The History of the Development of Clay Mineralogy

Grim, Ralph E.

doi:10.1346/ccmn.1988.0360201

Cited by 42 publications

(33 citation statements)

References 18 publications

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“…Interpretation of the experimental results concerning the effect of WSPs and their mixtures on the stability of the kaolin hydrosuspension can be carried out on the basis of existing concepts of stability of polymer-containing dispersed systems [2], taking into account the chemical structure peculiarities of the mineral particles under consideration [19], as well as the characteristics of formation of the polymer adsorption layer [20].…”

Section: Resultsmentioning

confidence: 99%

“…Kaolin is a bi-layered clay mineral where layers of tetrahedral silicon-oxygen structures are neighboring with octahedral aluminum-oxygen-hydroxyl ones [19]. Polymer adsorption and, more specifically, polyelectrolyte adsorption, on the surface of clay particles greatly varies with sign and value of the electric charge of the particles, which very significantly depending on рН.…”

Section: Resultsmentioning

confidence: 99%

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Aggregation of Aqueous Kaolin Suspensions in the Presence of Cationic Polyelectrolytes, Anionic Polyelectrolytes and their Mixtures

et al. 2016

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The influence of anionic, cationic synthetic polyelectrolytes and their mixtures on the aggregation of kaolin hydrosuspension has been studied by means of spectrophotometry, electrophoresis and dynamic light scattering (DLS). An enhancement of the flocculating property of the cationic polyelectrolyte FO 4650 in accordance with its consumption increases from 0.77 mg/g to 7.7 mg/g has been found. At these conditions the relative size of floccules (R) increases from 1.0 to 13.0. The increase of the flocculating property accordingly to the increasing charge of anionic polyelectrolyte is observed in mixtures of cationic and anionic polyelectrolytes. The time dependences of R in presence of the weakly charged cationic polyelectrolyte mixtures reach a plateau region. This can be associated with the formation of electrostatic contacts between the solid surface and the polymer mixtures, as well as with stabilizing equilibrium conformation of macromolecules. It has been found that mixtures of oppositely charged polyelectrolytes lead to more efficient aggregation of particles than individual polyelectrolytes. This process is enhanced by the introduction primarily of the cationic polyelectrolyte and then the anionic one (R = 6-10). Use of the pre-formulated mixtures of polymers leads to the marked increase in degree of particle aggregation (R = 12). The reason is an interaction of kaolin particles with inter-polymer complex formed by electrostatic attraction of oppositely charged polyelectrolytes.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Aggregation of Aqueous Kaolin Suspensions in the Presence of Cationic Polyelectrolytes, Anionic Polyelectrolytes and their Mixtures

et al. 2016

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“…is responsible for the swelling of hectorite in water, since the interlaminar space is widened [13].…”

Section: Resultsmentioning

confidence: 99%

“…cations can easily be exchanged in water by other water-soluble inorganic, organic or organometallic cations. The dinuclear complex benzene ruthenium dichloride dimer dissolves in water with hydrolysis to give, with successive substitution of chloro ligands by aqua ligands, a mixture of mononuclear benzene ruthenium complexes being in equilibrium [13] 2? , which has been isolated as the sulfate and structurally characterized [15], is the major species present in the hydrolytic mixture over the pH range from 5 to 8 according to the NMR spectrum.…”

Section: Resultsmentioning

confidence: 99%

Shape- and Size-Selective Preparation of Hectorite-Supported Ruthenium Nanoparticles for the Catalytic Hydrogenation of Benzene

et al. 2009

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The cationic organometallic aqua complexes formed by hydrolysis of [(C 6 H 6 ) 2 RuCl 2 ] 2 in water, mainly [(C 6 H 6 2? , intercalate into white sodium hectorite, replacing the sodium cations between the anionic silicate layers. The yellow hectorite thus obtained reacts in water with molecular hydrogen (50 bar, 100°C) to give a dark suspension containing a black hectorite in which large hexagonally shaped ruthenium nanoparticles (20-50 nm) are intercalated between the anionic silicate layers, the charges of which being balanced by hydronium cations. If the reduction with molecular hydrogen (50 bar, 100°C) is carried out in various alcohols, spherical ruthenium nanoparticles of smaller size (3-38 nm depending on the alcohol) are obtained. In alcohols other than methanol, the reduction also works without H 2 under reflux conditions, the alcohol itself being the reducing agent; the ruthenium nanoparticles obtained in this case are spherical and small (2-9 nm) but tend to aggregate to form clusters of nanoparticles. Whereas the ruthenium nanoparticles prepared by reduction of the yellow hectorite in refluxing alcohols without hydrogen pressure are almost inactive, the nanoparticles formed by hydrogen reduction catalyze the hydrogenation of benzene to give cyclohexane under mild conditions (50°C) with turnover frequencies up to 6500 catalytic cycles per hour, the best solvent being ethanol.Dedicated to Professor C. N. R. Rao, pioneer of nanocluster chemistry, on the occasion of his 75th birthday.

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“…O termo surgiu a partir do depósito desse tipo de argila, localizado em Fort Benton, Wyoming nos Estados Unidos (GRIM, 1988;VALENZUELA-DIAZ, 1992;ALBANEZ, 2008 Tanto as bentonitas sódicas quanto as cálcicas e policatiônicas possuem ampla aplicação industrial. Entretanto, as bentonitas sódicas destacam-se pela sua importância na indústria de exploração do petróleo e de poços tubulares para produção de água como constituinte dos fluidos de perfuração, e também na produção de nanocompósitos poliméricos.…”

Section: Objetivos Específicosunclassified

Preparação e caracterização de nanocompósitos de polipropileno reforçados com argila verde lodo e fibra da castanha-do-brasil.

Gomes¹

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A Deus, por permitir a conclusão de mais uma etapa da minha vida rodeada de muita luz e bênçãos.Ao professor, mestre e orientador Francisco Rolando Valenzuela Díaz que com paciência, amor e sabedoria soube aguardar os percalços e estar presente nos momentos solicitados. Agradeço também pelo apoio logístico, no laboratório LPPS, que foi fundamental para a realização dessa pesquisa.À professora e importante colaboradora Graça Valenzuela que com sutis gestos e palavras me fez compreender o universo da pesquisa. Aos professores do doutorado, Denise Crocce Romano Espinosa, Jorge AlbertoSoares Tenório e Hélio Wierbeck que fizeram diferença ao ministrarem as disciplinas com amor e empenho para repassar seus conhecimentos. (Mateus 12,(46)(47)(48)(49)(50). RESUMOA incorporação de nanocargas minerais e vegetais em matriz polimérica tem sido estudada, principalmente, com o objetivo de melhorar as propriedades de desempenho mecânico dos polímeros para aplicações industriais diversas. As argilas organofilizadas e as fibras vegetais estão entre os materiais que se destacam como cargas adicionadas ao polímero para a formação de nanocompósitos. Essa área de estudo tem despertado interesse também devido à obtenção de melhorias de propriedades físicas, químicas e mecânicas desses materiais quando comparadas às dos materiais compósitos tradicionais. O objetivo da pesquisa foi estudar algumas dessas propriedades em nanocompósitos produzidos com polipropileno, argila esmectítica brasileira e fibra do ouriço da castanha-do-brasil, com ênfase na melhora das propriedades mecânicas. Inicialmente, os materiais componentes foram caracterizados por diversos ensaios, tais como, difração de raios X, granulometria, infravermelho, microscopia eletrônica de varredura, temperatura de degradação térmica, além de ensaios específicos para medir características individuais da argila, como, viscosidade Fann, inchamento de Foster, limite de plasticidade, fluorescência de raios X, entre outros. Posteriormente, o polipropileno graftizado com anidrido maleico (PP-g-MA) foi incorporado ao PP puro (PP), em extrusora dupla rosca, nas proporções de 5%, 10% e 20% em peso e injetados os corpos de prova para os ensaios de tração e impacto. A partir dos resultados das propriedades mecânicas definiu-se o uso de 5% de PP-g-MA para preparação dos nanocompósitos definitivos. Finalmente, variou-se a quantidade de fibra na composição. Foram obtidos nanocompósitos de polipropileno (PP) e 5% PPg-MA reforçado com 5% em peso da argila organofilizada e fibra do ouriço da castanha-do-brasil em três proporções 5%, 10% e 15% em peso. As amostras foram caracterizadas por diferentes técnicas (DRX, MEV, FTIR, TG/DSC) e medidas as resistências mecânicas à tração, flexão e impacto. Todos os nanocompósitos apresentaram aumento na resistência mecânica quando comparados ao polímero sem argila e fibra.Palavras-Chave: Argilas. Argilas organofílicas. Nanocompósitos poliméricos. Fibras naturais. ABSTRACTThe incorporation of vegetable and mineral nanofillers in polymer matrix has been st...

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The History of the Development of Clay Mineralogy

Cited by 42 publications

References 18 publications

Aggregation of Aqueous Kaolin Suspensions in the Presence of Cationic Polyelectrolytes, Anionic Polyelectrolytes and their Mixtures

Aggregation of Aqueous Kaolin Suspensions in the Presence of Cationic Polyelectrolytes, Anionic Polyelectrolytes and their Mixtures

Shape- and Size-Selective Preparation of Hectorite-Supported Ruthenium Nanoparticles for the Catalytic Hydrogenation of Benzene

Preparação e caracterização de nanocompósitos de polipropileno reforçados com argila verde lodo e fibra da castanha-do-brasil.

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