poly-crystal was explored and it was found that fracture is more likely in polycrystals and that the transformation stresses increase as pillar diameter is increased, the opposite of what is observed in shape memory metals. This phenomenon is attributed to the higher stiffness of ceramics making the stored elastic energy more important. The effect of crystal orientation was investigated to aid in design and optimization. Orientation maps were produced for fracture behavior, elastic modulus, transformation stress, and transformation strain. Finally four different scale-up architectures were proposed and implemented - powders, wires, foams, and thin films - and each demonstrated shape memory properties thereby paving the way for deployment in practical applications.
by Alan Lai.
Ph. D.
Fafard, Jonathan. "Functionalized Materials Based on the Clay Mineral Kaolinite." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37307.
Full textWang, Yan. "Exploring Biopolymer-Clay Nanocomposite Materials by Molecular Modelling." Doctoral thesis, KTH, Teoretisk kemi och biologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166299.
Full textI denna avhandling har molekylär modellering och molekyldynamisk (MD) simulering använts för att studera modellsystem för bio-nanokompositer bestående av montmorillonit-lera samt två olika sorters biopolymerer – xyloglukan (XG) och kitosan (CHS). Båda dessa polymerer är naturligt förekommande och mycket vanliga. De är dessutom förnyelsebara och kostnadseffektiva. Då polymererna förstärkts med nanopartiklar av montmorillonit får det resulterande kompositmaterialet en unik kombination av egenskaper såsom mekaniska, elektriska, termiska och barriär egenskaper etc. Genom att använda molekyldynamiska (MD) simuleringar, studeras här växelverkan mellan dessa biopolymerer och lernanopartiklar (Mnt) på grundläggande atomistisk detaljnivå. Mellan XG och Mnt i ett fullt hydrerat system kunde stark bindningsaffinitet påvisas. Den dominerande drivkraften för affiniteten var entalpi, d.v.s. potentiell växelverkansenergi. Den adsorberade XG-kedjan antar en platt konformation på ytan. Ett förslag utifrån simuleringsresultaten var att galaktosresidyn i xyloglukanets sidokedja underlättar adsorptionen till lerytan. Simuleringarna kunde också visa att adsorption av XG till Mnt beror starkt på motjonernas hydreringsförmåga. Bindningsaffiniteten mellan XG och Mnt var som starkast i K-Mnt/XG- systemet. Därefter följde, i minskande ordning, Na-Mnt/XG, Li-Mnt/XG och Ca-Mnt/XG. Det kunde visas att strukturen vid gränsytan styrs av konkurrerande mekanismer mellan joner, vatten och XG. Dimensionsstabilitet vid fuktexponering, d.v.s. förmågan hos ett material att motverka svällning, är en viktig egenskap för biopolymer-lernanokompositer. Ren lera sväller signifikant även vid låga fukthalter. Dock kunde MD simuleringar visa att ett modellsystem av XG-Mnt behåller sitt ursprungliga interlamellära avstånd vid hydreringsnivåer under 50%, vilket indikerar ett stabilare material. Vid högre hydrering uppmättes dock svällningen vara densamma som för ren lera. I CHS-Mnt-systemet visade det sig att direkt elektrostatisk växelverkan med signifikant styrka mellan laddningar på polymer och Mnt-yta spelar störst roll för kompositformeringen. Olika effekt på polymer-lerväxelverkan uppnåddes genom att variera acetyleringsgraden (DA) respektive protoneringsgraden (DPr). För den tungt acetylerade CHS-polymeren (DA > 50%, även kallad kitin) visade sig den starka vidhäftningen bero på korrelation mellan acetylgrupperna och motjonerna som i sin tur verkade som ett elektrostatiskt “lim”. På liknande sätt kunde den svaga vidhäftningen mellan fullt deprotonerad (DPr = 0%) neutral CHS och lera förklaras med en betydligt svagare korrelation mellan aminogrupperna och motjonerna. Spänning-töjningsbeteendet hos CHS-Mnt modellen visar att dess mekaniska egenskaper beror kraftigt på volymsandelen Mnt och graden av exfoliering i kompositen. Materialets struktur är nära relaterat till materialegenskaperna. Framtiden för nanokompositer av biopolymerer och lera är ljus då de kan komma att ersätta oljebaserade plaster och användas frekvent i våra dagliga liv. Materialen kommer successivt förbättras genom utveckling av experimentella metoder i kombination med molekylmodellering för ökad förståelse för växelverkan mellan polymer, lera, vatten, joner och lösningsmedel.
本论文利用分子动力学模拟技术研究了两种备选生物大分子与蒙脱土(Montmorillonite, Mnt)(一种粘土)组成的生物纳米复合材料,分别是木葡聚糖(Xyloglucan, XG)/蒙脱土和壳聚糖(Chitosan, CHS)/蒙脱土。木葡聚糖与壳聚糖都是自然界广泛存在的生物大分子,资源丰富且取材面宽,提取及加工成本低廉,加之可以生物降解并可再生,是优秀的生物复合材料备选原料。经过蒙脱土纳米颗粒加固后,这些基于生物大分子的复合材料将获得多功能且有多种独特特性相结合的优点,比如,更好的力学性能,生物可降解,良好的导电性能,传热性能和屏蔽气体与液体侵扰的能力等等。论文中,我们采用分子动力学模拟的方法着重对生物大分子与蒙脱土在界面上的粘附相互作用机理进行了深入探讨。 首先,对于木葡聚糖/蒙脱土纳米复合材料,我们发现糖分子与土分子间有着很强的天然亲和力。研究证明它们之间的这种相互作用,热焓是主要的推动力,也就是糖和土分子间的相互作用势能。含有半乳糖残基的木葡聚糖分子(本文中亦称天然木葡聚糖分子)吸附到粘土表面后,分子构型呈现扁平状,半乳糖残基似有辅助木葡聚糖大分子吸附到粘土颗粒上的作用。 进一步研究发现,木葡聚糖分子在粘土表面上的吸附与溶液中抗衡离子的水和作用密切相关。在钾离子平衡的糖/粘土系统中,糖分子与土分子的相互作用最强,钠离子平衡的糖/粘土系统次之,紧接着是锂离子平衡的糖/粘土系统,最弱的是钙离子平衡的糖/粘土系统。研究发现,离子,水分子,以及糖分子在粘土层间的竞争机制在糖分子的粘附过程中起着重要的作用。 材料暴露于潮湿环境中的尺寸稳定性,也就是材料抗肿胀的能力是生物大分子/蒙脱土所构成的复合材料的重要参数。蒙脱土自身即使在很低的潮湿环境下就会有明显地膨胀现象,然而,对木葡聚糖/蒙脱土复合材料来说,尺寸稳定性可以在水和值低于50%以下有效保存。其夹层尺寸的稳定保持暗示了材料在这个程度的潮湿环境下的稳定性。然而,当水和值高于50%时,木葡聚糖/蒙脱土复合材料将出现明显的肿胀现象,表现在夹层尺寸的明显增大,且其膨胀速率与粘土自身的膨胀速率逐渐趋于相当水平。 其次,对于壳聚糖/蒙脱土复合材料,我们发现由电荷-电荷间直接产生地强烈的静电吸引作用是壳聚糖分子与蒙脱土分子相互粘附并构成复合材料的关键因素。通过改变壳聚糖分子的乙酰化程度(Degree of acetylation, DA)和质子化程度(Degree of protonation, DPr),糖分子与土分子的相互作用有着显著地不同。对于乙酰化程度(DA)高于50%的壳聚糖分子(亦成为甲壳素分子chitin, CHT),电中性的甲壳素分子与土分子间的强吸附作用源于乙酰基功能团与抗衡离子的强相关性。抗衡离子此时扮演着类似于“电子胶”的作用,可以有效地将电中性的甲壳素分子与土分子粘结在一起。类似地,当质子化程度最低时,亦即壳聚糖分子完全非质子化,即呈现电中性时,较差的糖/土吸附作用源于氨基功能团与抗衡离子的较弱的相关性。 进一步对壳聚糖/蒙脱土复合材料的分子系统进行应力应变计算发现,复合材料的力学性能直接受蒙脱土体积分数和其剥离程度的影响,通常,粘土的体积分数越大体系的力学性能越高,且剥离程度对材料的整体性能也有直接影响。因此,材料的结构与其性能的表征有着密切联系。 我们相信生物大分子与蒙脱土构成的生物复合材料有着光明的前景,可以取代石油提取物制成的塑料材料,并将能够广泛应用在日常生活中。通过实验技术的改善和应用分子模拟技术对复合材料体系中生物大分子,蒙脱土分子,水分子,离子,溶液环境等混合物质相互作用的理解增加,这种可再生的新材料将会得到重要改进,这也是整本论文的主旋律。
QC 20150520
Bio-nanocomposites
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